"Capture Sharpen" on a super cheap kit zoom

Again, after looking at "Capture Sharpen" in RawTherapee and seeing how it can clean up an image, and after taking a look at images that come from a system that has a strong anti-aliasing (AA) filter (for which "Capture Sharpen" was made for) and a system with a weak AA filter (for which "Capture Sharpen" might not have been designed for, but might have an influence on), I thought I'd have another look at a known "horrible" kitlens and see how it looks over its zoom range to see if there are any "sweet" spots in the focal length range, and if "Capture Sharpen" might work well enough to remove optical defects.

Setup -

• Using a Sony NEX7, one each image from
• Sony 18-55mm f/3.5-5.6 SEL OSS
• Shot at various focal lengths
  
• Shot at f/9
• Process in RawTherapee
• Lens Corrections
  
• chromatic aberrations
• field distortions
• "Auto Levels"
  
• Set "Curves" black to the bottom end of the image's histogram
• "Capture Sharpen"
• Pull 100percent resolution 500x500pixel sections from the image and display them along with a down-rez'd copy of the original image
  

Images -

[If you click on the following images and then select full-resolution versions of these images you will be able to see differences between the photos]

Starting with a Sony "el-cheap-o piece-o-crap" 18-55mm kit lens image at 18mm -

At 24mm -

At 32mm -

At 55mm -

Comments -

Sony got beat up pretty badly by some writers about the image quality of the 18-55mm f/3.5-5.6 SEL OSS.  I remember reading an article where the photographer felt his Sony NEX-7 with this kit-lens mounted on it was useless.  His claim was that it took a very sharp lens to "wake up" the NEX-7's potential.

Because of this man's comments, for many years I've avoided using the optic for anything "serious."  It was a fun "kicking around lens", but that was the farthest I'd go.  Over the years I've found myself using fixed focal-length lenses as a way to avoid spending "serious money" on Zeiss or higher-end Sony zoom e-mount lenses.

Just a few months ago a friend sent me a photograph of a pretty Ducati 750GT that was at a show up in Washington state somewhere.  I was blown away by the image.  The clarity, the resolution, and the colors were just drop-dead gorgeous.  I had to ask him which lens he'd used to make the photo, so he sent a full-rez version where I could read the EXIF information.  Yes.  You guessed it.  He'd used this super-cheap super-horrible kit-zoom.

Some people might feel shooting anything between f/8 and f/11 or f/13 is too limiting.  Certainly fixed focal length and more costly zoom lenses can perform better wide open.  But if a person finds they can live with shooting at a zoom-lens' best apertures, there will be nothing finer, regardless of cost, regardless of manufacturer.

"Capture Sharpen" does a nice Sigma and a super cheap kit lens

After looking at "Capture Sharpen" in RawTherapee and seeing how it can clean up an image, and after taking a look at images that come from a system that has a strong anti-aliasing (AA) filter (for which "Capture Sharpen" was made for) and a system with a weak AA filter (for which "Capture Sharpen" might not have been designed for, but might have an influence on), I thought I'd have a look at a known "horrible" lens and see how it compares with a known "good" optic.

Setup -

• Using a Sony NEX7, one each image from
• Sony 18-55mm f/3.5-5.6 SEL OSS
• Shot at 26mm
• Shot at f/10
• Sigma 30mm f/2.8 EX DN E
  
• Shot at f/10
  
• Process in RawTherapee
• Lens Corrections
  
• chromatic aberrations
• field distortions
• "Auto Levels"
  
• Set "Curves" black to the bottom end of the image's histogram
• "Capture Sharpen"
• Pull 100percent resolution 500x500pixel sections from the image and display them along with a down-rez'd copy of the original image
  

Comparison -

[If you click on the following images and then select full-resolution versions of these images you will be able to see differences between the photos]

Starting with a Sony "el-cheap-o" 18-55mm kit lens image...

Following up with a Sigma 30mm f/2.8 EX DN E image...

Comments -

Can you tell any difference between them?  Seriously.  Look carefully.  Any difference at all?  Now think about this.

OK.  Sure.  The kit lens has some "interesting" behaviors when shot wide open, but...  Sure.  The Sigma is brilliant from wide open.  But what's wrong with shooting a lens at its best aperture?  In the case of this Sony kit optic that would be f/8, f/9, f/10, or f/11.

Keep in mind that I'm using the lens correction functions in the image processing application.  Who doesn't these days? Things like chromatic aberrations and field distortions can be corrected.  Add "Capture Sharpen" to the processing sequence and I'm able to re-confirm for myself something that I've been saying for a long time, now.

Have a lens?  Good.  Use it!  No excuses.  None.

Crazy, isn't it? 

"Capture Sharpen" - AA filter and optical comparison

After having experienced "Capture Sharpen" in RawTherapee and seeing how it can clean up an image, I wanted to take a look at how it works on images that come from a system that have a strong anti-aliasing (AA) filter (for which "Capture Sharpen" was made for) and a system with a weak AA filter (for which "Capture Sharpen" might not have been designed for, but might have an influence on).

