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shim ground glass or what?

 
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eric



Joined: 20 Sep 2003
Posts: 10

PostPosted: Sat Sep 20, 2003 4:22 pm    Post subject: Reply with quote

So, this is kind of strange. My Series B ground glass focuses further than the film plane, that is to say, if I focus on something 60 inches away and take a picture, the zone of sharp focus will be at ~55 inches (just as an example) That implies that the glass needs to be moved further away from the lens to match the film plane distance, or to put it another way, the film plane is too far away from the lens.
The reason I think this is weird is because I don't see how it could have gone out of alignment in that direction -- If it were shimmed for a bag-mag and I switched to a 2-sided holder, it would err in the other direction, because the 2-sided holders are shallower than the bag-mag. So I'm wondering if I'm just confused or if something weird is going on.

Also, looking at the ground glass mounting, it looks like you can only adjust the position of one edge of the glass! What's the story with that? There appears to be plenty of room for adjusting the glass *closer* to the lens, but it appears to already be at the limit of adjustment away from the lens, but I need more.
I've temporarily shimmed it with a few layers of narrow tape on both edges of the glass, but there's got to be a correct way to do it.
Any ideas?

eric
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45PSS



Joined: 28 Sep 2001
Posts: 3211
Location: Mid Peninsula, Ca.

PostPosted: Sun Sep 21, 2003 5:00 am    Post subject: Reply with quote

You did not state whether you are using the rear ground glass or the mirror/top ground glass. Sounds like you are using the rear one.
The history book isn't cleat on what type of holders it uses which could be different depending on vintage(pre or post war).
With my pre historic RB Auto(1909/1910) I recieved 1 film holder and 2 plate holders. The film holder is 5 inches wide while a Fidelity Elite is 4 3/4 inches. The early wood Graflex film holder positions the film 5.9mm from the flat face of the holder while the Fidelity positions it at 5mm. I also checked one of my early Grafmatics and it positions the film at 5mm also.
I do not know when film holders changed size and distance.
Charles

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eric



Joined: 20 Sep 2003
Posts: 10

PostPosted: Sun Sep 21, 2003 4:25 pm    Post subject: Reply with quote

Yeah, film holder depth will be one issue to work on, but thanks to Bert Saunders the bigger problem has been diagnosed -- the mirror latch wasn't holding the mirror all the way down, but letting it come back a mm or so from it's proper position..

My grafmatic and 2-sided holders are pretty close depth-wise, and at any rate I'm going to have to go through the pain of calibrating the focus anyway now. May try and replace the mirror while I'm at it.
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eric



Joined: 20 Sep 2003
Posts: 10

PostPosted: Tue Sep 23, 2003 6:57 pm    Post subject: Reply with quote

Oh boy does adjusting the ground glass for proper focus suck.
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45PSS



Joined: 28 Sep 2001
Posts: 3211
Location: Mid Peninsula, Ca.

PostPosted: Wed Sep 24, 2003 1:38 am    Post subject: Reply with quote

I ass-u-me that you are refering to the one on top that the mirror's image is projected on, the one on the back should be a piece of cake(fresh baked, of course).
1).Ass-u-meing you have a removable ground glass piece on your back, remove the camera back from the camera.
2).Remove the ground glass section and install a known good film holder and remove the darkslide.
3).Lay a straight edge across the length of the back on the film side. To the streight edge tape or clamp a small ruller or piece of wood so that it is perpendicular to the film surface of the holder and streight edge.
4).Remove the straight edge and lay aside without moving the perpendicular piece.
5).Remove the film holder.
6).Reinstall the ground glass and check with guage made in step 3, adjust as necessary.
7).Reinstall back on camera.
8 ).Using the rear groundglass, lock focus on an object.
9).With mirror in viewing position adjust top ground glass to bring focused image sharp.
10).Compair rear to top and adjust top until both are the same.
11).Enjoy!

