Archived posting to the Leica Users Group, 1998/01/31
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hey Mike, You took my line! It's called 'oblique pespective distortion' and is exaggerated by the wider field of view specs of most RF lenses. As any lens is positioned closer to the film plane, it naturally requires a wider field of view to cover (than one situated farther away) than an equivalent SLR version would. Because our eyes have a distinct field of view, wider ones create more OPD than were used to. Though our eyes have a specific focal length, the effect applies to any focal length (or most any) as we recognize any divergence from the norm, irregardless of focal length. Of course, many longer RF lenses (anything 50 and above) can be designed to sit, rear element as far foward as equivalent SLR version, but, not all are designed that way. OPD give rangefinder cameras a different looking rendition than SLR's and, as I wrote on CIS so long ago, it is part and parcel to working within the genre of street photography (and some others). Another effect that has far more visual confusion than most give credit to is the 'telephoto effect', which is related to OPD in the sense that it artificially compresses the perspective, counter to a more normal rendition a long focus version would. Pull out your mirror lenses and have a look for yourselves. The DOF and persective rendition will look closer to what you might expect with a 1000mm, even though you're shooting at 350-500mm. Danny Gonzalez Danny Gonzalez