Leica S2 Lens Sharpness Test

[dougpeterson]

Full disclosure: We are a Leica dealer.

At our December 3rd Leica Open House (and the morning after) we had an opportunity to put a production S2 through it's paces for the first time. While the firmware/software was not finalized and contained some minor glitches (which is standard for a camera not yet shipping) we were very glad to be able to collect real world samples. Among other tests we tested the 70mm and 180mm at each available aperture*.

Mirror up was used on a heavy tripod and the very neat self-timer-plus-MUP function was used whereby you push the shutter release and the mirror goes up, waits for mirror vibration to reduce and then takes the exposure. Aperture priority metering was used, and the images were captured as quickly as a careful workflow and the buffer allowed. The camera (i.e. the aperture) was controlled by the computer using Leica's Image Shuttle program (still in beta).

Focus in the image of the cruise ship is a bit closer to the camera than you'd expect (only visible at f/3.5-f/4.5) given that we used the AF on the cruise ship itself (and forced the camera to find focus starting completely out of focus).

*One of the firmware/software glitches we experienced was that when the 180mm lens was set to above f/13.5 that the metadata would be recorded correctly, the camera LCD, but the actual aperture opening would be f/13.5. So those files were excluded to avoid confusion.

Below is a summary of the tests. The full test and raw files can be found at our Leica Test Page.




Doug Peterson (e-mail Me)
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[Mike M]

Doug, Thanks very much for the files!

There is one thing in particular that really excites me about the S2 and is what I feel makes it different from it's competition. The transitions between in-focus and out-of-focus parts of the images are super smooth. Whenever I look at an image, I try to do a quick glance from casual viewing distance to determine the exact point of focus or position of the focal plane. It's often very difficult to determine the exact placement when doing a casual view of the S2 files. The transitions are so smooth that even slightly out of focus parts of the image will appear sharp at casual viewing. This is something that I've missed since we all switched away from film...and haven't really seen it for about 10 years. Not sure if that's what you may have been alluding to with the "DOF?" comment in the photo. I see a similar thing in DFarkas, Dpreview and also the Get DPI tests so it's leading me to believe there is a pattern. I'm wondering if this has to do with the integrated design that has allowed for the removal of many filters that might normally be between the lens and sensor in typical 35mm dslrs or possibly protective filters on normal digital backs?

 

[thomas]

I looked through the images and first of all in C1 the files look harsh; especially with the high amount of sharpening with the C1 "pre-sharpening 1" preset.
Lightroom 3 Beta and RAW Developer look much better for my taste (less image artifacts).

With the 70mm IQ is getting better from wide open to f6.7 (which seems to be the best aperture).
Corner sharpness seems to be good at f4 maybe already at f3.4 … but certainly not wide open at f2.5 or f2.8.

I am having a hard time with sharpening… the files do not respond as I would expect they should. Something to get used to maybe.
I tried smaller radius + high amount of sharpening, higher radius + smaller of sharpening played around with threshold… but I couldn't find a setting that would satisfy me.
In LR 3 amount: 36 | radius 0.5 | detail: 22 seems to be a good starting point (regarding the 70mm at f8).
Focal Blade does a better job though.

I can't help it but my impression is there's nothing special with the S2 lenses in conjunction with the S2 sensor with regard to resolution or sharpness.
I looked through some comparable captures with my Contax 80mm at f8 and the P45 and I can't find a noticeable advantage in the S2 files.
Rather the contrary: with the P45 in C1 I can create a finer, but at the same time crisper look.
Hard to tell without side-by-side comparison, but that's my impression.
Maybe it has to do with the microlenses, I don't know…

 

[georgl]

Thanks for the test!

But I think DoF is critical here, I've tried similar tests and ran into the very same problems. The open-aperture samples are simply not in focus over the whole image.

 

[dfarkas]

Thanks for the test!

But I think DoF is critical here, I've tried similar tests and ran into the very same problems. The open-aperture samples are simply not in focus over the whole image.

Agreed. I ran similar tests with the S2 myself and found that even at close-to-inifinity distances, there were still DoF issues if the test subjects weren't squared up relative to the plane of focus. Judging corner sharpness on a picture shot at an angle doesn't tell the whole story. Unfortunately, there just aren't a lot of brick walls big enough for inifnity testing.

David

 

[gogopix]

I looked through the images … but certainly not wide open at f2.5 or f2.8.

I looked through some comparable captures with my Contax 80mm at f8 and the P45 and I can't find a noticeable advantage in the S2 files.
Rather the contrary: with the P45 in C1 I can create a finer, but at the same time crisper look.
…

On first point, to me the wide open looks pretty good, maybe not crisp, but certainly has the detail. It seems, as with many lenses, the contrast is lower. Maybe part of the trade-off to keep the resolution wide open.

Your point about sharpening is critical, as this is the one are that CAN improve an otherwise ok image to give it some strength.

On the Contax comparison, well, no fair - you ARE talking one of the best

Victor

 

[dougpeterson]

Friendly note:

Please do not use Capture One 5.0.0 to view these images. Use LR Beta 3 or Capture One 5.0.1 (or higher if it is available when you read this).

5.0.0 shows some strange artifacts.


Doug Peterson (e-mail Me)
__________________
Head of Technical Services, Capture Integration
Phase One, Leaf, Cambo, Canon, Apple, Profoto, Eizo & More
National: 877.217.9870 *| *Cell: 740.707.2183
Newsletter: Read Latest or Sign Up
RSS Feed: Subscribe
Buy Capture One at 10% off
Personal Work