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Author Topic: Can you see a difference in small prints between an MFDB and a DSLR?  (Read 36665 times)

Hans van Driest

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #160 on: March 06, 2014, 03:22:51 AM »

I thought the original subject was whether one would see a difference between a MFDB and a DSLR, in a 'small' print. it is possible to argue about all sort of subtle differences, that might be important to someone, but not to somebody else. Erik suggested to, when considering going to digital medium format, download some files and print this at a size that one would normally print on.
sound advice.
I am an engineer and that perhaps makes one a bit funny. I like to break problems down in simple sub-problems and look at each of those individuality. for me it seems that resolution is a important part of the likely differences (I am aware there is lot more).
I already described before how I had, for myself, made a comparison between an 24Mp file and one with four time the linear resolution, by means of making a multi row stitch with a lens of four times the focal length. but this is unnecessarily complicated. for just examining whether resolution makes a big difference, one could make a picture of ones normal subject, a landscape, whatever, with say a 50mm lens. using a tripod. after that shot, just replace the lens, without moving the camera, say with a 105 or 135mm lens. the idea is just to roughly double the focal length. as a next step, crop the result of the shorter fl to the same field of view. The same crop as obtained with the longer lens . one now has two identical pictures (i hope), with one having over double the linear resolution (four times the pixels). print them both at half the linear size of a 'normal' print (so 10x12, would be the size if one normal prints 20x24). And now just look if it makes a significant difference. if not, resolution of a digital mf camera is not going to make a significant difference. other things might.
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hjulenissen

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #161 on: March 06, 2014, 05:03:20 AM »

so happens that no matter what camera you use, you get better results with better light. And understanding good light is an important part of being a photographer.
I usually find it more pleasing to watch portraits of interesting/pretty people than mundane people.

I don't think that an evaluation of camera capabilities needs to include pretty people, though. I take it that people with an interest in photography are able to make that connection themselves.

-h
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synn

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #162 on: March 06, 2014, 05:22:22 AM »

I usually find it more pleasing to watch portraits of interesting/pretty people than mundane people.

I don't think that an evaluation of camera capabilities needs to include pretty people, though. I take it that people with an interest in photography are able to make that connection themselves.

-h

That does not negate my point, nor is it contrary.
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paul ross jones

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #163 on: March 06, 2014, 05:25:21 AM »

3 (the man showing the leather) and 12, 13, 14 (the middle age scenes)? But I am not sure about 23 (city) and 27 (car circuit) either.

 

Indeed. The shallowest depth of field can be had on 24x36 camera, because of the very fast lenses unique to this format.




hi jerome, you got the slot car circuit correct.
the shots with red frames are the p65/contax.

i have to say that the p65 is a very good file, heaps of res and headroom with the highlights (although, bad in the darks). but the "look" isn't that distinctive imo.

i think the lenses give more of a difference of look than just a format.

paul

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BartvanderWolf

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #164 on: March 06, 2014, 07:15:03 AM »

I thought the original subject was whether one would see a difference between a MFDB and a DSLR, in a 'small' print.

Hi Hans,

That's correct, but it is relatively obvious that either human visual acuity, or inherent image resolution after upsampling (less likely for a 'small' print), is the deciding factor. Besides that, there are more subtle (MTF related) differences, although many of those can be bridged by proper postprocessing.

Quote
I like to break problems down in simple sub-problems and look at each of those individuality. for me it seems that resolution is a important part of the likely differences (I am aware there is lot more).

Indeed, resolution as in sampling density is an important deciding factor.

Quote
For just examining whether resolution makes a big difference, one could make a picture of ones normal subject, a landscape, whatever, with say a 50mm lens. using a tripod. after that shot, just replace the lens, without moving the camera, say with a 105 or 135mm lens. the idea is just to roughly double the focal length. as a next step, crop the result of the shorter fl to the same field of view. The same crop as obtained with the longer lens . one now has two identical pictures (i hope), with one having over double the linear resolution (four times the pixels). print them both at half the linear size of a 'normal' print (so 10x12, would be the size if one normal prints 20x24). And now just look if it makes a significant difference. if not, resolution of a digital mf camera is not going to make a significant difference. other things might.

