Leica Wide M lenses on other FF brands

[Timmyjoe]

Would like to hear other's input on this. I've heard (though have not tried for myself) that Leica wide angle M lenses are less than stellar when mated with other brands of full frame digital camera bodies.

Years ago I worked in the motion picture camera field (service tech for Arriflex cameras) and I remember when all the full frame digital motion picture bodies were coming out, none of the beautiful old wide angle glass worked with them (Cooke Speed Panchros, Zeiss Primes, Schneiders). It had to do with the angle of the light coming off the back element of the lens, and how that would hit the outer most pixels of the camera sensor. Unlike film, the light had to come in at a nearly perpendicular angle for the sensor to pick it up properly.

I wonder if that is true with the wide angle Leica glass on cameras like the Sony A7 variants. Since the Leica M glass sits very close to the film plane (sensor) of the camera, this problem would be amplified, when comparing Leica M glass to most SLR lenses.

Anyway, was wondering what other folks thought about this. I've heard the Leica sensors have some kind of micro lenses on the outer most pixels to capture the light at severe angles, maybe the other manufacturers aren't designing those in.

Best,
-Tim

 

[KM-25]

Yes to the micro lenses, my M240 has them and I do believe the M9 does as well. My 35mm 1.4 asph on my friend's A7II was not good in the outer image circle until at least 5.6 but on the M240 is great at every aperture and spectacular from 2.8 on.

In my opinion, for exactly the reasons you cited of being so close to the film plane, non-micro lens sensors take lenses 35mm and wider to task in a big way.

 

[jaapv]

Well, it is not really non-micro lens; many, if not all sensors have microlenses, it depends on the way these lenses are implemented.

 

[rscheffler]

Yes, it is a problem, especially with the Sony a7 cameras, but also with various APS-C models, though to a less severe extent.

There are two image degradation problems. One is edge color shift, which is partly resolved with suitably designed microlenses, but is also a consequence of pixel size. The smaller the pixel, the greater the likelihood of color shift. This problem can be corrected later in software, which is the case with the Leica cameras. The other problem is sharpness degradation (smearing) towards the edges. It's due to a combination of factors - lens exit pupil distance (shorter is worse) and thickness of the sensor toppings (the glass over the actual sensor). The shorter the exit pupil distance and the thicker the glass, the worse the smearing becomes. Due to this, Leica's sensor's have very thin glass and the latest Leica lenses are less symmetrical in design to move the exit pupil farther away. It also helps if there isn't an AA filter. I'm not sure if a dust shake feature would also compound the problem.

There is a good series of posts about this at the Lensrentals blog, starting with this one.

You'll see mentioned in at least one of those articles a company called KolariVision. They do sensor glass replacements, such as IR and UV conversions. But they also have a service for replacing Sony a7 sensor glass with a thinner version, which as Lensrentals has shown in their tests, helps minimize the problem of edge smearing in the a7 cameras (though doesn't do anything about color shift).

If you want to see actual test images for yourself, I posted tests on my blog. That link is the a7S review which includes a direct comparison against the Leica M240, but I have tests for the other two a7 first generation cameras as well. You'll have to click on the link of a lens of interest, say the 28 Summicron, and it will take you to the download page for the zipped files, which include both the a7S and M240 sized to a7S native resolution.

 

[uhoh7]

Yes, as they say 🙂

A7 with Kolari sensor mod, where they remove the thick bit, brings that camera to near M240 level with most M Glass.

Cost is around 400USD

Here is 28 cron yesterday:


DSC09294 by unoh7, on Flickr

ZM 18 and SEM 21 are also very good, and all the 35s, even the skopar, are excellent. Cornerfix not needed.

Without the mod all A7s are meh with many M lenses.

However, new backlit sensor on A7r2 may change that 🙂

 

[Manuel Patino]

I thought I was the only one who found disappointing results using Leica M lenses adapted to M43 bodies. I have a Panasonic Lumix adapter and I mated the 50mm Lux ASPH f1.4 to my OM-D EM-1 camera. I thought I would get some wonderful images, but they were oh hum at best. For me, it's more difficult to focus the M mount lenses with the Oly body than with the RF M240... I tried other M mount lenses as well with similar disappointing results. They are not awful, but they are not satisfying either.

 

[YYV_146]

The modern Leica lenses will perform better than old, aspherical designs, even on un-modded A7 bodies. I maintain that corner sharpness at f1.4 and, to a lesser extent, f2 is inconsequential for practical photography. Fast apertures are used to isolate subjects, and as modern digital cameras go stopping down in any light is possible. Leica lenses are distinguished by size, bokeh, focus transition and many other things - corner sharpness is only one aspect.

I use the 35mm lux FLE, 21mm lux ASPH and 18mm SEM on the Sony A7 and A7s. Brick-wall results are perfectly acceptable at f2.8 for the first two and at F4.5 for the SEM (this is on the unmodified A7). On the Kolarivision mod corners improve by a stop uniformly, and becomes roughly on par with the M9.