View Full Version : Protarlinse question

20-Dec-2009, 21:38
I have a 35cm and a 48cm Protarlinse combination lens set in a compound shutter and was wondering if it makes any difference optically which set of lenses [the 35cm or the 48cm ] is positioned in the front of the shutter and which group is positioned at the rear of the shutter when using it as a normal combination element lens. Note my question is not referring to the use of the lens as a convertible.

N Dhananjay
20-Dec-2009, 22:35
The longer focal length is placed in front. This is probably the better arrangement since lenses are corrected for certain distances. In other words, a lens is usually designed to image an object that is far away on one side and project it in focus at a shorter distance on the other side. So, for typical landscape kinds of distances, using the lens as intended (i.e., with the longer focal length in front) would provide somewhat better results. If doing macro work, reversing the elements may be good (in the same sense that using a reversed taking lens in an enlarger works well).
Cheers, DJ

21-Dec-2009, 16:28
Thanks DJ.


Bernard Kaye
22-Dec-2009, 14:58
If you use the shorter (lesser diameter) lens in front, it acts as a diaphragm (stopped down) and reduces light for focusing and taking if used wide open.