Sinar zoom back

[Bob Salomon]

"To match the angle of the Linhof 6x12 camera than just use the same focal length lens as is on the Linhof. "

Not so.

Linhof uses a 56 x 120mm size for their 612 on the Techno Rolex 612 back and the Technorama 612 PC and PC II cameras. while the others, including Sinar, use 56 x 111 to 112mm.

Lens for lens the Linhof will always be wider on 612.

[Jim Bancroft]

Hi-

I've measured 6X12 slides taken with a Sinar Zoom at 56mm X 115mm.

jim

[Bob Salomon]

Stil half a centimeter shorter then Linhof.

[Paul Schilliger]

Something else to watch for, is the flatness of the film right to the end of the frame. The Sinar backs provide this. I had a Cambo 6x12 with an image slightly wider, but when I used wide angles, I ha d to trim about 4 mm of image on each side, for the curl of the film produced a focus shift. I don't know about Linhof, but guess it's up to the quality expected.

By the way, Peter, how is it going?

[David A. Goldfarb]

And when changing formats in the middle of the roll of film, be sure to do so BEFORE advancing the film.

An old thread, but since I just acquired a Zoom I back and found this information, it's worth correcting. I don't know if the Zoom II is more foolproof, but for the Zoom I, this is incorrect. The instructions inside the back say to wind after the exposure, implying that one should wind before changing formats, and I just tested it, and indeed, Sinar's instructions are correct. If you change formats before winding, you get overlapping frames when going from a larger format to a smaller format.

This makes sense, since it will wind the right amount for the new format, rather than the previous format, if you change before winding. So if you just shot 6x9, then switch to 645, then wind, it will only advance the film (approx.) 4.5cm plus the border, so the new 645 frame will overlap with the previous 6x9 frame. If you wind while the back is set on 6x9, then change formats to 645, it will advance by (approx.) 9cm plus the border, producing some wasted space between formats, but at least it won't overlap.

Also, when changing from a smaller format to a larger format, the film will automatically advance by the amount needed to prevent the new format from overlapping with the previous format. When changing from larger to smaller, you just get some wasted space (winding before changing), since it would be a bad idea to rewind 120 film.

[cdholden]

David,
I plan to test mine later this week. You just saved me a roll of film.
Thank you for posting.

Chris

[David A. Goldfarb]

Just processed another test roll, this time advancing the film before changing the format, and no overlapping frames in either direction. Next comes remembering that a 120 roll is 80cm long (shot two frames of 645 past the end of the roll).