Mark Segal's "Scanning with SilverFast"

[dchew]

Mark,

Thank you for a well-written and educational piece.  This is of particular interest to me.  I have a 5000 ED and quite a few 35mm slides that I have scanned over the past six or seven years.  I've been disappointed with the results, but I'm not sure why, and wonder if Silverfast would help.  I have a perception that the scanner is not focusing accurately, which may or may not be true.  As an example, I've attached some images of the raw scan, a 100% crop of the raw scan, and a modified file that looks like the original slide in color and luminance.  This was scanned in Nikon Scan 4 with ICE on, 16x, and in 16 (48) bit mode at full resolution. There were no gain adjustments or any other changes in the controls.  I chose this image because it exposes (sorry) the detail limits quite well.  My problem could be several things:

1.  There's nothing wrong; this is the best it gets and I have been simply spoiled by the additional detail from current digital cameras.
2.  The scanner does not auto focus correctly.
3.  The film just isn't flat in the plastic frame holders.  I was interested in the Epson 750 because of the wet mount capability, but you made a comment here that the dedicated (Nikon) scanner gives you slightly better results.  I used to think this was the problem but now I'm not so sure.
4.  The slide isn't that sharp.  I suppose this could be the case, but this was shot with a 70-200 f/4L IS at f/8 on Velvia with a sturdy tripod, and my view through a 10x loupe gives me a better impression of sharpness.  This, of course, could be my perception problem in #1 above.  I use this same lens on my current 5DII with great results.

Questions:  
Based on the 100% crop, is this a good result?  No sharpening or noise reduction has been applied at all.

Do you think this is a focus issue?  Would Silverfast's manual focusing help? Nikon Scan allows manual focus, but the feedback is miserable. I haven't figured out a good way to use it effectively.

Is this a mounting issue??

Original
[attachment=19046:DChew_06...OrigScan.jpg]

Levels & Curves Applied to Approximate Slide
[attachment=19047:DChew_06...01_slide.jpg]

100% Crop (no adjustments)
[attachment=19048:DChew_06..._100Crop.jpg]

Any opinions would be welcome.

Dave Chew

[Mark D Segal]

Hi Dave,

Thanks, glad you enjoyed the article.

A bit hard to say exactly what you are experiencing here, but as I read your explanation and looked at the images a few thoughts crossed my mind:

1. Slide film results will not necessarily look as sharp as digital from your camera, especially when you look at the scan results at 100%; but this is a stringent test, and absolute sharpness is hard to gage on a display. Try printing the scan at a decent printer resolution (at least 240 PPI without up-rezzing), at least on A3 or whatever is the largest size print you make at native resolution at least 240 PPI, and see what it looks like.

2. ICE can cause mild deterioration of overall sharpness, but shouldn't be very much. Try rescanning without using ICE and compare.

3. I do not have problems with the slide mounting system in the Nikon Super Coolscan 5000ED if this is the same machine you reference.

4. There is some (limited, but adequate) DoF in the scanner.

5. I did not get better results from the Epson 750 by wet mounting than I got from using their frame holder. It was pretty much the same.

6. Normally I find auto-focus works better than manual focus, and this should be true for Nikon-Scan as it would be for SilverFast. Not clear to me that SilverFast would do better at auto-focusing the scanner than would Nikon's own software. They are both driving an electro-mechnical process in the scanner itself.

7. If you suspect the scanner's auto-focus may be out of kilter, the best way to put your mind at ease on that issue is to send it to a Nikon service center for testing and if necessary adjustment. At least that way you will begin to know whether you have a scanner problem, a usage problem, a media problem or a film versus digital expectations problem. It could be one of the four.

[dchew]

Mark,

Your response helps in a couple ways.  First, up until now I thought my "problem" was mounting, i.e. media not flat.  I had nothing to base that on other than the inherent lack of any control to keep the transparency flat, plus a big dose of conjecture.  I'm quite happy that you saw no significant benefit from wet mounting; that means I'm using about the best hardware available aside from an expensive drum scan.  I probably will send the scanner to Nikon.  Based on all this, I don't think there is a focus issue, but it will set my mind at ease and it needs a good cleaning anyway.

Second, you've reminded me to "print it and see."  Until a few weeks ago I couldn't do this because I was limited to essentially 12x18, so I had to imagine results in larger prints.  As you probably know, imagining leads directly down the slippery slope of pixel peeping.  I can now print up to 24 wide, so I can actually see prints; a bit of a paradigm shift for me, in a good way.  I typically get slightly less than 5400x3600 px out of the Nikon, which is 22.5" at 240.  I'll try some this weekend.  I also want to try a scanned image at 20x30 (180ppi) vs. up-res to 240.  I'm very curious if I can stretch some of my slides to that size.

I hope the great fun of printing bigger wears off quickly; this could get expensive.  :-)

Happy New Year.

Dave

[Mark D Segal]

David,

Thanks and best of 2010 to you too.

Yes indeed it is a slippery slope, so being the money-sink that it is, we want best value for it.

Another thought crossed my mind about this last night - check through ALL the settings on the version of software you are using to see whether there is ANYTHING set there, such as an image-smoothing or noise reduction algorithm operating in the background. If there is, and with scanning programs you really need to poke through all the menus and options to be sure, this would definitely degrade resolution.

Finally, it occurred to me that if you want to do a double-check on your scanner sharpness before going to the trouble of sending the unit to Nikon, I may be able to help you with that. Please send me a private email and I shall lay out for you what we may be able to do.

Mark