Disappointing results from R lenses on Sony sensors

[jaay]

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After experiencing corner issues with M lenses on Sony NEX cameras I decided to try some R lenses on Sony DSLR bodies with the theory being that corner performance should be better due to the lens design.

I purchased an A77 body and a 35 R summilux and 90 R APO ASPH summicron and converted them to Sony Alpha mount using Leitax adapters which gave a very snug 'no play' mounting on the camera.

The results however were disappointing: both lenses suffered from huge amounts of CA/ purple fringing which could not automatically be removed by LR4 or Capture One and both suffered from worse corner problems than I experienced with M lenses on the NEX!

With the 35 lux it was impossible to get sharp corners in some circumstances at any Aperture and at f1.4 the image was significantly softer than examples I had seen on Nikon full frame cameras.

The 90 cron performed better but was just not as sharp as I was expecting given its legendary status - for example it was not as crisp as my 90 M elmarit on the NEX.

 

Now both lenses were in superb condition and with live view focussing I know these problems weren't down to user error - I suspect the 24MP APS-C sensor is the culprit as the R lenses performed better in my NEX 5N even with a cheap adapter!

 

I post this merely as a cautionary tale for anyone thinking that using an R lens on a Sony body with in body image stabilisation and EVF would be a great combo to be wary!

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[lct]

Purple fringing may come from overexposed shots but soft corners are not expected at all on a mere APS-C camera. For info, i'm using a dozen R lenses from 21 to 280mm with a full frame 5D1 and i've got soft corners with only two of them, an early 28/2.8 and a 21/4. Did you mount the Leitax adapters yourself?

[01af]

I post this merely as a cautionary tale for anyone thinking that using an R lens on a Sony body with in body image stabilisation and EVF would be a great combo to be wary!

You didn't shoot with the in-body image stabiliser enabled, did you?

[berndr]

I'm using a wide range of R Lenses on my Alpha A65 and I didn't have those problems.

 

On the other hand my lens with highest aperture is the R 2/50. But the 2,8/19 works fine too. The 2,8/16 doesn't work at all.

 

The 24MP is known to be very sensitive when the light rays angles getting extremer. There are color effects and unsharp corners.

 

I have the feeling that the individual sensors do not perform in the same way. Some say it's working good other have big problems.

 

But that's important: don't use the inbody image stabilisation!

 

Kind regards,

Bernd.

[farnz]

This sounds very odd because the 90 AA is an apochromatic lens that is purpose designed to prevent fringing by focussing all of the visible wavelengths at the same point.

 

I use 8 R lenses on my 5D MkII and I haven't had the problems you've unfortunately encountered so it sounds like Bernd may have hit on the answer.

 

Pete.

[ns_ng]

I have converted 4 of my 7 R lenses to alpha mounts. The Leitax mounts are all well made and I have not experienced any problems. However, with the ff A850, there are some softness and vignetting with my 19mm R (2nd ver.) and 28mm R (1st ver.) around the corners and edges at f2.8. But for my landscape shots at around f8.0 or f11.0, these are non issues. There is some CA but stopping down to my working apertures for landscape shots this becomes irrelevant in most cases.

 

The other 2 lenses, 35-70 VE and 180 f2.8 Apo, work great with the A850.

 

N.S. Ng

[jaay]

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Why not use the IBIS? For me it was the whole attraction of the larger camera- to stabilize those big lenses!

I fitted the mounts myself with focus confirmation chips.

[01af]

Why not use the in-body image stabilizer? For me it was the whole attraction of the larger camera—to stabilize those big lenses!

Because it works properly only with fully compatible AF lenses. Otherwise, it'll do more harm than good.

 

 

I fitted the mounts myself with focus confirmation chips.

Do these chips feed accurate information about both the focal length and the focusing distance to the camera?

[jaay]

The chips only provide focal length and max aperture - nothing else.

 

So I guess the sensor is shifting inaccurately then? This would make all the problems I mention worse I guess - but I can't believe it's entirely responsible for the soft corners.

[Sp12]

After experiencing corner issues with M lenses on Sony NEX cameras I decided to try some R lenses on Sony DSLR bodies with the theory being that corner performance should be better due to the lens design.

I purchased an A77 body and a 35 R summilux and 90 R APO ASPH summicron and converted them to Sony Alpha mount using Leitax adapters which gave a very snug 'no play' mounting on the camera.

The results however were disappointing: both lenses suffered from huge amounts of CA/ purple fringing which could not automatically be removed by LR4 or Capture One and both suffered from worse corner problems than I experienced with M lenses on the NEX!

With the 35 lux it was impossible to get sharp corners in some circumstances at any Aperture and at f1.4 the image was significantly softer than examples I had seen on Nikon full frame cameras.

The 90 cron performed better but was just not as sharp as I was expecting given its legendary status - for example it was not as crisp as my 90 M elmarit on the NEX.

 

Now both lenses were in superb condition and with live view focussing I know these problems weren't down to user error - I suspect the 24MP APS-C sensor is the culprit as the R lenses performed better in my NEX 5N even with a cheap adapter!

 

I post this merely as a cautionary tale for anyone thinking that using an R lens on a Sony body with in body image stabilisation and EVF would be a great combo to be wary!

