Phillipreeve.net

writes a conclusion after his long article and all the illustration and tests; about the KOLARI UT (ultra thin sensor glass modificiation). He referes primarily to Sony cameras.

"Conclusion

I have never had an interest in autofocus (or modern lenses for that matter) and have been particularly drawn to mirrorless for the size reduction it allows. This makes me the perfect candidate for thin filter conversion.

All of my lenses perform as good or better with this conversion than on a stock Sony camera and many of them perform much, much better. This conversion allows me to build a solid kit of really tiny lenses that includes ultra-wides. Pancakes like the CV 21/4 and earlier versions of 15/4.5 are suddenly much better performing and all my Contax G lenses are fully usable.

For me, this conversion is a no brainer.

If you use native E-mount lenses, the equation becomes more difficult. I would not worry about the performance of any of the 50mm or longer FE lenses, but many of the wider lenses really perform noticeably worse with the conversion. If you want to use one of the Batis wides or the 21mm Loxia for large aperture landscapes or astro, this conversion is probably a bad idea. If, on the other hand, you are only interested in using native lenses for stopped down landscape and portraiture, the conversion could make sense. I actually think that the FE 35/1.4 improves for portraiture on the Kolari UT.

The big deciding factor for me on whether the conversion is worth it would be how much of your shooting will involve lenses that show a noticeable improvement. If you see yourself doing 50% or more of your shooting with 35mm and wider rangefinder lenses, the UT conversion should be totally worth it. If you will only occasionally be dabbling in such lenses, the conversion does not really make sense".

 

My thoughts

I am with him on that I too use (in my example) a Sony A7s as a MANUAL FOCUS camera, which extends my existing and rather limited Leica M9 camera.

Especially when it comes to portrait and reportage in low light / bad light / indoor light.

With adapted Leica M lenses, even a Zeiss ZM lens (but also Canon FD lenses) - in which the Kolari UT conversion practically makes many of the tricky (read; blurry) lenses suddenly sharper. Lenses I avoided earlier with the Sony A7s.

So, the tricky lenses become suddenly highly interesting lenses

(tools) to be used. Especially the normally stellar Leica Summilux-M 35/1.4 ASPH FLE would suddenly perform in a manner, that spells quality - like it does on a native Leica M camera.

In fact, I tended to use the very old, very tiny Leica Summicron-M 35/2 "IV" on the Sony A7s instead: because it performed here (and on the Canon EOS R6) like i remember from the days of film; blurry in the extreme corners, soft at the borders - and relatively sharp in the center (when used wide open). All parameters get better once you stop the lens down. It never felt "more degraded" on a Sony A7s despite its very thick sensor glass. The "look" of that lens, was all the same, no matter what.

So, therefore I use that lens mostly on the Sony A7s with the original thick sensor stack. Plus it is a remarkably small camera + lens combo !

Diminutive so to speak.

A lovely combination.

Black & White

Also notice, that I often use the Sony A7s as a "black & White Leica M" camera. So, the discoloration you get from using lenses that have a light angle incoming in a way creating colors casts in the corners - are no problem to me, when i use Black & Images. Well, and even if i do use color - it is easily corrected in Lightroom or Adobe RAW-plugin. I sometimes even get that with other lenses, such as the Laowa Argus 28mm ƒ1.2 lens - which a very slight color cast in the corners.

I fix that in the Adobe RAW-plugin

In Leica M cameras

(with coded lenses) the colors cast at the borders and corners dissapear "automatically" due to Leica's built in color correction profiles. When a lens isn't coded, i believe you can dial in a profile manually. The problem here is, that when you switch lens, and don't think about switching to the correct color profile, it screws up the image later.