Greg Lytle Posted April 20, 2016 Share Posted April 20, 2016 Hi folks, I own a Porst 650 XL and Porst 1500 XL Microcomputer and was wondering about the the precision of the split viewfinders on each of them. I read the instructions which instruct me to zoom in all the was, focus zoomed in, the zoom out to a desired wider angle. When I zoom in to focus, the split finder lines up, but the split finder lines do not stay aligned upon zooming out and I guess I thought the lens should be parafocal upon zooming. Does this mean my split viewfinder is not accurate? Any guidance is appreciated. Thanks, Greg Lytle Link to comment Share on other sites More sharing options...
Mark Dunn Posted April 20, 2016 Share Posted April 20, 2016 (edited) Split-image rangefinders can be prone to error caused by the accommodation of the eye if there's no ground glass, but it's possible the lens is out of adjustment. Try a tape measure test to see if your focusing matches up with the lens scale. I would tend to trust the zoomed-in setting. Edited April 20, 2016 by Mark Dunn Link to comment Share on other sites More sharing options...
Greg Lytle Posted April 21, 2016 Author Share Posted April 21, 2016 Thanks Mark, I did just what you suggested, I think. I put the 1500 on a tripod and put a flat focus target 8 feet from the film plane. I then set the focus of the lens to 8 feet. It seemed dead-on. The focus ring does not move at all when zooming out, and it appears the rest of the field of view stays in focus, so I think that worked. I will do the same test on the 650 tonight. I appreciate your help! Greg Lytle Link to comment Share on other sites More sharing options...
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