From Fujifilm to Leica

[jaapv]

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That has little to do with it. The CL sensor has a filter stack and microlenses adapted to legacy M lenses, and the lenses under discussion here are not ones that give much edge smearing on Sony cameras -even unmodified- anyway. ( a modern 24, and 35 mm lenses)

 

We are talking about LENS aberrations, and those are cropped off by simple geometry on the smaller sensor, leaving the higher corrected center part as an image. That elevates these lenses that are all three known for weaker corners.

[lct]

I don't think so. The CL's sensor is designed for TL lenses in the first place so compromises have to be made for M lenses accordingly. What makes me suspect that the sensor filter of the CL is thicker is also that i got less moiré problems with it than with my other "thin filter" cameras an that the CL needs more sharpening in PP than the latters.

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[M.piras]

Good morning ICT (sorry this night i wrote wrong your name as “ICL”) could be interesting to understand what do you intend for Thicker sensor, do you mean the focus plane is closest to the lens?try to explain better what is your impression, i’m not telling you are wrong just it seems more for me that there is something wrong on your sensor. I tryed 3 different CL before buy mine all with same behaviour. I think is important to understand your point of view, because is a different experience from all the others. I know for sure some m9 have a problem on the positioning of the sensor, could be your sensor is not perfectly allineated, so the focus plane is wrong, lens got a shock and some elements moved giving the problem on the borders.

Theo

[jaapv]

No, it is not the sensor positioning. The problem with the Sony A7 is that it has a pronounced Anti-Aliasing filter, which will smear the corners of images taken with non-telecentric wideangles -broadly speaking-, like many Leica M ones. Mr. LCT has had the filter removed from his Sony camera by the firm Kolari (or, rather, replaced by a clear filter) and is extremely happy with the result. However, as the microlenses are not modified, the sensor is still suboptimal. But it will take improved images with Leica wideangles, especially older 28,24 and 21 ones.

 

All this has nothing to do with the cropping of the coverage on an APS-C sensor, as you correctly mentioned.

I agree that there is something strange going on with that CL.

[jaapv]

I don't think so. The CL's sensor is designed for TL lenses in the first place so compromises have to be made for M lenses accordingly. What makes me suspect that the sensor filter of the CL is thicker is also that i got less moiré problems with it than with my other "thin filter" cameras an that the CL needs more sharpening in PP than the latters.

Hmmm, I have been fighting colour aliasing a few times already on the CL. More so than my M240.

[lct]

Good morning ICT (sorry this night i wrote wrong your name as “ICL”) could be interesting to understand what do you intend for Thicker sensor, do you mean the focus plane is closest to the lens?try to explain better what is your impression, i’m not telling you are wrong just it seems more for me that there is something wrong on your sensor. I tryed 3 different CL before buy mine all with same behaviour. I think is important to understand your point of view, because is a different experience from all the others. I know for sure some m9 have a problem on the positioning of the sensor, could be your sensor is not perfectly allineated, so the focus plane is wrong, lens got a shock and some elements moved giving the problem on the borders.

Theo

 

 

Hi Theo, my dealer has tried two different CL bodies before mine which works like a charm as well as my (too) many M and R lenses thankfully. Now a bit of modern history will help me to explain if you don't mind. What gave the M8 its famous acutance was its very thin sensor filter (aka sensor stack). IR correction was also sub par then hence the necessity to use external IR-cut filters, you will recall it if you were born to photography yet. Just kidding. After that, digital M bodies have used slightly thicker sensor filters but they were designed for M lenses only so they did keep an optimal compatibility with same lenses, even if they don't beat the M8 at acutance IMHO. Anyway, then came Leica mirrorless cameras like SL, TL and CL which were not designed for M lenses in the first place but for L ones basically. They had also to work fine with M lenses and in fact that's what they do but this dual use of M and L lenses (also R ones but this is another story) implies some compromises obviously. Among them, i suspect the CL's sensor filter is somewhat thicker but it's just a guess from my part in trying to explain why at fast apertures, the CL with M lenses gives generally softer results at corners and edges than my M8.2, M240 and other thin filter cameras like my A7s mod besides my Ricoh GXR that i did not compare so far. Such a softness is not huge though and a bit of extra sharpening in PP helps to reduce it generally. Compared to my Fuji X-E2, the digital CL remains sharper at corners and edges anyway, reason why i bought it and the poor Fuji is gathering dust in a drawer now.

