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Author Topic: Does the size of the film capture affect dynamic range?  (Read 2128 times)
noparking
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« on: August 05, 2014, 10:34:07 PM »
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In an article by Richard Sexton he writes: "Anyone who’s compared the tonal scale of 35mm film to 4x5 film can fully appreciate what additional dynamic range can achieve in critical situations."

If the same exact film type were used in both the 35mm and 4x5 cameras, I would expect the dynamic range of the images to be the same.

Does anyone agree with Mr. Sexton's statement; and if so, could you explain why the image taken with the larger 4x5 would capture a greater dynamic range?

Thanks in advance,

- Jeff

Article: http://www.luminous-landscape.com/reviews/cameras/digital-ebony.shtml
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« Reply #1 on: August 05, 2014, 11:20:20 PM »
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In my film experience, with larger formats you definitely get finer tonal gradation. Assuming you're using the same film across the different formats. Technically this isn't the same thing as greater dynamic range, but the term is nonetheless sometimes used to describe gradation. Or was used that way prior to the sensor era.

-Dave-
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« Reply #2 on: August 06, 2014, 12:04:55 AM »
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Hi,

With digital sensors, DR is limited by readout noise. Without going into detail, a larger size of sensor will increase DR, if other factors are kept identical. (*)

With film it is a bit different, and it may be different using negative or positive film. With positive film, DR is limited by the film it self. With negative film there is more choice of exposure, so it is hard to tell. A larger format gives more options to play with, especially in B&W. Negative film has different characteristics for different developers. Also, film has often a smooth roll off in the highlights, giving up tonal discrimination for kind of a dynamic range.

Best regards
Erik

(*) This has not been normally the case. The recent release of MFD CMOS sensors may give some extra insight on this issue.

In an article by Richard Sexton he writes: "Anyone who’s compared the tonal scale of 35mm film to 4x5 film can fully appreciate what additional dynamic range can achieve in critical situations."

If the same exact film type were used in both the 35mm and 4x5 cameras, I would expect the dynamic range of the images to be the same.

Does anyone agree with Mr. Sexton's statement; and if so, could you explain why the image taken with the larger 4x5 would capture a greater dynamic range?

Thanks in advance,

- Jeff

Article: http://www.luminous-landscape.com/reviews/cameras/digital-ebony.shtml
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« Reply #3 on: August 06, 2014, 12:12:52 AM »
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I can only assume he's referring to final print / output size and what the multiplication factor will be from the original capture size to target output size. The less you enlarge (and stretch the tonal scale), the better the image 'looks'.
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uaiomex
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« Reply #4 on: August 06, 2014, 12:16:46 AM »
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In the past I have proposed a theory about this enigmatic mistery. Or perhaps it's just inexistent.
I have said that capture of real life in a 2D medium like the one that happens in film or digital sensor capture inside a camera obscura is somehow analog to capturing real life sounds with a recording medium like a vinyl disc or a usb pen drive.

All recording methods of sound or image recording go through different stages of conversions. Inside these different conversions there's always one that degrades the most the fidelity of the original information. It is compression. In real life, sounds come from myriad of different sources. Once these sounds are emitted, the recording medium puts them all together in a relative minute storage. A piano will sound exactly as piano as long it remains a piano. Its recorded sound will be only an emulation.
In analog sound recording, the bigger the recording medium, the better the fidelity. Technology made these smaller and smaller while keeping about the same degree of fidelity. When digital showed up, we were announced the advent of a sound recording technology that was meant to be 100% faithful and that infinite copies were possible because a one was always a one and a zero was always a zero.  As we all know, this never happened. Then mp3 came to scene with its sophisticated compression of redundancies that could be fully restored during playback by decompression. No such thing. Once the original got compressed, the quality got degraded beyond fix.

Well, I believe that image capture either analog or digital has in many ways similar issues.
Let me explain: When I'm capturing a real life scene of a street perspective, what happens is that I'm compressing all that visual information that lies in hundreds of meters into just an inch or four. Most of the original information in real life is likely to be beyond the resolving power of the human eye but this is what constitutes the solid image. All this information is lost for good. When reviewing the capture, this information is enlarged leaving empty spaces of information that become solid blacks and washed-out highlights.
The bigger the capture, the less compression there is, permitting little chunks of detail to form the extra dynamic range some people see in bigger formats.
In short, the smaller the format, the more compressed the original information becomes. At more compression, more lost.

Putting super megapixels in very small sensors is analog to using MP3 for music storage.

