Hi!
Dgud asked me to give some info on this matter, since I wrote the original dialog.
I looked up the Pentax 645 on Wikipedia and it has as you say a negative size of 45 x 60 mm. The article shows a picture of one "with a 75 mm normal lens", and normally a normal lens has the length of the diagonal of the negative, which in this case matches perfectly (sqrt(60^2 + 45^2) = 75).
So the normal lens is 75 mm for that negative format. For the other lenses i did choose common lens lengths for the format I knew i.e 24x36, so if we scale these lengths from 50 mm normal lens to 75 mm normal lens we get: wide angle: 35 mm (36), moderate wide angle: 55 mm (52.5), standard: 75 mm, short tele: 135 mm (127.5), tele: 200 mm (202.5). I have looked up the lenses in the same wikipedia article and rounded from their corresponding 24x36 lens.
I have not found a camera with 34x60 mm negative format. Have you invented that one to get a 16:9 widescreen format? If so the invented lens lengths should be 33, 48, 69(standard), 117, and 186 mm.
Looking at the 120 film still cameras does not give much. 16:9 would correspond to 6x10.6 and the closest known (Wikipedia, again) are 6x9 (same aspect ratio as 24x26) and 6x12 (16:8?) - a bit off.
There should be some 70 mm movie film camera that has got 16:9, but I do not know if there is any point in having lenses from such for the amateur unknown cameras in the lens dialog...
Today the sensor size of digital cameras seldom follows any standard, so having a fabricated negative size for 16:9 maybe is just fine. But may I since 24x36 still seems to be the norm (everybody knows what an 85 mm short tele does even if it is not 85 mm) suggest an invented negative format of 22x39 (16:9) with the same lens lengths as for 24x36? Otherwise a negative format of 9x16 units with lenses 8.8, 13, 18(standard), 31 and 50 units.
Another approach could be to look at what happens in a contemporary full frame (small format (24x36 mm)) digital camera. If you tell it to use 4:3 it would crop the image on the sides to 24x32 mm, and for 16:9 top and bottom to 20.25x36 mm. But you still use the same lenses i.e 24, 35, 50(standard), 85 and 135 mm.
Dgud asked me to give some info on this matter, since I wrote the original dialog.
I looked up the Pentax 645 on Wikipedia and it has as you say a negative size of 45 x 60 mm. The article shows a picture of one "with a 75 mm normal lens", and normally a normal lens has the length of the diagonal of the negative, which in this case matches perfectly (sqrt(60^2 + 45^2) = 75).
So the normal lens is 75 mm for that negative format. For the other lenses i did choose common lens lengths for the format I knew i.e 24x36, so if we scale these lengths from 50 mm normal lens to 75 mm normal lens we get: wide angle: 35 mm (36), moderate wide angle: 55 mm (52.5), standard: 75 mm, short tele: 135 mm (127.5), tele: 200 mm (202.5). I have looked up the lenses in the same wikipedia article and rounded from their corresponding 24x36 lens.
I have not found a camera with 34x60 mm negative format. Have you invented that one to get a 16:9 widescreen format? If so the invented lens lengths should be 33, 48, 69(standard), 117, and 186 mm.
Looking at the 120 film still cameras does not give much. 16:9 would correspond to 6x10.6 and the closest known (Wikipedia, again) are 6x9 (same aspect ratio as 24x26) and 6x12 (16:8?) - a bit off.
There should be some 70 mm movie film camera that has got 16:9, but I do not know if there is any point in having lenses from such for the amateur unknown cameras in the lens dialog...
Today the sensor size of digital cameras seldom follows any standard, so having a fabricated negative size for 16:9 maybe is just fine. But may I since 24x36 still seems to be the norm (everybody knows what an 85 mm short tele does even if it is not 85 mm) suggest an invented negative format of 22x39 (16:9) with the same lens lengths as for 24x36? Otherwise a negative format of 9x16 units with lenses 8.8, 13, 18(standard), 31 and 50 units.
Another approach could be to look at what happens in a contemporary full frame (small format (24x36 mm)) digital camera. If you tell it to use 4:3 it would crop the image on the sides to 24x32 mm, and for 16:9 top and bottom to 20.25x36 mm. But you still use the same lenses i.e 24, 35, 50(standard), 85 and 135 mm.