In principle that should work, if not for the introduction of several variables at the same time. Different lenses have different performance, and different focal lengths have different MTF for a given level of detail (cycles/mm), and different Depth of Field. Resampling the smaller sized version for output also introduces a variable, but that is maybe the most stable one for a straight comparison between larger and smaller sensel array sizes.

If it is only the number of pixels available for printing that one wants to compare, it's perhaps easier to compare a (several) down-sampled version(s) of the same image and print those at the same output size. Of course a very good down-sampling method should be used. However, the conclusion will probably be the same as the one I mentioned first, although good up-sampling may narrow the gap with real pixel content to a degree.

With specific image resolution (sampling density) out of the way, the rest of the platform induced differences will be of an optical and image magnification nature, and color rendering design choices.

Cheers,
Bart
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Hans van Driest

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #165 on: March 06, 2014, 07:52:53 AM »

Hi Hans,

That's correct, but it is relatively obvious that either human visual acuity, or inherent image resolution after upsampling (less likely for a 'small' print), is the deciding factor. Besides that, there are more subtle (MTF related) differences, although many of those can be bridged by proper postprocessing.

Indeed, resolution as in sampling density is an important deciding factor.

In principle that should work, if not for the introduction of several variables at the same time. Different lenses have different performance, and different focal lengths have different MTF for a given level of detail (cycles/mm), and different Depth of Field. Resampling the smaller sized version for output also introduces a variable, but that is maybe the most stable one for a straight comparison between larger and smaller sensel array sizes.

If it is only the number of pixels available for printing that one wants to compare, it's perhaps easier to compare a (several) down-sampled version(s) of the same image and print those at the same output size. Of course a very good down-sampling method should be used. However, the conclusion will probably be the same as the one I mentioned first, although good up-sampling may narrow the gap with real pixel content to a degree.

With specific image resolution (sampling density) out of the way, the rest of the platform induced differences will be of an optical and image magnification nature, and color rendering design choices.

Cheers,
Bart

I agree the lens would play a role, but when the difference is as extreme as a factor of two or more in linear resolution, I would expect (assuming two decent lenses), this to be secondary. Indeed down sampling an existing file is also an option, although the down sampling will increase the pixel quality a lot (assuming a Bayer mask sensor). but in the end the idea would be to see of how much influence a big increase in resolution would have on the quality of the printed output, for a certain size. either method would do fine.

In my own experiment, with a stitched file to get the same field of view with four times the linear resolution, I was surprised how 'little' of this extra quality, so visible at 100% on screen, was visible in a 20x30 inch print. Although I must admit that the longer I look at both prints, the more visible the differences become. This is at close distance. Looking from a 'normal' viewing distance, there is little or nothing to differentiate the two print. My eyes are above average.

kind regards,

Hans
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jerome_m

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #166 on: March 06, 2014, 08:34:00 AM »


hi jerome, you got the slot car circuit correct.
the shots with red frames are the p65/contax.

i have to say that the p65 is a very good file, heaps of res and headroom with the highlights (although, bad in the darks). but the "look" isn't that distinctive imo.

i think the lenses give more of a difference of look than just a format.

Certainly it is the lenses and what I used as a guide were lens aberrations. Interestingly, it failed me. What camera/lens combination and aperture did you use for the leather (3) and middle age shoots?
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jerome_m

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #167 on: March 06, 2014, 08:44:58 AM »

I agree with the first part of your comment. However, while good natural subject rendering is the goal, I do not think that natural objects are good for isolating the issues. I think a few test shots of a Star target will give a much less ambiguous basis for analysis of the root causes(es).

