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02-21-2016, 12:26 PM   #1
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Connect K3 to 4x5 Speed Graflex camera

I was on Amazon the other day and saw and ordered a "digital" back for my 4x5 Speed Graflex camera. It consists of a plate with a mounting bracket where you can attach you Pentax to the plate and then take the back off the Speed and attach the plate to it. This allows you to take a digital picture using the 70+ year old camera. Pretty cool. My SG has a 127mm lens on it. The problem is that to get it to focus at all I have to move the bellows all the way into the body of the SG, in the storage position, to achieve focus at about 20 feet.
Is there any way to adjust the focal distance so that I can extend the bellows and use them more traditionally to focus? I go to WWII reenactments and it would be cool to be able to take some picture with something like this.
Any help would be appreciated.
Wayne

02-21-2016, 12:54 PM   #2
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Absent additional corrective optics, no.
02-21-2016, 01:21 PM   #3
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Where would you get corrective optics?
02-21-2016, 01:59 PM   #4
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QuoteOriginally posted by Wayneheim Quote
Where would you get corrective optics?

It would have to be some kind of bespoke solution, since I don't know of anything that is marketed for this purpose. Basically, the mount of your camera is sitting a bit behind the original film plane of the camera, so you add the thickness of the adapter mount plus the distance from the camera mount to the film plane (45.46mm), and that is how much further back your lens than normal will have to sit to reach infinity. With a longer focal length lens, it might not be a big deal, but as you get wider, you'll get to situations like the one you have here where you bottom out at the back of the bellows.

The corrective lenses you commonly see in e.g. Canon FD to Pentax K, etc. are correcting for a lot less than the ~50mm you would need, so they are out as a source for cannibalizing parts. If you contact the Surplus Shed, you might be able to find something that will correct the right amount, but you will have to fashion your own mount and will be losing light and image quality

02-21-2016, 02:10 PM   #5
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I saw those backs some time ago, and it seems they would be much better suited to rail cameras, not press-style cameras.

You could find a longer lens for the Speed Graphic... There was a 147 or something, IIRC that would work, or any of the longer lenses...

-Eric
02-21-2016, 07:18 PM   #6
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Can you put an extension tube on the SG?
02-21-2016, 07:21 PM   #7
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Extension tube would be taking you in the wrong direction. You need to get the lens closer to the sensor to achieve infinity.
02-21-2016, 07:25 PM   #8
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whoops! of course. How about a camouflage blanket with the K3 under it and using the MF SG as it's meant to be used?
Good luck.

02-21-2016, 08:08 PM   #9
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QuoteOriginally posted by Wayneheim Quote
The problem is that to get it to focus at all I have to move the bellows all the way into the body of the SG
It looks like you have discovered the problem with LF/dSLR adapters. The sensor on your Pentax is 45.46mm behind the mount flange. As a result, the taking lens must be moved that much closer to the rear standard to attain infinity focus. With most LF cameras this means loss of most movements, if indeed the camera is able to collapse that far without "kissing" the lens rear element to the dSLR body

There are systems using the dSLR body as the rear standard in conjunction with a bag bellows that work with some success though the shortest usable lens is still likely to be in the 90mm or greater range.


Steve
02-21-2016, 11:27 PM   #10
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Use lenses with registration distances suitable for the bellows extension you want to work with. You need to account for the Pentax lens type RD (45.46mm) plus the additional bellows extension you want.

Here's an RD chart: http://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html

You will undoubtedly need to fabricate a lens mounting plate compatible with the lens mount -- temporary trials with less than 'perfect' mounts will facilitate experimenting with lenses. You may even be able to use a mounting board with a 'set-back' to position the lens somewhat back into the bellows. I could describe a DIY recessed mount board via PM if you'd like.

Search on 'view cameras' to get a better idea of the universal solutions possible.

(I'm dealing with the opposite problem of accessing the controls of a GoPro-type camera mounted directly behind the lens plate within the bellows of a Press Graphic body.)

Last edited by pacerr; 02-21-2016 at 11:41 PM.
02-22-2016, 05:14 AM   #11
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QuoteOriginally posted by pacerr Quote

(I'm dealing with the opposite problem of accessing the controls of a GoPro-type camera mounted directly behind the lens plate within the bellows of a Press Graphic body.)
Wow and I was thinking that the use of an APS-C sensor was a shameful waste of all that glorious LF focal plane real estate
02-22-2016, 10:14 AM   #12
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QuoteOriginally posted by dcshooter Quote
Wow and I was thinking that the use of an APS-C sensor was a shameful waste of all that glorious LF focal plane real estate
It is, but that is the next level of foolishness.

IIRC, Fotodiox (and possibly others) makes a Graflex compatible shift plate that facilitates stitched dSLR images of the full 4x5 frame using longer focal lenses on a view camera. With such a system you gain the advantage of the camera movements, but wide angle is still a problem.


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02-22-2016, 03:27 PM   #13
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QuoteOriginally posted by dcshooter Quote
. . . the use of an APS-C sensor . . .
Not to use the sensor in my case. Just using a cheap GoPro knock-off housed within the 4x5 body as an attention-getter and conversation piece (a Q is just a little too big - maybe with a 5x7 body?). No actual lens involved, just a hood to disguise the fake.

Rigging accessible controls for the hidden body without trashin' the 4x5 body is a challenge.
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