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Mamiya 7 and IQ180 in black and white

timparkin

Member
The 8000dpi scan of the 4x5 is more contrasty than the 4000dpi. In my view, it also shows more detail, although some of that detail is grain. IN my view, scanning to a level where grain becomes visible is an advantage, since it also shows the true character of the film, but no everybody will agree on that.

What is important is that, since there are strong artifacts on the 8000dpi scan of the Mamiya 7 image, that scan can't be trusted and makes it irrelevant for the comparison. That's a pity, considering all the work that must have gone into this and since for some of us, finding the resolution potential of medium format film gives us an indication of where the limit for our cameras are, at least for the film used in this test.
Just to be clear - can you tell me what the 'strong artefacts' you are talking about are?


I'm not sure what you mean by "can't be trusted" - I've now had three 8000dpi scans done and they all show slightly jitter (if this is the artefacts you are talking about).

If you have an 8000dpi scanner or can recommend one where you haven't see slight artefacts at 8000dpi, let me know - I'm quite happy to send the film off again.

As it stands, this is the result that you can be expected to get from your film when scanned - hence trust isn't an issue.

You should only say "can't be trusted" when someone is trying to con you or that they've screwed up something - can you explain if this is your intent?

p.s. The 8000dpi scan of the 4x5 isn't as good as Lenny's scan
 
S

SCHWARZZEIT

Guest
Now we can play with aperture to reduce the grain but at the cost of some resolution - that is an aspect we are looking into.

Tim
Hi Tim,

which aperture did Lenny use for this 8000 ppi scan? 3 micron?

timparkin said:
I'm afraid I can't see your point as it doesn't look like the 8000dpi scan improves on the 4x5 view. In fact you'd be hard pushed to say that that 8000dpi scan improves on the 4000dpi scan.

If you look at the microscope view you can clearly see horizontal lines up to 12 and maybe 13. On the 4000/8000 scan they stop at 10 maybe 11.

Of course the scan of 4x5 will get more of the full amount out because of the resolution limit of the lenses means you can't put as fine a line down on film, which makes it easier to read by the scanner.
It really depends on your criterion what you consider as resolved or not. Especially with line targets this can be difficult. Long lines work in favor of film because film does not have a hard resolution limit. It's just that with higher spatial frequencies the probability decreases that details separated by a fixed contrast gets resolved on film. With long lines you increase that probability that at least at some points of those lines the detail is projected on fine enough grain to be resolved by the film. Our visual system is really good at reconnecting the missing space between the unresolved parts and at the limit it's less clear but you get a feel for resolved detail.

On the TMX 4x5" shot I can see that there is some detail in those lines up to 13 but I can only count those fifteen lines up to 11 on the microscope image (10 on the 8000 ppi scan and 9 on the 4000 ppi scan).

timparkin said:
With the Mamiya 7, the lenses can put down such fine detail that the scanner has difficultly in reading it. The 8000dpi scanner that Lenny has manages better than any other scanner I've tried yet though!
This resembles what I found in my own tests a few years ago. I tested TMX in 35mm with the Canon 1.4/50 lens. At f5.6 I could see about 160 lp/mm on film through a microscope but my ICG drum scanner could only detect a little more than 100 lp/mm, similar to what Lenny could get from the Premier.
But for all practical means on real world subjects the grain of these films is already obscuring most of the details at those high frequencies that the slight loss from scanning is really insignificant. The only film where I saw a significant real world resolution advantage from an optical print compared to a high-res drum scan has been the microfilm Adox CMS 20. If you want to test what your Mamiya 7 lenses can do you should get some in 120.

-Dominique
 

timparkin

Member
which aperture did Lenny use for this 8000 ppi scan? 3 micron?
3,6,8,10,13,16,19,22
The one we are looking at is either 6 or 8 -- the three just lost nearly everything in a mass of noise.


