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Author Topic: Edge sharpness falloff Coolscan IV vs V?  (Read 2912 times)
AFairley
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« on: March 25, 2010, 11:34:23 AM »
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I just picked up a used Coolscan IV, and while the center of the scans are scary detailed, there is considerable image softness at the edges of the scan.  I think some of this may be attributable to the curvature of the slide in the cardboard mount, but not all.  Scans of super-flat old neg strips fare better at the edges than the slides, but there is still sharpness falloff at the edges, and it's greater at the ends of the 36mm dimension rather than the 24mm dimension, which leads me to think its optics as well as focus.  I bring this up because I don't recall seeing that amount of falloff on Coolscan V scans.  Can anyone comment?

Thanks
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Mark D Segal
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« Reply #1 on: March 25, 2010, 11:50:23 AM »
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I've been using both a Nikon Super Coolscan 5000ED (new) and a Minolta Dimage Scan Elite 5400 (about 8 years old), and I haven't seen this problem. Both appear to have enough depth of field to handle small amounts of media curvature. It may be an idea to have a Nikon service center check your scanner.
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Mark D Segal (formerly MarkDS)
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francois
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« Reply #2 on: March 25, 2010, 11:57:17 AM »
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I second Mark's suggestion. I had to send mine to Nikon for various problems and they calibrated the optics and fixed another issue...
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Francois
AFairley
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« Reply #3 on: March 26, 2010, 10:51:07 AM »
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After further investigation, it seems like what I had was slides with too much curvature for the lens DOF to handle.  I put an old negative in a glass slide mount, and the grain on the scan was sharp pretty much edge to edge.  However, even with slides with minimal bowing, there is not enough DOF in the scanner to give the same sharpness edge to edge.  I am able to get acceptable results by autofocusing on the center and on the edge, noting the focus numbers, and manually focusing on the average. That bumps edge sharpness some without decreasing center sharpness unacceptably.  I do think I saw greater DOF on the Coolscan V I used for a day a while ago.  Anyway, with this scanner it looks like glass mounting is the way to go for critical scans.

Thanks to you who responded.  I will give the Nikon service center a call and see what they have to say.

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francois
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« Reply #4 on: March 31, 2010, 04:40:58 AM »
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Just wanted to add that I read the March issue of French mag Chasseur d'Image and they found that the CoolScan V is also affected by the slide curvature issue…
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Francois
AFairley
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« Reply #5 on: March 31, 2010, 01:37:00 PM »
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Quote from: francois
Just wanted to add that I read the March issue of French mag Chasseur d'Image and they found that the CoolScan V is also affected by the slide curvature issue…

Was this online, and if so, do you have a link?  Thanks.
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francois
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« Reply #6 on: March 31, 2010, 01:54:05 PM »
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Quote from: AFairley
Was this online, and if so, do you have a link?  Thanks.
No, the issue is not available online only in print. The article compared different types of scanners for negs & slides. The CoolScan was the overall winner. I'll have a look at the article tomorrow when I'm in the office. I'll report the + and the - mentionned in the article.
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Francois
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« Reply #7 on: April 01, 2010, 05:40:41 AM »
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Hi,
So, here's the pluses and the minuses of the CoolScan V

Plus
- Best image quality (for affordable scanners)
- Full featured scanning software but no guaranteed support for Mac OS 10.5 & 10.6
- Very effective ICE system (via IR)
- ICE, ROC and GEM are very powerful
- Quick, stable and powerful lighting system (LED)
- Good loading mechanism for negs and slides

Minus
- Cannot scan panoramic images (X-Pan)
- Grain is visible in standard mode, need to fine-tune for each type of film
- Focus issues with non-flat negs/slide
- Anti-dust (IR) doesn't work with Kodachrome films

Preview time (slide, 24x36): 45 seconds
Scan time (slide, 24x36, with ICE/ROC/GEM): 185 seconds
« Last Edit: April 01, 2010, 05:41:57 AM by francois » Logged

