Tonal Curve of Leica M Monochrom

[Martin B]

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You could say that in an ideal world of very exact exposure of the film given the dynamic range of the scene in reality and the ideal development given that exposure to the film in that situation. Moreover, this ideal situation is very hard to reach on 35mm film, you would at least need 4*5 inch.

Also, I am not so sure whether you are comparing here with sensors with or without the Bayer filter

 

 

Me either and this is my experience too, which I cannot theoretically combine with MartinB's statement. And I wonder if MartinB has practical experience with the MM1. 

One has to consider the end-product too, is it paper or transparencies, like screen or slide. A transparency or good screen has one or two more stops to encompass the DR of reality.

In my poor technical wisdom the S-curve is just a way of forcing the dynamic range of reality into the dynamic range of the medium that is going to represent this reality in a reduced manner. 

So, stating that an S-curve is better than linear,... I don't know

 

As seen in one of my links above, the DR might depend on the sensor size - it is wider for medium formal digital sensors, but the film format does not play a role on the tonal latitude (it only affects the resolution of course). You don't change the chemical process by going from 35 mm B&W film to 4x5" film for example....it is still the same. Not sure how the Bayer filter will play a role in there either, please elaborate. 

 

Likely our responses crossed over, as I replied to giulioz, I have no practical experience with the MM. I used it once in a store for half an hour, but I never was able to compare or play with the images from this camera. But before doing an investment, I want to understand the benefits - and I am a technical guy, so the sensor is the heart of any kind of digital camera for me. I understand its limitations as expressed above, and I - again - don't say that film is per se better than digital. It is different, this is my point. And my question is how close can the MM really get to B&W film. Simple question, but doesn't seem a to have a straight forward answer. 

Your statement about the S curve is not fully correct regarding the physics of film. Check the double logarithmic scale of the S curve vs. linear plot in one of my links above. You can't change this. But you might be able with tricks to get close to the S endings of the film curve - this is pretty much the question I have. The S curve is better because this means in practical terms that for example twice the amount of light does not cause twice the brightness on film - but it does in a linear response from a digital sensor. This is very useful because highlights won't be as easily clipped with B&W film. The same is true for details in the shadows at the other end of the S curve - a digital sensor lacks the smooth curved slope at both ends of the tonal range spectrum. Hope this explains it better!

[Manolo Laguillo]

In traditional B/W film and paper procedures, the film's S shape is quite moderate, and the paper's S shape is quite steep, so that the latter compensates for the former.

 

The toe in the film's S shape is THE problem: that's the place where shadows belong, and 1/2 stop underexposure can ruin the subtle, and nice, differences between zones II and III, and zones III and IV. When this 1/2 stop of less light happens, instead of having II, III and IV, we will have I 1/2, II 1/2 and III 1/2. The problem is that shift from III to II 1/2, actually, because we enter into the toe, where the curve becomes more and more horizontal.

 

The shoulder in the film's S shape is not a problem. In modern films there is really no shoulder: if I remember well, T-Max accepts exposures going up until zones XI or even XII. The densities will be very high, but there is information available, I mean, those densities will deliver detail and separation on print if we work hard enough (dodging and burning in, water bath, soft developer, even pre-exposure of the paper...).

 

BTW, Ansel Adams, back in 1981, wrote about this difference between the films he had around the 30's and 40's, which had shoulder, and those he had 40 years later, which did not have it in the same extent.

 

With the Monochrom it's the same, but the other way round. We MUST expose so that there is NO CHANCE of losing details in the highlights. What the shadows were on B/W film, are now the highlights with the MM. The shadows will be there, available, and we shall bring them out by playing with the curve in PP. How? Easy: in order to enhance separation, we shall make the curve steeper in those lower parts, via the curve control, and after that we will, via the exposure controls, work in regaining the original densities in those parts.

 

Of course, if the scene's contrast is too high, the shadows will be unrecoverable, because we will have an ugly banding on them if we go too far in the lightening of them.

