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12-10-2013, 05:47 AM   #1
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DSLR scanning

Whilst I am logged in, thought I would just share my 2c of recent experience scanning using a DSLR. I have a light box from Calumet, and using my negative carrier, have been digitizing some negatives. The results are significantly sharper than using my V300 scanner. With medium format, its clear that the negative contains more information than the camera sensor can pick up as the digital raster can be seen before grain. With 35mm, its a wash between the two on TMAX100 in XTOL.

I got the idea from here:
http://www.addicted2light.com/2012/11/23/best-film-scanner-canon-5d-mark-ii-...vs-epson-v700/

I am using a Tamron 90mm on my E420, but just bought a Pentax KM to use instead which is on the way.

Results are best for BW work, as the orange mask on colour negatives creates problems. A brief play with Vuescan yielded ok colours, but the best come from mucking about with the RGB channels in GIMP. I guess Photoshop is on my Christmas wishlist now, to accompany the film side of things. As much as I like getting a wet print out, being realistic, its easier to keep track of the photos I have taken by digitizing them. The main thing is speed or time required to make the "contact sheet". The DSLR speeds the process up massively.

When looking at my medium format stuff out of my Bronica, there is simply no way you could create the depth of field effects on digital, so this hybrid process is still in my opinion better than just shooting digital if only for the beauty of these originally top of the line lenses. But I feel I have succumbed a bit to the digital side!

01-01-2014, 11:52 AM   #2
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I don't have a macro lens. Nor a light table…but I made do and improved with a laptop screen and some extension tubes.

Near impossible to get a whole 6x7 frame done well like this due to the thin DOF and getting things parallel. However, here is an idea of what a K-5 is like vs an Epson 4870:

Whole Rollei Retro 400 frame:



Epson:



K5:



Most impressive, albeit labour-intensive.
01-01-2014, 12:38 PM   #3
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QuoteOriginally posted by whojammyflip Quote
With 35mm, its a wash between the two on TMAX100 in XTOL.
Can you clarify what you mean?
01-06-2014, 01:13 AM   #4
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100 speed TMAX 35mm film is comparable to DSLR resolution. Easiest to see when comparing digital scans of medium format vs 35mm, and the relative size of the effects in the image which are nothing to do with the image itself. With medium format, the rasterisation from the demosaicing of the digital sensor clearly loses information which the film held. This is easiest to see on straight edges, where jagged digital effects become very apparent. On 35mm, this is still apparent, but less so.

As mentioned, I still really like the 35mm stuff, as the depth of field effects from the lenses cannot be replicated with an APS-C sized sensor.

Less obviously, tonal information which the film holds is lost at the scanning stage, due to the difference in analogue vs digital. This occurs to the same extent with both 120 and 135 formats. Its hard to explain, but a wet print, vs stuff I have ordered digitally, has a much deeper look to it. The tonal gradation is smoother, and has an overall nicer quality, for want of a better description.


Last edited by whojammyflip; 01-06-2014 at 01:19 AM.
01-19-2014, 10:02 PM   #5
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QuoteOriginally posted by whojammyflip Quote
Results are best for BW work, as the orange mask on colour negatives creates problems.
I have done some testing in this area myself, as I'm still a fan of film but am frustrated by the difficulties of capturing all the information available in the film image. I have an Epson V700 but have never been that happy with the image quality from it.

Using a DSLR is a pretty good way of digitizing film, though as you say, most cameras don't have the resolution to be able to capture all the information in a medium format frame.

When using colour neg film, I have managed to get a pretty decent colour response by using some cheap colour printing filters underneath the film to negate the orange mask. This brings the colour balance closer to what the sensor is designed to capture and so requires less extreme manipulation of the colour channels in post. The downside is that you lose quite a bit of light and will need longer exposures, but that's not the end of the world. I can't remember exactly what filtration I used but probably around 40 units of cyan and 10 magenta.

Ragarding detail, I used a (borrowed) Canon 5D mkII and Sigma 105mm macro to do some tests on a 6x7 neg from a Bronica GS1 shot on FP4. Despite the higher resolution of the 5D compared to the E420 you have been using, it's still clear that some detail is being lost, and representation of grain is not that clear. My conclusion was that in order to capture a really good representation of the film frame I would have to photograph the left and right sides of the frame separately and stitch them together. For finer-grained films like Delta 100 you'd need even more resolution. I never got around to actually trying the stitching because of the time involved. Having said that, you're still getting good image quality overall even with a single shot - good enough for most purposes.

So in theory a 40MP DSLR and good macro lens would allow you to digitize medium-grain 6x7 negs adequately. The 36MP Sony A7r would come close - and you could still use your Tamron macro .... but for this money you could buy a dedicated MF film scanner. With 645 negs I would guess that 24MP would be just about enough - so a good excuse to buy a K-3!

