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lens board & rangefinder
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doughowk
Joined: 05 Feb 2004
Posts: 3
PostPosted: Mon Feb 16, 2004 11:41 am

I recently purchased a top RF Crown Graflex thru eBay.It came with a 162mm Graflex lens that has cleaning scratches, and the seller said the rangefinder cam is for a 135mm lens. I have a 135mm Schneider Zenar in good condition, but it requires different lensboard opening.
1) How can you tell the cam lens length for rangefinder, & are they readily avaialble (I also have a 90mm graflex lens)?
2) Can I get pre-cut acrylic lensboards ( I can drill the hole with a drill press)?
Nick
Joined: 16 Oct 2002
Posts: 494
PostPosted: Mon Feb 16, 2004 12:56 pm

I don't know about acrylic but lensboards are pretty common on the used market. Odds are if you have a drill press you have all the tools to make your own out of wood. A lensboard isn't much more then a flat piece with a hole drilled in it. Doesn't even have to be in the exact middle.
t.r.sanford
Joined: 10 Nov 2003
Posts: 812
PostPosted: Mon Feb 16, 2004 4:03 pm

The "Pacemaker" cam should have a number stamped on one face, stating the focal length of the lens with which it's been shaped to work.

The difficulty always is in making sure that the actual focal length of your "Xenar" is close to the design focal length, and within the tolerances of the cam. I suspect that too much can be made of this, but the only straightforward way to find out is to assemble the system the way you intend to use it, and conduct some tests.

There is a good article on this site about making "Pacemaker" cams, and it might repay your study. The Graflex service manual "Graphic Rangefinder with Viewfinder and Rangelite" has useful information (but not as useful as one might wish; it contains the sentence, "To be assured of accurate measurement of a lens, it may be shipped to the nearest Graflex Service Department for collimation and selection of cam and scales" -- I could wish for a bit more informaton on just what the Graflex Service Department did! (The manual, a reprint of the original, can be purchased from Craig Camera, and may be available online somewhere.)

The "Pacemaker" lens board is not easy to duplicate, and I agree that the easiest solution would be to find one with the appropriate hole, or a smaller one that you could enlarge with a fly cutter.

You also could take a piece of sheet aluminum, brass, opaque plastic or thin wood, cut out a square perhaps 2-1/2 ins. on a side, drill it accurately for your "Xenar," and affix it to the existing board with four small machine screws.

If the infinity stops were in the right position for a 135mm. lens, they would need to be repositioned to compensate for the standoff added by the adapter board, but if the camera came with a 162mm. lens, they may not be, and you'll need to adjust them anyway.

The 162mm. lens may be a wreck, but it may not be. I've seen lenses with some pretty alarming scratches that were good picture-takers. In the old days, some students of the problem favored filling in really huge scratches with India ink, to prevent light scatter from the edges of the gouge. I'm not sure whether this is worth the effort -- again, a test may be in order. The "Kodak Anastigmat" is a well-designed, accurately constructed four-element lens, and they had a good reputation over their long production life.

Historically, press photographers favored the 135mm. (or 127mm.) lenses because of their wider fields, but 162mm. is just about the "normal" length for the 4X5 format, and may yield more pleasing perspective in some cases. It would be a shame to discard it if it can be made to work acceptably.
worldphoto
Joined: 05 Feb 2003
Posts: 199
PostPosted: Mon Feb 16, 2004 4:07 pm

I have the same camera as you with a 40 page manual that should help. (Read Pages 4 and 5). Find Rich's web site witn a search on this forum for a view and/or download. He has saved the file with pdf extensions.
Harry
http://www.southbristolviews.com/


<font size=-1>[ This Message was edited by: worldphoto on 2004-02-16 08:45 ]</font>
glennfromwy
Joined: 29 Nov 2001
Posts: 903
PostPosted: Mon Feb 16, 2004 4:22 pm

I have made myself a wooden mold out of oak to form my own aluminum lens boards out of sheet aluminum from the hardware store. It's not too difficult to do and they look much like the originals except for the bumps. Cleaning marks -- there is a product being advertised on TV for repairing scratched eyeglasses. I'm curious to learn if it would work on camera lenses, or if it works at all.
t.r.sanford
Joined: 10 Nov 2003
Posts: 812
PostPosted: Mon Feb 16, 2004 4:56 pm

I've wondered whether that hardware store sheet aluminum (it used to be called "Reynolds Do-It-Yourself") could be formed into a "Pacemaker" board by cutting a small piece, securing it over a hardwood form and working it with a ball pein hammer. I'm glad to know that something like this is practical!

I, too, have been curious about the eyeglass scratch remover. I suppose it works by filling in the scratches with a transparent material which then is buffed off the smooth surface of the lens. I have a hunch that it would not be necessary on a lens with few scratches, and might do more harm than good on one with many -- I imagine that, if it is well formulated, it will match the refractive index of the glass (and plastic) used for spectacles. That probably is not the same as the refractive index of a photographic lens element.

If the effect is purely cosmetic with no impact, one way or the other, on lens performance, it might be worth doing. If it reduces light scatter (like India ink) without degarding image formation, it certainly would be.

glennfromwy
Joined: 29 Nov 2001
Posts: 903
PostPosted: Tue Feb 17, 2004 1:33 am

T.R.: I buy 6X8 inch sheets of .025 aluminum for the lensboards. It is very easily formed over the mold with very light hammering. Even the radiused corners come out perfect.
Why would anyone pay 20 bucks for one on Eprey?
disemjg
Joined: 10 Jan 2002
Posts: 474
PostPosted: Tue Feb 17, 2004 1:34 am

The lensboards are readily available new from Midwest photo; just tell them what size hole you want drilled. Be sure you give them the right dimension; some holes are sized to fit the retaining ring, not the threaded barrel on the shutter itself. It depends on whether your retaining ring has a shoulder or is flat.
RichS
Joined: 18 Oct 2001
Posts: 1468
PostPosted: Tue Feb 17, 2004 3:41 am

Quote:

On 2004-02-16 08:22, glennfromwy wrote:
I have made myself a wooden mold out of oak to form my own aluminum lens boards out of sheet aluminum from the hardware store. It's not too difficult to do and they look much like the originals except for the bumps. Cleaning marks -- there is a product being advertised on TV for repairing scratched eyeglasses. I'm curious to learn if it would work on camera lenses, or if it works at all.


Boy, I have to keep up :wink:

I never thought of making a wood mold and forming a Pacemaker lensboard. Great idea and it'll go on my "list of many things to do and probably never get the time for". I get a kick out of forming metal but never really applied it to cameras...

About that eyeglass stuff. I've seen one add on TV, seen it in the drug store and seen a review of it on tv. Apparently it's a hrd black wax! It just fills the scratches so you don't get that white glare, but it's supposed to make a mess of the glsses and hard to clean them afterwards. The testing folks gave it a huge "F" and recommended not buying it. But now that for eyeglasses. With old lenses, a very common technique is to fill minor scratches with black India ink. The obvious purpose of course is to stop the white glare :wink: The hair-line thin black line left is pretty much ignored by both the lens & film. So, the eyeglass stuff would probably work. But I would be afraid of the waxy, difficult-to-clean mess it would leave behind? Worth a try on a non-user?

And now I have to catch up on what else has been going on around here :wink:

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