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[ This Message was edited by: 45PSS on 2003-09-23 18:56 ]
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eric



Joined: 20 Sep 2003
Posts: 10

PostPosted: Wed Sep 24, 2003 6:08 pm    Post subject: Reply with quote

Yeah, it's step 9 that's the real kicker

Actually, it wasn't that bad, but I doubt it's as perfectly adjusted as it could be. For one thing the ancient f/4.5 Kodak Anastigmat lens is crappy, especially wide open. For another, the ancient ground glass is wretched and difficult to focus on precisely anyway.

I wasn't aware that a ground glass back was available. Mine doesn't have one, at any rate.

I think at this point at least the position of the G.G. isn't the limiting factor.

Ideally I'd have liked to be able to use this camera to make better 16x20 prints than I can with a 2 1/4 SLR, but I don't think it's going to happen without a better lens.
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45PSS



Joined: 28 Sep 2001
Posts: 3211
Location: Mid Peninsula, Ca.

PostPosted: Wed Sep 24, 2003 9:11 pm    Post subject: Reply with quote

The Series B with fixed horizionzl back, according to the history book, is the same body used on the discontinued Auto Graflex while the RB Series B is the body of the discontinued Tele Graflex. There are 5 models of reflex Graflex's that use Auto in their name, and the Series (2)B's,C, and 2 D's for a total of 10 cameras all based on the same body/design. This listing has a good picture of an early RB Auto Back with rear ground glass installed with its cover closed.
The outside deminsions of the rear gorund glass holder(back) are 6 1/16 x 5 inches x 7/16 thick with leather covering o the outside. There is a rabbit 3/16 x 1/8 inch along the long sides for attaching to the camera. The ground glass opening, camera side, is 4 15/32 x 3 15/32 inches. The view side is 5 3/8 x 4 inches. The glass is held in place by a 1/4 inch wide strip of spring steel ,screw holes centered 3/32 from outter edge, possibally a #1 wood, starting at end where cover hinges the screws are at 1/8, 1 3/16, 2 1/4, and 3 5/16 with the last 1/2 inch turned up to provide a spring opening for the cover. The cover is about 1/32 smaller than opening, hinged by two small hinges on one long side and retained closed by two small turn clips on the other. The ground glass appears to be an exact 4 x 5 x 1/8 set 6/32 deep (6/32 line just shows at edge with end of ruler touching glass.)
Your Bag Mag is at the old depth standard and newer film holders will need a thin shim plate to make both work without reseting the glass.
Charles

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eric



Joined: 20 Sep 2003
Posts: 10

PostPosted: Thu Sep 25, 2003 5:17 pm    Post subject: Reply with quote

Thanks for all the detailed measurements!

I've got it adjusted now to be correct for the two-sided holders I have. I don't really intend to ever use the bag mag since the individual holders are for glass plates. I've got a graflex-back grafmatic on its way back to me. I haven't measured it, but I sure hope it's the same depth as the two-sided film holders.

Anyway, I took some pictures with it yesterday and I'm getting sharp 16x20s with handheld exposures, so I guess I can't complain

A better lens would certainly help a whole lot though. Aside from being crappy, it's got some fungus on the front surface. ew.

eric
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45PSS



Joined: 28 Sep 2001
Posts: 3211
Location: Mid Peninsula, Ca.

PostPosted: Thu Sep 25, 2003 9:36 pm    Post subject: Reply with quote

Congrats on getting some sharp pics!
Now, remove the lens and disassemble it and clean all the surfaces with a microfiber lens cleaning cloth(heavy weight prefered, contact Adorama if you don't have one) and reassemble. All kinds of stuff builds up on the surfaces even if they are sealed. You might even be able to kill that fungus. Craftsman model number 45531 strap wrench comes in handy when removing retaining rings.
When using a strap wrench the wrench handle should not go past 900 or be less than 800 to the cylinder you're trying to turn when turning pressure is applied.
Charles

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While a picture may be worth a thousand words, a quality photograph is worth a million.

