What image circle do Xpan lenses cover?

bugmenot · 10-26-2012

Out of pure curiosity, I am wondering what is the diameter of the image circle that Xpan lenses cover?

My first thought was that given the length of a panorama Xpan image is twice that of a regular 35mm frame, then the diameter of the image circle should be at least 72mm. Would this be a correct assumption?

kzphoto · 10-26-2012

I think it's somewhere like 66mm? It covers a 6x7 frame which would measure 56x65 millimeters. Not sure tho.

bugmenot · 10-26-2012

Quote:

Originally Posted by kzphoto

I think it's somewhere like 66mm? It covers a 6x7 frame which would measure 56x65 millimeters. Not sure tho.

You are correct. Thank you for the very quick response.

I was mistaken to believe the panoramic images were 72x24mm, while in reality, they are 65x24mm.

Another mystery solved for me XD ... 66mm minimum image diameter it is.

Rob-F · 10-26-2012

Not so fast. Your 72mm answer seems closer to the truth. The frame is 65mm wide, but the image circle has to cover the diagonal, and not just the width. In fact, I suspect it's larger than 72mm--maybe closer to 80. Excuse me while I trudge down to the basement for my calculator.

Rob-F · 10-26-2012

OK the diagonal of a 65 x 24mm rectangle is 69.29mm. So the image circle needs to be something just over that: say, 70mm or so, as a minimum. So 72mm was a really good estimate!

bugmenot · 10-26-2012

Quote:

Originally Posted by Rob-F

Not so fast. Your 72mm answer seems closer to the truth. The frame is 65mm wide, but the image circle has to cover the diagonal, and not just the width. In fact, I suspect it's larger than 72mm--maybe closer to 80. Excuse me while I trudge down to the basement for my calculator.

Quote:

Originally Posted by Rob-F

OK the diagonal of a 65 x 24mm rectangle is 69.29mm. So the image circle needs to be something just over that: say, 70mm or so, as a minimum. So 72mm was a really good estimate!

Thank you for the insight. I completely missed the fact that it isn't just the length that needs to be covered, but also the diagonal.

Just amazing how such rather small lenses can cover such a large image circle.