Do any kits exist that will allow me to build my own digital back?

[maurice_bryant]

While I'm waiting for digital backs to drop in price, I'd like to try

to design my own digital back, maybe with the parts fitting inside

the shell of a medium format 6x6, or 6x7 or 6x9 back, or even design

a back from scratch, and stick it on a Mamiya 645, or other medium

format camera. It's not really important that the pixel count equal

the fully digital cameras that professionals use, since I am an

amateur. Someday I may get an all digital camera, but I can't afford

the ones I really like. Does any of this sound plausable?

[audidudi]

I cobbled together an adapter that let me attach a Minolta RD-3000 to my Toyo 23g view camera (it's medium-format, not large format) and it worked quite well, except for the multiplication factor being way too high (roughly 2.25:1) for practical use. I'm sure this could be done with other digital SLRs as well -- the Canon D30 comes to mind -- but so far as I know, you're on your own when it comes to building a back from scratch.

 

Actually, now that I think about it, there's a page somewhere where a photo instructor appropriated parts from a cheap scanner to work in a 35mm body -- I seem to have misplaced the link -- but the photos from it didn't strike me as being particularly good. Still, it's a start.

[oliver_s.]

Maurice, what worries me, how are you going to process the data from the sensor? That´s where the work starts. You know, Phase One Lightphase (and oldtimer by now) and the other advanced MF digibacks send their data straight to a computer. Before you think about the actual sensor, think about the ´how´ and ´where´ of the data processing.</p>And tell me, if you can spare the time, about the process of you project. It´s quite interesting!

[david_goldfarb]

I've looked into this a bit. Homemade CCD capture devices are popular among astrophotography types and there are kits and instructions out there, but the CCDs are somewhat small, as is the resolution. I would imagine you could also hack a cheap digital camera so you could use the software and electronics from the camera, but remove the sensor and mount it in an MF back, but again, the focal lengths will be very long, given the size of the sensor.

 

Good luck, and if you have any success, do post!

[peter nelson]

Does anyone know how <B>any</B> of the digital backs for MF work? Do they use some kind of optical system to compensate for the small size of the sensor? Or do they use multiple sensors?<P>

 

The thing is that the size of the die of even large CCD arrays is still so much smaller than the size of a 2-1/4 negative that it's hard to imagine that you could just play mental games with the lenses - a "normal" lens would be - what? 35mm or something? How many MF users even own such short lenses?<P>

 

Yesterday I was looking at the Kodak KAF16800 CCD array. It's <B>HUGE</B> by CCD standards - 36.8mm x 36.8mm! And hi-res: 4096x4096 pixels (monochrome). And it's got a price to match: depending on the (quality) grade it costs between $41,000 and $75,000 per chip! Presumably a photographer would only want the highest grade, and remember, that's for a chip with only 38% of the area of a 2-1/4 negative!<P>

 

Numbers like that make me think it's going to be awhile before

medium format is replaced by digital technology. Getting any kind of commercially acceptable yield on a 60x60cm CCD array is <B>way</B> beyond current technology, and even if they eventually manage to do it, it will be longer still before the price comes down to where anyone but the wealthiest photographers can afford it.

[peter nelson]

I assume you're planning to use this for test shots, as an alterative to a Polaroid back. I've had good luck using a digicam (Olympus 3000) for test shots prior to taking final shots with an RB67.

[duane_kucheran]

In response to Peter's question, yes there is at least one back available - the CreoScitex Leaf: http://www.creoscitex.com/products/input/leaf/index.asp.

 

If memory serves me it uses a 24 * 36 mm CCD which is about 35 mm frame size. As a result you are using only the center of the image of MF lenses effectively narrowing the angle of view. The Leaf backs also cool the CCD which reduces dark noise and improves the contrast ratio.

 

I don't know of any backs that use multiple CCD arrays to make a larger imager. The sensitive areas don't cover all the device so there would be blank spots in the image. I think some cameras use beam splitters and filters so that the colors can be imaged simultaneously.

 

I've toyed with getting a CCD and building my own back. Various companies make CCD chips. Just to show what's available: http://www.tcs.thomson-csf.com/ccd/areaarray.htm I don't know what the cost is, but I suspect it's $$$$$. The devices have to be pretty much perfect.

