Large format lens question

Discussion in 'Large Format' started by sean_merz, Dec 2, 2017.

  1. Hello everyone. I am hoping the experts here can give me some insight on large format lenses so I can make an informed decision on a future purchase. I am very interested in the Fotoman 69 camera. It is a medium format camera that takes LF lenses. When I first heard of the system I thought that sounded great because I would just be using the center of the lens which should give corner to corner sharpness. Recently I read that because LF film has so much more detail/resolution the lenses don't need to be as good and using LF lenses on 120 film would produce results that are inferior to a MF lens on 120 film. Is this correct? Even if MF and full frame lenses are technically superior to LF lenses am I going to see it in the image?

    Thank you,

  2. There is some truth in the statement that LF lenses are inferior to MF lenses in absolute terms. But not for the rather bizarre reason you've quoted.

    LF lenses are made to cover a much larger image circle, and so some design compromise has to be made between coverage and resolving power. You don't get something for nothing, so a lens designed to cover 5"x4" plus movements (say 200mm image circle) is never going to be quite as sharp as one designed specifically to cover 6x9cm with only a 100mm circle. That's other things being equal; such as the cost and complexity of the lens.

    Having said that, the limiting resolution is probably going to be the film and focussing accuracy that can be achieved. In short - I wouldn't worry too much about lens sharpness.

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