Nikon Micro-Nikkor, Nikkor 105mm ~ point light source comparison

For many years I looked at just one dimension of commercially available optics - resolution.  Now I continue to look at other aspects of optical performance.  For this series I look at under, neutral, and over corrected spherical aberration in out of focus rendition on subject matter behind the point of focus.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, +1 EV
• Big Beefy Manfrotto tripod
• Lenses using with a Lens Turbo II focal reducer -
• Nikon Micro-Nikkor 105mm f/4 Ai
• Nikon Nikkor 105mm f/2.5 P pre-Ai (early Sonnar design)
• Nikon Nikkor 105mm f/2.5 Ai (later modified Sonnar, slightly more symmetrical design)
• NOTE1: Lenses were shot at their widest apertures only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

  Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

NOTE: I feel the Lens Turbo II focal reducer adds a bit of under-corrected spherical aberration.

 I had expected the Micro-Nikkor to show similar neutral very smooth out of focus rendition to the pair of 55mm Micro-Nikkors I looked at.  Alas, this is not the case.

These three Nikon Nikkor, Micro-Nikkor 105mm f/4 and f/2.5 P pre-Ai and Ai lenses show under corrected spherical aberrations.  At the point of focus, the Micro-Nikkor is one of the sharpest lenses I've looked at.  But that's not what this comparison is about.

In normal photography I would expect, based on these comparisons, that there will be a very smooth and delicate (to use Nikon's own word on the topic) out of focus field rendition, with the f/4 Micro-Nikkor showing a stronger "condom ring" (which will contribute to a distracting out of focus rendition) than the two f/2.5 lenses (compare the smooth, rounded edges of the out of focus disks of the f/2.5 lenses against the sharp edged disks of the Micro-Nikkor).


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Nikon Nikkor 28mm lenses ~ point light source comparison

Returning home after passing a winter in the south I am inspired to continue my look into point light source in-focus, out of focus comparisons.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, +1 EV
• Big Beefy Manfrotto tripod
• Nikon lenses using with a Lens Turbo II focal reducer -
• Nikon Nikkor 28mm f/2.8 Ai
• Nikon Nikkor 28mm f/3.5 H pre-Ai
• Nikon Nikkor 28mm f/3.5 PC
• NOTE1: Lenses were shot at their widest apertures only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

  Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

NOTE: I feel the Lens Turbo II focal reducer adds a bit of under-corrected spherical aberration.

The Nikon Nikkor 28mm f/2.8 Ai shows under-corrected spherical aberrations with just a moderately strong bright ring around the edge of the image circle.  In normal photography I would expect, based on these comparisons, that there will be a hint of a "busy" rendition in a smooth, delicate out of focus field.

The Nikon Nikkor 28mm f/3.5 H shows stronger over-corrected spherical aberration with a fairly bright edge ring on out of focus disks.  The center, as with it's brother lens the f/2.8, shows under-corrected spherical aberration.  In normal photography I would expect, based on these comparisons, that there will be a somewhat confusing rendition of the out of focus field, mixing the two aberration types as this lens does.

The Nikon Nikkor 28mm f/3.5 PC (perspective control) lens shows moderate under-corrected spherical aberration with a hint of a bright ring around the edge of the out of focus disk.  In normal photography I would expect the lens to be a hint of a "busy" field against a smooth, delicate out of focus rendition.


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Sigma 19mm, 30mm, Sony 50mm ~ point light source comparison

Having looked at the out of focus rendition of vintage Nikon lenses, I wanted to see what, if anything, had changed over the years of optical design and look at three current lenses.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, +1 EV
• Big Beefy Manfrotto tripod
• Lenses designed for Sony E-mount APS-C cameras -
• Sigma 19mm f/2.8 EX DN E
• Sigma 30mm f/2.8 EX DN E
• Sony 50mm f/1.8 SEL OSS
• NOTE1: Lenses were shot at their widest apertures only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

  Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

The Sigma 19mm f/2.8 EX DN E out of focus rendition confuses me.  There is a slight bright ring around the out of focus disk, along with a bright center with a dark whole in the middle.  The further out of focus the point, the more "choppy" the disk becomes.  Concentric circles form the farther out of focus the disk becomes.

The Sigma 30mm f/2.8 EX DN E out of focus rendition confuses me just like the 19mm Sigma does.  There is a bright outter ring to the disk, followed by a brighter center with a dark hole in the middle.  The "choppy" field effect across the disk is less than with the 19mm, but it's still clearly visible.

The Sony 50mm f/1.8 SEL OSS starts out having a nice smooth disk with a brighter center just like the lens is under-corrected.  But the further out of focus the point is, the stronger the outter ring becomes.  It's as if the Sony lens is both under and over-corrected.


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Nikon Nikkor 100mm to 300mm lenses ~ a closer look

It so happens that I picked up a rather inexpensive (supposedly in need of repair, but in reality didn't need any such thing) 100-300mm Nikon Nikkor f/5.6 AiS.