I am not interested in knowing how much this limit amounts (is it N+2, or perhaps N+3?), because I will know, by looking at the histogram, what is going to happen.

The limits we had to cope with when working with B/W film are still present. It's great to have limits! :-)

 

I've found that the MM delivers the same quality, in detail and tonality, I could achieve with 4x5'' negs printed on 20x24''. Actually, back in 2013 I reproduced with a M9 lots of my 4x5 negs, and printed those digital files with ink jet on 20x24'', and the end results were nearly undistinguishable from wet prints made by myself in the 80's, when I had a lab.

 

Bottom line: both the MM1 and MM2 deliver B/W pictures which are REALLY NICE, very flexible and maleable, with an unbelievable high potential in shadow recovery.

[Martin B]

In traditional B/W film and paper procedures, the film's S shape is quite moderate, and the paper's S shape is quite steep, so that the latter compensates for the former.

 

The toe in the film's S shape is THE problem: that's the place where shadows belong, and 1/2 stop underexposure can ruin the subtle, and nice, differences between zones II and III, and zones III and IV. When this 1/2 stop of less light happens, instead of having II, III and IV, we will have I 1/2, II 1/2 and III 1/2. The problem is that shift from III to II 1/2, actually, because we enter into the toe, where the curve becomes more and more horizontal.

 

The shoulder in the film's S shape is not a problem. In modern films there is really no shoulder: if I remember well, T-Max accepts exposures going up until zones XI or even XII. The densities will be very high, but there is information available, I mean, those densities will deliver detail and separation on print if we work hard enough (dodging and burning in, water bath, soft developer, even pre-exposure of the paper...).

 

BTW, Ansel Adams, back in 1981, wrote about this difference between the films he had around the 30's and 40's, which had shoulder, and those he had 40 years later, which did not have it in the same extent.

 

With the Monochrom it's the same, but the other way round. We MUST expose so that there is NO CHANCE of losing details in the highlights. What the shadows were on B/W film, are now the highlights with the MM. The shadows will be there, available, and we shall bring them out by playing with the curve in PP. How? Easy: in order to enhance separation, we shall make the curve steeper in those lower parts, via the curve control, and after that we will, via the exposure controls, work in regaining the original densities in those parts.

 

Of course, if the scene's contrast is too high, the shadows will be unrecoverable, because we will have an ugly banding on them if we go too far in the lightening of them.

I am not interested in knowing how much this limit amounts (is it N+2, or perhaps N+3?), because I will know, by looking at the histogram, what is going to happen.

The limits we had to cope with when working with B/W film are still present. It's great to have limits! :-)

 

I've found that the MM delivers the same quality, in detail and tonality, I could achieve with 4x5'' negs printed on 20x24''. Actually, back in 2013 I reproduced with a M9 lots of my 4x5 negs, and printed those digital files with ink jet on 20x24'', and the end results were nearly undistinguishable from wet prints made by myself in the 80's, when I had a lab.

 

Bottom line: both the MM1 and MM2 deliver B/W pictures which are REALLY NICE, very flexible and maleable, with an unbelievable high potential in shadow recovery.

 

Thanks for your reply, even I disagree a bit with its main message therein that film has no longer an S curve for the tonal response. That sounds like an excuse to make it fit to the limitation of the linear response of the digital sensor. I might be corrected here, but if so, please send me a link to any reputable site which describes what you are saying. I did nowhere find this information that newer film suddenly has a linear response. In fact, the S curve is an advantage for film to have as I pointed out earlier. The shoulders of the S curve in film extend about two stops (or zones) into the black and white - much better than digital - in theory at least. 

 

I definitely disagree with your last point that digital inkjet files are indistinguishable from silver gelatin / wet prints - I see exactly the opposite, and when I show my wet prints, I am always asked how I managed to get this different B&W look. When I answer that this comes directly from film, people are very surprised. So far I was unable to reproduce this look with my good inkjet printer on any kind of paper. Again, I am not saying that the digital is worse, it is just different. 

