Leica S lens on Fuji GFX 50s

[Einst_Stein]

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The textbook grade AF system typical goes through speed-up then speed-down process according to the sensing assistant and the inertia or resistance. If the iniertia or resistance is not constant, some complexity is added, so will be if manual focus can overide at anytime.

Since GFX is using (linear) focus by wire, different from Leica S, this may add more difficulty and perhaps something lack of reliability in Leica S to GFX adapter. It is not impossible, but the adapter need some intelligence to bridge the gap that the camera is clueless. 

Edited September 30 by Einst_Stein

[sostinv]

Just bought a copy of Summarit-S 70 and tried to make a shot of planar landscape scene. Was surprised to get not quite sharp periphery even on F8. Somebody here told that this lens has field curvature which prevents rendering sharp edges on a planar landscape scene, but I tried to focus on an edge using a 100% loupe and could not get details clearly defined. I'm curious whether it S70 that cannot match 100MP demand, or I just got defective sample. Can someone share a 100MP RAF of a planar inifinity focused scene using this lens on F5.6 or F8, please?

[helged]

1 hour ago, sostinv said:

Just bought a copy of Summarit-S 70 and tried to make a shot of planar landscape scene. Was surprised to get not quite sharp periphery even on F8. Somebody here told that this lens has field curvature which prevents rendering sharp edges on a planar landscape scene, but I tried to focus on an edge using a 100% loupe and could not get details clearly defined. I'm curious whether it S70 that cannot match 100MP demand, or I just got defective sample. Can someone share a 100MP RAF of a planar inifinity focused scene using this lens on F5.6 or F8, please?

Yes, S70 has some field curvature. But the cornes should be in focus at f8. For a distant landscape, I typically put the focus point 1/3rd off the image centre to get the full image in focus. I haven't the GFX anymore so I can't provide you with an image, but I am sure that people will chime in.

Edited October 2 by helged

[Stuart Richardson]

Try f11. The 70mm has significant field curvature. I also thought my lens was broken when I got it, but it's just how it is. The 45mm or 120mm are better for very flat scenes. You should see very sharp areas in the edges if you are photographing something three dimensional, but they just won't be at the same distance, they will be closer to the camera. If you try to focus for the corners, the sharp part of the center will be past infinity, so it will render the center soft. As Helge said, you can try to find a happy medium, but DOF is your friend for this lens with those compositions. It may even be worth stopping all the way down and dealing with some softening from diffraction. 

[epines]

@sostinv In my experience with the S 70mm (which I have, love and use regularly), shooting a flat surface from 10-15 feet away, it's sharp from corner to corner, even wide open. I'm happy to send you a couple of raw files if you'd like to see (DM me here). But, again, this is at closer distances. I'm seldom shooting at infinity. 

It's the same for the 45mm and 120mm. The 35mm and 30mm show some field curvature in the corners, but sharpen up with stopping down. 

 

 

Edited October 4 by epines

[sostinv]

As I discovered, doesn't really matter what the distance is. My copy doesn't seem to produce a sharp edge at F5.6 or F8 at any distance. I've attached crops from my copy at F5.6 – the center and edge. GFX100S II. Used a distance about 15 feet and tried my best to manually focus on the edge using 100% magnifier and DOF preview (to eliminate possible focus shift), but this is the best I could get. In case of FC, it should have been sharp when focused on the edge. It gets better at F11 and the best at F16 (diffraction dulls details though, but it become clearly defined, not smudged). The question is it considered "normal" for 100MP or I've just got a lemon.

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[chrismuc]

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I did a quick comparison between the GF63f2.8, the S70f2.5 and the GF80f1.7, all at f2.8 on my GFX 100 ... but I can't upload the jpg files 😬.

Field curvature and sharpness at about 3m distance. The S70 has a bit field curvature and sharpness decline towards the image sides, the GF63 a bit less and the GF80 basically none. But I never saw issues with the S70 in real life. 

 

(I know, Leica Forum has this silly image size restriction, but even one image at 1.4 MB did not work to upload, and no specific reason noticed.)

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Edited October 5 by chrismuc

[Pieter12]

8 hours ago, sostinv said:

As I discovered, doesn't really matter what the distance is. My copy doesn't seem to produce a sharp edge at F5.6 or F8 at any distance. I've attached crops from my copy at F5.6 – the center and edge. GFX100S II. Used a distance about 15 feet and tried my best to manually focus on the edge using 100% magnifier and DOF preview (to eliminate possible focus shift), but this is the best I could get. In case of FC, it should have been sharp when focused on the edge. It gets better at F11 and the best at F16 (diffraction dulls details though, but it become clearly defined, not smudged). The question is it considered "normal" for 100MP or I've just got a lemon.

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So what is the image circle for the S 70mm? I think your examples show it doesn't cover the GFX sensor.

[chrismuc]

The image circle of a camera with 4433 sensor (Fuji GFX, Hasselblad X1D) is 55mm, of a 4530 sensor (Leica S) is 54.1 mm, basically equivalent. 

[Tirpitz666]

At the end ordered also the XPImage S-GFX adapter and waiting for it, in the meantime they have added preliminary AF support via FW apparently, so keen to test it against the Kipon, then will decide which one to keep 🙂 (and I'm pretty annoyed that the Kipon doesn't work with the 180, notwithstanding is among the "officially supported" lenses..)

