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DSLR for high volume digital archiving
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Dec 3, 2016 12:03:11   #
jwvincent
 
I'm managing a state wide project to capture (digitize) historical documents using professional lighting, a rigid stand and a 36 mp DSLR (currently a Sony a7R.) These images will be published on a state hosted free web portal for historical researchers including family historians. We're about to expand the pilot program from one capture set to (hopefully) ten units placed in local genealogical societies around Texas. We are a volunteeer only organization. I am not a professional photographer but would appreciate advice from some. I believe we have the lighting and stand right, but I'm not sure the a7R is the best camera within our budget limit of $2K per camera and lens. Sony recommended we use the f2.8 35 mm fixed lens. Our volunteers would love to have zoom to reduce the number of times the camera has to be moved on the rigid frame. We've so far shot about 75,000 images with this setup.

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Dec 3, 2016 13:06:18   #
MT Shooter Loc: Montana
 
jwvincent wrote:
I'm managing a state wide project to capture (digitize) historical documents using professional lighting, a rigid stand and a 36 mp DSLR (currently a Sony a7R.) These images will be published on a state hosted free web portal for historical researchers including family historians. We're about to expand the pilot program from one capture set to (hopefully) ten units placed in local genealogical societies around Texas. We are a volunteeer only organization. I am not a professional photographer but would appreciate advice from some. I believe we have the lighting and stand right, but I'm not sure the a7R is the best camera within our budget limit of $2K per camera and lens. Sony recommended we use the f2.8 35 mm fixed lens. Our volunteers would love to have zoom to reduce the number of times the camera has to be moved on the rigid frame. We've so far shot about 75,000 images with this setup.
I'm managing a state wide project to capture (digi... (show quote)


On the A7R its hard to beat the Sony/Zeiss 24-70mm F4 OSS lens for what you what to do.

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Dec 3, 2016 13:19:53   #
chasgroh Loc: Buena Park, CA
 
...did and do similar work with my Nikon gear. Don't know Sony's stuff, but there has to be a 24-70mm-equivalent lens in their range (I use a Sigma...but I think you may be a bit limited choice-wise what with your 7R) and you don't require a "fast" model, either, because you don't need it with a static setup like you describe providing good lighting. It *is* handy to have the consistent f-stop to gain a steady exposure in manual mode, however. Looking at current prices, you can pick up a Nikon D610 FX body for under 1500 bux...add a decent lens (Tamron makes a 17-50mm f2.8 for $500 or so) and you're within your budget...these are new, top quality, items with warranty.

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Dec 3, 2016 14:43:10   #
Apaflo Loc: Anchorage, Alaska
 
jwvincent wrote:
I'm managing a state wide project to capture (digitize) historical documents using professional lighting, a rigid stand and a 36 mp DSLR (currently a Sony a7R.) These images will be published on a state hosted free web portal for historical researchers including family historians. We're about to expand the pilot program from one capture set to (hopefully) ten units placed in local genealogical societies around Texas. We are a volunteeer only organization. I am not a professional photographer but would appreciate advice from some. I believe we have the lighting and stand right, but I'm not sure the a7R is the best camera within our budget limit of $2K per camera and lens. Sony recommended we use the f2.8 35 mm fixed lens. Our volunteers would love to have zoom to reduce the number of times the camera has to be moved on the rigid frame. We've so far shot about 75,000 images with this setup.
I'm managing a state wide project to capture (digi... (show quote)

If you are recording documents that ever have any graphics the target should be the greatest amount of fine detail. That is not necessarily the most pixels. The Sony a7R has a 4.88 micron pixel pitch, and provides a maximum of 102.3 line pairs per millimeter (4912 pixels / 24.0 mm / 2). Compare that to the Nikon D7100 with a 3.92 micron pixel pitch, which provides a maximum of 128.8 lp/mm (4020 pixels / 15.6 / 2). (Note that the Nikon D7200 is the same, but cost more for features that are not beneficial to your needs.)

A 24mm or 35mm fixed focal length lens will provide sharper results than a zoom lens. If your copy stand can be adjusted for camera to subject distances between 12" and 18" with a D7100 you get a range of subject sizes from about 8x12" to 12x18" with a 24mm focal length and about 6x8" to 8x12" with a 35mm focal length.

Note that the convenience in use of the copy stand would be slightly improved with a full frame 36MP camera! If nothing to be recorded is other than machine printed text (a very unlikely case), then the higher resolution of the APS-C sensors is not important. And in either case if the size of the documents to be photographed is larger than indicated above a larger copy stand is indicated.

If the idea of using a zoom lens was to avoid adjusting the copy stand, you are better off looking for ways to make adjusting the copy stand easier. One would be setting up an inexpensive HDMI monitor to allow focusing with the camera in Live View.

