Medium format to 35mm camera lens adapters?

[brianentz]

I've been eyeing some bronica etrs to nikon lens adapters but am having a hard time getting good info on it. Is a 75mm 2.8 bronica lens still 75mm 2.8 on a nikon FE2? Is there light loss or a different focal length? And would there be a step down in terms of optical quality between my new bronica lenses and my old nikkor lenses?

[David A. Goldfarb]

The focal length and the aperture do not change when you mount the same lens on different cameras. Image quality depends on the particular lenses being compared. You can't generalize about that really, though it was once thought that you could assume that 35mm lenses were better for 35mm. It might turn out that a modern multicoated medium format lens with a more sophisticated design is better in the center of the image circle than an older 35mm lens. On the other hand a lens designed for 35mm will probably be faster, and a lens designed for medium format will have excess coverage that should be reduced with a longer lens shade, and the medium format lens will probably be larger and heavier.

[2F/2F]

The only thing that will be different will be the size of the film frame (and the loss of automatic aperture, but I am speaking in terms of the image itself, not the operation of the lens). It is basically like putting a lens designed for 35mm format onto an APS-C camera, or using an 8x10 lens with 5x7 or 4x5 film. People do these things all the time.

However, for less than the cost of a high quality adapter, you could get a Nikon 85mm f/1.8, and you would have auto aperture, a smaller lens, more light gathering ability, and less D of F if you want it. And you would have a lens designed for the format, which will generally be sharper and have higher resolution than a lens designed for a larger format.

[keithwms]

The main concern is the differing distance between the lens flange and the film plane, when you compare the two formats. The Mamiya-to-Nikon adapter that I have takes this into account and provides an extra space, and so I have happily used a Mamiya 645 200/2.8 apo lens on a Nikon F body with this adapter.

If you want to play around, you can take a 35mm body cap and epoxy it to a medium format lens rear cap, back to back, and then drill a hole through the middle and voila, you have an inexpensive adapter. It won't be ideal and the flange-to-film distance will almost certainly be wrong, but, in a pinch....