what does mean to OPTIMIZE MY LENSES FOR THE USE WITH DIGITAL LEICA M CAMERAS?

[CS Gray]

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I read this on the Leica FAQ section, I just got a M10, I used to shoot a Leica M4P. I am buying M lenses so I want to know what the statement means before I buy any used lenses.

Thanks for your help. Here is the quote.

WHY SHOULD I OPTIMIZE MY LENSES FOR THE USE WITH DIGITAL LEICA M CAMERAS?

Due to the brilliant image performance as well as high resolution of the Leica M sensor even the smallest details are displayed rich in contrast.
When viewing the images on the computer screen at a 100% zoom they can easily be evaluated in a size equivalent to a 1,20m x 1,80m poster print.
In the analog photography this is only possible with an extensive amount of additional work.
That is the reason why the requirements for lenses in digital photography by far exceed those of analog photography.
In many cases this difference only becomes apparent when a lens is used on a digital camera for the first time and variances in the lens calibration become visible.
Especially lenses with a long focal length or a wide aperture benefit from a calibration since even slight miss adjustments become apparent due to the low depth of field.

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[Joakim]

Leica’s most modern lenses are designed for digital sensors rather than film so in general you can expect better results with those lenses on the M10. 

At the same time many of us are enjoying using somewhat older or much older lenses as well on our digital M cameras because of their rendering, small size or whatever the reason might be so there is no one truth here on what is best other than that Leica naturally want you to buy new lenses from them rather than used ones from the second hand market.

 

Edited September 10, 2019 by Joakim

[jaapv]

Even so, "lesser" lenses will perform better on a better sensor. This is not a weakest link situation.

[CS Gray]

5 minutes ago, Joakim said:

Leica’s most modern lenses are designed for digital sensors rather than film so in general you can expect better results with those lenses on the M10. 

At the same time many of us are enjoying using somewhat older or much older lenses as well on our digital M cameras because of their rendering, small size or whatever the reason might be so there is no one truth here on what is best other than that Leica naturally want you to buy new lenses from them rather than used ones from the second hand market.

 

 

2 minutes ago, jaapv said:

Even so, "lesser" lenses will perform better on a better sensor. This is not a weakest link situation.

Thank you both, 

Chris

[dau]

The text you quoted above appears to be about calibrating the lenses.

A lens which makes sharp pictures on film might seem a bit soft when used with a digital camera. This is mostly due to digital images usually being viewed at larger magnifications. However, part of the difference seems to derive from the fact that the emulsion on the film has a greater depth than the corresponding layer of the sensor. Hence, a lens which makes sharp pictures on film might appear to be off when used with a sensor. Leica advises to re-calibrate older lenses that have been used with film only before in order to compensate for the more critical focusing with digital cameras.

[Ecar]

Yes, digital basically requires tighter tolerances. This is also made possible by better calibration equipment, which IIRC Leica has been investing in since shortly after the M8 was announced. Although it's fair to say that a competent technician equipped with a LV-enabled camera should be able to arrive at the same result, without needing a collimator.

[pico]

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From one who does not pixel-peep because it is irrelevant to aesthetics, I am entirely satisfied with my so-called analog lenses on M10 and M9 bodies. 1:1 viewing is for nerds, forensic mavens and spooks,

Edited September 10, 2019 by pico

[dau]

From one who at times peeps pixels and at other times does not.

The importance of aesthetics can depend on a number of things, most notably on the artist's intent and on the subject. Architecture, technical subjects but also living things and even portraits may or may not require the maximal archievable sharpness without actually being forensic or spooky.

In the case where photography is indifferent to aesthetics (or aesthetics irrelevant to photography), pixel peeping might be the very thing to do. A lens of adequate focal lens might have been unavailable at the time the photograph was taken, or a larger format might not have been practical. I call to mind one Oskar Barnack with his pigmy camera. That one certainly was - well, perhaps not pixel peeping but certainly grain peeping.

[pico]

17 minutes ago, dau said:

[...]
The importance of aesthetics can depend on a number of things, most notably on the artist's intent and on the subject. Architecture, technical subjects but also living things and even portraits may or may not require the maximal archievable sharpness without actually being forensic or spooky.

My point, exactly.

[Ko.Fe.]

Just as many I checked some film only Leitz made lenses on digital M.

Most of the worked right away. Some where showing focus shift.

This is the only optimization I would take as real. Any digital M out resolved 135 film. So some focus shifting was not visible on film; but easier to catch and correct with digital.

[Mute-on]

This is mostly about focusing accuracy, not lens capability. 

The digital format is not forgiving of small errors in focusing with the rangefinder mechanism. This is different from film which has both the film thickness, and some potential resolution differences, to absorb any focusing error. 

Optimising means adjusting the lens and camera together to ensure optimal focus accuracy. It will not make a lens perform any better than it was originally designed to. 

