selmslie Loc: Fernandina Beach, FL, USA

Yes, a 35 mm prime should be just fine. What was left out of the enlarger digression was the need for a bellows and other adapters. The most you will need with a prime lens might be extension tubes.

TriX Loc: Raleigh, NC

Floyd, what I think is that it would be good manners to stop hijacking threads with interminable, off-subject arguments. You have injected this particular contrarian, and in my opinion, mistaken concept into at least 4 relatively non-related threads in the last few months, and I am suggesting that we move the sensor discussion off-thread where we can discuss in a gentlemanly way, rather than continuously injecting it into other topics. Frankly, I'm not interested in convincing you, which I doubt is possible, but it is painful to see this particular demonstrably wrong concept continuously propagated. This isn't personal Floyd, you're a smart, well-read guy, who often contributes useful information, but in this case we completely disagree, and it's not a trivial subject.

selmslie Loc: Fernandina Beach, FL, USA

I just checked and had no problem focusing on a 35 mm lens on a 46" wide object without any extension tubes. You might need the extension tubes for a smaller subject but then a 50 or 55 mm lens should be just fine.

Here's a practical bit that will be more useful than all of the MTF and resolution BS you have had to wade through. What you really should be careful of is to get the axis of the lens perpendicular to the plane of the document.

The easy way to do this is to get a small mirror and lay it flat on the surface where the document will be placed. Then line up the camera so that the image of the lens is dead-center in the viewfinder. Could not be simpler.

RWR Loc: La Mesa, CA

Kind of going by memory here, but I think my two 35mm primes focus down to something close to 1:6, so would not need an extension tube. I personally would prefer a 50 - 60mm lens, but you’d sure need a tall stand. Even 17 x 24 is pretty large for a vertical copy stand, and for documents up to 46" wide you might want an elevator! Needing to copy so many documents is definitely a challenge!
And you’re right, the sensor needs to lined up properly with the subject.

romanticf16 Loc: Commerce Twp, MI

Back in my "film days" I remember that the Omega Enlarger Chasis ((6x7) and 4x5 could be easily converted to a copy stand. People are giving these enlargers away! Why not adapt these rugged units instead of spending hundreds of dollars for copy stands?

romanticf16 Loc: Commerce Twp, MI

The Omega 6x7cm and 4x5 enlarger column can be easily converted into copy stands. People are selling or giving these items away. They are as sturdy or sturdier than the commercial copy stand you are buying.

selmslie Loc: Fernandina Beach, FL, USA

Yes, it's done all of the time, but I think some of jwvincent's requirements might rule that out: high volume, multiple operators and the need to occasionally handle a 17x reduction.

The last one alone makes the enlarger route somewhat difficult. In order to get that much reduction (enlargement) with a 24x36 sensor I have had to turn the enlarger head on its side and project onto a wall. The same setup would be needed for copying. It's cumbersome, difficult to focus and not suited for high volume.

He also mentioned ten separate sites around the state. That's also going to be difficult to pull off if you need to teach the process to ten different teams.

I think the path jwvincent seems to be headed for is probably better suited to a more conventional setup with ten camera/lens combinations, a simple setup and what may be volunteer operators.

By placing the larger documents on the wall rather than on the floor, the requirement to use a 35 mm lens goes away and you can do the whole project with a more affordable 50-60 mm macro lens. Any document that is 8x10 or smaller can simply be scanned.

It's not a question of what it technically possible. It has a lot more to do with that is actually doable within the total constraints of the project.

Apaflo Loc: Anchorage, Alaska

Why talk about extension tubes? The problem is not how to focus closer, and what is needed is a way to extend the copy stand!

selmslie Loc: Fernandina Beach, FL, USA

Go away. You have nothing to contribute here.