I've recently been impressed by the Nikon 75-150mm E-series (yes! it's true) and the Nikkor 80-200mm f/4.5 N Ai zoom lenses.  None of the more modern Canon EOS zoom lenses were ever this close to being wonderfully razor sharp at the point of focus and creamy smooth in the out of focus regions.  So when this 100-300mm AiS Nikkor came along for so little money, I had to have a look at it's performance.

Setup -

• Sony A6000, 100ISO, 2 second delay timer, RawTherapee conversion software 
• Big Beefy Manfrotto tripod 
• Lenses compared
• Nikon Nikkor 105mm f/2.5 Ai
• Nikon Nikkor 135mm f/3.5 Ai
• Super-Takumar 200mm f/4
• Nikon Nikkor 300mm f/4.5 pre-Ai 
• Nikon Nikkor 100-300mm f/5.6 AiS 
• compared at 100mm
• 135mm
• 200mm
• 300mm
• Lens Turbo II adapter with the Nikkors, but not the Takumar

Comparison Results -
[If you click on the image it'll take you to the Flickr hosting site. Once there, look at the file at full resolution. In many cases the differences between lenses is small and likely can't be seen until you take a squint at the comparison at 100 percent.]



Comments -

Comparing the Nikon Nikkor 100-300mm f/5.6 AiS to a Nikon Nikkor 105mm f/2.5 Ai, I see that both the 105mm and 100-300mm lenses are both very sharp in the center of the frame.  At the edges, the 100-300mm lens remains very sharp.  It appears the 105mm f/2.5 Ai suffers from a bit of field curvature as the edges of the frame are clearly not as sharp as the zoom on this 2D subject.

Comparing the Nikon Nikkor 100-300mm f/5.6 AiS to a Nikon Nikkor 135mm f/3.5 Ai, I see that both the 135mm and 100-300mm lenses are very sharp in the center of the frame.  At the edges, the 135mm lens remains very sharp, with the 100-300mm lens trailing ever so slightly in terms of absolute resolution.

Comparing the Nikon Nikkor 100-300mm f/5.6 AiS to a Super-Takumar 200mm f/4 M42 lens, I see that the 200mm is very slightly sharper than the 100-300mm lens in the center of the frame.  At the edges, the 200mm lens is very slightly less sharp than the 100-300mm lens.

Comparing the Nikon Nikkor 100-300mm f/5.6 AiS to a Nikon Nikkor 300mm f/4.5 pre-Ai, I see that the 100-300mm lens is very sharp straight across the field.  The fixed focal length 300mm f/4.5 lens is clearly behind the zoom in terms of resolution.

Overall, the Nikon Nikkor 100-300mm f/5.6 AiS lens is truly outstanding at f/5.6 (which is wide open with this optic) and f/8.  In the center it can keep up with the fixed focal length lenses I compared this zoom to.  The optic's field is surprisingly flat and exceeds three of the four fixed focal length lenses in terms of flat field resolution at the extreme edges of the frame.

So, how much did this super sharp wonder zoom set me back?   30Euros.

Nikon Nikkor 100-300mm f/5.6 Ai ~ point light source comparison

For many years I looked at just one dimension of commercially available optics - resolution.  Now I wanted to start looking at other aspects of optical performance.  For this series I look at spherical aberration (looking for under, neutral, or over correction) in out of focus rendition on subject matter behind the point of focus.

Setup -

• Sony A6000, ISO 100, 2 second timer
• Big Beefy Manfrotto tripod
• Lens using with a Lens Turbo II focal reducer -
• Nikon Nikkor 100-300mm f/5.6 Ai zoom

• NOTE1: Lens was shot at the widest aperture only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

 Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

NOTE: I feel the Lens Turbo II focal reducer adds a bit of under-corrected spherical aberration.

The Nikon Nikkor 100-300mm f/5.6 Ai zoom at 100mm shows a flat out of focus disk.  The further out of focus a dot becomes, the more a slight under-corrected spherical aberration in the out of focus regions is revealed.  Based on this comparison, in normal photographic use this lens at this focal length should produce a smooth out of focus rendition.

At 200mm, this Ai zoom continues to show a flat neutral disk.  The further out of focus a dot becomes, the more a slight under-corrected spherical aberration in the out of focus regions is revealed.  Under normal photographic conditions I would expect that this lens at 200mm will continue to show a smooth out of focus rendition.

At 300mm, this Ai zoom shows very neutral out of focus rendition.  Under normal photographic conditions I would expect this lens at this focal length to produce extremely smooth out of focus rendition.


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Nikkor Soft filters ~ another look

I quickly realized that using a point light source to explore how Nikkor Soft #1 and #2 filters might influence out of focus regions was insufficient.  Since the camera was out and the pears were in season, I took a series of images to illustrate optical renditions a bit more clearly.