Edited September 11, 2019 by Mute-on

[250swb]

6 hours ago, Mute-on said:

 

Optimising means adjusting the lens and camera together to their own separate benchmarks to ensure optimal focus accuracy. It will not make a lens perform any better than it was originally designed to. 

Fixed that for you.

[jaapv]

8 hours ago, Ko.Fe. said:

Just as many I checked some film only Leitz made lenses on digital M.

Most of the worked right away. Some where showing focus shift.

This is the only optimization I would take as real. Any digital M out resolved 135 film. So some focus shifting was not visible on film; but easier to catch and correct with digital.

Focus shift cannot be optimized. It is a property of the lens. The only thing one can do is adjust the lens for optimal focus at a given aperture.

[01af]

Am 10.9.2019 um 19:04 schrieb CS Gray:

... so I want to know what the statement means ...

It's mostly bullshit.

Digital sensors are more sensitive than film to all kinds of ... um, deviations—so adjusting the lens to the camera needs to be done more precisely, more carefully. But the optimum of adjustment for digital is no different from the optimum for film. It's just the precision of the adjustment required. So if the lens is perfectly adjusted for use on film, it also is perfectly adjusted for use on digital (and vice versa).

[TomB_tx]

9 minutes ago, 01af said:

It's mostly bullshit.

Digital sensors are more sensitive than film to all kinds of ... um, deviations—so adjusting the lens to the camera needs to be done more precisely, more carefully. But the optimum of adjustment for digital is no different from the optimum for film. It's just the precision of the adjustment required. So if the lens is perfectly adjusted for use on film, it also is perfectly adjusted for use on digital (and vice versa).

Fully agree. One other factor is that the modern tendency to shoot fast lenses wide open much of the time, when historically the speed was needed only in dim light due to the limited speed of film. Even with fast lenses this meant a bit of motion blur was common, and it wasn’t expected that images would be as sharp in those circumstances. So, knowing all fast lenses had some focus shift stopping down, they were optimized for best focus stopped down a stop or so, to be best at more commonly used apertures. According to DAG even Summicrons were focus optimized for f2.8 in past years.

So not only is a digital sensor not as focus-forgiving as film, but people look more critically at high magnification, and shoot more often wide open, and expect perfect sharpness. Thus the shift to better optimize performance and focus wide open. I have had DAG calibrate focus on a few lenses like this myself.

[ChicagoMatthew]

5 hours ago, TomB_tx said:

Fully agree. One other factor is that the modern tendency to shoot fast lenses wide open much of the time, when historically the speed was needed only in dim light due to the limited speed of film. Even with fast lenses this meant a bit of motion blur was common, and it wasn’t expected that images would be as sharp in those circumstances. So, knowing all fast lenses had some focus shift stopping down, they were optimized for best focus stopped down a stop or so, to be best at more commonly used apertures. According to DAG even Summicrons were focus optimized for f2.8 in past years.

So not only is a digital sensor not as focus-forgiving as film, but people look more critically at high magnification, and shoot more often wide open, and expect perfect sharpness. Thus the shift to better optimize performance and focus wide open. I have had DAG calibrate focus on a few lenses like this myself.

I like how you “fully agree”, and then make a totally contradictory response. 👏

[ChicagoMatthew]

I agree with most of the comments above, this is Leica explaining why your analog era lenses may not perform as well on the digital M. Mostly a calibration issue. 

I’m sure I’ll draw some ire for using “analog era”. 😐

[01af]

vor 10 Stunden schrieb TomB_tx:

... they were optimized for best focus stopped down a stop or so, to be best at more commonly used apertures.

They are still optimised this way today. Not to the best "at more commonly-used apertures" but to minimise focus-shift blur across the whole aperture scale. It made sense on film and it makes sense on digital.

Lenses get optimised for best focus at full aperture only on customer's request. Which makes sense only if you're going to use the lens at full aperture always and exclusively (which would be a stupid thing to do, in my opinion), and then it does so on film and on digital either. That's not specific to digital.

Edited September 12, 2019 by 01af

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Hallo,

Look here: Leica M

[CS Gray]

Thanks for all the great discussion. It makes sense to me now.

Chris

[Manicouagan1]

From my reading it seems that a M lens "designed for digital" is one designed with consideration of the infra red (IR) filter over the sensor which in the cases of Leica digital M camera is about 0.8 mm thick.   I would also assume that Leica "designed for digital" lenses are designed to work with Leica's approach to "microlenses."   Is my infrence is correct that Leicas combination of microlenses and IR filter thickness set limitations on lens designs ?    In my experience my lenses that were released prior to 2000 (24mm f2.8 ASPH, 35mm 1.4 ASPH, 90MM f2 APO) all work just fine across the entire field on the 24 megapixel cameras.   What can be expected if the lenses are mounted on a 41megapixel M10M or a 47 megapixel SL2 (via adapter)?