Edited September 22, 2018 by lct

[jaapv]

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Hi Theo, my dealer has tried two different CL bodies before mine which works like a charm as well as my (too) many M and R lenses thankfully. Now a bit of modern history will help me to explain if you don't mind. What gave the M8 its famous acutance was its very thin sensor filter (aka sensor stack). IR correction was also sub par then hence the necessity to use external IR-cut filters, you will recall it if you were born to photography yet. Just kidding. After that, digital M bodies have used slightly thicker sensor filters but they were designed for M lenses only so they did keep an optimal compatibility with same lenses, even if they don't beat the M8 at acutance IMHO. Anyway, then came Leica mirrorless cameras like SL, TL and CL which were not designed for M lenses  in the first place but for L ones basically. They had also to work fine with M lenses and in fact that's what they do but this dual use of M and L lenses (also R ones but this is another story) implies some compromises obviously. Among them, i suspect the CL's sensor filter is somewhat thicker but it's just a guess from my part in trying to explain why at fast apertures, the CL with M lenses gives generally softer results at corners and edges than my M8.2, M240 and other thin filter cameras like my A7s mod besides my Ricoh GXR that i did not compare so far. Such a softness is not huge though and a bit of extra sharpening in PP helps to reduce it generally. Compared to my Fuji X-E2, the digital CL remains sharper at corners and edges anyway, reason why i bought it and the poor Fuji is gathering dust in a drawer now.

This is completely incorrect; the thickness of the IR filter (not the filter stack - Leica cameras have no AA  filter) has mainly to do with colour shifts towards the corners. The incidence angle problem is  addressed through special microlens designs. Leica went to great trouble - and has publicly said so- to ensure that the full- frame cameras and now the CL have steep-angle-acceptance microlenses to have full retro-compatability with legacy M and R lenses. Reason to position the CL as a fully capable M and R  mount camera by providing an active adapter. Even promoted by selling it as a bundle on some markets.

Other brands, like Sony, lack this design - obviously. It helps, though, to remove the AA filter from those cameras, which does have an impact on corner sharpness.

[ramarren]

I'm not going to get into this interminable debate about sensor stack thickness, blah blah blah, because there simply isn't enough information available AND I'm not a electrical engineer creditable with imager sensor design. Are any of you debaters qualified as EE sensor designers?

 

BUT: The sensor is not designed for the TL lenses. The TL lenses are designed for the sensor. The difference between the Leica sensors and those of most all other manufacturers is that Leica specifies the sensors they use to accommodate ALL of their lens lines well, and then provides specific lens profiles to help the lenses along for those that were not designed for the sensors. The TL (and SL) series lenses simply require less profiling in that respect, and those lens designs were intended to be completed with software image correction from the get go, not as a corrective measure after the fact.

 

Beyond that, I believe only the results I see with my own eyes and with my own testing. I get excellent performance with the CL and MY lenses that matches, to a very high fidelity, the image performance I get with the SAME lenses used on the M-D 262 when cropped to the APS-C format. With the lenses I mentioned before, the performance is an improvement on the M-D. The performance of all of these lenses used on the M-D, the SL, the M-P240, and the CL is better than what the same lenses performed like on the Sony A7 and NEX 6, and Olympus E-M1 and E-PL7. Those are the only things I can say with absolute surety. And I'm happy with it.

 

I'm no longer going to contribute to this senseless debate, as it is irrrelevant to my experience and testing.

