More Scan vs Dupe Pics

[cooltouch]

With the recent discussions on film scanning happening here, I thought I'd do some more tests and comparisons and then show the results here.

I decided to compare my Epson 4990 against my duplicator rig, which is a contraption I put together that consists of a 55mm f/3.5 Nikkor, a small extension tube, the duplicator tube only from an Opteka "digital" duplicator, and the slide/negative carrier, which has position adjustments. After reading that Orio got better results when scanning his film with his Epson when the film was placed directly on the glass, I decided to give it a try, both with the film holder and without. Well, actually, even when I scanned the slide on the glass, I set the film holder on top of it, so the 4990 would be able to properly meter the photo. (Epson scanners determine exposure based on a slot molded into the top of the film holder.)

Here's the dupe rig I use:



The slide carrier is on the left and the negative carrier is on the right. I removed the piece that holds the diffusion panel from the front of the Opteka tube, and fortunately the slide and negative carriers slide over the tube's flange. It's a little fiddly, but once things are set, it works very well.

I selected a slide that was both unmounted and critically sharp. This particular slide was taken in 1986 using Fujichrome 100. I mention this because 1986's regular old Fujichrome is probably grainier than any of the various flavors of modern ISO 100 Fuji slide film.

I used a Canon F-1 and a Canon FD 50mm f/3.5 macro lens. To light the subject, I placed a white handkerchief on a glass table and then located a
Vivitar 285 strobe underneath. As I dimly recall, I just guessed at exposure, and then bracketed (because I have three slides of varying brightness in my files).

This is the image taken with the duplicator:


Here's a scan using the Epson 4990 @ 3200 ppi with the strip film holder:


And a scan with the slide placed directly on the 4990's glass surface. Also at 3200 ppi:


I did some post processing -- removed dust spots and bumped up the contrast somewhat. I didn't do any sort of sharpening, however.

It's pretty hard to tell the difference between the three images isn't it? Well, at 900x600 resolution for the web, that's understandable. 100% enlargements are needed to show the differences. So, following are 100% crops of each image.

Dupe 100% crop:


Epson 4990 with film holder 100% crop:


Epson 4990 with film on the glass 100% crop:


Note the reflections of the white surface in the lens. With the dupe, you can clearly see the weave of the handkerchief. With the crop of the image where the film was mounted into the holder, resolution isn't sufficient to resolve much in the way of detail of the weave. But the last crop above, the one where the slide was placed directly on the glass, shows some slightly more detail of the weave. Not nearly as much as the dupe, but it's there. Also, if you look at the writing on the lens bezel, it's pretty obvious that the last image is a bit sharper than the middle one, although it's noticeably softer than the dupe.

Before I tried scanning images directly on the glass, I tried shimming a mounted slide first. That is, I located it higher than it normally would sit. I cut up some (flat!) waste film into strips and used strips as shims. With one film thickness, the difference was negligible. With two film thicknesses, it became a bit more obvious -- the image was getting softer. With three film thicknesses, it was beyond question.

There is a drawback to scanning with the film on the glass, however. Newton rings appeared. You can see them in both of the above "glass scan" images, although they are somewhat faint. So, if I were going to make a habit of scanning my unmounted slides and negatives on the glass, I would need to get some ANR glass for this -- and I'd probably have to make what Epson calls a "film area guide" so the scanner will expose properly.

[TBaker]

That's great for the duplicator. I have the Asahi Pentax slide dup coming soon. This is great news.

[cooltouch]

[TBaker]

I have the 40D and on the fence about getting a 7D or 5D MKII.

Funny thing is I won a slide dup and he sent me the Asahi bellows. So he said keep the bellows and he'll send me up the slide dup. Can't wait.

Right now I have a Canoscan 8400 and it does a so so job with them but scanning negs I find too much a chore after do PP.

[martinsmith99]

The dupe wins, but I'm not seeing enough difference in the scanner images to bother with the on-the-glass scans. It seems like a lot of extra work for very little improvement.

[poilu]

nice comparison, the Epson 4990 do a great job
you forgot to mention that a scan at 2400dpi is 7 minutes per slide on the Epson vs 1/125s on the dupe

last year, I made a comparison between the Nikon 9000 ED and the 40D
http://forum.mflenses.com/best-slide-scanner-t4661.html
Nikon 9000 ED on left


a dupe scan with a 5D is much better than with a crop like the 40D
the 5D show less diffraction at 1:1 and the sensor filter is weaker giving sharper images
http://forum.mflenses.com/ektar-high-tech-scanner-samples-t24360.html

[cooltouch]

[cooltouch]

[Orio]

The duplicator is sharper but introduces visible (and horrible) digital noise.

I'm glad to see that with your test too the film on glass is noticeably sharper than inside the holder. Like I said, that was exactly my experience, and AFAIAC I'm not going to use film holders anymore.

[cooltouch]

[cooltouch]

[eeyore_nl]

[poilu]

[cooltouch]

[poilu]

[martinsmith99]

[Orio]

[pablo]

Cooltouch:

Thank you for your efforts in providing these tests. I had been looking at Coolscan prices on ebay, and LS5000 prices are about 50% more than they were about 3 months ago. But your tests have convinced me that I would rather copy film in a DSLR.

However, rather than use a 50mm macro lens, I am thinking of using a 50mm or longer enlarging lens attached to a bellows. Any suggestions as to the best enlarging lens for the application?

[cooltouch]