The other way to see this, is to call it the old fashion way: Tonality.
Tonality is nothing but smooth gradations from shade to shade so subtle that the human eye can't tell. Once a smooth gradation is compressed to a fraction of its original size, the smoothness becomes, well... less smooth.
I know, this is harder to explain than it is to think about it. On the other hand, it is everybody's knowledge. I can't find a better way to explain myself, besides english is not my native language. Enough excuses.

As a last try, I'd like you to think of Selections in Photoshop. We all know the trick that once a selection is done, sometimes little chunks of selections are to be cancelled. By using Modify>Contract, we make the selection a little smaller. But then, using Expand we get the selection back to its original size but those little chunks don't come back.
As we can see, reversing size modification can produce a different outcome. Going back to Mr. Sexton, 4X5 compresses less the original information while keeping those random little chunks of information that constitute detail. Detail in shadows and highlights is called dynamic range. Detail in the shades in between is called tonality.
In absolute terms, dynamic range is latitude, not resolution. So, my analogies don't fully explain the phenomena (for believers). But somehow I believe, that shrinking real life not only diminishes resolution but also diminishes dynamic range by lost of light recollection and compression of the information.

I hope I didn't bore you.
Best
Eduardo

In an article by Richard Sexton he writes: "Anyone who’s compared the tonal scale of 35mm film to 4x5 film can fully appreciate what additional dynamic range can achieve in critical situations."

If the same exact film type were used in both the 35mm and 4x5 cameras, I would expect the dynamic range of the images to be the same.

Does anyone agree with Mr. Sexton's statement; and if so, could you explain why the image taken with the larger 4x5 would capture a greater dynamic range?

Thanks in advance,

- Jeff

Article: http://www.luminous-landscape.com/reviews/cameras/digital-ebony.shtml
« Last Edit: August 06, 2014, 01:15:40 AM by uaiomex » Logged
BartvanderWolf
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« Reply #5 on: August 06, 2014, 01:43:10 AM »
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In an article by Richard Sexton he writes: "Anyone who’s compared the tonal scale of 35mm film to 4x5 film can fully appreciate what additional dynamic range can achieve in critical situations."

If the same exact film type were used in both the 35mm and 4x5 cameras, I would expect the dynamic range of the images to be the same.

Hi Jeff,

It's not the film, it's the MTF of the optical system. Due to the generally larger on film magnification of subject detail, the subject features will be larger, and thus have a higher MTF response (relative to a similar lens design for a smaller image circle). This will lead to better local and micro-contrast, not dynamic range.

Quote
Does anyone agree with Mr. Sexton's statement; and if so, could you explain why the image taken with the larger 4x5 would capture a greater dynamic range?

If processed right, Negative film can have a large dynamic range than many mainstream sensors, but the latest generations of CMOS sensors do better than anything else.

Cheers,
Bart
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ErikKaffehr
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« Reply #6 on: August 06, 2014, 03:54:11 AM »
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Hi,

I checked the relevant part of the original article and there are a lot of inaccuracies on DR. Mr. Sexton states that his experience is that the back he uses has two stops more DR than Canon 1DsII he also owns. That is quite pausible. Both larger sensor (more pixels) and larger sensor (more photons) can be helpful with DR. But his discussion of number of bits is not accurate, just ignore that part and enjoy the rest.

Best regards
Erik


[equote author=BartvanderWolf link=topic=92304.msg750815#msg750815 date=1407307390]
Hi Jeff,

It's not the film, it's the MTF of the optical system. Due to the generally larger on film magnification of subject detail, the subject features will be larger, and thus have a higher MTF response (relative to a similar lens design for a smaller image circle). This will lead to better local and micro-contrast, not dynamic range.

If processed right, Negative film can have a large dynamic range than many mainstream sensors, but the latest generations of CMOS sensors do better than anything else.

Cheers,
Bart
[/quote]
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BJL
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« Reply #7 on: August 06, 2014, 09:15:44 AM »
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Printing at lower magnification (such as making the same-sized print from a larger negative) increases what I will call the "output dynamic range" by an affect related to dithering, so Sexton's claim makes sense to me with a reference such as comparing 10"x8" prints.  (Downsampling a digital file increase DR too, by a similar process.)  Practical "output" dynamic range has to account for factors like degree of enlargement and "apparent print size", the ratio of print size to viewing distance.  As an extreme example, viewing a traditional silver halide B&W negative with enough enlargement to see individual grains (such as through a microscope) gives a DR of about 1, as the negative itself has only two levels: black and white.  All tonal gradations seen with film and all the great DR claimed for some films are due to dithering of what is essentially a light detection system with billions of single bit detectors.
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ondebanks
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« Reply #8 on: August 06, 2014, 11:12:13 AM »
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"Anyone who’s compared the tonal scale of 35mm film to 4x5 film can fully appreciate what additional dynamic range can achieve in critical situations."

