Measured scanner resolutions

Started Jan 16, 2021 | Discussions thread
Sasquatchian Regular Member • Posts: 175
Re: interesting comparison !

This entire thread seems to echo what we all discovered 25 years ago when comparing scanners toward the end of the 90's.

That was basically that all of the CCD type scanners, no matter what their claims were, produced somewhere in the range of 2700-3200 real world dpi, no matter how many pixels they were asked to produce. That included the original Imacon CCD scanners as well.

The drum scanners, however, were a different story, and I can only speak to Howtek. My first Howtek, the HR4500 maxed out at 4000 dpi with a 6 micron aperture. The actual numbers were about 3800 when set to 4000. My second Howtek, which I still have and use, the HR8000 has a 3 micron aperture for a claimed 8000 dpi. The tests done back then showed that scanner to produce real resolution in the 7200-7400 dpi range. Being the lead beta tester at the time for Howtek's Trident scanning software, I also discovered a bug that limited the resolution on the HR8000. Normally when you set 8000 dpi in software, it also tells the scanner to use the native 3 micron aperture for that resolution, but in an effort to protect inexperienced and unknowing scanner operators, ColorByte decided that they would default the 8000 dpi setting to use the next larger aperture - the 6 micron aperture - which, in effect scanned at 4000 dpi - all in an effort to keep super large scans from 35mm or from color negs from getting too grainy. Took me a while to figure that out, but  thankfully you can easily override the auto aperture setting and get the full resolution of the scanner when you have film that demands that.

In an effort to look forward past the time when I can still get that scanner serviced, and I'm thinking sooner rather than later, I've also set up a digital camera scanning station using my old Beseler 4x5 enlarger converted into a motorized copy stand hovering over a Just/Normlicht light box. I'm using a  Fuji  GFX 100s 102mp camera attached to a Novoflex focusing bellows system with the absolutely spectacular Rodenstock 105mm 5.6 APO Macro Float lens, which, if you're smart, you get from Linhof Studios in the U.K. and not from B&H. Let's just say that B&H has it listed for $8300 but it's about 3 grand less from the U.K. even after duties and paying your sales tax on it here, once you get it. That lens is optimized from 1:3 to 3:1 reproduction ratios with its manually adjustable floating element and will make most of the standard macro lenses out there look like dog doo. And, of course, if you need to get a standard macro closer than 1:1 with tubes, the image quality takes a big hit due to the floating elements being in the wrong position, and you cannot forget about the two stops of effective aperture you lose at 1:1. To put that in perspective, at 1:1 and f/5.6, your effective aperture is f/11, but let's say you do what so many do and stop the lens down two or three stops and shoot at a marked f/11 on your lens. Your effective aperture is now f/22 and already losing a ton of actual resolution from diffraction. Now, move closer and shoot at 2:1, or double life sized, your effective aperture has now lost a whole 'nother stop and your f/5.6 is now f/16. And so on and so forth. Y'all can do the math.

I've just started learning this setup and so far the results are quite encouraging.

Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow