Split Diopters

[Adam White]

Ive used split diopters before to throw frame sections out of focus but never utilised them to pull two different distances pin sharp. Can anyone suggest a good site/book/advise on using these in the most efficient way?

 

Also how do you approach the calculations for such a shot? do you work from the furthest focus measurement and work backwards towards the camera?

 

Apologies if this sounds a bit messy, I just cant get my head around them. . . little devils <_<

[Jon Kukla]

The first thing about diopters is that the diopter number is the reciprocal of the new "infinity" distance in meters. In other words, a 1/2 diopter will make the infinity mark on the lens focus on 2 meters, while a 2 diopter would have it focused on 1/2 a meter. The rest of your scale will have to be refigured by eye focus. There are two other things to take note of: one, the reciprocal number is the distance from the subject to the diopter, not the image plane; two, if you stack diopters, they should be stacked from largest power closest to the lens on down. This may require a filter tray or two in between them, however, since larger power diopters have greater curvature.

 

If you have the time, doing a quick test during checkout or when you have free time should allow you to get the procedure down so that the time spent changing everything and setting the frame while on set will be minimal.

[Jon Kukla]

[double posting]

Edited September 14, 2006 by Jon Kukla