Achievable resolution with Epson V700/V750/V800/V850

jeffreyg said:

For what it is worth...

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More than nothing, because you make a excellent point. Another way to say what have said is that oversampling can produce a better image, with less artefacts. Which goes back to OP original point, how do you get the best out of what you have, in a practical way.

Very interesting work.

How do you decide where to put those red arrows?

The V7XX scan seemed to me that the scan didn't have proper focus. Even the numbers are blurred. Unless the scanner is really crappy.

Les Sarile said:

My experience is different then yours and I consider myself pretty competent with post tools.
Here are scans from an Epson V500, V7XX and Coolscan of the same frame of 35mm film (Fuji RVP - ISO50) shot using optimal setup with a 4 X 4 arrangement of test charts. The Epson were shot at various resolution settings and I also scanned with and without ICE.

Coolscan full res -> http://www.fototime.com/02BB797801DCA89/orig.jpg

Epson V500 full res -> http://www.fototime.com/33269E445D10043/orig.jpg

Epson V7XX full res -> http://www.fototime.com/11F59FA46FF9497/orig.jpg

When using test targets and shooting under optimal conditions the differences in achievable detail - provided the detail has been captured on the frame of film, is very obvious and cannot be manufactured in post. If you don't use good film, don't take care in taking the shot, don't use good equipment or the target itself doesn't have the detail then the difference may not be so noticeable. Incidentally, no post sharpening were applied to any of these.

My use of these Epsons is not optimized as intended by the OP so I don't know if these could have been improved to equal that of the Coolscan.

I was also curious to compare just how much detail can be resolved by the Coolscan relative to DSLR scanning so I used a Pentax K20D+Autobellows (14.6MP) and Nikon D800+Autobellows (36.3MP) and Coolscan on the same frame of Kodak Techpan shot at ISO25 and processed in Kodak Technidol and got the following results shown below.

• Bottom left shows test target arrangement. Center area bounded in red are shown as 100% crops.
• Above it is 100% crop from Pentax K20D.
• Above that is 100% crop from Coolscan.
• Above that is 100% crop from Nikon D800.
• To the right is an optical magnification (4.5X) that clearly shows real detail not resolved by these methods.

Full res version -> http://www.fototime.com/8372250EA44CB06/orig.jpg

BTW, you'll notice that even though the D800 has more pixels then a 4000dpi Coolscan file, there is very little difference between the two. Of course there is no dust and scratch removal using DSLRs and the Coolscan+Nikonscan ICE is the most effective tool available.

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philosli said:

Very interesting work.

How do you decide where to put those red arrows?

The V7XX scan seemed to me that the scan didn't have proper focus. Even the numbers are blurred. Unless the scanner is really crappy.

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The red arrows are positioned to the point where I can't see between the lines.
The V7XX does look out of focus by comparison of course.

Les Sarile said:

The red arrows are positioned to the point where I can't see between the lines.
The V7XX does look out of focus by comparison of course.

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Have you experimented to find the best film holder height?

alanrockwood said:

Have you experimented to find the best film holder height?

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I have not.

Les Sarile said:

I have not.

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It would be worth experimenting with the film holder height. Each individual specimen of the Epson scanners is a little different, and it is not unusual for there to be a 1mm or 2mm difference in optimal film height from one scanner to another. It often makes a noticeable difference to tune it up for the optimal film height.

I found an article that addresses the question in my original post:

Dead Link Removed

In that person's hands an Epson V/700 achieved a resolution of about 2800 line pairs per inch. That was after finding the optimal film height, and apparently it was also after finding optimal sharpening settings. That person also found that a scan resolution setting of 3200 gave the best resolution. A higher setting produced lower resolution, and a lower setting also produced lower resolution.

Without sharpening the resolution was around 2400, which is about what other people usually report.

2800 isn't too bad, maybe slightly better than 70% of what a 4000 dpi scanner can do, but it isn't great either. However, do you remember when people used to say that 2700 is all you need? I do. The claim was that going higher would only result in resolving grain. Of course, that theory was wrong, as was demonstrated when good 4000 dpi scanners came out. Then people said there was no point in going higher because going higher would only result in resolving more grain. Then the higher resolution Minolta scanners came out and proved that theory wrong as well.

My somewhat wild guess (thought not completely wild) is that if one had the most carefully crafted 35mm image, photographed under the best conditions, using the optimal lenses and film choice, using the optimal aperture setting you could probably see an increase in quality (though a subtle increase) up to about 8000 dpi. That would correspond to a Nyquist limit of 167 line pairs per mm, which is probably a bit more resolution than the lens/film system could produce, but I suspect that the ability to to better resolve the grain under those conditions would probably give a slight increase in quality, perhaps through a lower level of grain aliasing.