Francois
Mark D Segal
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« Reply #8 on: April 01, 2010, 08:23:46 AM »
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Francois, thanks for reporting that - I hope to find a copy of the magazine from an outlet carrying French publications and read the whole article. In the list of "cons" the lack of IR dust removal on Kodachrome is mentioned. This issue is not specific to that scanner. ICE is not supposed to work with Kodachrome in any scanner. But even that isn't completely true. I've used it and it can work. Apparently the problem is confined to some Kodachrome emulsions and not others. One of the other cons, grain being visible in standard mode - that is a good thing. One wants to see EVERYTHING the scanner collects before deciding on what needs to be mitigated and to what extent. This may give the user some control over managing the distinction between grain and micro-detail before smoothing anything.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
francois
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« Reply #9 on: April 01, 2010, 09:13:01 AM »
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Quote from: Mark D Segal
Francois, thanks for reporting that - I hope to find a copy of the magazine from an outlet carrying French publications and read the whole article. In the list of "cons" the lack of IR dust removal on Kodachrome is mentioned. This issue is not specific to that scanner. ICE is not supposed to work with Kodachrome in any scanner. But even that isn't completely true. I've used it and it can work. Apparently the problem is confined to some Kodachrome emulsions and not others. One of the other cons, grain being visible in standard mode - that is a good thing. One wants to see EVERYTHING the scanner collects before deciding on what needs to be mitigated and to what extent. This may give the user some control over managing the distinction between grain and micro-detail before smoothing anything.
The issue n°321 is the March 2010 of Chasseur d'Image. I also tend to scan "everything" and clean up - if neede - later.
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Francois
AFairley
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« Reply #10 on: April 01, 2010, 02:02:01 PM »
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Thanks, Francois.

I have been doing a little more research into the issue, and there is quite a bit of complaining in scanning forums about shallow DOF and slide curvature with the Coolscan IV and V (and the 4000 and 5000). There is an extended discussion and various approaches people have tried to address the problem here for anyone who's interested.  People seem to be saying that the DOF is around 10 focus units -- I have some slides that are so bowed they approach a 40 focus unit difference between the center and the edge, though that is an extreme.
« Last Edit: April 01, 2010, 02:04:37 PM by AFairley » Logged

Czornyj
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« Reply #11 on: April 01, 2010, 03:24:00 PM »
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Quote from: AFairley
Thanks, Francois.

I have been doing a little more research into the issue, and there is quite a bit of complaining in scanning forums about shallow DOF and slide curvature with the Coolscan IV and V (and the 4000 and 5000). There is an extended discussion and various approaches people have tried to address the problem here for anyone who's interested.  People seem to be saying that the DOF is around 10 focus units -- I have some slides that are so bowed they approach a 40 focus unit difference between the center and the edge, though that is an extreme.

To counteract the problem with shallow DOF I'm using anti-newton glass holder for my 9000 - maybe there is something like that for V/5000, or some custom made holders?
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Marcin Kałuża
Mark D Segal
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« Reply #12 on: April 01, 2010, 04:05:03 PM »
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Quote from: Czornyj
To counteract the problem with shallow DOF I'm using anti-newton glass holder for my 9000 - maybe there is something like that for V/5000, or some custom made holders?

If you read down the discussion of the referenced article you will see that the use of anti-Newton glass can actually degrade sharpness.

I note as well that this discussion dates from 2005. Are we to assume that the models still under production or replaced with up-graded models between then and 2009 were not at all improved in this respect? I also wonder about unit to unit variation of outcomes, because there is also a report of no such problems in the discussion under the main post.