Except that this subject is designed to ignore the effects of what we want to test:
-it is a flat subject, so we ignore all lens aberrations which arise outside of the plane of focus and these are a very important part of the "MF look" and even the effect of sharpening (sharpening influences the rendering of infocus to outfocus transitions on tridimensional subjects)
-it is a high-contrast monochrome subject, so we are in an ideal case for demosaicing and noise reduction. In my experience, grass is one of the most difficult subjects for post processing.
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ErikKaffehr

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #168 on: March 06, 2014, 02:06:18 PM »

Hi Hans,

You are right about the original subject, and I feel that your suggestions make a lot of sense.

Best regards
Erik

I thought the original subject was whether one would see a difference between a MFDB and a DSLR, in a 'small' print. it is possible to argue about all sort of subtle differences, that might be important to someone, but not to somebody else. Erik suggested to, when considering going to digital medium format, download some files and print this at a size that one would normally print on.
sound advice.
I am an engineer and that perhaps makes one a bit funny. I like to break problems down in simple sub-problems and look at each of those individuality. for me it seems that resolution is a important part of the likely differences (I am aware there is lot more).
I already described before how I had, for myself, made a comparison between an 24Mp file and one with four time the linear resolution, by means of making a multi row stitch with a lens of four times the focal length. but this is unnecessarily complicated. for just examining whether resolution makes a big difference, one could make a picture of ones normal subject, a landscape, whatever, with say a 50mm lens. using a tripod. after that shot, just replace the lens, without moving the camera, say with a 105 or 135mm lens. the idea is just to roughly double the focal length. as a next step, crop the result of the shorter fl to the same field of view. The same crop as obtained with the longer lens . one now has two identical pictures (i hope), with one having over double the linear resolution (four times the pixels). print them both at half the linear size of a 'normal' print (so 10x12, would be the size if one normal prints 20x24). And now just look if it makes a significant difference. if not, resolution of a digital mf camera is not going to make a significant difference. other things might.

tho_mas

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #169 on: March 06, 2014, 05:23:14 PM »

Synn - great image!
Is it a single image or part of a series? If so I'd love to see it.
Many thanks!
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synn

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #170 on: March 06, 2014, 08:26:47 PM »

Synn - great image!
Is it a single image or part of a series? If so I'd love to see it.
Many thanks!


Hi Thomas,

Thanks, that's just my regular "Test shot scene" out of my window. :)

I use this frame as my test scene every time I get some new piece of camera gear. This was taken to test the Mamiya 35mm lens. Shot was made with a 3 stop Lee grad ND on the lens.
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Fine_Art

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #171 on: March 07, 2014, 02:30:07 AM »

I mentioned months ago that there seemed to be a problem with the lens. If all the lenses are the same than the body must be badly adjusted.

I will donate a raw in overcast light to the discussion. It is part of a pano with not much meaning by itself (although quite pretty), so it can be out on the net. This is the type of mountain landscape with snow that Erik likes.
http://www.sendspace.com/file/ke2pce

The .nef is in a blue box. you should see the .nef extension when you hover your mouse. Ignore their ads.

In overcast there should be abundant D/R.
It should be sharp at 100% view. If your trees look much worse check your equipment.
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tho_mas

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #172 on: March 07, 2014, 04:23:05 AM »

that's just my regular "Test shot scene" out of my window. :)
;D however, it's interessting. The scene looks a bit artificial (the subject, not the photo) and this is why I like it.
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BartvanderWolf

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #173 on: March 07, 2014, 05:21:10 AM »




I agree with the first part of your comment. However, while good natural subject rendering is the goal, I do not think that natural objects are good for isolating the issues. I think a few test shots of a Star target will give a much less ambiguous basis for analysis of the root causes(es).