 

But I agree in your point regarding reproduction of details with an M camera compared to larger format negatives. I recently showed some of my silver gelatin prints in 11x14" size and was asked which kind of medium format camera I had used for this incredible sharpness....oh, well, it was my M6 . 

 

I totally believe that files from the MM cameras look excellent. Your point above is that they reproduce nearly exactly what film does. I state corrected if you show me proof that new film has no longer an S curve response and behaves linear as digital does. 

[jaapv]

Nops, this is not correct. B&W film gives you a tonal response in the zones 1-10. In the shadow and highlight ending, the response it non linear (ending of the S curve). Only in the grey zones the response is linear similar to the digital sensor. Any digital sensor only displays zones from 3-8 (that's why often bracketing is needed). The response is strictly linear - that's why you can get easily clipped highlights or pitch black unstructured shadows. Or in other words: The number of photons registered inside the photon wells of a digital sensor is always linear to the amount of light/brightness displayed in the image. This is not the case with film where the chemical process in the darker and brighter areas is non linear. There are ways in digital to minimize this of course - like applying a curve into the linear tonal response setting for example. This still doesn't change your limited zone response compared to film.

That may have been the case in 2004, but modern sensors have much higher dynamic ranges, the 240 for instance 13.3 EV value. The zone system fits easily within this range. As a matter of fact, it matches the DR of film quite neatly. The Monochrom should do a bit better.

 

The phrase "displays only zone 3-8" does not make sense anyway, as it implies that it is impossible to get zone X (pure white paper) or zone 0 (fully black) with a sensor. You are saying that it is impossible to have a blocked shadow or a blown highlight in a digital image.

 

As for an S-curve, to me it is standard procedure to apply it to a digital file. The standard preset in LR or PS works just fine and can easily be modified to taste. And, as said, the Dynamic Range is more than ample for this purpose.

 

 

 

I believe the electronic image will be the next major advance. Such systems will have their own inherent and inescapable structural characteristics, and the artist and functional practitioner will again strive to comprehend and control them. - Ansel Adams

[Manolo Laguillo]

Martin, I am not saying that films are lacking a S shaped curve, nor that its response is linear. I do only say that modern films have its shoulder displaced to the higher levels of exposure, beyond zone XII. The curve is therefore more a straight line than a curve, coming close to a linear response. The goal of a linear response is actually the explanation for the compensation I was referring to in my previous post (the fact that the film's curve is much less steep than the paper's curve).

 

A. Adams wrote, back in 1981, this:

 

"Contemporary emulsions have a much longer straight-line section than earlier films, and frequently they do not shoulder off until a very high level of exposure is reached. The result is a greatly reduced tendency for highlights to "block up", making development contraction somewhat less critical than in the past."

pp. 87-88. The Negative. The New Ansel Adams Photography Series. Book 2. 1981.

 

In page 90 he compares the curves from FP4 and Pan-F.

The medium speed film has actually a nearly straight characteristic curve, more a line than a curve, because of a quite straight toe, and a practically absent shoulder.

Pan-F, on the other hand, has a classic-looking curve.

 

Regarding ink jet prints vs. classic prints: I've made ink jet prints, a lot of them, which do look very very very similar to classic prints. Actually, when looking at some of them framed, hanging on a wall, a friend of mine, a very good professional printer who uses only classic methods (he is really a master with the enlarger), did believe they were made from negatives. This was possible because he could not look at the print's surface with the light hitting it from a certain angle.

 

From a sensitometric point of view it is perfectly possible to print the same collection of densities both with inkjet and on, let's say, Oriental Seagull enlarging paper.

 

Ok, a given photograph can be enlarged, printed with inkjet, printed with 4 inks (quatricromia) on a press, printed on platinum (a procedure I employed very often in the early 80's, BTW), on AZO printing out paper, or on whatever surface, and each print will have its own look, personality, mood, character... How could I disagree with you on this?

[otto.f]

Just want to say one simple thing from experience to Martin: the shadows in MM files can be brought up to a much larger extent (and with very low effort) than with modern films in the darkroom, without loss of any aspect of quality of tonal scale and contrast. Most of the time it is better for the end-result to underexpose at 320ISO when the right exposure would have been at even as high as 3200ISO, lightening up shadows comes with few or no problems even in that case. 