 

24MP on an APS-C sensor is very taxing for such old designs. I've used IBIS very effectively with older lens designs. I don't think focus distance should matter -- the in focus part of the image will be at the sensor's plane anyway.

[farnz]

24MP on an APS-C sensor is very taxing for such old designs. ....

I'm not sure what you're getting at here but the 90 APO-Summicron-R asph, for example, was introduced in 2002 so it's hardly an old design. And besides, all of these lenses were designed for use with 135 format film 'full frame' with the finest resolution of 160 lp/mm (3.1 microns) provided by Fuji Velvia so they will out-resolve a 24 MP APS-C sensor with 3.9 micron pixels; and APS-C format doesn't extend all the way into the corners so vignetting at this diameter will be less than 1 stop and barely noticeable.

 

Pete.

[Sp12]

I'm not sure what you're getting at here but the 90 APO-Summicron-R asph, for example, was introduced in 2002 so it's hardly an old design. And besides, all of these lenses were designed for use with 135 format film 'full frame' with the finest resolution of 160 lp/mm (3.1 microns) provided by Fuji Velvia so they will out-resolve a 24 MP APS-C sensor with 3.9 micron pixels; and APS-C format doesn't extend all the way into the corners so vignetting at this diameter will be less than 1 stop and barely noticeable.

 

Pete.

 

Not that I agree with your claim on Velvia's resolving power.

 

Those lens designs simply aren't perfect at this sort of pixel density at the edges. The Summilux 35 especially is not actually that awesome of a performer below 2.8 besides. The AA has very noticeable coma on modern digital sensors. Even great lenses like the Voigt 125 and Sigma 150 OS have flaws when examined this closely.

[farnz]

I'm surprised by what you say because:

 

1. You don't get to see the lens's edges on APS-C sensors because they're cropped out by the sensor's dimensions

2. Coma is caused by spherical aberration but the 90 AA contains an aspherical element to correct for SA. I use a 90 APO-Summicron-M asph, which has the same formula as its R sister, on my M9 and coma is not visible.

3. What you mean by "modern digital sensors" isn't clear. CCD, CMOS, Fovean? High MP count? Low pixel pitch? etc.

 

I can't speak about the 35 Summilux-R because I've never used one but I have heard other speak highly of its performance wide open.

 

Pete.

[lct]

[...] You don't get to see the lens's edges on APS-C sensors because they're cropped out by the sensor's dimensions. [...]

+1. Why not disabling IS to be sure?

[michali]

I've converted the following R lenses to Sony Alpha mount via Leitax mounts (no chips):

19mm Elmarit vers.2, 28-90mm Vario Elmar, 105-280mm Vario Elmar, 80mm Summilux, 100mm APO Macro Elmarit and 280mm f4 APO-Telyt and 1.4 APO extender.

 

Am in agreement with Pete, there's no question that these lenses will out resolve the sensor.

 

I use these lenses on a Sony Alpha 850 and have had no issues at all. Camera is set to full manual and Image stabilization off. Results are outstanding.

 

It sounds like the sensor would be the most likely culprit n this instance.

I'm not familiar with the A77, what mode are you using the camera in?

Is there possibly a setting buried in in the menu somewhere that needs to be de-activated?

[01af]

The chips only provide focal length and max aperture—nothing else. So I guess the sensor is shifting inaccurately then?

At longer focusing distances—say, 200× the focal length and more—it should work fine but at medium and short distances you'll run into problems.

 

 

... but I can't believe it's entirely responsible for the soft corners.

Maybe you're right, because an improperly working stabiliser should impair the whole frame's sharpness evenly, not just in the corners ... but why don't you simply try it? Use a tripod and disable the stabiliser, then you'll know for sure.

[michali]

I've just been on to DP Review.com wbesite and had a look at their Sony A77 review.

Looking at Menu settings page I see that on Page 5 of the camera menu there's a setting:

"Lens Comp, Chro Aber"

Is this set to Auto or Off? I think this should be set to Off. That's assuming you haven't done so already....

 

I would also set the settings above and below this one, "Lens Comp: Shading" & "Lens Comp: Distortion" to Off as well.

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[jaay]

Those settings you refer to we're all turned off - and even if left on they don't affect the RAW files anyway.

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[Paolo.Battista]

I use the pre asph version of 90 Summicron-R on Ricoh GXR, Leica Digilux 3 and several Olypus bodies. It's really sharp, on the GXR it so sharp starting from f:4 that for some photos you could like to "unsharp" it a little.

The APO version should be even sharper, and, at least in the center of the frame, it should almost outresolve even the 24 Mp sensor. So I think that's better to check the whole shooting process if even centre performance is not up to your expectations.

Anyway, on the Ricoh GXR I have no problems with Leica R lenses down to 35 mm.

Under 35 mm I tired only more modern lenses or the Nikkor AF 20 f:2,8 and Olympus OM 24 f:28. The Nikkor perferoms wonderfully, the Olympus has less resolving power than the Nikkor but has wondrful colors and it's great at f:5,6 or F:8 for shooting people.

Anyway, if you check Photozone that's doing some tests with Nex-7 now, you will see that the corner problem is frequently present with wide lenses that are not of the very last aspherical design.