As well there is an issue about distinguishing between edge unsharpness caused by the camera lens versus that caused by the scanner assembly. This one is easy enough to handle by looking at  grain and artifacts, because neither depend on the quality of the camera lens. I've just done that with some slides I scanned using my Nikon SC5000-ED bought last November (sadly, one of the last ones at "normal" retail price left in the world it seems!) and the results look pretty-much uniformly sharp throughout the image (51 MB files) at 100% display magnification (LaCie 321 1600*1200 resolution display). I could check this further by printing enlarged segments on my Epson 3800, but I can predict without going to the trouble that the results will be extremely close to what I observed.

This isn't to question that there have been and perhaps remain legitimate issues which some people are experiencing, but so much to say that it seems hard to generalize, and therefore hard to identify a specific culprit, except to start by making sure the scanner is in the best possible condition it can be.

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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
Clearair
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« Reply #13 on: April 01, 2010, 04:59:47 PM »
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Quote from: Mark D Segal
I've been using both a Nikon Super Coolscan 5000ED (new) and a Minolta Dimage Scan Elite 5400 (about 8 years old), and I haven't seen this problem. Both appear to have enough depth of field to handle small amounts of media curvature. It may be an idea to have a Nikon service center check your scanner.

Hi Mark

Interested in what driver you are using re the Minolta 5400.
I recently dug out my 5400 to make a long overdue start on some 7000 slides and 4000 negs. HELP me someone!! So I know the Minolta supplied driver will not work with recent any recent OS and I have checked the Sony site.
I left an old Macbook running Tiger just for this but it's a bit slow and judging with a 13 inch monitor is not ideal.
What about Silverfast? I must admit I like the Minolta work flow.
Don't use Microsoft PC so it has to be Mac specific.

Regards
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Mark D Segal
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« Reply #14 on: April 01, 2010, 06:50:58 PM »
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How do you know the Minolta driver won't work with any recent OS? Have you actually tried it, or are you assuming it? If you haven't tried, perhaps worthwhile doing so if it won't cause any problems (don't know). Sometimes these things work even though they are dated. The latest version for the Mac is 1.1.5 for OSX 10.3 as far as I could determine, and it dates to 2005. If you use SilverFast or Vuescan as the scanner software, you still need the Minolta driver. While the 5400 is a very high quality scanner, it is also very SLOW. I know, I have one of those too. With 4000~7000 images to scan you will be at it for a long time.
« Last Edit: April 01, 2010, 06:51:47 PM by Mark D Segal » Logged

Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
BartvanderWolf
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« Reply #15 on: April 01, 2010, 07:03:31 PM »
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Quote from: Clearair
Interested in what driver you are using re the Minolta 5400.
I recently dug out my 5400 to make a long overdue start on some 7000 slides and 4000 negs. HELP me someone!! So I know the Minolta supplied driver will not work with recent any recent OS and I have checked the Sony site.

Try the VueScan Pro solution. It supports most of 'all' scanner specific firmware functionality. It might require some tweaking (which it allows, rather than a choice from a limited set of options, including color management) and it adds options that are not available from the original native OS drivers. The most important feature is new OS support ...

Cheers,
Bart
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Mark D Segal
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« Reply #16 on: April 01, 2010, 07:19:14 PM »
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Yes, a check of Hamrick's site indicates that for Mac OSX no other vendor software should be needed. Not necessarily the case for Windows, where vendor software MAY be needed, but he also says with a WIA driver it should work with most scanners.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
francois
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« Reply #17 on: April 02, 2010, 01:49:27 AM »
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Quote from: Mark D Segal
Yes, a check of Hamrick's site indicates that for Mac OSX no other vendor software should be needed. Not necessarily the case for Windows, where vendor software MAY be needed, but he also says with a WIA driver it should work with most scanners.
I'm using NikonScan on my old Mac but on my latest Macs I use ViewScan only (no other softwre needed).
« Last Edit: April 02, 2010, 01:52:30 AM by francois » Logged

Francois
Clearair
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« Reply #18 on: April 02, 2010, 04:53:13 AM »
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Thanks all for the information on alternative scan software re 5400. This opens up new possibilities and will help me.
Regards
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