What I wanted to see was what effect, if any, a soft filter might have on out of focus rendition comparing a neutrally corrected for spherical aberration against an under-corrected lens.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, -1 EV
• Big Beefy Manfrotto tripod
• Lenses using with a Lens Turbo II focal reducer -
• Nikon Micro-Nikkor 55mm f/2.8 Ai (neutrally corrected spherical aberration)
• Nikon Nikkor 85 f/1.8 K pre-Ai (under-corrected spherical aberration)

• NOTE1: Lenses were shot at the widest aperture only
• RawTherapee to convert RAW files into black and white and to set the black levels

 Comparison -

If you click on the following images you can inspect them at 100 percent.


Nikon Micro-Nikkor 55mm f/2.8 Ai - no filter

Nikon Micro-Nikkor 55mm f/2.8 Ai - #1 Soft filter

Nikon Micro-Nikkor 55mm f/2.8 Ai - #2 Soft filter

Nikon Nikkor 85mm f/1.8 K ~ no filter

Nikon Nikkor 85mm f/1.8 K ~ #1 Soft filter

Nikon Nikkor 85mm f/1.8 K ~ #2 Soft filter


Comments -

Differences between the neutrally and under-corrected spherical aberration out of focus renditions can be subtle.  Look at the out of focus stems and the shadows on the left side of the pears.  If you study the images carefully, you will begin to see the real world effects of out of focus rendition optical corrections.

When using Nikkor Soft filters, you can see how mid-tone contrast is lowered as well as reducing resolution.  Looking carefully, again, you can begin to see how the light/dark transitions are different between the two lenses.

Here is one final example.  It was made using a Nikon Nikkor 50mm f/1.8 AiS which is under-corrected for spherical aberration in the out of focus areas behind the point of focus.  I added a Nikkor #1 Soft filter and shot the lens wide open to get the maximum out of focus rendition effect.




Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Nikkor Soft filters 1 and 2 ~ point light source comparison

Here's a question: What effect might a soft focus filter have on out of focus rendition?  I decided to have a look.

For many years I looked at just one dimension of commercially available optics - resolution.  Now I wanted to start looking at other aspects of optical performance.  For this series I look at spherical aberration (looking for under, neutral, or over correction) in out of focus rendition on subject matter behind the point of focus.

More specifically, I wanted to see how Nikkor soft filters might influence the out of focus regions of under-corrected spherical aberration lenses.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, -1 EV
• Big Beefy Manfrotto tripod
• Lenses using with a Lens Turbo II focal reducer -
• Nikon Nikkor 50mm f/1.8 AiS
• Nikon Micro-Nikkor 55mm f/2.8 Ai
• Nikon Nikkor 85 f/1.8 K pre-Ai

• NOTE1: Lenses were shot at the widest aperture only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

 Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

NOTE: I feel the Lens Turbo II focal reducer adds a bit of under-corrected spherical aberration.

The Nikon Nikkor soft filters appear to mute out of focus disk intensity.  The stronger the number filter, the stronger the effect.  In general, the basic underlying effect of spherical aberration appears to remain, such as the bright center spot that is common to under-corrected lenses.

So, what have I shown?  Not much that is readily/easily visible from the point light source comparison.  Based on experience, however, the effects of using a soft filter are more easily judged across a full image.  Even though I doubt I will significantly deepen my understanding of soft filters, I will take a look at this effect in a future post.


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Nikon Nikkor 80-200mm f/4.5 N Ai zoom ~ point light source comparison

I heard that spending time along the Cote d'Azur could be good for one's art.  While I make no claims to be an artist, spending time in the sun along the Mediterranean Sea inspired me to more deeply consider optics as applied to the craft of photography.

For many years I looked at just one dimension of commercially available optics - resolution.  Now I wanted to start looking at other aspects of optical performance.  For this series I look at spherical aberration (looking for under, neutral, or over correction) in out of focus rendition on subject matter behind the point of focus.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, -1 EV
• Big Beefy Manfrotto tripod
• Lens using with a Lens Turbo II focal reducer -
• Nikon Nikkor 80mm - 200mm f/4.5 N Ai zoom

• NOTE1: Lens was shot at the widest aperture only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

 Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

NOTE: I feel the Lens Turbo II focal reducer adds a bit of under-corrected spherical aberration.

The Nikon Nikkor 80mm - 200mm f/4.5 N Ai zoom at 80mm and 135mm shows slight under-corrected spherical aberration in the out of focus regions.  Based on this comparison, in normal photographic use this lens at this focal length should produce a very smooth out of focus rendition.

At 200mm, this Ai zoom shows very very neutral out of focus rendition.  Under normal photographic conditions I would expect this lens at this focal length to produce extremely smooth out of focus rendition.