[jaapv]

How true

[mdroe]

Can I thank everyone for contributing to the thread I started. The feedback has been illuminating and full of nuance, and taught me a lot about the state of knowledge regarding TL and M lenses on the CL body. I’m a purist at heart and have been wavering from CL/TL lens to CL/M lens to M body and lens! Ultimately I set out to consider what to buy with a gift from my grandmother, and still favour a CL + TL 11-23, an M 35 f1.4 or f2 for low light, and maybe a TL 60 for macro/short tele/portrait. I appreciate the TL 35 was designed for the CL but the lure of an M lens is strong for someone who has dreamed about them for 30 years. I will attend an upcoming Leica Akademie day at a U.K. store to trial all these alternatives and let you know the result! Matthew

Edited September 22, 2018 by mdroe

[ramarren]

 

The best thing about buying an M 35mm lens, even if you do buy a CL body and other lenses, is that if/when you decide to get a Leica M, you'll be able to use the same lens on both cameras. The minor differences in how the lens might perform on the CL vs M, other than the difference in field of view, are completely inconsequential: Nearly any Leica lens is an excellent performer and will make you happy. A fast M35 lens will be easy to focus, manually only on the CL, and if you give up Program and Shutter priority exposure modes, eh? So what?

 

If I'm typical of most Leica "purist" users (and I have to believe that I generally am), you'll mostly want manual focus used with manual or aperture priority exposure modes anyway. When I had the SL and its magnificent SL zoom lenses, I almost always used them in manual focus mode with aperture priority exposure anyway, switching to manual exposure for difficult situations, just like I use the M-D and now use the CL. It's my habit from 50 years of doing photography, and that kind of habit is very very hard to change at this point.

[jaapv]

Summicron-C 40, f 2.0, ISO 3200, 1/60th  Just a domestic shot I took yesterday

 

 

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[mdroe]

Thanks Ramarren and this was my thought too regarding the choice of an M35 over TL35, an opportunity to also buy an M body with access to FF when portability is not important! I’d be OK with the TL 11-23 (for only the CL) as for me landscape and city usually requires portability.

[mdroe]

Thank you for the lovely picture jaapv and yes, I haven’t forgotten your earlier comments on the 40mm f2.0; although I don’t know how to buy a good’n or where from? There are so many on eBay for example. Does the website contain any guides to buying bodies or lenses?

[ramarren]

Thanks Ramarren and this was my thought too regarding the choice of an M35 over TL35, an opportunity to also buy an M body with access to FF when portability is not important! I’d be OK with the TL 11-23 (for only the CL) as for me landscape and city usually requires portability.

Matthew,

 

I wouldn't worry about portability between the M and the CL very much. The CL body is very nearly the same length and width, only 4 mm shorter than a Leica M-D or M10 body. Any Leica M35 lens will only project out the front of the body by about 9mm more on the CL due to the adapter. The biggest difference between the two cameras on a 'portability' measure is that the Leica M body weighs about 200g more than the CL body. The difference between the two is quite honestly hardly even noticeable, depending on what lens you have fitted: These two cameras are a fine complement to each other because they're so close in size and ergonomics, when you set the CL up to match the M's ergonomics as closely as possible.

 

The main points of difference if choosing between them are:

 

- FF vs APS-C (different angle of view with the same focal lengths, different DoF characteristics, etc)

- EVF vs opto-mechanical viewfinder focusing mechanism

- broader lens adaptability and versatility for long lenses and close-up/macro work with the CL

- easier to see and focus viewfinder in bright sun with the M

- easier to achieve critical focus and see in dim circumstances with the CL

 

Each of those points has its advantage and disadvantage in use ... again, this is why the two cameras work so well together as complements. They're both great performers and produce outstanding photographs.

 

G

[jaapv]

Thank you for the lovely picture jaapv and yes, I haven’t forgotten your earlier comments on the 40mm f2.0; although I don’t know how to buy a good’n or where from? There are so many on eBay for example. Does the website contain any guides to buying bodies or lenses?

Buy from a trusted dealer.

[gyoung]

There has been extensive debate elsewhere about the effect of sensor stack thickness and design on short focal length lenses with high angles of incidence of the light rays to the stack. See particularly the Fred Miranda Sony forum, where the search for a good performing 35mm lens has been like that for the holy grail.