What you will miss in digital B&W is the characteristic effect of grain, that's all

[250swb]

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But before doing an investment, I want to understand the benefits - and I am a technical guy, so the sensor is the heart of any kind of digital camera for me.

 

I would say your idea of a 'benefit' would be if you can club other photographers into submission wielding superior technical facts about the Monochrom, other photographers just buy one to make photographs. If you aren't convinced and need the subject arguing over and over again I'm sure I'm not alone in thinking please, please, don't buy one.

[Martin B]

Martin, I am not saying that films are lacking a S shaped curve, nor that its response is linear. I do only say that modern films have its shoulder displaced to the higher levels of exposure, beyond zone XII. The curve is therefore more a straight line than a curve, coming close to a linear response. The goal of a linear response is actually the explanation for the compensation I was referring to in my previous post (the fact that the film's curve is much less steep than the paper's curve).

 

A. Adams wrote, back in 1981, this:

 

"Contemporary emulsions have a much longer straight-line section than earlier films, and frequently they do not shoulder off until a very high level of exposure is reached. The result is a greatly reduced tendency for highlights to "block up", making development contraction somewhat less critical than in the past."

pp. 87-88. The Negative. The New Ansel Adams Photography Series. Book 2. 1981.

 

In page 90 he compares the curves from FP4 and Pan-F.

The medium speed film has actually a nearly straight characteristic curve, more a line than a curve, because of a quite straight toe, and a practically absent shoulder.

Pan-F, on the other hand, has a classic-looking curve.

 

Regarding ink jet prints vs. classic prints: I've made ink jet prints, a lot of them, which do look very very very similar to classic prints. Actually, when looking at some of them framed, hanging on a wall, a friend of mine, a very good professional printer who uses only classic methods (he is really a master with the enlarger), did believe they were made from negatives. This was possible because he could not look at the print's surface with the light hitting it from a certain angle.

 

From a sensitometric point of view it is perfectly possible to print the same collection of densities both with inkjet and on, let's say, Oriental Seagull enlarging paper.

 

Ok, a given photograph can be enlarged, printed with inkjet, printed with 4 inks (quatricromia) on a press, printed on platinum (a procedure I employed very often in the early 80's, BTW), on AZO printing out paper, or on whatever surface, and each print will have its own look, personality, mood, character... How could I disagree with you on this?

 

So far this is the best response in regard to my question, and I see now where you are coming from. Thanks for putting this all in writing here - I will later today have a look at those pages which you have cited. If the shoulder in the S curve is more linear in slope, yes, the function would be more similar to digital indeed. Even this still keeps me wondering why film manufacturers would do this since the shoulder is an advantage for film vs. digital. But I will try to get the actual response curves for the films which I am currently using, maybe I see the same what you described above.

[Martin B]

That may have been the case in 2004, but modern sensors have much higher dynamic ranges, the 240 for instance 13.3 EV value. The zone system fits easily within this range. As a matter of fact, it matches the DR of film quite neatly. The Monochrom should do a bit better.

 

The phrase "displays only zone 3-8" does not make sense anyway, as it implies that it is impossible to get zone X (pure white paper) or zone 0 (fully black) with a sensor. You are saying that it is impossible to have a blocked shadow or a blown highlight in a digital image.

 

As for an S-curve, to me it is standard procedure to apply it to a digital file. The standard preset in LR or PS works just fine and can easily be modified to taste. And, as said, the Dynamic Range is more than ample for this purpose.

 

You are right that more modern FF sensors have a higher DR. This will affect the amount of how many zones the sensor will be able to display correctly in B&W. If we still assume that the S curve from film is present - which might be not fully the case anymore as pointed out above - film still would have advantage here due to the non linear response in the blacks and the highlight areas. For my own experience I can only tell that my A7R with fairly modern Exmor FF sensor does not allow me to get B&W photos in a single shot with the same tonal range as I get it from film - even after post processing of the digital RAW. It is similar but not the same.