Except that this subject is designed to ignore the effects of what we want to test:
-it is a flat subject, so we ignore all lens aberrations which arise outside of the plane of focus and these are a very important part of the "MF look" and even the effect of sharpening (sharpening influences the rendering of infocus to outfocus transitions on tridimensional subjects)
-it is a high-contrast monochrome subject, so we are in an ideal case for demosaicing and noise reduction. In my experience, grass is one of the most difficult subjects for post processing.

Hi Jerome,

I disagree. To ferret out potential lens issues, one should use a methodical test that eliminates as many variables as possible. So, a flat subject is preferred, it will show (when focused well) the maximum in achievable resolution. When that resolution is lacking, the rest becomes moot. When camera shake is detected, technique can be improved. When all corners, individually focused for the best resolution to eliminate field flatness and other lens aberration issues, show the same kind of resolution, then the lens is well centered, otherwise there is a lens decentering issue (not uncommon, especially with second hand lenses).

For all that, it is best to reduce the influence of the Raw converter, so a monochrome grayscale target is preferred. It also produces a nice test object to compare Raw converters with the same image.

When we have established that the lens is adequate, then we can grill the Raw converter and Capture sharpening workflow.

When all that is done, we can test the lens rendering quality in front or in the back of the focus plane, at various apertures. At least we have now established a solid correctly focused basis to compare with.

So we agree that real image performance is the ultimate goal, and that may lead to purchasing different lenses for their specific image qualities. But for a methodical test benchmark, problem solving, it's best to reduce the number of variables to those things that can be individually quantified and perhaps addressed.

Cheers
Bart
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Frits

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #174 on: March 07, 2014, 07:18:07 AM »

With 9 pages of discussion in this thread it must be getting pretty close.
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JohnBrew

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jerome_m

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #176 on: March 07, 2014, 10:53:36 AM »


Quote
Except that this subject is designed to ignore the effects of what we want to test:
-it is a flat subject, so we ignore all lens aberrations which arise outside of the plane of focus and these are a very important part of the "MF look" and even the effect of sharpening (sharpening influences the rendering of infocus to outfocus transitions on tridimensional subjects)
-it is a high-contrast monochrome subject, so we are in an ideal case for demosaicing and noise reduction. In my experience, grass is one of the most difficult subjects for post processing.


Hi Jerome,

I disagree. To ferret out potential lens issues, one should use a methodical test that eliminates as many variables as possible. So, a flat subject is preferred, it will show (when focused well) the maximum in achievable resolution. When that resolution is lacking, the rest becomes moot. When camera shake is detected, technique can be improved. When all corners, individually focused for the best resolution to eliminate field flatness and other lens aberration issues, show the same kind of resolution, then the lens is well centered, otherwise there is a lens decentering issue (not uncommon, especially with second hand lenses).

For all that, it is best to reduce the influence of the Raw converter, so a monochrome grayscale target is preferred. It also produces a nice test object to compare Raw converters with the same image.

When we have established that the lens is adequate, then we can grill the Raw converter and Capture sharpening workflow.

When all that is done, we can test the lens rendering quality in front or in the back of the focus plane, at various apertures. At least we have now established a solid correctly focused basis to compare with.

So we agree that real image performance is the ultimate goal, and that may lead to purchasing different lenses for their specific image qualities. But for a methodical test benchmark, problem solving, it's best to reduce the number of variables to those things that can be individually quantified and perhaps addressed.

Bart: if Erik takes a picture of plants and it looks generally as detailed as the one I posted, we can conclude that:
-the lenses work in a similar manner on flat and 3-d subjects
-the focus system works accurately enough for a real subject
-the post-processing works, even on difficult subject.

All these are the likely sources of problems. A single picture would then allow us to determine if we need further tests or not.

Besides, I am fairly confident that Erik has already taken enough pictures of test charts to wear them down.
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ErikKaffehr

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #177 on: March 07, 2014, 02:42:13 PM »

Hi Jerome,

I agree with Bart on test charts being best tools to sort out lens issues. The lens used here is a macro lens designed for short distances, so testing it in an infinity like setting may not be a very good idea. In the context presented I feel the use of a macro lens doesn't distort the findings, because:

1) The main issue with the Planar is field curvature. The focal plane is curved but the lens will be sharp in the areas that have focus.