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Nikon 75-150mm f/3.5 E-series zoom ~ point light source comparision

I heard that spending time along the Cote d'Azur could be good for one's art.  While I make no claims to be an artist, spending time in the sun along the Mediterranean Sea inspired me to more deeply consider optics as applied to the craft of photography.

For many years I looked at just one dimension of commercially available optics - resolution.  Now I wanted to start looking at other aspects of optical performance.  For this series I look at spherical aberration (looking for under, neutral, or over correction) in out of focus rendition on subject matter behind the point of focus.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, -1 EV
• Big Beefy Manfrotto tripod
• Lens using with a Lens Turbo II focal reducer -
• Nikon E-series 75mm - 150mm f/3.5 AiS zoom

• NOTE1: Lens was shot at the widest aperture only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

  Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

NOTE: I feel the Lens Turbo II focal reducer adds a bit of under-corrected spherical aberration.

The Nikon 75mm to 150mm f/3.5 AiS zoom at 75mm shows under-corrected spherical aberration in the out of focus regions.  Based on this comparison, in normal photographic use this lens at this focal length should produce a very smooth out of focus rendition.

At 100mm, this AiS zoom continues to show under-corrected spherical aberration.  Under normal photographic conditions I would expect that this lens at 100mm will continue to show a very smooth out of focus rendition.

At 150mm, this AiS zoom shows very very neutral out of focus rendition.  Under normal photographic conditions I would expect this lens at this focal length to produce extremely smooth out of focus rendition.


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Nikon Nikkor 35mm f/3.5 - 105mm f/4.5 zoom ~ point light source comparison

I heard that spending time along the Cote d'Azur could be good for one's art.  While I make no claims to be an artist, spending time in the sun along the Mediterranean Sea inspired me to more deeply consider optics as applied to the craft of photography.

For many years I looked at just one dimension of commercially available optics - resolution.  Now I wanted to start looking at other aspects of optical performance.  For this series I look at spherical aberration (looking for under, neutral, or over correction) in out of focus rendition on subject matter behind the point of focus.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, -1 EV
• Big Beefy Manfrotto tripod
• Lenses using with a Lens Turbo II focal reducer -
• Nikon Nikkor 35mm f/3.5 - 105mm f/4.5 Ai zoom

• NOTE1: Lens was shot at the widest aperture only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

  Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

NOTE: I feel the Lens Turbo II focal reducer adds a bit of under-corrected spherical aberration.

The Nikon Nikkor 35mm f/3.5 to 105mm f/4.5 Ai zoom at 35mm shows under-corrected spherical aberration in the out of focus regions.  Based on this comparison, in normal photographic use this lens at this focal length should produce a fairly smooth out of focus rendition.

At 50mm, this Ai zoom shows under-corrected spherical aberration with a somewhat bright over-corrected spherical aberration out of focus disk edge.  Under normal photographic conditions I would expect that this lens at 50mm might product a "busy" and slightly confusing out of focus rendition.

At 105mm, this Ai zoom shows very neutral out of focus rendition.  Under normal photographic conditions I would expect this lens at this focal length to produce very smooth out of focus rendition.


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Nikon and Schneider 135mm lenses ~ point light source comparison

I heard that spending time along the Cote d'Azur could be good for one's art.  While I make no claims to be an artist, spending time in the sun along the Mediterranean Sea inspired me to more deeply consider optics as applied to the craft of photography.

For many years I looked at just one dimension of commercially available optics - resolution.  Now I wanted to start looking at other aspects of optical performance.  For this series I look at  spherical aberration (looking for under, neutral, or over corrections) in out of focus rendition on subject matter behind the point of focus.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, -1 EV
• Big Beefy Manfrotto tripod
• Lenses using with a Lens Turbo II focal reducer -
• Nikon Nikkor 135mm f/3.5 Ai
• Nikon Nikkor 135mm f/2.8 Q Ai'd

• Lens using a straight through adapter (ie: no focal length reduction to APS-C sensor) -
• Schneider Keuznach Tele-Xenar 135mm f/3.5 (late 1950's to early 1960's)

• NOTE1: Lenses were shot at their widest apertures only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

  Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

NOTE: I feel the Lens Turbo II focal reducer adds a bit of under-corrected spherical aberration.

The Nikon Nikkor 135mm f/3.5 Ai lens shows under corrected spherical aberrations.  In normal photography I would expect, based on these comparisons, that there will be a very smooth and delicate (to use Nikon's own word on the topic) out of focus field rendition.

The Nikon Nikkor 135mm f/2.8 Q Ai'd lens shows under corrected spherical aberrations. The out of focus disk shows variable luminosity and is not as smooth as the f/3.5 Ai.  In normal photography I would expect, based on these, that there will be a smooth and delicate (to use Nikon's own word on the topic) out of focus field rendition.

