canned
Hello,
What lens focal length is required for medium-format enlargements (6x7) up to a maximum size of 30 x 40 cm?
Is a 50mm lens sufficient?
Best regards and thanks for any replies,
canned
cfb_de
Hello canned,
A 50mm lens will have an image circle that is too small and won’t cover the entire negative. Use an 80mm lens; as an enlarger lens, it has a sufficiently large image circle.
Best regards,
Franz
MirkoBoeddecker
Canned,
even an 80mm lens can sometimes be a bit tight for 6x7.
I’d go for a 105mm to have some leeway, e.g. for full-frame.
But I reckon you actually wanted to ask something else, and I suspect that your enlarger can’t be raised high enough to enlarge 30x40, and you were thinking that, just like with a camera, you could simply use a different focal length to achieve a higher magnification.
Unfortunately, this isn’t possible with an enlarger (the only exception being Rodagon WA lenses, but they are no longer manufactured) because the lenses are designed for standard format.
From this point of view, my advice would be counterproductive, as a longer focal length does indeed provide better illumination and quality, but also results in a lower magnification ratio.
Therefore, it would be best if you bought a larger enlarger or screwed it onto an old table and cut a hole in it with a jigsaw so that you can enlarge onto the floor.
Best regards,
Mirko
cfb_de
Hi Mirko,
> The only exception is Rodagon wide-angle lenses, but they’re no longer being manufactured
Oops. Is Linos just clearing them out? Their shop only mentions that the 120mm wide-angle lens is being phased out; there’s no such mention for the others.
Best regards,
Franz
canned
Thanks for the quick help.
drbue
With the exception of the WA, a 90mm lens is the minimum requirement. The Rodagon 105 is a really excellent lens. To increase the magnification, we recommend using a column extension, a (raised) wall mount, or...
Best regards
cfb_de
I don’t take the wide-angle thing quite so seriously. Linos (Rodenstock) wouldn’t be promoting the 4/80 Rodagon as suitable for 6x7 format without good reason.
Although generally speaking, Rodenstock lenses have a larger image circle: a friend’s 60mm lens covers 6x6 so well that I’m almost annoyed I bought a 60mm wide-angle lens myself.
With Schneider, however, the 80mm is only specified for up to 6x6.
Best regards,
Franz
max
Hi,
The whole issue of the image circle still depends on the VG scale. A 6x7 print enlarged to 13x18 should almost certainly work with a standard 50mm lens. However, I find it hard to believe that Schneider or Rodenstock would risk exposing themselves by having the image circle suddenly no longer suffice at a scale of 1:10 to 1:15 when specified for the format. In that case, the circle would only be slightly larger than at the ‘infinity’ setting due to rounding errors.
Regards
Martin
Wolfgg
Hello,
For 6x9 negatives, I use the Rodagon (without ‘Apo’) 4.0/80 from f/8 onwards. I’ve never noticed any issues in the corners, not even at 30x40. And, as you know, I’m quite demanding.
Regards, Wolfgang