You might get better advice if you can better describe exactly what kinds of documents are being photographed. Not so much what the average document is, but what the largest and smallest are. Also a picture and model number for your copy stand too, or at least some measurements.

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Dec 3, 2016 17:21:21   #
jwvincent
 
Thanks much. I may have some of the technology confused but here's more detail on our project. We shoot all types of documents from hand written Tax Rolls, to women's club scrapbooks, to typescripts, to 8x10 photos of groups of people. We built our own rigid stand using material from 8020.com. The unit, partially disassembled must fit in the back seat of a car for transport across Texas. Commercial stands that could handle these sizes were either not available or far beyond our budget. We're in the DFW area so 80/20 had one of their design engineers help us design the thing. All of our measurements on the stand are based our alpha and beta test prototypes constructed from wood until we got what we needed. Our working maximum image size is 46" by 26" and we've already shot some that large. The vertical riser that holds the adjustable camera diving board is 48" tall so we can get the camera and lights that far from the table top. So far the smallest images we've shot in any volume are 8" x 10". Most of our documents are in the 17" x 24" size range. We can use a scanner for small stuff. The supervisor of the Tech Lab at the Portal to Texas History told us that we needed an FX DSLR camera with at least 36 mp for OCR to work and to be sure we avoided blurring at the corners (the documents we shoot often have marginal notes that are significant to historians.) We worked through the staff at Arlington Camera and they put us in contact with Sony people who came up with the camera and lens. They also recommended that we use a mirrorless camera as it has few moving parts. So far the sample shots we've sent to the Portal lab have passed muster. We're now preparing a grant request to purchase ten of these capture sets, all to be operated by volunteers, the majority of whom are retirees. The Sony has overheated twice, so we use a small fan (not shown) to keep it cool. We tether the camera to the tablet via wifi for our operators to insure images are aligned and to release the shutter. We've learned that Sony has replaced the a7R with the a7RII at a higher price. So, do we stay with Sony or explore other options, and if so, what might they be. Also can we get away with a zoom lens and use lens correction algorithms in Photoshop to address the very slight distortion we're getting in the corners of documents?



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Dec 3, 2016 19:07:13   #
chasgroh Loc: Buena Park, CA
 
...moving parts are not an issue with good equipment...and I don't think you need 36mp, either...the camera is stationary and shooting with a lanyard or using the timer takes care of any extra "movement"...but mirrorless is fine, I was just recommending an equipment solution applicable to the 10x factor of your budget...

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Dec 3, 2016 19:08:25   #
forjava Loc: Half Moon Bay, CA
 
A few points:

1) Lighting setup, reflections, etc. for your scenario is described in the last two editions of Hunter et al., "Light, Science,..."
2) Nikon's 55mm f/3.5, with and without the M2 appliance, may have the best fine detail or nearly so, as it approaches theoretical resolution; not costly; comes in manual and AF. There is the issue of lens resolution, mentioned here and then there is sensor resolution, mentioned earlier
3) The formula for resolution depends on aperture -- cf. apaflo remarks on fine detail -- which IMO is important, and critically so, to hand-written artifacts as well as to graphical artifacts
4) I look askance on zoom lenses for this kind of work; the prime lens in (2) will focus from something like one foot to infinity, however
5) Nikon made a killer copy stand, still available used; I mentioned that stand in an earlier UHH post. Choice of stand is a big deal. For example, you may end up with paint flakes on your artifacts if you buy the wrong stand. And then there is awkwardness that can kill your pleasure.

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Dec 3, 2016 19:39:55   #
Bugfan Loc: Toronto, Canada
 
In my film days I used a similar set up for photographing copy. In my case however I used a macro lens, a 60mm macro lens. This got me edge to edge sharpeness. Lighting was handled by a photo lamp on each side, I used a white sheet at the side so that the lamp gave me a diffuse light. The copy being photographed I would cover with a sheet of clean glass to keep it flat. As documents changed in size I would move the camera up and down on the copy stand to adjust for the difference in size.

One day I was also at a photo show where they had automated this process with books. They had a professional DSLR aimed at an open book and they had a machine that changed pages in addition to triggering the camera. I have no idea what that rig cost and it's probably not useful for you since many of your documents would vary in size and would not need page flipping. But it was a simple quick way to digitize a book.

