Lens and Sensor Optimization: What Optimizations?

[saptarshi]

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Hello,

I'm in the queue to get the 35 Summicron for the SL (though i sold the SL). But i'll hold on to it since the near future has some L-mount surprises: Sigma's Foveon and the SL2. But I've heard that the SL lenses are optimized for the SL sensor. What exactly does this mean? In other words, when camera manufacturers buy the same sensor (i understand Panasonic and Leica will use the same sensor in the SL2 and the S1R?), how do the engineers optimzie the sensor for the lenses? Or are the lenses optimized for the sensor?

What degradation would i see if the 35mm Leica lens were used on say  the S1R ?

Thanks much in advance and a photo (San Francisco Airport) too.

 

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[thighslapper]

err ..... partly correct .....

The lenses incorporate firmware adjustments to correct some residual aberrations .... but that is passed through direct to whatever processor you use in the RAW file. I'm sure this is part of the L-Alliance specifications and should work with any lens/body combination.

The SL sensor is optimised for M-Mount lenses to ensure backward compatibility .... and any lens recognised with 6 bit coding should have some adjustment applied to the RAW file to compensate for any issues ...... and the same probably with a R-ROM lenses where the camera can recognise the lens. 

Any native L-Mount lens .... whatever the manufacturer .... should produce basically the same images if used on any L-Mount body ..... irrespective of the sensor (and that includes the APS-C CL ... although you will only get a part of the FF view as the sensor is smaller). Any differences between various L lenses/bodies are down to functionality .... such as how MF is implemented, ability to use teleconverters and other adapters etc. etc. 

The 35/2 SL on the SR1 should work exactly as on the SL .... or SL2. Whatever sensor Leica put in the SL2 is immaterial ..... it will probably either be a derivative of the one used in the Q and SR1 modified to give good results with M lenses ...... or an entirely custom sensor.

Panasonic took 2-3 years to design, build and produce the S1R and S1 whilst Leica have been farting around for 4  years on an upgrade. That either means they have been doing something quite revolutionary which has taken time ..... or they have had a lot of problems implementing something...... probably due to the processing power required for fast AF, IBIS (if included) and heat issues shoving all those pixels about. I bet they designed the body first and have found it runs like a furnace with all the electronics crammed into it .....

Edited August 7, 2019 by thighslapper

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[saptarshi]

22 minutes ago, thighslapper said:

e one used in the Q and SR1 modified to give good results with M lenses

I'm curious about this. What modifications do engineers make to  sensors to give "good results with M lenses"

 

[thighslapper]

1. Shallow sensor wells .... at least that was one solution on the M240 .... not sure if carried over the the M10

2. Microlenses in the periphery designed with M lenses in mind that have very oblique ray paths. (https://www.michelebelloni.com/the-leica-m-sensor/)

3. Thin sensor cover ...... usually <1mm.

The latter seems to be the most important in getting good M lens performance. 

[Jeff S]

1 hour ago, thighslapper said:

err ..... partly correct .....

The lenses incorporate firmware adjustments to correct some residual aberrations .... but that is passed through direct to whatever processor you use in the RAW file. I'm sure this is part of the L-Alliance specifications and should work with any lens/body combination.

The SL sensor is optimised for M-Mount lenses to ensure backward compatibility .... and any lens recognised with 6 bit coding should have some adjustment applied to the RAW file to compensate for any issues ...... and the same probably with a R-ROM lenses where the camera can recognise the lens. 

Any native L-Mount lens .... whatever the manufacturer .... should produce basically the same images if used on any L-Mount body ..... irrespective of the sensor (and that includes the APS-C CL ... although you will only get a part of the FF view as the sensor is smaller). Any differences between various L lenses/bodies are down to functionality .... such as how MF is implemented, ability to use teleconverters and other adapters etc. etc. 

The 35/2 SL on the SR1 should work exactly as on the SL .... or SL2. Whatever sensor Leica put in the SL2 is immaterial ..... it will probably either be a derivative of the one used in the Q and SR1 modified to give good results with M lenses ...... or an entirely custom sensor.

Panasonic took 2-3 years to design, build and produce the S1R and S1 whilst Leica have been farting around for 4  years on an upgrade. That either means they have been doing something quite revolutionary which has taken time ..... or they have had a lot of problems implementing something...... probably due to the processing power required for fast AF, IBIS (if included) and heat issues shoving all those pixels about. I bet they designed the body first and have found it runs like a furnace with all the electronics crammed into it .....

Four years has been the norm for most Leica major product upgrades for several generations now, with the M, with the S and now likely with the SL.  Hardly a surprise. Dr. K did indicate that 3-4 years, or longer, was possible, depending on how aggressive the changes, but his interview was already near the 3 year point and Leica had mostly moved off what seemed to be the prior 3 year release cycles.

