50mm vs. 50mm

RezaLoghme · Jun 4, 2025

I’m debating the real-world differences between the Leica 50mm Summilux-M stopped down to f/2.0 and the Leica 50mm Summicron-M shot wide open at f/2.0.

Specifically, when viewing images on a high-resolution screen at 100% zoom, how noticeable are the differences in:

Sharpness (center vs. edges)
Contrast and micro-contrast
Bokeh quality and rendering
Color rendition and tonal character

Is the Summicron noticeably crisper and more clinical, while the Summilux delivers a warmer, more “organic” look? Or are these distinctions subtle enough to be negligible for most practical uses?

Would appreciate any real-world experience or sample comparisons if you have them.

Thanks!

Kodachromeguy · Jun 4, 2025

Which versions of the Summilux versus which version of the Summicron? Without specifying, you won't get useful data.

RezaLoghme · Jun 4, 2025

Ah, right. Let's say lenses of the same era of course.

wiltw · Jun 4, 2025

Few generalizations can be made, conclusions only come from objective testing data (measureing resolution at diffetrent levels of contrast).

Generalization: lenses generally perform better NOT 'wide open' but 'stopped down' -1EV or -2EV

So the Summicron wide open at f/2 performing better than Summilux stopped down to f/2?...only lens testi m easurement will know for sure. It might, it might not!

Paul Howell · Jun 4, 2025

In the day lens were tested with microfiche with a LPM of around 800. As Tmax 100 at 200LPM I doubt that in terms of resolution you will see any difference between the 2, the more modern of the 2 may have better coating, less flare and improved contrast.

Don_ih · Jun 4, 2025

RezaLoghme said:
I’m debating the real-world differences between the Leica 50mm Summilux-M stopped down to f/2.0 and the Leica 50mm Summicron-M shot wide open at f/2.0.

There are no real-world differences. In the real world, lenses are used to take photos. Same focal length at same aperture is 100% the same in the "real world".

RezaLoghme · Jun 5, 2025

Don_ih said:
There are no real-world differences. In the real world, lenses are used to take photos. Same focal length at same aperture is 100% the same in the "real world".

Ok I am deciding between the two lenses, but as I dont really need the large aperture with its small DoF...maybe the -cron is "good enough" then.

RalphLambrecht · Jun 5, 2025

RezaLoghme said:
Ok I am deciding between the two lenses, but as I dont really need the large aperture with its small DoF...maybe the -cron is "good enough" then.

definately good enough. I don't know exactly how this works with Leica lenses but I always felt that my Nikon 50mm f/2 was just a little sharper wide open than my Nikon 50mm f/1.4 at f/2 but ,in any case, hardly any difference.

RezaLoghme · Jun 5, 2025

Picking the -cron instead of the -lux does not earn you any bragging rights on forums though.

grain elevator · Jun 5, 2025

In many systems, the faster lenses are intended for reportage and as such may have a less even plane of focus, more fall-off in light and sharpness, (very often) more distortion, or compromises on other such metrics, compared to the slower ones. I'm not sure about the specific lenses you mention, but these are factors to research and consider.

RezaLoghme · Jun 5, 2025

Given that I mostly shoot with zone focusing and often stop down for depth of field control, I’m starting to think I might not need the faster Summilux after all.

The Summicron at f/2.0 or stopped down will likely deliver everything I want in sharpness and character, especially for street and documentary styles where precise focus at wider apertures is less critical.

Would love to hear if others have felt the same—has zone focusing made you question the value of faster lenses like the Summilux?

grain elevator · Jun 5, 2025

RezaLoghme said:
Picking the -cron instead of the -lux does not earn you any bragging rights on forums though.

Oh and it absolutely does. Some of us lowly plebs use non-leica lenses, you can feel superior to us even with a lowly Elmar.

Saganich · Jun 5, 2025

I don't think this way anymore about lenses that have been kicking around the world awhile because lenses can have idiopathic issues introduced over the years while others seem to improve with age and 'to death do us part'... you can't tell until you work with them awhile. I've had a few 50 Lux and Cron's over the years all from the same era because I like the 0.7m focus and adjust my RF to suite and not two were the same regarding the list specified in the OP. I will say that IMO the 50 Lux's with built in hood has a bit more contrast than the 50 Cron with external hood. In the real world... exemplary example of either lens are harder to get then you think and if you find one you will be happy nailing the focus at F2 and won't care about anything much else.

RezaLoghme · Jun 5, 2025

Lenses "seem to improve with age"?

50mm vs. 50mm

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