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Dec 3, 2016 20:10:20   #
Apaflo Loc: Anchorage, Alaska
 
jwvincent wrote:
Thanks much. I may have some of the technology confused but here's more detail on our project. We shoot all types of documents from hand written Tax Rolls, to women's club scrapbooks, to typescripts, to 8x10 photos of groups of people. We built our own rigid stand using material from 8020.com. The unit, partially disassembled must fit in the back seat of a car for transport across Texas. Commercial stands that could handle these sizes were either not available or far beyond our budget. We're in the DFW area so 80/20 had one of their design engineers help us design the thing. All of our measurements on the stand are based our alpha and beta test prototypes constructed from wood until we got what we needed. Our working maximum image size is 46" by 26" and we've already shot some that large. The vertical riser that holds the adjustable camera diving board is 48" tall so we can get the camera and lights that far from the table top. So far the smallest images we've shot in any volume are 8" x 10". Most of our documents are in the 17" x 24" size range. We can use a scanner for small stuff. The supervisor of the Tech Lab at the Portal to Texas History told us that we needed an FX DSLR camera with at least 36 mp for OCR to work and to be sure we avoided blurring at the corners (the documents we shoot often have marginal notes that are significant to historians.) We worked through the staff at Arlington Camera and they put us in contact with Sony people who came up with the camera and lens. They also recommended that we use a mirrorless camera as it has few moving parts. So far the sample shots we've sent to the Portal lab have passed muster. We're now preparing a grant request to purchase ten of these capture sets, all to be operated by volunteers, the majority of whom are retirees. The Sony has overheated twice, so we use a small fan (not shown) to keep it cool. We tether the camera to the tablet via wifi for our operators to insure images are aligned and to release the shutter. We've learned that Sony has replaced the a7R with the a7RII at a higher price. So, do we stay with Sony or explore other options, and if so, what might they be. Also can we get away with a zoom lens and use lens correction algorithms in Photoshop to address the very slight distortion we're getting in the corners of documents?
Thanks much. I may have some of the technology con... (show quote)

Absolutely fascinating! And it obviously makes a huge difference to know more about what you are shooting and the specifics of what you currently are using.

The 8020 T-Slot materials are just super nice to work with. And while what you are doing is necessarily as simplified as possible, 8020 can come up with almost anything you might need. Imagine, as an example... taking multiple shots of 12x18 segments of a document is at your maximum size, 26x46 (or even larger), and then stitching them together to get several times higher resolution than your camera can produce with a single image. Then imagine having a computer controlled motor driven mechanism to position the camera precisely where you want it for each shot. Maybe you will never need anything like that, but it can be done as an extension of what you are currently doing.

I do have suggestions for the "rigid stand", to make it more rigid. Don't hang the lights off the vertical riser that supports the camera. Either have two separate stands for lights, or have two additional risers attached to the left and right base arms. I would also be more likely to use a couple of inexpensive studio strobe lights, probably 120 WS units, each with a small softbox diffuser.

The stand itself could use bracing on the vertical riser, with one rod or bar on each side going from near the top down to the corner on each side. Plus you really need that vertical riser to be angled to put the top out over the center of platform where the document will be. The camera absolutely must be aligned dead on in the center, otherwise you'll get perspective distortion that you do not want.

The next thing I would do is design and build a really nice, and accurate, easel on the base with sliders that make it very easy to mechanically locate a rectangular document precisely under the camera regardless of what size it is. With a little thought this could be very light, sturdy enough to survive travel, and yet save a lot of time in use.

Also, I can't tell if you have a scale, such as a metal yard stick, attached to that vertical riser, but it should have one bolted to the back if at all possible. I'm not sure how much value there is to having more or less precision, and smoothness of adjustment, for the camera position. The one T-Slot linear bearing that I use (on a macro bench) is mounted horizontally and because it mounts a 200mm motor driven focusing rail it doesn't need to be very smooth or very precise. But what I'm thinking of is how a photo enlarger works. Larger ones (that were not motor driven) were gear driven and spring loaded to be smooth and easy to work even with a heavy light head mounted. This again comes down to just how much of a problem are you having with the existing design? Is this need for a zoom lens actually significant, or just a passing thought? Another thought is a safety mechanism to prevent the camera from ever sliding from the top to the bottom uncontrolled! That would probably at least destroy the lens.

Not much that I commented on previously about the camera and lenses means much! I didn't figure you were going that large! With large documents as a likely subject, probably the 36 MP full frame camera is better. Mirrorless due to fewer moving parts is silly. Sony is perhaps okay, but they don't have the lens selection that Nikon does. Nikon cameras use Sony sensors (and often enough get better quality from the same sensor). The one problem is that Nikon's D810 camera, with 36 MP, does not sell for anything close to $2000. You can get used D800's and today maybe even refurbed D810's for that price though. Personally, I'd go with Nikon, either the D800 or the D810.

And then we are down to lenses... and this is a bit tricky. Given the size range of your documents, and the size of your stand, the choice of 35mm focal length is essential! At your maximum distance of 48" a 35mm focal length will shoot a field of view of approximately 33x49 inches, which is just bigger than the 46" space you have. Any lens with a longer focal length just won't do the trick! It also happens that your common size of about 17x24 will work with the camera at about 2 feet above the document, which is probably a very nice working distance. But... the hitch is that there are no really good macro lenses available in a DSLR mount with a focal length of 35mm! And that is exactly what you want because only lenses designed for macro work have the very flat field that you need!

