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Pierre L
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 06, 2004 - 12:36 pm: | 
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Hi. Based on an earlier archived post about removing the waist level finder block on the Flexaret VII, and with some advice directly from Andreas about how to remove the front leatherette, I managed to remove everything successfully. I cleaned the mirror and ground glass (they were quite dirty). Just one problem. When I pushed out the ground glass to remove it from its slot, I found that it was actually two pieces - (1) the ground glass itself and (2) a plastic fresnel screen that is dark yellow (maybe even orange). First, I don't like the dark viewfinder from that orange fresnel (it makes it almost impossible to see anything in the viewfinder except in bright sunlight, so I would like to not put it back, and secondly, if I do put it back, I don't know if the plastic fresnel screen goes above or below the ground glass. I don't see any way for it to go in except above the glass, but I'm not sure (the both fell out together and I could see which is on top of the other). I don't want to change the focus plane. Anyone have any knowledge or advice for me about this. I can't understand why the factory would put such a dark fresnel in there in the first place. The viewfinder is incredibly brighter without it.
After I figure that out, then I still have to figure out how to best get those 4 little screws back in their recesses holes (one at least is really going to be hard), and then how to best glue the leatherette back on.
But if anyone has advice about that orange fresnel, I would appreciate it greatly.
Pierre |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 06, 2004 - 01:27 pm: |
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I have disassembled some Hasselblad focussing screens which are also made from two components - a ground glass and a plastic fresnel, and on all 35mm SLRs I have seen the fresnel lens was on top of the ground glass.
If you find a cheap Hasselblad screen (they sell pretty cheap if they have minor scratches which are hardly visible once they are installed) you can easily separate the plastic fresnel and cut it to proper size. I have improved the viewfinder on three old TLRs with that method. In case the ground glass rests on top of a frame you don't have to readjust the viewing lens. |
Pierre
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 06, 2004 - 01:56 pm: |
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Thanks. I guess I need that fresnel on there, because without it, the ground glass rattles a bit in its track. The fresnel screen seems to fit over it and keeps everything snug. I still don't know why they would use such a dark yellow, unless the plastic yellowed more over the years, maybe. Luckily the mirror is crystal clear, and so is the glass. |
Chris
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 06, 2004 - 04:20 pm: |
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Hi,
I fixed an older Flexaret (and in my old post here I did recommend not totally removing the 4 recessed screws... ;) )
Getting to the point, my Flexaret has no fresnel lens (and my Rolleiflex TLR doesn't either).
It's purpose should be to make the corners of the focussing screen brighter. If it's doing more harm than good (undoubtly yellowed by time), just eliminate it (use a suitable spacer) or use an old Hasselblad fresnel (as suggested by another poster). Make sure that the screen focusses accurately afterwards: You can loosen a screw on the focussing lens to adjust it.
Chris |
Pierre
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 06, 2004 - 09:15 pm: |
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Thanks Chris. I did try to follow your recommendation about not removing the screws 
... but they just fell out when lifting the finder block up out of the camera body. I'll have to find a magnetic screwdriver or something to get them back in their holes.
Without the orange fresnel, using just the ground glass, the finder on the Flexaret VII is 10 times brighter than any Rolleiflex TLR or Yashica-Mat I've ever used. |
rick oleson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, May 07, 2004 - 10:20 am: |
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You can try cutting a square out of a "flat magnifying glass" to replace your fresnel element. Most of these have a longer focal length than the originals so it won't be as efficient at lightening the corners, and the rings are a bit coarse... but if your original is taht bad, this may be better than nothing. (If you don't want to install it under the screen, you can just drop it on top. They used to make drop-in Fresnels for TLRs in the 1950s... these usually had a 1/2" - 3/4" diameter hole in the center for critical focusing.)
The larger these are, the longer the focal length, so try to find the smallest size that you can cut a 6x6cm square out of.
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