Hello, I’m about to start a campaign of DSLR scan. I have all the gear (a stand, Valoi 360 etc) and software needed but not much experience in this specific task.
I’m willing to get the best of my scans (all 35 mm, no bigger format), and I’m a bit of a pixel peeper in general. I’ll be using a canon R5 and probably my RF100 2.8 macro (with that focus shift thing I have to compensate somehow).
I understand 45MP is a bit overkill but I have no other option in RAW with the R5.
My first test on some slides gave me inconsistencies in resolution power, some red fringing at certain apertures, I’m a bit confused.
From your experience, what would be the best camera settings on the R5 to get successful and sharp as possible scans. There are tons of features which I use or not for regular photography but I’m not sure which ones would be relavant for scanning.
Are you using Vlad’s Test Target to test your lens? If not then it’s very good for setting up your system, checking for the best aperture, accurate focus and alignment, as well as that chromatic aberration you seem to be getting. I think you’ll find that there is a narrow range of apertures that will give you the best results, probably centred, and close to, f5.6/f8. Then you have the choice of whether to use manual focus or AF so you’d need to compare results with each, using focus-peaking with manual focus. Alignment is very crucial so unless you’re using an ‘ES-2’ style holder attached to the lens you need ideally to use a mirror.
As far as settings go, switch off all image stabilisation and use either fully manual exposure with your chosen optimum aperture or aperture priority. You have pixel-shift but I don’t think you’ll be needing it for 35mm.
Well, correct me if I’m wrong because I don’t have an R5 but the resolution is down to the sensor and the lens. The lens will have a profile for your software I imagine so that’s the distortion taken care of but the rest would be down to your setup and technique. Both of those need to be spot on at 45MP with a good lens, and I believe that is a good lens for ‘camera scanning’ if it’s based upon the older DLSR version.
I have done thousands of scans with my R5/100 f/2.8 Macro and really like the results. With strong lighting, in AV mode I use ISO 100 @ f/4 (supposedly the best aperture for that lens) and let the shutter speed float. I found the need to dial in exposure compensation, typically +1/3 to +2/3.
I leave the spherical aberration control ring set to the middle.
I did some tests on a slide with some sharp details and there is indeed a difference in sharpness between f/4 and f/8 for example. The issue I might see is that f/4 implies a very narrow DOF, hence very sensitive to a slight movement of the whole setup or the exact position of any specific slide, or the curvature of a negative if any. Though choices ?
If you manually focus a bit closer than what you’d want if there was no FS, you should be fine. Mark the positions on your lens or use some tape to prevent unwanted movement of the distance ring…or use f/11, which is a bit too tight, but still good enough with a 45 mpix camera (I suppose) and eases the macro DOF challenge.
I scan with the R5, but with the sigma 70mm 2.8 ART macro lens.
I align my camera with a mirror on the film holder.
As others have said, aperture depends entirely on your lens - i use f/8.
I use autofocus on each frame individually, in the centre (if the centre is misbehaving i place my focus point on the subject of the film photograph.)
For exposure, I tend to use the RGB histogram. I use a blank section of the roll, and I push it until one of the three histograms hits the right hand edge, then take 3 shots, 1/3 up and down from there. I then open all 3 in FastRawViewer and choose the highest one that has 0% clipping. I then use that exposure for the whole roll.
Av mode is not ideal if you want to use Roll Analysis, as this depends on the whole roll being scanned with the same settings.
