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Author Topic: macro lens vs film scanners for digitizing transparencies  (Read 31215 times)

mediumcool

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itsskin

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Re: macro lens vs film scanners for digitizing transparencies
« Reply #41 on: January 07, 2012, 11:56:58 pm »

What's the problem with stitching? It's the fastest part done with PTGui.
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mediumcool

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Re: macro lens vs film scanners for digitizing transparencies
« Reply #42 on: January 08, 2012, 12:19:17 am »

What's the problem with stitching? It's the fastest part done with PTGui.

Which is commercial software. More cost.  :(
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torger

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Re: macro lens vs film scanners for digitizing transparencies
« Reply #43 on: January 08, 2012, 05:27:25 am »

SNS-HDR is not an HDR creator, but a tonemapper (granted though, the best for that purpose). The Neutral preset just gives the exposure blended result that's assembled from the individual exposures, before any tonemapping but after exposure fusion/merging.

I now worked tested some more, I guess it is more about me being a beginner in HDR than stuff is not working. I stitched each exposure separately to 16 bit tiff in Hugin, 3 layers 2 stop separated, and then made a neutral tone-mapping in SNS-HDR and saved as 16 bit tiff, and then I got desired result - no clipped highlights, noise-free shadows, and a totally neutral render.

One should not be in a hurry though, it is not fast software. I had a crash too, will be interesting to see 3 x ~190 megapixel merging that 6x6 medium format will be... I now do my test on 36x24mm, sampled at about 45 megapixels.
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itsskin

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Re: macro lens vs film scanners for digitizing transparencies
« Reply #44 on: January 08, 2012, 06:58:11 am »

Which is commercial software. More cost.  :(
They don't charge per stitch :) If you are a pro, you should have this software already anyway.
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mediumcool

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Re: macro lens vs film scanners for digitizing transparencies
« Reply #45 on: January 08, 2012, 07:44:35 am »

They don't charge per stitch :) If you are a pro, you should have this software already anyway.

Ha! Thanks for the should; at least you didn’t have the temerity to say must.

Who is entitled to say anyone should own any particular software? And does have = own? Just asking.  ;D
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itsskin

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Re: macro lens vs film scanners for digitizing transparencies
« Reply #46 on: January 08, 2012, 09:20:09 am »

Ha! Thanks for the should; at least you didn’t have the temerity to say must.

Who is entitled to say anyone should own any particular software? And does have = own? Just asking.  ;D

My bad. Sorry  ;D
Read it like: "As pro you should already have a software, capable of making stitching 1 minute task with great quality. Paid of free, as both exist"
Ok?  ;D
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torger

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Re: macro lens vs film scanners for digitizing transparencies
« Reply #47 on: January 08, 2012, 04:16:57 pm »

I realize that it will be a bit more work than I'd like to present comparisons and I would need a flatbed scanner too in there. So I just say what the likely result of such test would be based on my own informal tests this weekend :-)

I change my mind and think 5Dmk2 provides enough density at 1:1, which is close to 4000 ppi. Due to lens and f/8 for enough dof to manage focus resolution is a little bit worse than a 4000 ppi film scanner, but probably significantly better than any flatbed. I did 6000 ppi with the 7D but I doubt it will show on even large prints, the grain is probably adequately resolved with 5D. This reduces the stitching work. I would not want to go lower than 5D density though.

Concerning DR single shot is worse than multipass on good film scanners, but probably better than single pass flatbed. With 3 shot 2 stop spaced HDR (one ettr shot and two brighter for reducing shadow noise) it is better then the multipass scan. Probably single shot is good enough when no shadows are pushed in post, but on dark transparencies you will want HDR since there is detail to find there if pushed in post.

Getting predictable and satisfactory results from HDR software proved a bit messy, but I succeeded with SNS-HDR with neutral preset and reducing brightness slider to avoid highlight clipping. I did stitching in Hugin, outputing one exposure at a time to merge in external software. Hugin's own HDR is too poor quality.

Using this technique one will probably get  slightly better quality than a 3200 ppi medium format scanner for medium format transparencies. I think it is certainly good enough for fine art prints.

Use a sharp lens with good corner performance and low chromatic abberations, use bracket mode in camera and live view to minimize vibration, and to make sure no alignment for HDR is needed since that can reduce sharpness.
« Last Edit: January 08, 2012, 04:35:44 pm by torger »
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torger

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Re: macro lens vs film scanners for digitizing transparencies
« Reply #48 on: January 12, 2012, 04:30:40 am »

I got some issues with grain afterall... my idea was that I could sample at some X resolution and then it would be fine enough to print at any size, and X seemed to be 4000 ppi, enough to capture the film's real detail and some extra. However, after some test printing I have realized that to do that one needs some sort of grain simulation to get pleasing results if print sizes go large, or else that digital texture I don't like will emerge. Or digitize at extremely high resolution.

http://www.luminous-landscape.com/forum/index.php?topic=61088.0
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