 

You might want to look thru surplus shops and their websites (use google with various search strings such as: CCD imager)

 

As someone else pointed out, this is a big job to make up a board with a digitizer and get the data into a computer. A cheaper alternative is to get a video camera and try to mount it with it's array at the film plane of the camera. A CCTV camera would probably require a great amount of work but one of the compact ones may be shallow enough. Note though that with a 1/3 or 1/2" CCD (~8-12 mm) a 40 mm wide angle lens for MF suddenly becomes the equivalent of a 150-250 lens!

 

IMHO as far as a product is concerned, it'll be cheaper and easier to just buy a digital camera than try to retrofit a CCD to MF. There's just too much disparity in the image sizes. The real world sets limits on the upper size of a practical CCD. It's much easier to make a smaller CCD and design a lens to work with it so that's where the effort is going. For a hobbyist though, well, that's another story.

 

Good luck with whatever you do,

 

Cheers,

 

Duane

[yuri_sopko]

Actually, I have been attempting to make a digital camera back for my Minolta X-700 (today to be exact). Except, I had decided to hack a cheap-o 1.3 mega-pixel digital camera into a back. The problem is choosing a camera that when the shell is removed you can attach it so the CCD comes within the correct focal length for it to be in focus. This, I have deemed, will be impossible unless the sensor happens to be on a seperate and smaller circuit board that can be manipulated to position it correctly or raised enough so it comes to the correct distance from the lens. I am lucky enough to have found a fiberoptic image conduit that is roughly 1.5" by 1.5" square and a fiberoptic enlarger/reducer. I tried the enlarger/reducer first...

 

I removed the cheesy wanna-be lens that the camera came with, hacked this assembly and mounted the reducer/enlarger in it. It kinda worked. The thing I did not realize is that the CCD is protected by a thin layer of glass or plastic so the focal length was just a bit off. Adjusting the lens did no good. You can't position the reducer/enlarger mid-focal length and have the image projected out the back of it and manipulate the focus that way. It takes the image that hits either end and then displays it on the other end with little or no projection.

 

I removed this assembly and laid the conduit on top of the CCD module. I thought this would work a little better but the same effect as before. The image is not correctly transmitted to the CCD sensor.

 

So... I will probably have to come up with some make-shift lens assembly to properly take the image projected from the lens and project it correctly onto the CCD. I did have the camera lens project directly onto the CCD and the image was fine. So, I will be asking this question in a next thread if my web searching turns up nothing... in hopes of someone who knows.

 

The digi-cam was a Vivitar DSC 350. A total turd of a camera. Was under $100 at wal-mart, simple fixed lens assembly, no iris or anything. Perfect for experimenting. If this works out well. I will attempt at buying a digital camera that has a damaged lens assembly (but works otherwise) and grafting it onto the back.

 

Later!

[michael_halberstadt2]

Has anybody thought about slapping a normal scanner to the

back of a large format camera? Scanners are very cheap, and

fairly lightweight now adays and you can pick up an old 8x10 view

camera for a few hundred bucks. Any ideas as to how to do

this? I guess you would have to remove the lens and lights from

the scanner?

 

Cheers,

 

Mike

[gallen]

Hello everyone,

<p>

This link to "Photography Articles by RIT faculty members" has

some discriptions of exactly what you are looking for. A very, very

interesting read.<p>

Examples:

"This is a report on how a simple Kodak Snapshot scanner was

"gutted" and the remains adapted to a traditional 35mm camera

to demonstrate image plane scanning photography, as well as

panoramic and peripheral photography. "<p>"Work is based on

the use of a linear CCD array removed from a cheap hand

scanner and installed in a 35mm camera body for doing

peripheral, panoramic and image plane scanning. "<p>

 

<a href="http://www.rit.edu/~andpph/articles.html">Photography

Articles by RIT faculty members</a>

<p>Cheers!

[maurice_bryant]

Intriguing concept.

[maurice_bryant2]

And, voila! Leica comes up with a digital-thingy that fits onto one of their 35mm cameras!

I'll be sure to snap it up when I get 4 or 5 thousand dollars. In the meantime, I'll have to

make payments on the used Nikon D1H that I have on layaway.