Ground glass and fresnel for speed graphic?

[mike rosenlof]

Hi,

I'm working to make an early 50s speed graphic a little more "modern". Mostly it does what I want in a portable camera, but the viewing is awfully dim with a definite hot spot.

Can anybody suggest a source for a nice ground glass and fresnel that I can simply replace the existing GG? A grid would be a good thing, maybe even clipped corners, but that's less important. If I'm doing much with movements, I have a monorail that's much easier to deal with. It's the Graflock back if that makes much difference. Looks like a few screws and the GG can be changed.

-mike

[Nathan Smith]

That camera would have originally come with a fresnel lens, so my guess is you have a replacement GG without the fresnel, and it's not up to snuff.

If you search for "graflex +(fresnel)" in ebay you'll find some options.

I've often seen original replacements for both the GG & fresnel together, but don't see one off hand right now, though there are a number of entries that look interesting.



Hi,

I'm working to make an early 50s speed graphic a little more "modern". Mostly it does what I want in a portable camera, but the viewing is awfully dim with a definite hot spot.

Can anybody suggest a source for a nice ground glass and fresnel that I can simply replace the existing GG? A grid would be a good thing, maybe even clipped corners, but that's less important. If I'm doing much with movements, I have a monorail that's much easier to deal with. It's the Graflock back if that makes much difference. Looks like a few screws and the GG can be changed.

-mike

[IanG]

You can just add a fresnel behind the screen (on the viewing side) that makes a huge difference.

It really also depends on the quality of the screen as well, some older ones are dim, you can make your own or Steve Hopf - Brilliant Glass sells excellent inexpensive screen. You can also regrind the old screen, I've done all three and all are appreciably better than the originals.

I won't recommend the US supplier I used for a fresnel as the service was extremely unsatisfactory. There's some good Chinese fresnels on Ebay at very reasonable prices.

Ian

[Dan Fromm]

Guys, fresnel lenses were optional extras for Pacemaker Graphics. Graflex Inc. made focusing panels for use with ground glass alone and for use with ground glass plus fresnel, with the fresnel in front of -- between GG and lens -- the GG. There's a casting number for each size of focusing panel (2x3, 3x4, 4x5) that is unfortunately the same for both types.

If you think about it, you'll realize that putting a fresnel in front of a GG will put the GG out of register with the film plane. For this reason, Pacemaker Graphic focusing panels made for use GG alone have the GG sitting on high bosses. Focusing panels made for use with the GG-fresnel sandwich have low bosses.

Mike, if you've been getting good focus and your Speed's focusing panel has no fresnel now, when you get a fresnel put it behind the GG as Ian suggested -- between you and the GG -- instead of in front. If you put it in front of the GG the GG will be out of register with the film plane and you'll have problems putting the plane of best focus (in the subject) where you want it.

[IanG]

Mike, if you've been getting good focus and your Speed's focusing panel has no fresnel now, when you get a fresnel put it behind the GG as Ian suggested -- between you and the GG -- instead of in front. If you put it in front of the GG the GG will be out of register with the film plane and you'll have problems putting the plane of best focus (in the subject) where you want it.

I'd add that if you have & use the Pacemaker focus screen hood you need to shim behind the two metal retaining clips with a bit of card. This doesn't affect the screen/glass position at all but allows the hood to fit securely, otherwise the hood does quite lock into the retaining clips.

Ian

[Ari]

I haven't tried this product yet, but I mean to soon:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280659026173&ssPageName=STRK:MEWAX:IT#ht_4698wt_907

[mike rosenlof]

Mike, if you've been getting good focus and your Speed's focusing panel has no fresnel now, when you get a fresnel put it behind the GG as Ian suggested -- between you and the GG -- instead of in front. If you put it in front of the GG the GG will be out of register with the film plane and you'll have problems putting the plane of best focus (in the subject) where you want it.

Thanks everybody!

I think I'll start with Mr. Hopf and then look for the fresnel.

I've had the thing for 20 years now and haven't questioned the focus, so I'm guessing put the fresnel on my side of the GG. Do I put the ridges toward me or toward the lens? A wide open on-film test might still be a good idea!

-mike

[IanG]

Yes ridges towards the screen, All 3 of my Speed/Crown Graphics had no fresnel, that's quite common.

Ian

[Jack Dahlgren]

For an almost free option you might try cleaning the gg. It probably has 60 years of dirt on it.

[IanG]

For an almost free option you might try cleaning the gg. It probably has 60 years of dirt on it.


My experience restoring 9x12 cameras (as well as Graphics) is that old glass needs more than a clean and a simple regrind with #600 grit silicon carbide gives a far brighter screen, and takes about 5 minutes :D

A fresnel will increase overall brightness by about 3 stops.

Ian

[tom thomas]

If you are looking for cheap fresnel lens material to experiment with, checkout your local office supply store (or even Wallyworld.) Look for the fresnel page magnifiers in sizes up to Letter. They offer up to 3X magnification when used to magnify text. About $10 or so for the 8 1/2X11 size. I dont' notice magnification when the sheet is in contact with text on a piece of paper so it shouldn't affect the image on the viewing glass in the Graflex.

I wanted a fresnel for a 23 Crown Graphic that was a bit dim. I found a 4X6 size page magnifier, nice and thin flexible plastic, easily cut it to size with a razor knife to fit the Graflok back viewer. Helps in the corners quite a bit. I havent' developed any film yet to check effects on focus yet but I was shooting mostly infinity landscape so I may not notice any problems with focus.

Tom