I expect he means additional DR at the dark end; more discernable shadow details. This is a natural consequence of enlarging 4x5 film by a smaller factor than 35mm film, to achieve the same size print. Unless you really blow the film up enormously, the positive print averages the images of adjacent negative grain clumps; and the less you enlarge, the more you average. This is exactly analagous to pixel-binning (down-sampling), where N averaged pixels improves signal to noise by the square root of N over a single pixel (assuming random noise with a zero mean, which is generally true). Details, which would be below the (subjective) threshold of signal to noise for detection at a single grain clump (or pixel), become detectable when averaged. This extends the DR further into the shadow region.

I think what's misleading or confusing about the original statement is the use of the word "film":"compared...35mm film to 4x5 film". It is not the film itself which differs - a square centimeter of Velvia or Ektar is the same regardless of overall format size - but the resulting prints.

Ray
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« Reply #9 on: August 06, 2014, 12:39:52 PM »
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I think what's misleading or confusing about the original statement is the use of the word "film":"compared...35mm film to 4x5 film". It is not the film itself which differs - a square centimeter of Velvia or Ektar is the same regardless of overall format size - but the resulting prints.
That sounds right to me too. I mean, the film is the film, how can the larger piece have a higher dynamic range? What may appear as higher dynamic range has been proposed but the language used in the article is a bit sloppy IMHO or gives the false impression of what is really causing the visual effect.

If you take two men, each exactly 6 feet tall and place one 3 feet in front of the other, from an observer one looks taller than the other. But saying one IS taller than the other isn't true.
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billthecat
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« Reply #10 on: August 06, 2014, 01:17:23 PM »
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It sounds that the larger format has better tones, so the darks look better, and the brights also I assume. Then subjectively the DR would be better since you can see the image better on greater range.

Bill
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« Reply #11 on: August 06, 2014, 11:01:16 PM »
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This could explain it also. Larger or better lenses give the idea of more dynamic range. I remember when I just started using my Canon 17TS in lieu of a 17-40, I could swear my 5D2 gained in dynamic range.
But that's not possible, is it?
Eduardo

It sounds that the larger format has better tones, so the darks look better, and the brights also I assume. Then subjectively the DR would be better since you can see the image better on greater range.

Bill
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« Reply #12 on: August 07, 2014, 12:23:38 AM »
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Hi,

Yes and no.

What I would suggest you see is that 17TS has a lower level of veiling flare than the 17-40. Zoom lenses are more complex than single focals, with lens groups moving around a lot so it is more difficult to shield the light path trough the lens. So, that increases contrast, making the images more snappy.

Technically speaking, DR is not increased, but the DR (which is a property of the sensor alone) will be utilised better.

It could be the other way around, too. The 17 TS has more lens elements than the 17-40, which could lead to more veiling flare. The flare would actually reduce DR, by making shadows brighter, but brighter shadows are often misinterpreted as better DR.

In reality, an increase in DR gives a potential to render highlights and deep shadows better, essentially meaning brighter highlights and deeper shadows, but the sensor cannot improve on what it gets delivered by the lens.

All lenses, modern or old have significant level of flare, but highlights often represent a small part of the incoming light, so the total effect may be small.

The shot below is a good illustration. The windows are very bright, well past saturation, but their surface is small so they contribute little to the veiling flare. So the sensor can still handle deep shadows.

Best regards
Erik

This could explain it also. Larger or better lenses give the idea of more dynamic range. I remember when I just started using my Canon 17TS in lieu of a 17-40, I could swear my 5D2 gained in dynamic range.
But that's not possible, is it?
Eduardo

« Last Edit: August 07, 2014, 12:30:25 AM by ErikKaffehr » Logged

ondebanks
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« Reply #13 on: August 07, 2014, 06:54:30 AM »
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It sounds that the larger format has better tones, so the darks look better, and the brights also I assume.

In most cases, what I outlined above (enlarging less = averaging to improve signal to noise) only really makes a difference in the shadow end of the DR from a film photo.

With optical prints of negative film, or any use of slide film, the "brights" are already of very high signal to noise, so averaging them doesn't move them into greater detectability. However, if negative film is scanned, then the "brights" are darker, denser regions, and this may place them in the shadow end of the scanner's DR. So downsampling to the print can also help the bright end in that situation.

