As with many photographers, my collection consists of B&W and colour prints of various sizes and formats, 35mm B&W and colour negatives in both rolls and cut strips, 35mm slide/reversal material both in rolls and as mounted slides. Film stock covers many brands including Agfa, Ansco, Fuji, Kodak—including its Eastman movie emulsions—and others. Kodak holds special place, with Kodacolor, Ektachrome (including infrared versions) and Kodachrome. At a guess, I've have about 30,000 Kodachrome slides alone. And that's not all, I've also larger format photos, prints, B&W and colour negatives and reversal stock.
Most of this material has still not been scanned because of the challenges involved, for instance those in the know will be aware of the difficulty of scanning Kodachrome slides because of residual silver that's still in the processed emulsion. Then there are scanning difficulties, mounting various formats (slides, rolls of negatives, etc.) and technical difficulties such as focus adjustment, avoiding Newton's rings, etc. Simply, I've not been able to get the tech necessary to do what I consider an adequate job.
Restricting my comments to just 35mm I can confidently say there is NO 35mm film scanner on the market today that can do full justice to a large range of film types—except perhaps exotic and expensive drum scanners which are unavailable to the vast majority of photographers including many professionals. (Drum scanners are only found in high-end professional and technical environments, they cost upwards of tens of thousands of dollars and are a damn pain to use.)
Fact is there is NO film scanner on the market today that can faithfully reproduce in digital form the full dynamic range and resolution† of old fashioned chemical film emulsions. I say 'old fashioned' because modern digital photography, HDR etc., is capable of much wider dynamic range, resolution and colour gamut than film emulsions, so it's not a technology limitation (converting the limited dynamics of old film ought to be easy but no manufacturer makes equipment that does). It's really shameful that no manufacturer has stepped in to fill this technical gap when clearly the technology is available to do so.
Below, I've kept to the basics, an in-depth comment would be much more detailed:
• Argument goes that no one would pay for a film scanner with those specifications—as its manufacture would require precision/exotic tech, and anyway it's doubtful anyone would notice the difference with currently available scanners. I question both those assumptions as I'll explain.
• Leaving drum scanners and a few very expensive ones aside, in the past the best 35mm scanners on the market were the Nikon COOLSCAN range but Nikon discontinued them some years back and nothing has equalled or replaced them since. They were not perfect but they had the best optics and overall provided the best resolution and dynamic range available of any scanner. The COOLSCAN's most significant limitation was its incredibly slow scanning speed (nothing much has changed here with the possible exception of this soke engineering device, film scanners have always had snail-like speeds for seemingly inexplicable reasons).
• Nowadays, for most photographers the best compromise between quality and usability are Plustek scanners, whilst they have neither as good a resolution nor the dynamic range of the Nikon COOLSCANs they are about the best available. I'd add neither are Plustek's mechanics for scanning films as good as the COOLSCANs (that said, in this regard the Nikons weren't much better than just adequate).
• So is there really a noticeable difference between a Plustek and a COOLSCAN? Yes there is, COOLSCANs have noticeably greater dynamic range in dark shadowy areas, and despite the Plustek having comparable resolution specifications with the Nikons the COOLSCANs produced visually sharper scans.
• Why are all film scanners so pathetically slow? A good question I cannot fully answer. Perhaps 20 or so years ago there may have been some excuse but even back then I'd argue they should have been much faster. For argument's sake even if the electronics had slewing limitations and had difficulty in processing images—which wasn't the case—then scanners could have been made much faster by simply increasing the number of rows of sensors—for example, increasing the rows from one to 10 and stepping 10 pixels at a time would increase scanning speed by 10. This is so obvious that it's mindboggling that it hasn't been incorporated into scanners previously. (Note, the other obvious option of photographing an image as does a camera has serious quality limitations.)
There's much more to say about speeding up scanners which I cannot cover here except to say have you noticed that scanners still use USB-2 and not USB3-3? Why?
• There are other significant issues that haven't been addressed adequately in many scanners such as colour calibration. For instance, every type of colour negative has a unique set of parameters often referred to as 'film terms'. In short, these parameters define how the destructive colour mask should be decoded (that's the orangy mask that's incorporated in all colour negatives). Many scanners only approximate or guess these parameters and expensive third party proprietary software such as SilverFast is needed to correct these limitations.
If I didn't know better I'd reckon the lack of a competitive range of high performance film scanners on the market was some form of conspiracy—electronics designers having an intrinsic distain for old fashioned analog film technology or such but clearly there's more to it than that. Whilst I can surmise reasons I'd only be guessing but for sure it has little to do with technical limitations.
Why the scanner crisis hasn't been a much hotter topic amongst serious photographers and professional reviewers has perplexed me. Perhaps if nothing else this scanner from soke engineering might fan the debate, it could perhaps force scanner manufacturers such as Plustek to upgrade their long-stagnant designs.
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† Kodachrome has a resolution of 100 lines per mm which roughly equates to an image with 3600x2400 pixels (a frame being 36x24mm). Some films have even higher resolutions. Nyquist math says that the sampling rate should be doulde which means a scanner should be able to resolve to 7200 lines per frame but in practice no commonly available scanner comes anywhere near this figure. Diehards note, I'm aware this isn't a precise calculation but it'll do for argument's purpose.