A couple more Norma questions

[jonreid]

Hi all,
I'm still yet to use my new-to-me 5x7 Sinar Norma. Am replacing light traps but have a few questions:

Please see attached pics regarding the position of the GG in the rear frame. There is a ~2mm gap between GG and rear frame at the top and a ~1.5mm gap between rear frame and GG to the left while the GG touches the frame at right and at bottom. Is this normal? Should it be centred?

Also, the black markings on the GG are a little worn. Not really a problem but can I clean that side of the glass without worsening it?

The last pic shows the camera at about 410mm of extension, longer than my longest lens, but does the bellows look a bit saggy?

Jon729167291772918

[jonreid]

Bump

[Struan Gray]

My 5x7 back came with a factory Fresnel, mounted on the inside of the gg. The space between the plastic Fresnel and the gg was full of dust and some kind of algae/mould that had grown there. Cleaning the gunk off with water and a tissue removed all the silkscreened lines :-(

That said, I don't frame exactly, and I don't do a lot of architecture, so I really only use the lines to provide a reference for focussing my loupe prior to focussing the image.

I did take the chance to centre up the gg in the frame. I don't think it makes any difference unless you are the sort who prints borders *and* fills the frame with important detail right to the edge.

Your bellows sag looks normal to me.

[Richard Wasserman]

I concur with almost all of what Struan wrote with the exception of the frame lines. I have washed my Norma ground glass—gently, which is not to imply that Struan was overly vigorous—with dish-washing detergent and a soft cloth and the lines are fine. My 5x7 Norma does not have a fresnel, so there must be different versions.




My 5x7 back came with a factory Fresnel, mounted on the inside of the gg. The space between the plastic Fresnel and the gg was full of dust and some kind of algae/mould that had grown there. Cleaning the gunk off with water and a tissue removed all the silkscreened lines :-(

That said, I don't frame exactly, and I don't do a lot of architecture, so I really only use the lines to provide a reference for focussing my loupe prior to focussing the image.

I did take the chance to centre up the gg in the frame. I don't think it makes any difference unless you are the sort who prints borders *and* fills the frame with important detail right to the edge.

Your bellows sag looks normal to me.

[Struan Gray]

It is quite likely that whatever the gunk was between the Fresnel and the ground glass, it had compromised the silk-screened markings. They just wiped off with a very gentle motion. My 4x5 back, which had no such gunk, and no Fresnel either, came up gleaming from a bath in normal washing up liquid, followed by a brief dip in isopropanol, with all markings intact.

I just wanted Jon to know that there was a *possibility* he could lose his markings.

[Richard Wasserman]

I certainly didn't mean to imply anything else.


I just wanted Jon to know that there was a *possibility* he could lose his markings.

[jonreid]

I tried a little Residual Oil Remover last night on a tiny patch and it lifted the black line, so I can't use that. I'll hand it to the missus tonight when she washes up and see what happens. Worst case scenario; can the lines be put back on somehow? Particularly the edge of frame?

[Frank Petronio]

Why not just redraw the lines with a pencil and a ruler?

I never knew Sinar made any inside-the-camera mounted fresnels especially when they have fixed the seating for the ground glass with a definite "seat"? I'd expect the ground glass to have some shims added (or material removed) to get accurate focus if that were the case.

[jose angel]

You can draw (or to go over) the lines with a thin permanent ink marker (that`s what I do when needed). If cleaning your GG the grid and frames are erased, leave it clear and draw the format frames with that marker (if needed). Don`t use other than kitchen soap; I think there is no need of using something stronger.

Agree with Frank; I`m not aware of fresnels between the GG and the frame in the Normas. My Linhoff had this system, and was a real pain. Also, the plastic fresnels I have used tend to bend, so they must be used with knowledge. I prefer a single GG and if so, a detachable fresnel behind (and this is how my Norma was made).

To know if the GG must be shimmed, you need to carefully take some measures. Mine doesn`t, but yours could be a different version. Anyway, mine has that "definite seats" I think Frank refers. "Definite seats" are clear, grinded portions of the frame where the GG should rest. If yours doesn`t have this "seats", it probably needs to be shimmed. I doubt so. If you post a pic showing the sides, or the whole contour of the GG frame (better without GG), we could maybe say anything more.

The bellows is normal. If it is too much saggy when extended, use an sponge to lift it up a bit.

[Struan Gray]

Why not just redraw the lines with a pencil and a ruler?

I never knew Sinar made any inside-the-camera mounted fresnels especially when they have fixed the seating for the ground glass with a definite "seat"? I'd expect the ground glass to have some shims added (or material removed) to get accurate focus if that were the case.

My Fresnel has built-in shims, like fins along the edges, which are thinner than the main Fresnel sheet, and go in-between the frame and the GG to move the GG backwards by the right amount. The Fresnel doesn't say 'Sinar' anywhere on it that I can find, but with Normas that doesn't mean anything. Everything else on the camera is factory original.

[jonreid]

Hi everyone,

There's no evidence of a missing fresnel on this one. I'll wash with soapy water. It really needs it, and pencil lines back on after.

Jon

[jonreid]

Ok, I've just removed the ground glass and can see the 'seats' referred to above.

Next question might be really dumb. Forgive me if it is. The ground glass has two frames drawn on it, partially visible in the pics above. The inner frame has both 13x18 and 5x7 marked in it but measures only 112mm x 157mm. The outer frame is about 10 mm larger in each dimension.

I trust the entire glass area represents my image area. What are the frames? Conservative cropping guides?

Jon

[Frank Petronio]

Hmm I don't know, I always figure I am going to clobber the edges so I always frame loose enough for my clumsiness. Never actually measured but I know 4x5 and 5x7 and 8x10 are not exactly that.

[jonreid]

I think they must just be (very) conservative cropping guides for clumsy people like you Frank. Either that or they date from times when people avoided circles of confusion? The ground glass measures just under 5x7, about the same as my deardorff.

Since I'm mostly contact printing in platinum I tend to be fairly anal about the edges of the frame. I'll do some testing once I get a lens board sorted.

The black lines didn't end up washing off in soapy water anyway....

[Struan Gray]

Film sizes are actually glass plate sizes. Some are exact, some are nominal, and there is some wiggle room. When sheet film came along it was originally sized to fit into adapter sheaths in a glass plate holder, so the film dimensions are smaller than the nominal size and the image area is smaller yet.

The actual sizes and image area are tabulated at various places around the web (perhaps even on this site), but there's an easier way. Put a filmholder in the camera and pull the darkslide facing you. You should be able to make out the edges of the film guides through the gg. That will tell you where the edges of your image are going to be.

[jose angel]

What Struan says. Right now in my hands I have two holders, an old Graflex and a new Lisco... the Graflex lend a slightly bigger image. If you want accuracy, you have to draw the corners of your own holders.

[jonreid]

I'll load some white paper into a holder tonight and see where my frame edges are. Thanks fellas.

Jon

[jonreid]

Ok, if anybody cares. My frame edges correspond to the outer, darker, frame shown in the above pics.