 

regarding the zone system, I pointed out earlier in post #8 that film is between zones 1-10 at maximum. 0 and 11 can not be achieved realistically. I said the opposite - that digital blocks out black and highlights too early due to the linear slope in digital. This simply gives you an earlier cutoff in the blacks and the highlights whereas (older?) film still extended here with the shoulders of the S curve.

 

You can apply as much S curve into your digital file in post processing, but it doesn't help you if the registered information in the blacks and highlights is already cut off from the beginning in the RAW file itself. This was my whole point. With bracketing techniques you can certainly get there in digital - but my impression is not in a single shot. Again, I am strictly speaking of B&W here - for color this is a totally different pair of shoes since film does not contain this wide tonal latitude in color film.

[Martin B]

Just want to say one simple thing from experience to Martin: the shadows in MM files can be brought up to a much larger extent (and with very low effort) than with modern films in the darkroom, without loss of any aspect of quality of tonal scale and contrast. Most of the time it is better for the end-result to underexpose at 320ISO when the right exposure would have been at even as high as 3200ISO, lightening up shadows comes with few or no problems even in that case. 

What you will miss in digital B&W is the characteristic effect of grain, that's all

 

I can do the same well with my A7R files, the shadows can be pushed extremely well there (I believe this sensor has 14.8 eV). Since I still don't get the same latitude compared to film this was the reason for my question here.

[Martin B]

I would say your idea of a 'benefit' would be if you can club other photographers into submission wielding superior technical facts about the Monochrom, other photographers just buy one to make photographs. If you aren't convinced and need the subject arguing over and over again I'm sure I'm not alone in thinking please, please, don't buy one.

 

I understand that this discussion can sound a bit boring for some. But I am just not one of the people who "just buy [a camera]" - I want to understand first what is behind and if there is an additional benefit which would be helpful for me. I have never said that the Leica MM is bad or inferior which it might have come across against you - the opposite is the case. My question was simply how it compares to film, and I got a few reasonable responses to my initial question which is good. This is the advantage of having a forum to exchange knowledge and information. If you feel that this discussion is not beneficial for you, simply skip it and move on.

[otto.f]

 But I am just not one of the people who "just buy [a camera]" - I want to understand first what is behind and if there is an additional benefit which would be helpful for me. 

I doubt whether you want to understand, you seem directed towards confirming your theory instead of exposing yourself to facts that could be critical for your theory

[Martin B]

I doubt whether you want to understand, you seem directed towards confirming your theory instead of exposing yourself to facts that could be critical for your theory

 

?! Not sure if you read my replies above....I think the suggestion brought up by Manolo could make sense. He made a good point there after telling me more about the information he originally mentioned. This was something I was not aware about. Do you have any other technical reasons to contribute to answer my question? Thanks!

[LeicaPassion]

Martin B,

 

May I suggest that you rent or borrow a Monochrom body. Then you can determine if you prefer BW film or digital.

[Martin B]

Martin B,

 

May I suggest that you rent or borrow a Monochrom body. Then you can determine if you prefer BW film or digital.

 

That is actually something I am planning to do, indeed! Nevertheless, I still need to understand what would make this effect in case it compares well to film. Well, at least I got a step closer with some of the responses received here. If it is just because of extended DR in the sensor, the next question is - not covered here in this thread - how it would be better than B&W coming from my A7R since its sensor has even a wider tonal latitude (again, not talking now of camera/brand preferences).

[jaapv]

I can do the same well with my A7R files, the shadows can be pushed extremely well there (I believe this sensor has 14.8 eV). Since I still don't get the same latitude compared to film this was the reason for my question here.

 The Monochrom2 should have a similar DR or better, it is not yet in DXO, so I cannot give the exact number, but it must be more than the M240 (13.8) This gives you ample space to tweak the blacks and whites and get similar or better shoulders than film. The main limiting factor will be your computer screen as it is most likely not to be able to render the full gamma of shades of grey.