While the angle of the microlenses is of importance for many lenses, so too it seems that the thickness of the cover glass is significant with lenses which have curvature of field issues. If you have 4mm cover glass (as per Sony A7) the light rays striking it obliquely will be refracted to a greater degree than if yhe coverglass is 0.8mm (M9?). Thus for instance a 35mm Summicron asph performs particularly poorly on an A7 at the edges, it being possible to focus distant sunbjects at such different 'distances' on the focussing scale that even dof cant rescue the situation, its never possible to get centre and edges acceptably sharp at the same time, at any focus setting or aperture. I understand this isn't the case with the thinner cover glass of the M9 and other leica full frame cameras. Even on aps-c cameras with a thick cover glass (such as my Xpro2) this is still a problem which even the crop factor doesn't rescue, whereas on my Sony Nex 6 its much better as the camera has a much thinner sensor stack (the reasons for such inconsistency being known only to Sony). So I would expect the leica aps-c cameras to have problems in spite of crop UNLESS they have both angled microlenses as well as thinner coverglass.

As I understand it the Kolari mods to Sony full frame cameras are only to the coverglass and not any replacement of the microlenses. And this are only partially successful.

 

Gerry

[lct]

[...] If you have 4mm cover glass (as per Sony A7) the light rays striking it obliquely will be refracted to a greater degree than if yhe coverglass is 0.8mm (M9?) [...]

 

0.5 mm on M8 and 0.9 mm on M9 according to Lensrentals. Would be interesting to ask them if they know the thickness of the CL's sensor stack. More than 1.0 mm i suspect but i may be wrong. 

https://www.lensrentals.com/blog/2014/06/sensor-stack-thickness-when-does-it-matter/

[jaapv]

That is not the filter stack. that is the thickness of the IR filter, irrelevant in this discussion. You are confusing it with the AA filter, which is the one that the Kolari people removed from your Sony.

 

A filter stack consists of a number of layers: *

1. The AA filter. this is basically a piece of matte glass to prevent moiré and colour aliasing. This is responsible for corner smearing.

Some cameras, including Leica, don't use this filter, as it causes a general resolution loss of 20-30% As said, this was removed from your Sony. They didn't touch the rest.

2. The IR filter. This is the one that causes colour shifts towards the corners and edges. Leica is struggling with the thickness of this filter. It will have a minor effect on acuity.

3. The Bayer filter, which enables the camera to record colours. This produces a significant resolution loss and is not present on the monochrom cameras.  (or rather, replaced by a clear filter).

4. The microlens layer. These will cause -in conjunction with the sensels (pixels)- vignetting and resolution loss towards the corners. Leica uses specially designed microlenses to combat this problem.

5. The sensels. They will lose light and resolution for geometric reasons, and crosstalk will cost resolution and produce colour bleeding. Leica uses shallow sensels to reduce this effect. The size of the sensitive area will affect S/N ratio and sensitivity.

 

4 and 5 are, of course, technically not part of the filter array, but constitute the sensor.

 

So you see that the thickness of this whole array is not relevant, the results are determined by the combination of the various parts, with the AA filter and microlenses the main players.

 

All this has nothing to do with the corner sharpness of the image projected onto the sensor by the lens. A lens projection will inevitably deteriorate towards the edges. The more you crop the image, the better the lens will perform. That is why Full-Frame lenses will improve on an APS-C sensor. And that is what this discussion is about.

 

 

*)  Lens Rentals obviously only regards the AA filter and IR filter as the filter stack. As the Leica cameras do not have an AA filter, they will give the thickness of the IR filter only. (correctly, BTW).

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[lct]

That is not the filter stack. that is the thickness of the IR filter, irrelevant in this discussion. You are confusing it with the AA filter [...]

 

I don't think so. I referred to the filter stack above, neither the IR (you mean IR-cut i guess) nor the AA filter. Lensrentals don't refer to IR or AA either if i read them well. The question i'm raising is that of the thickness of the entire filter, not the presence or absence of such or such layer into it. This is what Lensrentals were measuring when they found 0.5mm for the M8 and 0.9mm for the M9 IINW. 

Edited September 23, 2018 by lct