Friday, June 29, 2018

Fungus ~ Nikon Nikkor 300mm f/4.5 pre-Ai before/after CLA

It so happened that I picked up a cheap 300mm Nikon Nikkor f/4.5.  After receiving the package I realized why it was so cheap.  Here was a second opportunity to see how fungus could affect image rendition.  This time the lens was pretty clouded with champignons.  The inside forward elements were covered with nastiness.  And it looked like the inside and outside of the rear element set hadn't ever been cleaned.

Setup -
  • Sony A6000, 100ISO, AWR converted in Sony's software 
  • Big Beefy Manfrotto tripod 
  • Nikon Nikkor 300mm f/4.5 pre-Ai with very very light scratches on the front element (as the control optic)
  • Nikon Nikkor 300mm f/4.5 pre-Ai filled with fungus (before CLA) and cleaned (somewhat)
  • Lens Turbo II adapter

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.]

Nikon Nikkor 300mm f/4.5 pre-Ai


Comments -

The control optic is a fine lens.  Sharp from wide open, this lens, even with the light scratches, is contrasty and just plain downright good.

The fungus infected 300mm did indeed show performance degradation.  This really is no surprise.  There was so much gunk and crud that just about any amount of cleaning would've done the lens good.  And it did.

However, the CLA'd lens still suffers for a very slight lack of contrast.  A re-inspection of the lens revealed that the inside of the rear element set is a little cloudy.  The way Nikon manufactured these lenses makes it difficult to disassemble.  The various threaded retainers tend to be nearly impossible to remove.  So... I'm not sure what to do with the lens... perhaps I'll sell it as is?

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