There are no such thing as a 4x5 lens. Large Format lenses are just that, lenses that are mounted on a box with a bellows to simplify it a bit.Originally Posted by thegman
5 inches is only about 12cm, how will a 4x5 lens cover a 6x17 frame? Am I missing something?
A 6x17 back will be moved back from the GG so as long as the lens is not to far away you will be able to get a width of 17cm. If you move the lens too far away the 5" width will restrict the image. When using longer focal lengths you will have to use tele designs and not conventional lenses.
They have different focal length and speed but most important they also have different image circle and it is the image circle that is important. A 150mm lens can have anywhere from 140 to 400mm IC depending on the design of the lens.
The point Jesper is making is important if you go with a 6x17 back for your 4X5 it is also important to think about shorter focal lenght lenses as you may not be able to compress your bellows enough to focus at infinity.
A dedicated 6x17 with the propper cone for your lens of choice will be nicer to work with. The disadvantage is that you almost need to dedicate that lens to the 6x17 as mounting, calibrating and removing again takes time.