The solution is to adapt a 35mm focal length enlarging lens to mount on the camera. You won't have Auto Focus, or even Auto Aperture! You don't need either! BH Photo has at least a couple of different 35mm lenses that range in prices from $300 to $700 each. (One warning though, enlarging lens tend to have a lot of flare if your light hits the front of the lens. Some kind of a lens hood would be nice, or just make sure the lights are behind the camera!)

If you go looking for enlarging lenses there aren't too many available at a 35mm focal length, and there are specific things to avoid. Any lens that was shipped with an enlarger is not worth having! Besler and Omega made great enlargers and shipped them with horrible lenses. None of the lenses that were inexpensive back in the days of film were any good at all. But today many of the fairly good lenses from back then can be found at great prices, except 35mm was not common. Avoid Componar and Comparon (names with 'a' in them) and look for Componon or Componon-S from Schneider. Rodenstock should be good too.

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Dec 4, 2016 02:03:06   #
forjava Loc: Half Moon Bay, CA
 
Adding to my prior post, Nikon designed the 55mm 3.5 lens with copy work in mind as a core mission.

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Dec 4, 2016 04:00:41   #
Apaflo Loc: Anchorage, Alaska
 
forjava wrote:
Adding to my prior post, Nikon designed the 55mm 3.5 lens with copy work in mind as a core mission.

Nikon's 55mm f/3.5 is a fine lens, but on the OP's stand, with a maximum camera to subject distance of 48 inches a focal length of 55mm will only cover a field of view that is 21x31 inches.

They need 26x46 inch coverage, and the shortest focal length that can accomplish that is 35mm.

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Dec 4, 2016 06:01:20   #
Dik
 
A little off subject - Lighting.
Look into EquaLight software to equalize your lighting. You shoot a plain white paper at the same settings as your document/photograph, and the software creates a profile you apply to give perfectly even light (including lens falloff).

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Dec 4, 2016 07:52:23   #
jerryc41 Loc: Catskill Mts of NY
 
jwvincent wrote:
I'm managing a state wide project to capture (digitize) historical documents using professional lighting, a rigid stand and a 36 mp DSLR (currently a Sony a7R.) These images will be published on a state hosted free web portal for historical researchers including family historians. We're about to expand the pilot program from one capture set to (hopefully) ten units placed in local genealogical societies around Texas. We are a volunteeer only organization. I am not a professional photographer but would appreciate advice from some. I believe we have the lighting and stand right, but I'm not sure the a7R is the best camera within our budget limit of $2K per camera and lens. Sony recommended we use the f2.8 35 mm fixed lens. Our volunteers would love to have zoom to reduce the number of times the camera has to be moved on the rigid frame. We've so far shot about 75,000 images with this setup.
I'm managing a state wide project to capture (digi... (show quote)


Welcome to our forum!

I can understand your wish for a zoom lens, but using the prime lens might give better quality at zero cost. When a zoom lens is held pointing downward, it tends to extend itself - called lens creep. This would be extremely frustrating for those taking the pictures. You say you have the lighting and stand right, and the Sony a7R is a very good camera with a very good sensor - lots of MP. To avoid moving the camera on the stand, they could sort the documents according to size. First shoot all the 8 1/2 X 11, then go to another size. For a job like this, you want quality, not speed and ease. Long after the job is done, you will be stuck with whatever results you produced, so do the best job possible the first time around.

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Dec 4, 2016 09:57:18   #
BobHartung Loc: Bettendorf, IA
 
There are several parts of your post.

First: What camera and cost. Would a good condition used camera such as a Nikon D800 or D810 be a consideration? The Sony's are not the least expensive camera available.

Second: Have you considered shooting tethered to a laptop using LR or other tethering software. This would eliminate the need for transferring images from SD or CF cards.

Third: Some zooms have a bad tendency to creep when positioned with the barrel facing down. I would think that something on the order of the Nikon 50 mm or a Nikon 85mm f/1.4 lens would be a good choice. The latter would give a little more camera to target space. Both are very sharp. I am assuming that the objects to be archived would be on the order of 8x11.5" in size.

Try working with say B&H or a Texas provider to see if they can help you on camera and lens costs. Uniformity across the state would help with training and support.

My $0.02. Good Luck!

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Dec 4, 2016 10:11:55   #
Apaflo Loc: Anchorage, Alaska
 
Apaflo wrote:
They need 26x46 inch coverage, and the shortest focal length that can accomplish that is 35mm.

ACKkkk. I said that backwards. The longest focal length that will work is 35mm.

All suggestions for 55mm, 60mm, 85mm etc are without merit!

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