Question about tilt-shift adapting a normal lens.

michaeladawson wrote:

Truman Prevatt wrote:

What would the 80 mm of the medium format be on the APS-C, as I still can not visualize how much of that lens would be used (the image circle)?

The image circle on an Hassey 80 mm is designed to cover corner to corner a 60 mm by 60 mm negative. The equivalent FOV is about a 50 mm FF lens (the 80 is the "normal lens for the 6x6). So there is plenty of image circle to cover an APSC - only using the sweet spot of the of the lens. You might want to pick up an adaptor that uses the Hassey on the X mount (if one exist) and see how it works.

This goes right back to your original question. 80mm is 80mm. It doesn't matter whether it's on a medium format, full frame, or APS-C camera body. The image circle will change of course, but the focal length is what it is.

An 80mm lens coupled with an APS-C sensor is still an 80mm lens. It doesn't matter what the image circle is. If you put an 80mm lens on an APS-C camera it's going to give you a FOV that would be equivalent to having used a 120mm lens on a full frame camera.

And medium format lenses don't come that wide. 40mm in medium format lenses is considered ultra-wide (there are some wider ones) and that would still only be a 60mm FOV on APS-C.

Of course focal length is independent of sensor size.  That is freshman physics - not anything earth shattering there.  But for tilt shift - the issue is image circle and an 80 mm or 40 mm or 35 mm designed for a 6x6 cm sensor will have a image circle large enough to support the required image circle.  In reality we are talking specialized lenses and specialized applications and if you want the image circles requires for shifts and tilts and Fuji does not support this application then if this is a real requirement then one has to look otherwise - now don't you.