The Schneider Kreuznach Tele-Xenar 135mm f/3.5 lens shows over corrected spherical aberrations. In normal photography I would expect, based on these comparisons, that there will be the tendency to hollow out highlights and brighter areas of the out of focus field rendition.  Some would call this a tendency toward a "harsh" out of focus rendition.


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Nikon Nikkor 105mm f/2.5 P and Ai ~ point light source comparison

I heard that spending time along the Cote d'Azur could be good for one's art.  While I make no claims to be an artist, spending time in the sun along the Mediterranean Sea inspired me to more deeply consider optics as applied to the craft of photography.

For many years I looked at just one dimension of commercially available optics - resolution.  Now I wanted to start looking at other aspects of optical performance.  For this series I look at under, neutral, and over corrected spherical aberration in out of focus rendition on subject matter behind the point of focus.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, -1 EV
• Big Beefy Manfrotto tripod
• Lenses using with a Lens Turbo II focal reducer -
• Nikon Nikkor 105mm f/2.5 P pre-Ai (early Sonnar design)
• Nikon Nikkor 105mm f/2.5 Ai (later modified Sonnar, slightly more symmetrical design)
• NOTE1: Lenses were shot at their widest apertures only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

  Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

NOTE: I feel the Lens Turbo II focal reducer adds a bit of under-corrected spherical aberration.

Both Nikon Nikkor 105mm f/2.5 P pre-Ai and Ai lenses show under corrected spherical aberrations.  In normal photography I would expect, based on these comparisons, that there will be a very smooth and delicate (to use Nikon's own word on the topic) out of focus field rendition.


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Nikon Nikkor 85mm, Pentax 85mm Soft ~ point light source comparison

I heard that spending time along the Cote d'Azur could be good for one's art.  While I make no claims to be an artist, spending time in the sun along the Mediterranean Sea inspired me to more deeply consider optics as applied to the craft of photography.

For many years I looked at just one dimension of commercially available optics - resolution.  Now I wanted to start looking at other aspects of optical performance.  For this series I look at under, neutral, and over corrected spherical aberration in out of focus rendition on subject matter behind the point of focus.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, -1 EV
• Big Beefy Manfrotto tripod
• Lenses using with a Lens Turbo II focal reducer -
• NikonNikkor 85mm f/1.8 K pre-Ai
• Pentax 85mm f/2.2 Soft in Nikon F mount (rare? I've never seen this lens in a Nikon mount before)
• NOTE1: Lenses were shot at their widest apertures only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

  Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

NOTE: I feel the Lens Turbo II focal reducer adds a bit of under-corrected spherical aberration.

The Nikon Nikkor 85mm f/1.8 pre-Ai shows under corrected spherical aberrations.  In normal photography I would expect, based on these comparisons, that there will be a smooth out of focus field rendition.

The Pentax 85mm f/2.2 Soft shows very strongly under spherical aberration corrections.  In normal photography I would expect, based on these comparisons, that there will be an extremely smooth and very soft rendition across the field.

There is something interesting about the Pentax soft that should be carefully noted.  The point light source remains strongly represented in the center of the out of focus disk well beyond what might be considered the normal point of focus. This is physical evidence for how a severely under-corrected spherical aberration optic can exhibit extreme depths of field, even when the lens is shot wide open.


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Nikon Micro-Nikkor 55mm lenses ~ point light source comparison

I heard that spending time along the Cote d'Azur can be good for one's art.  While I make no claims to be an artist, spending time in the sun along the Mediterranean Sea inspired me to more deeply consider optics as applied to photography.  For many years I have looked at one dimension of commercially available optics.  Now I wanted to start looking at other aspects of optical performance.  For this series I look at under, neutral, and over corrected spherical aberration in out of focus rendition on subject matter behind the point of focus.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, -1 EV
• Big Beefy Manfrotto tripod
• Nikon lenses using with a Lens Turbo II focal reducer -
• Nikon Micro-Nikkor 55mm f/2.8 Ai
• Nikon Micro-Nikkor 55mm f/3.5 pre-Ai
• NOTE1: Lenses were shot at their widest apertures only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

  Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

NOTE: I feel the Lens Turbo II focal reducer adds a bit of under-corrected spherical aberration.

The Nikon Nikkor 55mm f/3.5 pre-Ai shows very very slight over corrected spherical aberrations.  In normal photography I would expect, based on these comparisons, that there will be a smooth out of focus field rendition.

The Nikon Nikkor 55mm f/2.8 Ai shows quite neutral spherical aberration corrections with just a hint of under-corrected behavior in the center of the out of focus disk.  In normal photography I would expect, based on these comparisons, that there will be an extremely smooth out of focus field rendition.

There is something interesting about the Micro-Nikkor 55mm macro lenses.  They are pretty neutral in their renderings.  These are the first (though not the only) lenses I encountered that exhibit this kind of behavior.  In practical use I loved the f/3.5 version in this regard for many of the images I made along the Cote d'Azur this winter.  Now, after these comparisons, I have mounted the f/2.8 version on a camera and have already found it's out of focus rendering to be as beautiful as I expected/hoped it would be.


