[Thagomizer]

Hi all;

In normal orientation, a DSLR lens is going to project an image circle of either full frame size or APS-C size on a sensor at the registration distance, depending on the format for which the lens is designed. If it is reversed for macro work, is the resultant image circle now going to be determined by the focal length of the particular lens, rather than its intended format? Will a reversed wide angle lens thus have a larger image circle at the sensor plane than a reversed normal lens? Just wondering this because of the possibilities of macro tilt/shift applications using reversed w/a optics. I know that for DIY T/S rigs larger format lenses are recommended because of the longer registration distance and the larger image circle. For macro work, the former is not be an issue because infinity focus isn't needed, but the latter is still going to be necessary to accommodate the desired lens movement.It would be nice to have more control over placement of the plane of focus in macro shooting. Whether this practical for my preferred hand held way of working might be another matter...

Not that I'm anywhere near doing tilt/shift macro stuff, but it might be good to know for future reference. It might also inspire me to put something together sooner than I would otherwise.

---

Last edited by Thagomizer; 06-30-2018 at 07:23 PM.

[pcrichmond]

Great question. I'm posting so I'll get a follow up and find out the answer also. If you do give the T/S a try, would love to see the results.

[Not a Number]

I can't answer your questions but I suppose you could just measure the image circle of a lens hand-held projected on a white card - normal vs reversed.

When Minolta introduced their Auto Bellows III with tilt / shift functions they also redesigned their bellows lenses to throw a larger image circle for 35mm cameras (full frame).

I've had no problems using the older 100mm bellows macro on crop sensors with tilt and shift. Since the 100mm won't do much over 1:1 magnification there is no need to reverse it. I don't have any of the Minolta 50mm bellows macro lenses.

[Thagomizer]

I can't answer your questions but I suppose you could just measure the image circle of a lens hand-held projected on a white card - normal vs reversed.

Good idea!

---------- Post added 06-30-18 at 11:51 PM ----------

If you do give the T/S a try, would love to see the results.

Don't hold your breath for this. I've got a big, long list of things want to try that I might never get to....

---

Last edited by Thagomizer; 06-30-2018 at 08:59 PM.

[Not a Number]

I just did a quick and dirty test. It looks like the image circle reversed is many time larger than the normal position. Which makes sense because normally you are taking a larger image area to fit on a smaller area. Doh!

[Thagomizer]

I just did a quick and dirty test. It looks like the image circle reversed is many time larger than the normal position. Which makes sense because normally you are taking a larger image area to fit on a smaller area. Doh!

This is what I would have guessed, but I'm no optical genius.