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Beseler large format enlarger not level

craigclu

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I agree, Bernard.... Knowing that the film stage is aligned with the baseboard and the lens is aligned with both seems the most accurate to me. Also, having a quick tool like the VersaLab will indicate if your gear loses some alignment in extreme positions and makes for easy confirmation. I found that one of my older 23CII's when left in full-up position would introduce some droop when left that way between sessions. This alerted me to the baseboard material not being as firm as I assumed. The small change at that leverage point magnifies many times at the other end, it seems.
 
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MingMingPhoto

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Yeah the secod part I understand, and I was thining get a sheet of mirrior thats slightly bigger than lens stage and align that to easle with the tool and then do the same with the lens. should make both parallel to each othr
 

bernard_L

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Yeah the secod part I understand, and I was thining get a sheet of mirrior thats slightly bigger than lens stage and align that to easle with the tool and then do the same with the lens. should make both parallel to each othr
Actually that you accumulate the errors of aligning each (film stage ; lens stage) separately to the easel. Of course if you are lucky they compensate. But whether you count worst case or statistical (RMS) error, you lose. And did I state before that film//lens is the most critical?

More generally. You should have in mind not only that the method works in principle (as in the proof of a geometry therorem), but the comparison between:
  • required accuracy to achieve a defined goal, e.g. 0.2mm circle of confusion on the print (or whatever your preferred value)
  • achievable accuracy, the result of the error budget, that tallies the small deviations from the ideal that may occur during the alignment procedure.
 

Kilgallb

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If you scratch a negative with a perfect square and the image projects as a perfect square on the easel then the film plane and easel MUST be parallel.

If all the scratch marks are in focus then the lens is parallel.

I think that is the most simple method.
 

snusmumriken

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Heh, that’s very neat! A step improvement over what I knew and posted above.
 
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MingMingPhoto

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oh wait meant to say that to you