[Einst_Stein]

On 10/5/2025 at 12:39 AM, sostinv said:

As I discovered, doesn't really matter what the distance is. My copy doesn't seem to produce a sharp edge at F5.6 or F8 at any distance. I've attached crops from my copy at F5.6 – the center and edge. GFX100S II. Used a distance about 15 feet and tried my best to manually focus on the edge using 100% magnifier and DOF preview (to eliminate possible focus shift), but this is the best I could get. In case of FC, it should have been sharp when focused on the edge. It gets better at F11 and the best at F16 (diffraction dulls details though, but it become clearly defined, not smudged). The question is it considered "normal" for 100MP or I've just got a lemon.

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Could you clarify is this problem just on GFX or also on Leica S camera? or worse on one than the other?

[sostinv]

41 minutes ago, Einst_Stein said:

Could you clarify is this problem just on GFX or also on Leica S camera? or worse on one than the other?

Currently, I cannot have an access to S body, so cannot comment on this. But I downsampled 100MP to 37.5MP and the problem is barely visible. One needs to zoom 200% and more to see this on Retina 5K display. So, if it is a lemon, probably S body won't show it as apparently. Or you mean, it might be a problem similar to Leica M wide angle lenses on Sony A7 (wrong sensor stack thickness)?

[sostinv]

On 10/5/2025 at 6:22 PM, chrismuc said:

I did a quick comparison between the GF63f2.8, the S70f2.5 and the GF80f1.7, all at f2.8 on my GFX 100 ... but I can't upload the jpg files 😬.

Field curvature and sharpness at about 3m distance. The S70 has a bit field curvature and sharpness decline towards the image sides, the GF63 a bit less and the GF80 basically none. But I never saw issues with the S70 in real life. 

 

(I know, Leica Forum has this silly image size restriction, but even one image at 1.4 MB did not work to upload, and no specific reason noticed.)

Could it be uploaded to dropbox or google drive?

[Einst_Stein]

If there is difference between two cameras, it might be hardwar or firmware, or both.

It is known that Leica M lens performance better on Leica SL2 than on Lumix S1R, even though both cameras share same sensor, apparently Leica SL2 achieved this through firmware. 

I'd not doubt that Leica apply this technical on all their cameras and lenses. 

Edited October 7 by Einst_Stein

[Tirpitz666]

As soon as I have some spare time, I'll try myself to see whether my 75 behaves differently on the S-E and the GFX100S 🙂

[sostinv]

A couple of notes:

1. Edge performance improves on short focus distances. It is perfectly fine at 0.5-1m, and acceptable at 1-2m, then detoriates almost abruptly.

2. My sample has strange knocking sounds when shaking along optical axis. I have a feeling that some lens(es) loosened inside its sitting place(s).

Tend to think my sample needs to be serviced.

[helged]

16 minutes ago, sostinv said:

A couple of notes:

1. Edge performance improves on short focus distances. It is perfectly fine at 0.5-1m, and acceptable at 1-2m, then detoriates almost abruptly.

2. My sample has strange knocking sounds when shaking along optical axis. I have a feeling that some lens(es) loosened inside its sitting place(s).

Tend to think my sample needs to be serviced.

The S-lenses I have are all silent - and no wobbling or something similar at all.

[albireo_double]

FYI - I sold my S24 to a buyer on eBay very recently. He returned it, saying that it mis-focuses in 3 out of 5 times. After the return, he revealed that he had been testing it on a GFX100 II (I presume via the Kipon adapter). Incredulous, I've just re-tested the lens on my SL3 via the S-Adapter-L: not a single out-of-focus shot in the 50 or so that I took, either with single AF field or with face/eye recognition. I had been toying with the idea of getting a Fuji GFX as platform for my remaining S lenses but in the end decided to sell them all and use the newer SL lenses on my SL3. I may keep the S24 in anticipation of the S4. In the meantime, if somebody's desperately looking for an S24 with the updated AF motor, feel free to drop me a message (there's no need to "move this in the  buy/sell section 😉 "....).

Edited October 16 by albireo_double

[Stuart Richardson]

On 10/7/2025 at 4:39 PM, Einst_Stein said:

If there is difference between two cameras, it might be hardwar or firmware, or both.

It is known that Leica M lens performance better on Leica SL2 than on Lumix S1R, even though both cameras share same sensor, apparently Leica SL2 achieved this through firmware. 

I'd not doubt that Leica apply this technical on all their cameras and lenses. 

They have different cover glass on the sensors. Though the underlying sensor is the same, each company can specify their own filtration and cover glass, and tune the output to their taste. I am not sure if the SL2 cover glass also includes offset microlenses, like the M sensors, but at the very least it is thinner. The softening is caused by off-axis light needing to travel through a greater distance of glass, which refracts it and causes softening. This is quite severe in M bodies, whose lenses and bodies were not designed to deal with digital sensors. As such, Leica spends a lot more time dealing with this issue and has done so better than any other manufacturer. 

Edited October 16 by Stuart Richardson

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[Tirpitz666]

Yes, I think it is the case and why the SL are usually the best alternative to M bodies for M glass. Also the Nikons Z tend to have a thinner cover glass and usually fare pretty good with adapted M lenses (but I still prefer to mount them on my SL2s 🙂 ).