Setup -

• One image from
• Canon 5D MkII
  
• strong AA filter
• 24-105mm f/4 L IS
  
• shot wide open
  
• Sony A6000
  
• weak AA filter
• Sigma 60mm f/2.8 Art DN
• shot wide open
  
• Process in RawTherapee
• Lens Corrections
  
• chromatic aberrations
• field distortions
• "Auto Levels"
  
• Set "Curves" black to the bottom end of the image's histogram
• "Capture Sharpen"
• Pull 100percent resolution 500x500pixel sections from the image and display them along with a down-rez'd copy of the original image
  

Comparison -

[If you click on the following images and then select full-resolution versions of these images you will be able to see differences between the photos]

Starting with a Canon 5D image...

Following up with a Sony A6000 image...

Comments -

Starting with the Canon image we see that the photo looks nice and seems to have fairly decent resolution.  Without the "Capture Sharpen" processing step, however, the image is rather soft. Knowing the Canon system as I do I can say that there are two things to take into account.

First, the AA filter Canon uses is strong.  It deliberately softens an image so as to get around any moire effects that might crop up.  Looking at a Canon image all by itself I doubt people would be displeased with their results, but...

Second, the 24-105mm f/4 L IS (version 1) was highly touted at the time I purchased it.  I thought nothing of its performance and assumed it was as good as I could get, regardless of price (at the time the 5D MkII was introduced a kit was rather expensive at 3500USD).  Over time and with many many photoshoots under my belt I started to uncover subtle performance degradations. 

When I shot it side by side with a Sony mirrorless system I was instantly struck by how soft images were with my Canon gear.  The following is a hint of how I came to the decision to sell my Canon equipment. 

Take a look at the second image and the differences between the two systems (Canon and Sony) should be readily apparent.  The Sony A6000 + Sigma 60mm f/2.8 Art DN is fabulously sharp.  And under the treatment of "Capture Sharpen" the overall image "sharpness" is over the top incredible.

I bought a Sony A6000 body new at the local Salon de la Photo some years ago and paid 450Euro (less than 500USD at the time).  Shortly after I bought the body I picked up a new Sigma 60mm f/2.8 Art Dn for less than 200Euro (around 220USD).

You can see where I'm going with this, right?

Before anyone gets upset about me comparing a Canon zoom against an aftermarket prime, my overall experience of using the Canon DSLR was very consistent.  It didn't seem to matter if I used a prime lens or a zoom on any Canon I ever owned (and I owned a lot of them).  The strength of the Canon AA filters over-ride pure optical resolution.  The 24-105L proved to be less than satisfying in addition to the AA effects.

What I see here is that taking a camera with a strong AA filter and passing it through "Capture Sharpen" can bring an image the appearance of "sharpness."  It is by comparison with other systems that one might question the use of strong AA filters in general photography.

What I see here in taking a camera with a weak or non-existent AA filter and mating it with a sharp lens (remembering, of course, that it is difficult to find a lens that is _not_ sharp) and passing it through the "Capture Sharpen" process can yield images that are sharper than I could ever have imagined.

Does software level the playing field? [2]

I previously shared my thoughts that, yes, software and the "capture sharpen" function in particular, can indeed "level the playing field" in terms of "sharpness" in an image, independent of which lens is used.

Before moving on to see how this compares and works in the real world I would like to confirm what I have come to understand by looking at three more lenses

In this comparison I look at two Nikon Nikkor 85mm lenses with a LensTurboII focal reducer and one Sony 50mm SEL OSS.  These lenses were commonly touted as being good "portrait" lenses.  In fact, the Nikkor K 85mm f/1.8 is a gorgeous "portrait" lens.  It is not as wickedly sharp as some of my other lenses when shot wide open, but the overall wide open rendition, I find, is just amazing.

Setup -

• Big Beefy Manfrotto tripod (so big that it is suitable for stabilizing an old 8x10inch view camera)
• Sony NEX-7 - 2 second delay, ISO 100
• Lenses - shot wide open and at f/2.8 only
• Sony 50mm f/1.8 SEL OSS - effective full frame focal length of 75mm
• Nikon Nikkor 85mm f/1.8 K pre-Ai + Lens Turbo II - effective APS-C focal length of 56mm
• Nikon Nikkor 85mm f/2 Ai + Lens Turbo II - effective APS-C focal length of 56mm

Scene -

What I setup was a simple situation of a tree that had complex, beautifully detailed bark.

Comparison -

Click on the following image and find the full resolution image to inspect the image at 100percent.

Comments -

In general, "soft" or out of focus image areas will remain so after passing the "capture sharpen" step.

I have to say, I'm particularly happy to see how well the Sony 50mm f/1.8 SEL OSS did from wide open.  As we will see in a future blog entry, I had a Sigma 60mm f/2.8 Art that I nearly regretted selling, until I saw this, that is.  In any event, this Sony lens is truly the "cat's meow" of a lens and it's a "keeper."