If I find some time I'll post some examples on here.
01-20-2014, 11:28 AM   #6
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QuoteOriginally posted by jonby Quote
When using colour neg film, I have managed to get a pretty decent colour response by using some cheap colour printing filters underneath the film to negate the orange mask. This brings the colour balance closer to what the sensor is designed to capture and so requires less extreme manipulation of the colour channels in post. The downside is that you lose quite a bit of light and will need longer exposures, but that's not the end of the world. I can't remember exactly what filtration I used but probably around 40 units of cyan and 10 magenta.

If I find some time I'll post some examples on here.
Can you describe more about this? I'd definitely be interested in some photos of your setup and results.
01-20-2014, 03:33 PM   #7
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QuoteOriginally posted by jonby Quote
When using colour neg film, I have managed to get a pretty decent colour response by using some cheap colour printing filters underneath the film to negate the orange mask. This brings the colour balance closer to what the sensor is designed to capture and so requires less extreme manipulation of the colour channels in post. The downside is that you lose quite a bit of light and will need longer exposures, but that's not the end of the world. I can't remember exactly what filtration I used but probably around 40 units of cyan and 10 magenta.
The orange mask is usually (AFAIK) a simple monochromatic colour "cast". Therefore, it can often be balanced out merely by stretching the levels - provided that the original negative was shot in the light it was designed for. Here an example of a (1985) Kodak Gold negative shot with a simpe point-and-shoot camera (5 Mpix Olympus C-50Z from 2004) through a 135mm f/3.5 Takumar as 'close-up filter':

The negative:



The inverted negative:



The inverted negative after stretching of levels:



That said, balancing the digital picture this way of a negative shot under artificial light can be an exceedingly frustrating experience. Here your filter-solution really interests me!
01-20-2014, 10:06 PM   #8
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QuoteOriginally posted by Stone G. Quote
The orange mask is usually (AFAIK) a simple monochromatic colour "cast". Therefore, it can often be balanced out merely by stretching the levels

I'm intrigued by "stretching the levels"

I presume in the case of negative film you simply drop the blue/cyan channel right down? (after inverting colour)

or is it more involved than that?

01-21-2014, 01:47 AM   #9
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QuoteOriginally posted by hks_kansei Quote
I'm intrigued by "stretching the levels"
'Stretching levels' is a simple algorithm in digital image processing software where one changes the distribution of tonal levels (in all three channnels) to span more of, or the entire level range available (e.g. 0-255 in a 3 x 8 bit true colour image). See for example here:

Improving Image Tone With Levels In Photoshop

It is often found as an automated procedure in image processing software. In my PhotoImpact it is as imple as Photo -> Levels -> Stretch:

01-21-2014, 09:45 PM - 1 Like   #10
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QuoteOriginally posted by filoxophy Quote
Can you describe more about this? I'd definitely be interested in some photos of your setup and results.
I don't have photos of the setup I used unfortunately. I used a cheap Jessops lightbox as the light source, which is more or less daylight balanced. The colour printing filters lay directly on the light box. Colour printing filters are small square gel filters which you use to control colour balance when making colour enlargements on an enlarger that doesn't have in-built filters. They come in packs with cyan, magenta and yellow colours in different strengths, denoted by a 'unit' value - eg 5, 10, 20, 40 units, 40 being the strongest.

Above the filters, I used a negative carrier from an enlarger to hold the film flat. This also holds the film well above the filters and light box, so that dust and scratches don't come into focus. Above that of course there is the lens and camera, supported on a copy stand.

Stone G demonstrates here that using filters is not essential - it is possible to get pretty good results without them. However, you can see from his histograms how dark and compressed the red channel is compared to the green and especially the blue channel in the original image following inversion. In order to get 'normal' colour balance and contrast, the red channel must be stretched and brightened to a high degree. The same information is being stretched over a wider brightness range, which reduces quality. The idea behind the colour filters is to effectively counteract the orange mask (as much as possible) before shooting, so that the channels are more or less equal in brightness and contrast in the captured image. This then requires a less aggressive stretching of the red channel in order to reach normal balance and contrast, thus causing a smaller drop in quality.

If you shoot in raw, then I don't think the difference will be huge, but my philosophy is that you might as well do what you can to maintain as much of what is contained in the film as possible.

It's very late where I am and I must go to bed now but I'll post some images as soon as I can.

Last edited by jonby; 01-22-2014 at 12:02 PM.
01-22-2014, 07:45 PM   #11
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I haven't been able to find the colour tests I mentioned yet so I can't post images of them. However, I have located the tests I mentioned in my first post which were aimed at assessing the detail captured at different magnifications using a Canon 5D mkII (21MP full frame). I'll post some comparison crops here in case anyone's interested.

The tests were actually done on a 6x4.5 neg - not a 6x7 neg as I thought. The film frame was a lens test, shot on FP4 using a Mamiya M645 and 80mm f2.8 N lens. I think it's about as sharp as is possible with that combination.