[ This Message was edited by: 45PSS on 2003-09-25 14:38 ]
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eric



Joined: 20 Sep 2003
Posts: 10

PostPosted: Fri Sep 26, 2003 2:45 pm    Post subject: Reply with quote

Well, I've had the lens all apart and the fungus is actually only on the front surface! But it is definitely not coming off, at least not without doing even more damage to the lens. Also, it's just not a great lens to begin with -- though to be fair it probably wasn't designed with a goal of making negatives you can enlarge to poster size. I'm going to keep my eyes out for an old dagor or something, or else try to figure out a way to mount my 150 symmar on it.
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eric



Joined: 20 Sep 2003
Posts: 10

PostPosted: Sun Oct 26, 2003 1:12 am    Post subject: Reply with quote

just as an example, here is a 600dpi scan of a 20x24 print made from a Tmax 400 negative exposed in my 4x5 Series B. If your screen is 75dpi, this would be around a 40x enlargement, I guess. Not too bad, particularly for more reasonably sized prints. Note it's a 2.2Mb jpeg file so it may be a little slow to load.


http://limpoc.com/~eric/40xgraflex.jpg


Series B 4x5 Graflex
6 3/8" Kodak Anastigmat.

Exposure was probably ~ 1/135 @ f/11, but
that's just a guess. I try to always use this lens smaller than f/8.

The shutter speeds are right on, too.

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disemjg



Joined: 10 Jan 2002
Posts: 469
Location: Washington, DC

PostPosted: Mon Oct 27, 2003 3:22 am    Post subject: Reply with quote

You will probably be in for a rude surprise if you try your 150 Symmar. You will not be able to get it to go to infinity since the mirror will prevent bringing it close enough to the film plane. I put a 18cm Tessar on by 4X5 RB, and it seems to be as short a focal length as can be used without problems. This is why these reflex cameras are seen with rather long lenses. If you ditch the Kodak lens, I suggest you go looking for some older Zeiss lenses, as they can be inexpensive and are very good. I paid $50 for my Tessar and am thrilled with it. I got it from RITZCAM.COM Another consideration is finding a lens that is short enough to allow the front door on the camera to close.
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eric



Joined: 20 Sep 2003
Posts: 10

PostPosted: Fri Nov 21, 2003 9:43 pm    Post subject: Reply with quote

I think it will actually focus the 150 okay if you mount it a bit forward in the mount. But the symmar I have is in a shutter which doesn't clear the bottom rail anyway, so I'm not going to bother.

Also I've been shooting with the lens it came with (Kodak 6 3/8" Anastigmat) and now that focus issues are taken care of, I've decided to stop complaining about it -- it's turned out to be not bad at all! (as long as you watch out for flare

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45PSS



Joined: 28 Sep 2001
Posts: 3211
Location: Mid Peninsula, Ca.

PostPosted: Sat Nov 22, 2003 6:40 am    Post subject: Reply with quote

Eric,
The B&L, that came on my 1910 RB auto, aperture descringated. I saw a 10 inch f4.5 Kodak Anastigmat on eba_ and bought it for cheap as the seller said it had fungus and I thought I might get lucky and be able to use the aperture blades in the B&L. When I got the lens there was a crystal blob on the inside of the rear inner group, a bit of haze in a small area on the rear, and an oil on water pattern in the front.
I disassembled the lens and inspected each element, none of the inprefections were significant by themselfs. I took regular Q tips, dipped in Ultra Clorox then wiped each surface of each element completely. I used only one end of the Q tips per element. Once all 4 elements were done I rinsed them off under running water, blotted and allowed them to air dry.
I polished them 24 hours later with a microfiber lens cloth and reassembled. I discovered that the innerfront element has a brownish tint resulting in my question(s) in lens help.
Fully assembled the "ONLY" evident stuff is the "oil on water" in the front element and I will have to use a loupe to detect any of the "other fungus" if that is what it was.
While searching for cleaning tips I found a tip from a well know ebay lens seller saying Methol Ethol Keytone will kill/remove lens fungus. Use carefully!
Charles

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