The Nikon Nikkor 85mm f/2 Ai + LensTurboII focal reducer is really quite nice from wide open, too.  It isn't all that far behind the incredible Sony.  With this I think I can re-confirm that the "capture sharpen" function "levels the playing field" rather nicely.  This old Nikkor is a very usable optic.

Finally, the Nikon Nikkor 85mm f/1.8 K pre-Ai + LensTurboII focal reducer remains softer than the other two lenses when shot wide open.  Not that the wide open "capture sharpened" image is bad, mind you.  It's only by comparison that one can see any difference.  However, by f/2.8, the "playing field has been leveled" and this early f/1.8 Nikkor is just as brilliant as it's sister lenses compared here.

Do lenses actually matter?  It's turning out to feel as if it might not matter at all which lens you use, just as long as you "sharpen" an image correctly during processing.

Now there's some potential heresy for you.

Does software image processing "level the playing field?"

We were in in southern France this winter and taken the TGV.  This allowed me to pack a rather heavy suitcase.  But coming back north meant flying.  Suddenly the suitcase was a bit heavy.  My wife tried to pick up my carry-on and immediately asked what the h*ll I had in there.  It contained two computers and three cameras with Nikon Nikkor manual focus lenses.

My wife's question was a good one and I've now come to question that I should carry all my fun, preferred "stuff" when we're away from Paris.  Instead I might want to carry something light.

So... let's have a look around and see what I have... ah... yes... Sony E-mount autofocus lenses... and... some software... and... why not once more and without hesitation confirm that a lens is a lens is a lens... and... let's have a look at the impact of image processing on image "sharpness" to see if any differences between lenses remain after cleaning up an image with some software...

Recently RawTherapee has come bundled with something called "Capture Sharpen".  It is an image pre-sharpen module that works to reverse image softness that comes from imaging sensors that use anti-aliasing (AA) filters. 

This function is automatically applied, I understand, in popular non-open source software image processing applications such as Lightroom and Capture One.   

This makes sense as, for instance, Canon uses strong AA filters with their cameras to combat moire patterns.  This tends to hide optical resolution.  Canon digital images often appear softer before the "capture sharpen" image processing step than competitors imaging systems.

Sony is one of those competitors and based on personal experience they use weaker AA filters, and in some cases uses no AA filtration at all.  So it's easy to see lenses of varying degrees of "sharpness", particularly when shot wide open.

So I wondered if "capture sharpen" might clean up optical effects similarly to the way this function tries to reverse the effects of AA filters.

In this comparison I grabbed some of my beloved Nikon Nikkor glass (which tend to be soft wide open) and compared their images against a few small, sharp, auto-focus Sigma and Sony SEL lenses.

Setup -

• Big Beefy Manfrotto tripod (so big that it is suitable for stabilizing an old 8x10inch view camera)
• Sony NEX-7 - 2 second delay, ISO 100
  
• Lenses - shot wide open and at f/8 only
  
• Nikon Nikkor 24mm f/2.8 Ai + Lens Turbo II - effective APS-C focal length of 16mm
• Sony 16mm f/2.8 SEL
• Sigma 19mm f/2.8 EX DN E
• Sigma 30mm f/2.8 EX DN E
• Nikon Nikkor 35mm f/2 + Lens Turbo II - effective APS-C focale length of 35mm

Scene -

What I setup was a high contrast situation with strong highlights and deep shadows.

Comparison -

Click on the following image and find the full resolution image to inspect the image at 100percent.

Comments -

In general, "soft" or out of focus image areas will remain so after passing the "capture sharpen" step.

Comparing my Nikon Nikkor 24mm + LensTurboII setup against a Sony 16mm after the "capture sharpening" step I see that the centers are pretty much equal in terms of apparent sharpness.  The edges, however, of the 24mm + LensTurboII remain softer than the 16mm Sony.  In fact, at f/8 the 16mm Sony is really quite good, where it matches the performance of the brilliant 19mm Sigma EX DN E.

The Sigma 19mm and 30mm lenses are brilliant across the field at both wide open and f/8 after the "capture sharpen" step.  Not much more to say than this.

Which leaves us with looking at one last Nikkor, the 35mm f/2 pre-Ai.  I really like this lens.  When coupled with the LensTurboII focal reducer I find this focal length is nearly a perfect match for how I "see."  Wide open it tends to be just slightly "soft" compared to the Sigma 30mm.  However, after the "capture sharpen" step apparent "sharpness" the Nikkor cleans up beautifully.

Old, many times softer lenses can be made to look like their modern counterparts.  It's pretty easy to see that "capture sharpen" levels the playing field, as it were.

Returning to the question of camera system weight and portability, I'm now re(?)-convinced that I don't have to carry the Nikon Nikkors if I don't want to or if I find myself in a situation where less weight becomes important.