How 'accurate' is a folder?

Grytpype

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What would be a maximum acceptable error in the angular alignment of the lens/lens-board on a folder relative to the film-plane?

Obviously the effect on images would depend on the aperture, and the tolerable error limit might depend on whether it was in the long or the short direction of the frame (except on 6 x 6!), but is there a general 'rule of thumb'?

Steve.
 
Dear Steve,

I don't think there is one. "Close enough" is all you can ask, because "acceptable" varies too much according to who is doing the accepting.

Cheers,

R.
 
Thanks Roger,

I bought an Ikonta 520/2 recently. The diagonal struts were bent, and the strange thing is that the two sides were symmetrical as though someone had done it deliberately - hard to see how it could have occurred by someone trying to force the camera shut.

hhbt.jpg


I've straightened them and according to some fairly accurate measurements the lens still tilts back just under half a degree (.48) which I'm hoping might be within reasonable wear and tear limits on an 80-year-old camera.

The test would be to take one or two pictures wide open, I suppose.

Steve.
 
I'm far from an expert, but I'd imagine half a degree will be absolutely fine. If I was to tilt the lens back on my 4x5 camera by half a degree, I very much doubt I'd see any difference on the ground glass. That's just me though.
 
You're probably right. Actually I'm not sure how much those struts that were bent affect the alignment of the lens board. I haven't quite figured out how the system works on these cameras, but I think possibly the diagonals may be principally just to lock the main struts in position. These seem to rely rather heavily on tight clearances at the pivots for their accuracy, but it all seems to lock up quite solidly.
 
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