# lens question - 4x5 linhof w/ super rollex 56x72 back

• 06-16-2013, 09:01 AM
oolalajp
lens question - 4x5 linhof w/ super rollex 56x72 back
greetings,

i'm the proud new owner of a linhof master techinika camera and will at least initially be using the super rollex 56x72 roll film back until i feel up to speed with the camera before branching out into 4x5 film. i've never shot large format before.

my question relates to lens choice, though i'm not quite sure how ask it. am i correct in assuming that since i'll be shooting 6x7 images on roll film that that will influence what focal length i should choose? in other words, will a 110mm lens on a 4x5 camera with a 6x7 roll film back produce roughly the same focal length as if i were attaching that lens to my medium format camera? i know (think?!?) that if i were using 4x5 film, a 110mm lens would be equivalent to about a 55mm lens on my medium format camera.

• 06-16-2013, 10:25 AM
Dan Fromm
Focal length is focal length is focal length. A 110 mm lens will see the same view on 6x7 regardless of the camera that holds it and the 6x7 roll holder. Y'r 6x7 camera has an integral roll holder, y'r Master Tecnika has a detachable one.

Equivalences? The 6x7 format's diagonal is ~ 90 mm. The 4x5 format's diagonal is ~ 150 mm. If you compare the diagonals (some prefer to use the formats' long edges, in which case 6x7 is ~ 70 mm across and 4x5 is ~ 120 mm across), you'll see that that 6x7 is .6 (or .58, the difference between .6 and .58 is gigantic) the size of 4x5. .6 * 110 = 67, not 55.
• 06-16-2013, 10:40 AM
oolalajp
hi dan. thanks for the information and clarification. since i'm new to large format, i'm only kinda pretty sure that i understand the implications of your analysis.

i guess if i were to ask in more layman's terms, what i want to know is how the 6x7 roll film back is going to influence my choice of focal length when choosing a lens (i was using the medium format analogy because i am familiar with what the 80mm lens on my contax 645 looks like when i go to compose).

• 06-16-2013, 11:20 AM
Dan Fromm
The 645 format's diagonal is ~ 70 mm. Start thinking.

If 645 is what you're used to using and want to compare to, why did you ask for a comparison between 6x7 and 4x5?

Focal length is focal length is focal length. Cropping doesn't change focal length, it just discards part of the image.
• 06-16-2013, 11:25 AM
grahamp
It is not just the focal length. Coverage is important. If you intend using the lens for 5x4 make sure it has enough coverage for the large format and any movements you may wish to make with the camera. Example: I have a 105mm Solinar that does a good job on 6x9. It will illuminate the 5x4 frame, but the edges are too soft to be usable.