It really depends on your criterion what you consider as resolved or not. Especially with line targets this can be difficult. Long lines work in favor of film because film does not have a hard resolution limit. It's just that with higher spatial frequencies the probability decreases that details separated by a fixed contrast gets resolved on film. With long lines you increase that probability that at least at some points of those lines the detail is projected on fine enough grain to be resolved by the film. Our visual system is really good at reconnecting the missing space between the unresolved parts and at the limit it's less clear but you get a feel for resolved detail.

On the TMX 4x5" shot I can see that there is some detail in those lines up to 13 but I can only count those fifteen lines up to 11 on the microscope image (10 on the 8000 ppi scan and 9 on the 4000 ppi scan).
I agree... although we aren't talking about what is put down on film but what is resolved by the scanner. The film has lines at the 11 or possibly 12 mark according to the microscope (and looking by eye through the microscope resolves more than the photo through the eyepeice) and so it's the scanner that has failed to resolve in this case.

This resembles what I found in my own tests a few years ago. I tested TMX in 35mm with the Canon 1.4/50 lens. At f5.6 I could see about 160 lp/mm on film through a microscope but my ICG drum scanner could only detect a little more than 100 lp/mm, similar to what Lenny could get from the Premier.
But for all practical means on real world subjects the grain of these films is already obscuring most of the details at those high frequencies that the slight loss from scanning is really insignificant.
yes I agree... the goal at that point is more about clarity of picture, rendering of grain etc

The only film where I saw a significant real world resolution advantage from an optical print compared to a high-res drum scan has been the microfilm Adox CMS 20. If you want to test what your Mamiya 7 lenses can do you should get some in 120.
That is on the cards :)
 
C

ClydeR

Guest
Tim, the Mamiya image is digitally enlarged, isn't it? The Mamiya trumpet is the same size as the 4x5, and it should be about half the size. That pretty easily accounts for the Mamiya looking a fair bit worse side-by-side with the 4x5.

Later,

Clyde
 

timparkin

Member
Tim, the Mamiya image is digitally enlarged, isn't it? The Mamiya trumpet is the same size as the 4x5, and it should be about half the size. That pretty easily accounts for the Mamiya looking a fair bit worse side-by-side with the 4x5.

Later,

Clyde
Hi Clyde - yes they've all been enlarged digitally in order to show the detail - they've been enlarged to match the microscope photograph.

So, yes, if you expect these to be 100% pixels then we'd have very different size images (e.g. microscope would be 3x bigger than 8000 which would be 2x bigger than 4000 which would be 2x bigger than the Mamiya 7 4000dpi

Tim
 

Jorgen Udvang

Subscriber Member
Just to be clear - can you tell me what the 'strong artefacts' you are talking about are?


I'm not sure what you mean by "can't be trusted" - I've now had three 8000dpi scans done and they all show slightly jitter (if this is the artefacts you are talking about).

If you have an 8000dpi scanner or can recommend one where you haven't see slight artefacts at 8000dpi, let me know - I'm quite happy to send the film off again.

As it stands, this is the result that you can be expected to get from your film when scanned - hence trust isn't an issue.

You should only say "can't be trusted" when someone is trying to con you or that they've screwed up something - can you explain if this is your intent?

p.s. The 8000dpi scan of the 4x5 isn't as good as Lenny's scan
I'm talking about the "artifacts" or "noise" shown in the 8000dpi scan in this image:



If you look at the numbers above the line, there are more detail shown in the 4000dpi scan than in the 8000dpi scan. The fact that all of this, including the lines, come out relatively clear in the microscope view, is a strong indication that this is a scanner limitation and not a film or camera/lens limitation. I can understand that scanner has limitations, and this is obviously something one has to consider when scanning any high resolution film. What puzzles me is that a similar kind of "noise" doesn't show up in the other 8000dpi scans. On the 4x5 scans, the 8000dpi scan shows more detail than the 4000dpi scan, but with the Mamiya, it's the other way around. That doesn't make sense to me. I do understand the implications of the different formats, but still, the quality ratio should go in the same direction, shouldn't it?