2) The lens compared with is a premium quality zoom, not a high end prime

The tripod is standing on soft ground. That is fact of life. I would say it matters little.

I actually shoot some other subjects than test charts, a small selection is here:

http://echophoto.dnsalias.net/ekr/index.php/photoarticles/80-my-mfd-journey-summing-up?start=5

and here: http://echophoto.dnsalias.net/ekr/index.php/photoarticles/80-my-mfd-journey-summing-up?start=6

All those page include raw images, for anyone interested, so it is feasible to see weather the inferior results are due to lens, focusing or raw processing.

When the P45 arrived, our host Michael Reichmann tested it with friends Charlie Cramer and Bill Atkinson and they published a series with different test cameras. The crop below is from one of those test shots APO Sironar HM 100/5.6 at f/11 on the right and my 120/4 at f/8 to the left. Yes, I feel that APO Sironar wins, but I also feel the Planar 120/4 is not so far behind. Both images are processed similarly.

Best regards
Erik




Hi Jerome,

I disagree. To ferret out potential lens issues, one should use a methodical test that eliminates as many variables as possible. So, a flat subject is preferred, it will show (when focused well) the maximum in achievable resolution. When that resolution is lacking, the rest becomes moot. When camera shake is detected, technique can be improved. When all corners, individually focused for the best resolution to eliminate field flatness and other lens aberration issues, show the same kind of resolution, then the lens is well centered, otherwise there is a lens decentering issue (not uncommon, especially with second hand lenses).

For all that, it is best to reduce the influence of the Raw converter, so a monochrome grayscale target is preferred. It also produces a nice test object to compare Raw converters with the same image.

When we have established that the lens is adequate, then we can grill the Raw converter and Capture sharpening workflow.

When all that is done, we can test the lens rendering quality in front or in the back of the focus plane, at various apertures. At least we have now established a solid correctly focused basis to compare with.

So we agree that real image performance is the ultimate goal, and that may lead to purchasing different lenses for their specific image qualities. But for a methodical test benchmark, problem solving, it's best to reduce the number of variables to those things that can be individually quantified and perhaps addressed.

Bart: if Erik takes a picture of plants and it looks generally as detailed as the one I posted, we can conclude that:
-the lenses work in a similar manner on flat and 3-d subjects
-the focus system works accurately enough for a real subject
-the post-processing works, even on difficult subject.

All these are the likely sources of problems. A single picture would then allow us to determine if we need further tests or not.

Besides, I am fairly confident that Erik has already taken enough pictures of test charts to wear them down.
« Last Edit: March 07, 2014, 02:58:58 PM by ErikKaffehr »
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Fine_Art

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #178 on: March 07, 2014, 03:34:32 PM »

My computer says this file is infected.

Maybe their sendspace accelerator is infected, my file is not. I use 2 top rated AV programs to scan my PC. Webroot and bitdefender.
Uncheck their download accelerator box.

A nef is not an executable.
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jerome_m

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Re: Can you see a difference in small prints between an MFDB and a DSLR?
« Reply #179 on: March 07, 2014, 03:40:58 PM »

I agree with Bart on test charts being best tools to sort out lens issues.

But you don't know that it is a lens issue. I think it is not a lens issue.



Quote
I actually shoot some other subjects than test charts, a small selection is here:

http://echophoto.dnsalias.net/ekr/index.php/photoarticles/80-my-mfd-journey-summing-up?start=5

and here: http://echophoto.dnsalias.net/ekr/index.php/photoarticles/80-my-mfd-journey-summing-up?start=6

I did not write that you only shoot test charts, just that you shoot lots of them ;)
« Last Edit: March 07, 2014, 03:57:43 PM by jerome_m »
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