"The Dark Knight" (Sony A7s)

My second goal next year - will be the conversion of my Sony A7s - exchanging the very thick sensor stack (the glass above the sensor), with a much thinner one (via Kolari EU).

The Challenge

a thinner senor glass allows me to use tricky Leica M lenses (such as Elmarit-M 28/2.8 ASPH. and the Summilux-M 35/1.4 ASPH. FLE) resulting into much better border and corner sharpness.

These lenses, due to their very compact size, fare really bad on other cameras than Leica M - because all other cameras exhibit much thicker sensor glass. That affects the optical path in a negative way. The Leica M lenses usually work well in the center (sharp) - but towards the borders they fall apart (many of them, especially on the wide end). The second best alternative when using Leica M lenses is a Leica SL camera. all other cameras have too thick sensor glass. Sony in particularly uses very thick glass.

When you Elmarit-M 28/2.8 ASPH. on a Sony camera, it looks like one of the worst lenses, with no sharpness at the borders.

Now doing the Kolari conversion, the Sony A7s would become in combination with a little Leica M lens - a formidable small camera. Say, the tiny Summicron-M 35/2 lens - together makes a beautiful combo for reportage and people "on-the-fly". But the main thing is, that I also can use other "tricky" Leica M lenses, without them falling apart.

Or so is the idea.

Speaking of the Leica Summicron-M 35/2 "IV"

That one particularly works well with the thick sensor glass in the Sony A7s. The performance is about the same on this digital camera, as it was on film. Soft corners, good central sharpness. The "Fingerprint" of the lens - the way it renders images - are exactly the same. (Even on a Canon EOS R6).

The classic "Mandler" Noctilux 50/1 isn't much affected either when you use wide apertures. Especially at wide open aperture ƒ1 - you always have blurry corners - no matter on which camera you adapt it to. Therefore it really doesn't matter (in general). I also use it on the Canon EOS R6, with good results.

The Noctilux unique, optical "fingerprint" at wide open apertures remains the same. I find it even performing better overall on a digital camera, compared to a film Leica M6.

Also a Beautiful Combo:
Sony A7s + Canon FD 85/1.2 L

That is also a beautiful combination, even if the handling is a bit off due to that the lens is large, and the camera small. (A battery grip helps in this regard). The relative clean files in not so bright light - create a very intimate portrait of people with the Canon FD 85/1.2 L - especially when you use the profile of a face. And do it in Black & White.

It is gorgeous.

One drawback

with using manual, legacy lenses is, that you in the end forget which lens was used to which photo. I realize that now 7-8 years later when i used manual lenses on the Sony A7s... I don't remember exactly which lenses I used. (Nowadays however, i put that info manually into the files via an EXIF app. A bit fiddly, but worth it).

Kolari: Only 0.2 mm sensor glass thickness

Gosh; I am just reading that the latest Kolari version is as thin as 0.2 mm only. That is more than half of the thickness in the Leica M8 (0.5 mm), which was already extremely thin. The Leica M9 had a sensor glass of 0.9 mm.

While the original Sony A7s sensor glass was somewhere around 3.2 mm, i believe (but i am not sure of the exact number. It was however very thick). Micro Four Thirds cameras, have even thicker glass like 4+ mm ? - and that's why most adapted legacy / analog lenses look awful on them. Not particularly sharp either. (Plus; they turn out without any character, since the sensor is much smaller).

NOTE: When using this modification, the native Sony lenses will get affected somewhat. The optical formula for those, are calculated with the thick sensor glass in mind. So, if you suddenly only have a 0.2 mm thin glass, it will affect the sharpness somewhat in the corners.

For me personally that never mattered: I never bought Sony lenses. For me the cameras was always meant to be a second "Leica"; one that "can see in darkness". So, i always knew i would use it with adapted legacy / analog lenses.

The Sony A7s is such an interesting camera

due to its lovely high ISO quality - especially in black & white - which gives the photos a fantastic balance between grain and very high ISO, even at 25.000 you get away beautifully. (That's about the highest i find to have good quality in BW). Sure you can also go ISO 250.000 - which makes it look like a strongly developed T-MAX 3200 BW film. Full of grain (noise).

The noise usually is very low at typical dull scenes during winter / generally in the city during night times - where you often hover around ISO 6400-12500. You can really get that 50s, 60s and 70s feeling with the Black & White setting, moderate noise/grain - and take photos anywhere, even in low light.

While the Sony A7s is "only" a 12 MP camera - it has never been a drawback in my photography. I never felt it was "too little".

I call it the Sony A7s "The Dark Knight" due to its great high ISO properties. I only use manual lenses on it... sometimes also Canon FD lenses - which by the way work well with the thick sensor glass.

Here some photos during the time of 2019-2020 taken with the Sony A7s.