Please don't take it personal when I say "can't be trusted" about the Mamiya 8000dpi scan. What I mean is simply that when the scan doesn't represent properly what's apparently present on the film (ref. the microscope view) within the area of the lines and numbers, the same might be the case for other areas of the image as well.

If it's true that we are seeing a limitation of the scanner here, and if a rather common film like the T-Max 100 really resolves beyond the abilities of such a high end scanner, it's kind of good news for those of us who like film. Shows that there's still a lot of life left in the old, flimsy rolls of imaging material :)
 

Jorgen Udvang

Subscriber Member
As an aside to all this, I've had an interesting experience with one of my clients the last few weeks. They had acquired 4 different images, one from a photographer and three from a major stock agency (not microstock). The one from the photographer was a 35mm slide (Velvia) and the rest were digital images taken with DSLRs that ranged from 12 to 16 MP. They wanted me to have the images printed at a size around 200 x 130 cm for display on walls around the office.

It was very easy to conclude that the digital files were way to small for this purpose, and they all fell apart with noise showing up in big blotches in the shadow areas in addition to lack of detail. Still, I thought I'd give the slide a go, mostly to see what the limitations were. To my surprise, the film image looked a lot better when enlarged, and although 200 cm is beyond what it's really capable of, it clearly "survived" the enlargement better than the digital files.

I don't know the technical information of the digital files other than the size, since the photo agency had stripped that kind of data off the file, but this seems to be an advantage with film that at least I haven't thought about before: The grain structure of film has a more acceptable look when enlarged beyond its capabilities than noise and other artifacts present in digital files. And when observed from a distance, the irregularity of film grain gives a perceived impression of detail rendering that the digital files struggled to do, at least these files.
 

timparkin

Member
I'm talking about the "artifacts" or "noise" shown in the 8000dpi scan in this image:

[original comparison of mamiya 7 t-max 4000, 8000 and microscope]

If you look at the numbers above the line, there are more detail shown in the 4000dpi scan than in the 8000dpi scan. The fact that all of this, including the lines, come out relatively clear in the microscope view, is a strong indication that this is a scanner limitation and not a film or camera/lens limitation. I can understand that scanner has limitations, and this is obviously something one has to consider when scanning any high resolution film. What puzzles me is that a similar kind of "noise" doesn't show up in the other 8000dpi scans. On the 4x5 scans, the 8000dpi scan shows more detail than the 4000dpi scan, but with the Mamiya, it's the other way around. That doesn't make sense to me. I do understand the implications of the different formats, but still, the quality ratio should go in the same direction, shouldn't it?
Yes - as I said in the text, this is a previous 8000 dpi scan that wasn't so good. In addition to this, the scan is enlarged to over 2x that of the 4x5 scans because the 'image' for the 4x5 has been projected onto a lot larger peice of film (hence the scanner hasn't had to do as much work).

The 8000dpi scan of the 4x5 doesn't really contain more detail either, it's just more contrasty.

Please don't take it personal when I say "can't be trusted" about the Mamiya 8000dpi scan. What I mean is simply that when the scan doesn't represent properly what's apparently present on the film (ref. the microscope view) within the area of the lines and numbers, the same might be the case for other areas of the image as well.

If it's true that we are seeing a limitation of the scanner here, and if a rather common film like the T-Max 100 really resolves beyond the abilities of such a high end scanner, it's kind of good news for those of us who like film. Shows that there's still a lot of life left in the old, flimsy rolls of imaging material :)
Ah yes, I understand now. Sorry for over-reaction - in which case it's very much true that this is a limitation of scanning systems. Even an 8000dpi scanner can only really get to about 100 lines per mm of detail on the film and T-Max has a potential 140 or more. If you use something like Spur Nano then you can reach 260 lppmm which is only accessible by enlargement.
 
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