Metal mask for Opemus 6a

ultra8 · 2006-01-19T08:08:00+00:00

Hallo Impexer! Ich benutze schon längere Zeit einen Opemus6a mit Glasbühne. Meine Negative werden zwischen den Gläsern problemlos plan gehalten. Ersetze ich...

ultra8

Hello Impexers! I’ve been using an Opemus 6a with a glass stage for quite some time now. My negatives are kept perfectly flat between the glass plates without any issues. If I were to replace the lower glass plate with a metal mask, the flatness would be compromised, as the upper glass plate would not lie flat against the mask when the stage is closed, meaning the negative would not be held completely at the edge. Do I need special metal masks with a greater upward ‘curvature’? Best regards!

dkwrt200

Not in my opinion. I’ve completely ditched the glass mask from my Opemus and, out of sheer stinginess, made myself a rudimentary mask out of cardboard about 2 mm thick, which still holds the long sides of the film in place by 1–2 mm; I then painted it black. This means I lose a bit of the negative format, but it works perfectly. Even with films that are highly prone to warping, I haven’t noticed any areas that are out of focus in ‘normal use’ from f/8 up to 18x24. Best regards, Rainer

MirkoBoeddecker

Jörg, If these are genuine Meopta parts, they should actually fit together flush – unless your stage is: 1) warped 2) the spring is worn out 3) the mask isn’t seated properly, or the wrong mask is fitted from the pair of format masks. Best regards, Mirko

ultra8

3) The mask isn’t fitted properly, or the wrong one of the two from the pair of format masks is in place.

That’s it ;-) I’ve now fitted the second mask from the pack. Lo and behold: this one has a curve that’s about 1mm higher. Now, when the stage closes, the glass sits flush against the metal frame! Regards, Jü

Gast

I think you’re still doing something wrong here – these masks are always meant to be used in pairs, so there’s no glass involved at all. That’s precisely the appeal of it: it reduces the number of dust-sensitive surfaces in the focal plane …

Roman

Hello 'Guest', but it is precisely this misuse that is often employed – with two sheets of glass, you could spend ages dusting; with two metal masks, the flatness isn’t ideal, and especially with longer exposure times, the negative can warp upwards due to the heat – so you combine the two: a metal mask at the bottom (the negative NEVER warps downwards), glass on top, so you only have to clean half as much, and still have optimal flatness... Roman