Ray
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« Reply #14 on: August 07, 2014, 07:14:20 AM »
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When digital showed up, we were announced the advent of a sound recording technology that was meant to be 100% faithful
While Sony/Philips no doubt had creative people working in their marketing departement, experience suggests that digital really can be perceptually transparent. If you introduce a digital recording/playback "degrader" in a live sound stream, people are unable to reliably indicate when it is switched on or off (as has been published in peer-reviewed relevant scientific journals).
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and that infinite copies were possible because a one was always a one and a zero was always a zero.
There is always the possibility of a bit error in digital systems. It is possible to create digital systems that can recreate the same information many times with very, very low probability of errors (I am guessing that all of the people reading this post all over the world are reading the same copies). With analog systems this is practically impossible.
Quote
 As we all know, this never happened. Then mp3 came to scene with its sophisticated compression of redundancies that could be fully restored during playback by decompression. No such thing. Once the original got compressed, the quality got degraded beyond fix.
mp3 is lossy coding. I.e. the encoder introduce errors that can never be fully recovered. But in listening tests, it is found that a surprising amount of data can be thrown away before actual listeners become aware that something is missing.
Quote
In short, the smaller the format, the more compressed the original information becomes. At more compression, more lost.
Sure. The amount of information that can be recorded by a small patch of film must be less than what can be recorded using a large patch of film.
Quote
Putting super megapixels in very small sensors is analog to using MP3 for music storage.
I don't think that is a good analogy.
The other way to see this, is to call it the old fashion way: Tonality.
Tonality is nothing but smooth gradations from shade to shade so subtle that the human eye can't tell. Once a smooth gradation is compressed to a fraction of its original size, the smoothness becomes, well... less smooth.
[/quote]
Either it is visible, or it is not. I dislike the term "tonality" because it seems to often be used as a wildcard for "what I am thinking about cannot be understood, measured or distinguished in a side-by-side, you have to feel it".

-h
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« Reply #15 on: August 10, 2014, 03:44:20 PM »
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I've shot film side by side with the digital backs in high contrast scenes using otherwise the same camera and lenses. All I can say is that I was surprised by how nice the film handled this particularly when going all the way to traditional darkroom analog prints vs. digital prints. I don't know that I would say the same thing about color film or not.  

btw - Larger format film/sensor collect more light in total so you'd think they'd have more 'signal' to noise at least in theory if all else is the same.
« Last Edit: August 10, 2014, 11:52:05 PM by EricWHiss » Logged

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« Reply #16 on: August 16, 2014, 10:42:34 PM »
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In an article by Richard Sexton he writes: "Anyone who’s compared the tonal scale of 35mm film to 4x5 film can fully appreciate what additional dynamic range can achieve in critical situations."

If the same exact film type were used in both the 35mm and 4x5 cameras, I would expect the dynamic range of the images to be the same.

Does anyone agree with Mr. Sexton's statement; and if so, could you explain why the image taken with the larger 4x5 would capture a greater dynamic range?

Thanks in advance,

- Jeff

Article: http://www.luminous-landscape.com/reviews/cameras/digital-ebony.shtml

Film does not have "dynamic range" at all. This is all wrong. People who don't know what they are talking about should avoid saying foolish things. When enlarged to the same degree, all film will look basically the same. A 4x5 negative requires only 2x linear magnification to make an 8x10. A 35mm negative requires 8x linear magnification.
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« Reply #17 on: August 17, 2014, 08:53:06 AM »
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Film does not have "dynamic range" at all. This is all wrong. People who don't know what they are talking about should avoid saying foolish things.
Would exposure latitude be a better term?
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« Reply #18 on: August 17, 2014, 01:21:41 PM »
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Hi,

Interesting question…

Generally, negative film was exposed for the shadows, while slide film was exposed for highlights.

Post exposure we used to have a developer and a paper/developer combo having different characteristics of their own.

My take is that slide film had very limited DR (around five stops) while negative film had very wide DR, but needed advanced processing to make use of it.

Best regards
Erik

Would exposure latitude be a better term?
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Chris Livsey
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« Reply #19 on: August 17, 2014, 03:26:47 PM »
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An incorrect assumption here is that as format increases the film, as coated, remains the same ie it is simply scaled up.
In fact 120 film and larger is different than 35mm. They have different bases and anti-halation properties, which will affect captured "dynamic range" or "latitude" or whatever you wish to call it.
Note the rem-jet backing on movie film again gives different properties, not just in transport.
There is also the lens effect, flare in particular, it is possible to use lenses across formats but not common so a comparison is difficult.

So yes, different films have different dynamic ranges and comparisons across formats are unfair.
« Last Edit: August 17, 2014, 04:26:27 PM by Chris Livsey » Logged

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