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Nikon Nikkor 24mm, (2)28mm, 35mmPC ~ point light source comparison

Returning home after passing a winter in the south I am inspired to continue my look into point light source in-focus, out of focus comparisons.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, -1 EV
• Big Beefy Manfrotto tripod
• Nikon lenses using with a Lens Turbo II focal reducer -
• Nikon Nikkor 24mm f/2.8 Ai
• Nikon Nikkor 28mm f/3.5 pre-Ai
• Nikon Nikkor 28mm f/3.5 PC
• Nikon Nikkor 35mm f/2.8 PC
• NOTE1: Lenses were shot at their widest apertures only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

  Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

NOTE: I feel the Lens Turbo II focal reducer adds a bit of under-corrected spherical aberration.

The Nikon Nikkor 24mm f/2.8 Ai shows under-corrected spherical aberrations with just a hint of a bright ring around the edge of the image circle.  In normal photography I would expect, based on these comparisons, that there will be an ever so slightly "busy" rendition in a smooth, delicate out of focus field.

The Nikon Nikkor 28mm f/3.5 H shows strong over-corrected spherical aberration.  I find this interesting as this was designed by the man who developed the 105mm f/2.5 P and 50mm f/1.4 S Nikkors.  He clearly understood the effects of under-corrected spherical aberration on out of focus rendering.  In normal photography I would expect, based on these comparisons, that there will be a strong "soap bubble bokeh" rendition of the out of focus field.

The Nikon Nikkor 28mm f/3.5 PC (perspective control) lens shows moderate under-corrected spherical aberration with a hint of a bright ring around the edge of the out of focus disk.  In normal photography I would expect the lens to be slightly "busy" against a smooth out of focus field rendition.

The Nikon Nikkor 35mm f/2.8 PC (perspective control) lens shows moderate under-corrected spherical aberration with a somewhat strong bright ring around the edge of the out of focus disk.  In normal photography I would expect the lens to be "busy" against a somewhat smooth out of focus field rendition.


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Nikon Nikkor 50mm and Micro-Nikkor 55mm ~ point light source comparison

Returning home after passing a winter in the south I am inspired to continue my look into point light source in-focus, out of focus comparisons.

Setup -

• Sony NEX5T, ISO 100, 2 second timer, -1 EV
• Big Beefy Manfrotto tripod
• Nikon lenses using with a Lens Turbo II focal reducer -
• Nikon Nikkor 50mm f/1.8 AiS "pancake"
• Nikon Nikkor 50mm f/2 H pre-Ai single coated
• Nikon Nikkor 50mm f/2 Ai multi-coated
• Nikon Micro-Nikkor 55mm f/3.5 pre-Ai
• NOTE1: Lenses were shot at their widest apertures only
• NOTE2: Out of focus samples are from points _behind_ the point of focus to compare background out of focus rendition
• RawTherapee to convert RAW files into black and white and to set the black levels

  Comparison -

If you click on the following image you can inspect it at 100 percent.



Comments -

NOTE: I feel the Lens Turbo II focal reducer adds a bit of under-corrected spherical aberration.

The Nikon Nikkor 50mm f/1.8 AiS "pancake" lens shows under-corrected spherical aberration from the moment the point light source goes out of focus.  The brighter ring around the outside of the image circle seems to indicate a bit of over-corrected spherical aberration as well.  In normal photography I would expect, based on these comparisons, that there will be an ever so slightly "busy" rendition in a smooth, delicate out of focus field.

The Nikon Nikkor 50mm f/2 H pre-Ai single coated lens shows rather strong under-corrected and over-corrected spherical aberration.  In normal photography I would expect, based on these comparisons, that there will be a somewhat strong "busy" rendition set against a smooth, nuanced out of focus field.

The Nikon Nikkor 50mm f/2 H Ai multi-coated lens shows rather strong over-corrected spherical aberration.  In normal photography I would expect, based on these comparisons, that there will be a strong "busy" rendition of an out of focus field.  It would expect strong "soap bubble bokeh" rendition.

The Nikon Micro-Nikkor 55mm f/3.5 pre-Ai single coated lens shows neutrally corrected spherical aberration.  In normal photography I would expect, based on these comparisons, that there will be a smooth out of focus field.


Resources -

For further information on how the topic of out of focus rendition, optical properties, and Nikon lens design history, please refer to the following -

A PhD thesis on the impact of "soft focus" lenses on the history of photography - http://research-repository.st-andrews.ac.uk/handle/10023/505

An excellent starting point for understanding out of focus rendition (I might not completely agree with his interpretations/observations, but his foundation of understanding is quite good) - http://jtra.cz/stuff/essays/bokeh/

Nikon lens design histories - https://imaging.nikon.com/history/story/

Point light source discussions - https://www.dpreview.com/forums/thread/4031515

Zeiss comments on optical design -  https://lenspire.zeiss.com/photo/en/article/how-does-zeiss-define-bokeh-an-interview-with-dr-stefan-ballmann

Metabones Focal Reducer whitepaper - https://www.metabones.com/assets/a/stories/Speed%20Booster%20White%20Paper.pdf

Something other than resolution and sharpness...

