Arca-Swiss 6x9 film plane vs. ground glass location???

[Robert J Pellegrino]

My new Arca 6x9 F-line Metric will be here this week. As many of you know, from my previous question filled posts, Ive been waiting for Arca to deliver a shi pment of new cameras to Robert White U.K. they arrived last Thursday and mine is in transit now. This of course brings me to yet another question, no big surpr ise here. Since this camera obviously uses roll film only, my question concerns film plan e vs. ground glass location. After careful focusing, for which Ill use an 8x l oupe to verify ground glass sharpness. I will have to remove the ground glass t o install an Arca roll film holder adapter and film back, Ill be using a new Ho rseman film back. How closely will the film plane now match the ground glass lo cation, for which I spent considerable effort focusing for sharpness??? Is this really much of an issue with Arcas, if so how do you check and subsequently ad just this relationship??? Since Ill be using a 6x7 or 6x9 back, I know that I ll need very accurate focusing to make the most of a relatively small piece of f ilm. Hence my concern, thanks again for all the help in the past.

[Glenn Kroeger]

Bob:

When I had the 69FC, I ran an optical check of the calibration between the GG holder and the roll-back adapter. Mine had excellent registration!

[shaman]

Hi Glenn, could you please elaborate how to do this optical check? I bought my own Arca 6x9 in part because of your advice and am extremely satisfied with this camera! Thanks!

[Robert A. Zeichner]

The ground glass testing article that I authored a few years back, has in it, instructions for making an inexpensive ground glass test target. Your's is just the situation that could benefit from this test. It's totally non-invasive and the materials to make it are cheap! I would suggest you read that article (Nov./Dec 1996 issue of ViewCamera). If you have any questions, I'll be happy to address them via email. Hope this helps.