Jeff

[scott kirkpatrick]

There are examples in this forum of excellent results with SL lenses (all three zooms and SL-Summicrons including the 35) when used on the S1 and S1R platform.  At webscale they look great, and in some cases you can follow the images to their originals on Flickr or the like and download them for a closer look.  An eventual SL2 sensor at the full 48MPx resolution will probably have thinner cover glass, which is especially helpful for M lenses but enhances edge quality for all lenses.  So I don't think there is a problem.  Various Leica executives have stated that the lenses Leica sells today are capable of resolving up to the resolution required for 100 MPx sensors in the future.

On the other hand, the speculations about when each new generation will be announced and whether it will ship in volume or dribble out in tiny bursts in different markets is just a pleasant recreational exercise in Leica history indulged in by those who have lived it for a while as customers.

 

[Conrad69]

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To answer OP's question, the sensor should be considered as an optical element. Why? Because it does not consist solely of light sensitive "pixels". On top of the pixels a micro lens array is placed (to maximize the amount of light falling on each pixel). The next layer is a thin sheet of glass that serves as protection, IR filter, and creates stand-off distance for dust.

It is especially the glass layer that has impact on optical design. Without taking it into account, it will create spherical aberration. Unless it is very thin, or the lens is image side telecentric. This is the main reason adapted lenses can perform badly when used on digital. Sony has a ~3 mm thicness, m43 has even 4 mm. Strong non-telecentric designs like Leica M wide angles will not by far perform as well on those cameras, as they are theoretically capable.

With the L mount, also the stack thickness is specified. I do not know the exact thickness, but it will surely be less than 1 mm. This is to be able to deliver high performance with M lenses, but also makes the system better for adapting older lenses than any other system. The price you pay is a significantly higher visibility of dust on the sensor.

Then Sigma. They offer the same lenses for different systems. How? They build image side telecentric lenses. That's also the reason (which hardly gets any mention in public) the multi-mount designs are so big.

Hope this clarifies a bit.

[saptarshi]

Much appreciate this detailed answer. Thanks much

[CVickery]

On 8/11/2019 at 3:25 AM, Conrad69 said:

To answer OP's question, the sensor should be considered as an optical element. Why? Because it does not consist solely of light sensitive "pixels". On top of the pixels a micro lens array is placed (to maximize the amount of light falling on each pixel). The next layer is a thin sheet of glass that serves as protection, IR filter, and creates stand-off distance for dust.

It is especially the glass layer that has impact on optical design. Without taking it into account, it will create spherical aberration. Unless it is very thin, or the lens is image side telecentric. This is the main reason adapted lenses can perform badly when used on digital. Sony has a ~3 mm thicness, m43 has even 4 mm. Strong non-telecentric designs like Leica M wide angles will not by far perform as well on those cameras, as they are theoretically capable.

With the L mount, also the stack thickness is specified. I do not know the exact thickness, but it will surely be less than 1 mm. This is to be able to deliver high performance with M lenses, but also makes the system better for adapting older lenses than any other system. The price you pay is a significantly higher visibility of dust on the sensor.

Then Sigma. They offer the same lenses for different systems. How? They build image side telecentric lenses. That's also the reason (which hardly gets any mention in public) the multi-mount designs are so big.

Hope this clarifies a bit.

Great summary Conrad69, but I wonder about your statement on the L mount specifying the stack thickness. Have you seen anything official on this? The few comments that I've seen regarding using M-mount lenses with the Panasonic S1 and S1r  seem to indicate somewhat poorer performance than the M series or the SL. A thicker stack would be the likely culprit.

[thighslapper]

10 hours ago, CVickery said:

Great summary Conrad69, but I wonder about your statement on the L mount specifying the stack thickness. Have you seen anything official on this? The few comments that I've seen regarding using M-mount lenses with the Panasonic S1 and S1r  seem to indicate somewhat poorer performance than the M series or the SL. A thicker stack would be the likely culprit.

I'm sure that in an interview with Panasonics CEO it was stated that the 'official' collaboration involved the 'mount specifications only' by which I assume he meant the physical dimensions and electrical connectivity. The consideration of any optical consequences is entirely up to the producer using the mount. Panasonic will have tuned their sensor to function well with native L mount lenses. I doubt if they care at all about M mount performance. 

[scott kirkpatrick]

Jono Slack quotes Leica execs' statements about the glass thickness used in Leica products and their best guess about the thickness seen in the recent Panasonic S1s.  I've read the 3 mm and 4 mm figures elsewhere.  Roger Cicala, for example, cites these somewhere.

[jonoslack]

18 hours ago, CVickery said:

Great summary Conrad69, but I wonder about your statement on the L mount specifying the stack thickness. Have you seen anything official on this? The few comments that I've seen regarding using M-mount lenses with the Panasonic S1 and S1r  seem to indicate somewhat poorer performance than the M series or the SL. A thicker stack would be the likely culprit.

HI There

As I understand it the L mount specification DOES mention the stack thickness, but there is flexibility there because of the requirements of different aspects (video for example, M lenses for another)