As you are no doubt aware, there are many ways an interested party can consider photographic optical performance.

For going on thirty years I've been looking at camera system resolution.  Now I would like to begin to consider how lenses transition from sharp to out of focus regions behind the point of focus.

There is a useful approach outlined by Mariane Oelund in a discussion thread on DPReview.  For my look at the question I displayed a 2 pixel wide "dot" on a computer screen and photographed it with lens apertures set to wide open from sharp to increasingly out of focus.

Here are the results for a few lenses shot wide open, with and without a Lens Turbo II focal reducer.



 Comments and Observations -

The immediate question is how to interpret what we see?  Zeiss provides an good starting point.  On a practical level, Jakub Travnik provides a useful illustration. 

If an out of focus circle is bright around the outside edges, it is said to be over-corrected for spherical aberration.  Some people refer to this as "soap bubble bokeh."

If the out of focus circle is evenly lit across the disk, it is said to be neutrally corrected.  Zeiss currently champions this approach to lens design.

If the out of focus circle is bright in the center and less bright toward the edges then the lens is said to be under-corrected for spherical aberration.

With these things in mind, we can see that my Nikon Nikkor 50mm and 55mm lenses used with a Lens Turbo II focal reducer increases under-corrected spherical aberration.  The Nikon Nikkor 105mm and 135mm lenses seem to be under-corrected for spherical aberration to very similar degrees when used with or without the Lens Turbo II focal reducer.

An important question is how does this work in the real world?

We already have a hint from the way the over-corrected spherical aberrations are interpreted photographically.  That is, such lenses create "soap bubble bokeh" in the out of focus regions.

For neutrally corrected lenses we have two very good examples.  One is Zeiss' own 135mm f/2 and, perhaps surprisingly, the Rokinon/Samyang 135mm f/2.  These lenses are said to provide neutrally corrected out of focus renditions.

Lastly, the thing that started me on this quest (which I am only now beginning and am by no means understanding as fully as I would like) were comments made about the history of Nikon lens designs.  Read carefully I found out that Nikkor designers from the outset deliberately under-corrected for spherical aberrations in certain designs (1950's Sonnar formula RF lenses - 5cm, 8.5cm, and 105cm as well as many standard and longer than stardard focal length lenses for the F-series SLRs).  Nikon appears to have continued this approach up until rather recently.

Nikon designers felt that under-corrected spherical aberrations in the out of focus areas behind the point of focus lead to a "delicate rendition" of a scene.  This property of a lens would change as the aperture was stopped down.  One or two stops down from wide open would change a lenses character to being sharp across the field and quickly reduced/eliminated spherical aberration in out of focus areas.

At the same time I read the Nikkor lens history site I stumbled upon information provided by the Metabones adapter manufacturer.  They suggest that their focal reducer adds a little under-corrected spherical aberration.  While the Zhongyi Lens Turbo II I use was likely not designed by Metabones, I'm wondering if it too doesn't add a bit of spherical aberration to some lenses?  Nearly all of my 50mm-ish lenses seem to "improve" their out of focus renditions when mounted on the Lens Turbo II.

I really appreciate Nikon's lens designer comments and feel they have given us an idea of why their lenses behave the way they do.  If anyone knows of similar sources of lens design choices for Zeiss, Leica, Canon, and other photographic application lens manufacturers, please let me know.

Now Available ~ le Mans Classic ~ dans les Paddocks ~ 2018

I have published a second book.  This is also from le Mans Classic.  This time its from year 2018.

As with the first book, the 2018 book is rendered in black and white.  The print edition is high quality and uses heavy paper that gives the book a certain "heft."

The print copy is rather expensive, as far as books go.  So if you'd like to see what the book is about, consider the PDF edition that is also available through Blurb.

Thanks for looking.

Capturing the "glow" of old Black and White photographs - Vastly Simplified Procedure

In May 2018 I wrote about black and white conversions in digital.  It was a very early effort and I see I rather missed the mark.

It is going on a year, now, and I am very much enjoying the process.  I find I have a renewed enthusiasm for black and white photography.  And I find that converting digital files is, in general, nowhere near as complicated as I first wrote.

So here is a vastly simplified process, complete with examples of the image and the curves function that I use to make digital black and white images "glow" like old silver halide prints.

Step One - 

Start with a color image where the highlights and shadows are not clipped.

Step Two -

Convert the color image to black and white.  In this example I simply desaturated the image.

Step Three - 

Open the curves function, grab the middle of the curve, and raise it.

