what is an optimal distance to have the cameras mounted with respect to the location of the platen? does it really matter? i just want to be sure that the cams clear the platen in the up position but the image is still as crisp as possible.
like dans 3rd design, i plan on having it fold up, however it will definitely not fit in the plane's carry-on
is the general consensus that a rail mounted platen is superior to the hinged design?
ignore my ghetto mspaint diagraming skills
need some advice
Moderator: peterZ
Re: need some advice
Hey, I think its mainly got to do with the cameras you end up using . Personally I tried a basic 3 x optical zoom and it worked just fine, just did it once the rig was finished. If you want to get more accurate idea then google 'lens calculator' and you can see the expected results for the lense you are to use.
Love your MS paint skills
Love your MS paint skills
Re: need some advice
thanks, i'll try it outHasher wrote:Hey, I think its mainly got to do with the cameras you end up using . Personally I tried a basic 3 x optical zoom and it worked just fine, just did it once the rig was finished. If you want to get more accurate idea then google 'lens calculator' and you can see the expected results for the lense you are to use.
Love your MS paint skills
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Re: need some advice
I put my camera as close to the page as it will focus, which for my Canon is about 20 inches.
Since I've also attached the cameras to the platen, the focus is always the same, and I've made setting the focus a part of my CHDK script.
Since I've also attached the cameras to the platen, the focus is always the same, and I've made setting the focus a part of my CHDK script.
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Re: need some advice
You1 has a diagram here: http://www.diybookscanner.org/forum/vie ... p=843#p843
I used it in constructing my 3rd-gen folder scanner thinger. But because my platen is very rigid, I have it almost grazing the cameras -- there is maybe 1" of clearance.
I used it in constructing my 3rd-gen folder scanner thinger. But because my platen is very rigid, I have it almost grazing the cameras -- there is maybe 1" of clearance.
Re: need some advice
Hasher wrote:Personally I tried a basic 3 x optical zoom and it worked just fine,
Two quite different point of views, yet two (as far as I can say) satisfied users. That probalby means that's not a critical factor, as long as you don't have the camera so close that it annoys when you turn pages, or so far away that you can't enlarge a small page so that it covers most of the page.Spamsickle wrote:I put my camera as close to the page as it will focus, which for my Canon is about 20 inches.
Photographically speaking usually lenses perform better if you keep away from both extremes of zoom (I mean, don't use the widest setting, zoom in a bit but not too much)
(Using strong zooms also means that (relatively speaking) the camera must be farhter away from the page i.e. you have a larger design)
Re: need some advice
spamsickle-any chance you could share the chdk script?
be much appreciated here.
be much appreciated here.