The digital photographs of the film were shot in RAW on the 5D mkII with Sigma 105mm f2.8 Macro OS. I bracketed focus with each shot to ensure best focus. I shot at three different magnifications:

1) one to one magnification
2) composed so that the long dimension of the 5D frame matched the short dimension of the film frame (the idea here being that you could capture the whole film frame with two shots)
3) composed so that the short dimension of the 5D frame matched the short dimension of the film frame (so the whole film frame is captured in one shot)

All the examples shown have been inverted and a normal tone curve applied in Adobe Camera Raw. No sharpening was used.

These first three are crops from the same area of the film frame, shot at the three different magnifications and presented unmodified.
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Canon EOS 5D Mark II  Photo 
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Canon EOS 5D Mark II  Photo 
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Canon EOS 5D Mark II  Photo 
01-22-2014, 08:03 PM   #12
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… and here are the latter two images again, but this time scaled up to match the 1:1 image. Finally, there is a scaled down view of the shot of the whole film frame, to give it some context.
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Canon EOS 5D Mark II  Photo 
View Picture EXIF
Canon EOS 5D Mark II  Photo 
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Canon EOS 5D Mark II  Photo 
01-22-2014, 09:37 PM   #13
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Conclusions

It's clear from these images that photographing the whole frame of this 645 FP4 negative with a 21MP full frame camera does not capture all of the image detail in the film. The higher magnification shots show substantially more image detail and much better representation of the grain. The difference between the shot at 1:1 and the intermediate magnification is less obvious. While the grain is being represented more clearly there's only a tiny amount of extra image detail present in my view.

In terms of using this method of 'scanning' film for print purposes, the shot of the whole frame would yield a print of 24 x 18 inches at 200 pixels per inch.
If two shots were made at the intermediate magnification and then stitched together to form the whole frame, the print would be 37 x 28 inches at 200 ppi.

Finally, here is a scan of the same negative using my Epson V700 scanner. This was scanned at 4800 ppi. The first one is unsharpened, the second one has quite strong sharpening applied (you get best results from this scanner by over-sampling and then sharpening).

They have been scaled down slightly to match the resolution of the 1:1 shot with the 5D.

When sharpened, the scan clearly produces more detail than the 5D shot of the whole frame. I'd say it's just a tad worse than the 5D intermediate magnification shot. The V700 is therefore looking like the better option overall for the 645 format. Although you can get more out of the film by using a 5D and stitching shots together, the extra work involved in this is probably not worth it in most cases.

Theory would suggest that it's a different story for 35mm. Shooting at 1:1 with the 5D, you would capture the whole frame in one shot, and these tests show that at this magnification, the camera captures significantly more detail and clarity than the scanner.
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01-27-2014, 12:59 AM   #14
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This is interesting. Nice post.

The 5D can see 21x10^6 pixels. This works out as 150 pixels per mm, which in turn is 75lp/mm. I doubt the Epson can see more than about 25lp/mm. Sharpening etc doesn't add anything to the resolution, it just increases the apparent contrast of low frequency details.

Decent film, shot through a sharp normal, like the 80mm (I've got a Bronica and saw a test on line for PE lenses, Hasselblad and Mamiya, and I seem to remember the Mamiya glass was highly rated) will reach 100lp/mm. There are Zeiss docs online recording 400lp/mm, but this is unlikely unless you have awesome film and glass, shot with specific lighting conditions etc. But 100lp/mm is feasible.

The fact that neither the 5D nor the Epson hit 100lp/mm means that they need to look at an enlarged section of the negative and then have it stitched together. The Epson cannot do this.

If you look at this link:
http://www.addicted2light.com/2012/11/23/best-film-scanner-canon-5d-mark-ii-...vs-epson-v700/

its clear that the stitched 5D scans exceed the Epson by a long way.
02-26-2014, 04:32 PM   #15
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I just had to try this, but I don't have a light box, or a negative carrier, or even a flash. So I set up my tripod in front of the desk, put a flat white image on the pc monitor and cranked up the brightness, and suspended the film between The Lord of the Rings and The Silmarillion using rubber bands. This ghetto setup worked surprisingly well, and in many ways the result compares favourably with my developer's scans. Oh, and I managed to enhance the negative with a big fat greasy fingerprint after the experiment...

From top to bottom:
1. Whole frame from DSLR
2. 100% crop of scan
3. DSLR crop scaled to match scan
4. 100% DSLR crop

The scan shows obvious macroblocking; I don't know if they are compression artifacts (1.5 MB JPEG) or some scanner idiosyncracy. The DLSR version is very soft, but compared to the scan it looks much more pleasant up close. I may have missed focus, something may have moved during the 1-second exposure, and/or the focal plane may not have been parallel to the film plane - I suspect all three.

The film is Ilford Pan F Plus exposed in an Olympus OM-10. According to the EXIF data, the scanner is a Noritsu QSS-32 or QSS-33 (listed as "NORITSU KOKI QSS-32_33"). Raw file from Pentax K-5 with SMC D-FA 100mm WR. Coarse lighting adjustments and monochrome conversion in PDCU. Inverted, cropped, and compressed in GIMP.
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