If the image you are working on looks like it might benefit from being lighter or brighter, simply raise the center of the curves more.  I deliberately "overcooked" the effect to illustrate the effect.

Example Image -

Here is an example of something that I feel fully expresses the gray tones and looks a lot like something I would have printed back in the day of film.

Comments - 

Desaturating a color image to make a black and white photograph in digital photography creates a dead, lifeless image.  Just look at the results of Step Two.  Ghastly, I say.

Now take a look at the results of Step Three (first image).  The image is starting to "sing."  The effect is now beginning to mirror film photography.

Important Observation: Scanning a black and white film negative will give the same results as in Step Two above with the very same ghastly results.  The "magic" is how the tones are raised when a print is made.  Silver halide papers effectively raised the mid-tones.

Borrowing further from film photography, keep in mind that the viewer's eye will seek lighter portions of an image.  This is why the classic technique is to vignette the edges of the frame.  I find that around a 1/2 stop works well for the kinds of subjects I photograph.

Once you have these basic steps sorted out you can now move the brightness slider to lighten or darken the overall image.  You can also move the contrast slider to increase or decrease contrast.  Using the two sliders a person can quickly find the balance between tones and contrast that appeals to them.

The topic of filtering an image can quickly become complex, so I make the following over-simplification to start from.  If a starting image was made out of doors under bright sunlight I find that using a yellow, orange, or red digital filter to convert the file can have some benefit in darkening the sky, just like in film photography.   

For myself I feel I have made a lot of progress using the simple three step technique illustrated above and tend not to mess around with contrast while in some cases gently moving the brightness slider.

Macro vs Non-Macro ~ a small comparison

Something I've wondered about for far too long is what, if any, meaningful difference is there between a dedicated macro and "normal" lenses when shooting close-up subjects?  So, one dull morning I grabbed a few "supplies" and set about looking at what kind of answer I might come up with.

Setup -

• Sony NEX-5T, 100ISO
• Big Beefy Manfrotto tripod 
• Nikon lenses -
• Micro-Nikkor 55mm f/3.5 pre-Ai
• Nikkor 105mm f/2.5 P pre-Ai (early Sonnar design) with Nikkor F E2 extension tube
• Nikkor 105mm f/2.5 Ai (later modified Sonnar design) with Nikkor F E2 extension tube
  
• 0Euro Napoleon "currency" - for it's sharp image, text and paper fibers
• Sony RAW converter software used at it's default settings (no sharpening, no contrast, no exposure changes) to convert 100 quality jpg

Comparison Results -

[If you click on the image it'll take you to the Flickr hosting site. Once there, look at the file at full resolution. In many cases the differences between lenses is small and likely can't be seen until you take a squint at the comparison at 100 percent.]



Comments -

The Micro-Nikkor 55mm f/3.5 pre-Ai is a very fine optic.  I've tested this on subjects at "normal" working distances and it's brilliant.  I see for macro work that two things stand out.  First, the lens is, indeed, very sharp from wide open.  Second, the field is flat from wide open (just as advertised). 

I'm enjoying this lens so much that I've brought it with me to the cote d'Azur where my wife and I are spending the winter.  This lens is shouldering the bulk of the photographic duties while we're here.

I wasn't entirely sure what to expect from the 105mm Nikkors.  These are of two slightly different optical designs and I wasn't sure if that would play a role in their macro performance.  Hence this comparison, right?

For the 105mm Nikkors with an E2 extension tube I see the optical performance wide open suffers visibly.  The centers are slightly soft and the edges are visibly soft (when viewed at 100 percent file resolution).  But stop either lens down to f/4, and things clean up quite nicely.  The centers become as sharp as the Micro-Nikkor and the edges are getting better.  By f/5.6 and certainly at f/8, the center and edge resolutions look to be as good as the Micro-Nikkor.

Based on prior comparisons and what I learned about field curvature in many lenses I wondered how much that might come into play with the 105mm lenses used here.  So I went back to the camera, set the focus magnifier in a corner of the field of view and changed the focus slightly.  Both lenses were still soft in the corners wide open, but it wasn't quite as bad as the comparison images.  At f/4 I could clearly see that if an absolutely flat optical field isn't required that the edges would be in clear good focus somewhere near the center focus point, but not exactly.

One of the things I learned in this comparison is that I might not "need" a 105mm Micro-Nikkor (either f/4 or f/2.8) when shooting close ups.  If I made my living shooting 2D subject matter with the lens set wide open, well, yes, then I might see a good benefit by acquiring additional lenses. 

But since I'm retired and am making these kinds of comparisons out of intellectual curiosity, I think my current Toy Collection remains sufficient to just about any task.  Unless, that is, I happen to stumble upon a nice Micro-Nikkor 105mm lens at a rather attractive price.  Then all bets would be off.  Isn't there always room for "more" if it comes along for cheap?