Note that the tonality of a monochrome sensor will always be more subtle than a converted file from a colour (filtered and interpolated) sensor, including your A7R.

[Martin B]

 The Monochrom2 should have a similar DR or better, it is not yet in DXO, so I cannot give the exact number, but it must be more than the M240 (13.8) This gives you ample space to tweak the blacks and whites and get similar or better shoulders than film. The main limiting factor will be your computer screen as it is most likely not to be able to render the full gamma of shades of grey.

 

Thanks - this can be very well be the case. I will test it!

[jaapv]

That is actually something I am planning to do, indeed! Nevertheless, I still need to understand what would make this effect in case it compares well to film. Well, at least I got a step closer with some of the responses received here. If it is just because of extended DR in the sensor, the next question is - not covered here in this thread - how it would be better than B&W coming from my A7R since its sensor has even a wider tonal latitude (again, not talking now of camera/brand preferences).

Only saw this one now.

The Bayer pattern on the A7R has to be interpolated to create colour information causing a loss of effective resolution of at least 50%.. The filters will cut the light striking the sensor by approx one stop, reducing DR by one EV value.The filters will also introduce  diffraction and refraction on the filter and chromatic errors, causing further deterioration. Thus a Bayer-less sensor will render higher resolution, more acuity and clarity. In fact, one pixel on the sensor will render one pixel in print (quote from Erwin Puts) It will, if postprocessed properly, outperform a converted file from your A7R with ease.

 

However, look for the difference in print. My Monochrom1 files do very well on Canson Baryta paper.

[Martin B]

Only saw this one now.

The Bayer pattern on the A7R has to be interpolated to create colour information causing a loss of effective resolution of at least 50%.. The filters will cut the light striking the sensor by approx one stop, reducing DR by one EV value.The filters will also introduce  diffraction and refraction on the filter and chromatic errors, causing further deterioration. Thus a Bayer-less sensor will render higher resolution, more acuity and clarity. In fact, one pixel on the sensor will render one pixel in print (quote from Erwin Puts) It will, if postprocessed properly, outperform a converted file from your A7R with ease.

 

However, look for the difference in print. My Monochrom1 files do very well on Canson Baryta paper.

 

Another very good info to have - wasn't aware of this difference! This is interesting that DR is reduced by one EV with the Bayer filters. This could explain the differences which I am seeing, too. Excellent suggestion!

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Hallo,

Look here: Leica M

[zlatkob]

Film registers more than any digital sensor can do. We need to distinguish between popping up information in an existing digital file by post processing and what film captures all at once without need of post processing. The limited zone range from 3-8 in digital is well described in the literature, for example here:

 

In the paragraph of dynamic range - comparison between film and digital:

http://photography.tutsplus.com/articles/light-photography-exposure-and-tonal-range-considerations--photo-5685

 

There is a quite good graph referring to what I expressed above with the limited DR of digital vs film under "Non-linear Film Photography Processes":

http://thucydides.sjca.edu/~stars/ccd.html

 

The handbook of photography from Marchesi also explains this difference.

 

Sorry but your comment that any digital sensor only displays zones from 3-8 is contrary to my everyday experience.  You say this is "well described in the literature" and then cite: 

 

- a 2011 post by a blogger with unknown credentials on a basic learning site.  The author claims: "Cameras, however, only make instantaneous exposures, with film and expensive medium format digital cameras being able to capture 12 different stops of light variations, while most other digital cameras can only capture about 5 stops of light variations or even less."  That 5-stop claim is just not true.  The author has no idea.  

 

- an undated (says 2007 at the bottom) article by an unidentified author that talks about some unspecified CCD.  That's hardly supportive of your claim about only getting zones 3-8 from "any digital sensor".  The graph just says digital is linear, film has a curve ... obvious stuff ... nothing more, nothing about 5 stops.

 

Neither of these count as "literature" about current camera sensors.  It's just stuff some people put on the web and it's terribly out of date.  It's also so contrary to experience that it's not worth arguing about.