Timmyjoe Posted January 5, 2012 Share #1 Posted January 5, 2012 Advertisement (gone after registration) Just picked up a Zeiss 25 Biogon from B&H. Really like the focal length on my M8.2 but when I tested the lens this afternoon, when shooting with the sun off to my left, I am getting a weird prism spot on all the shots. Originally started with the lens shade and the IR cut filter in place. When I noticed the spot, I took the lens shade and the IR cut filter off the lens, but the spot is still there on each shot. Then took my 35 cron asph and shot the same scene, no spot. Can anyone tell me what is causing this and if this is just something with the Zeiss lenses? I think it could become an issue with the photo documentary work I plan on doing with the lens. Here are three shots. First a shot from the 25 Biogon showing the prism spot, then the same scene with the 35 cron asph where no spot appears, and finally a zoom in on the spot, showing the prism pattern. [ATTACH]294746[/ATTACH] [ATTACH]294747[/ATTACH] [ATTACH]294748[/ATTACH] Thanks for any and all assistance on this. Being that it is B&H, if I can't solve this, then the lens is going back. Link to post Share on other sites More sharing options...
Advertisement Posted January 5, 2012 Posted January 5, 2012 Hi Timmyjoe, Take a look here Help, lens issue. I'm sure you'll find what you were looking for!
Wrersanddaw Posted January 5, 2012 Share #2 Posted January 5, 2012 Hello guys, cool forum you have Link to post Share on other sites More sharing options...
UliWer Posted January 5, 2012 Share #3 Posted January 5, 2012 Having no Zeiss lenses I am not sure wether this is right, but it has been described elsewhere in this forum and in the Rangefinder Forum that some Zeiss lenses cause a light leak in the camera because a screw at the lens is exactly at the same position of a screw at the M bayonet. This can be solved easyly by putting some black colour on the screws or at the Zeiss customer service. Though may be in your case it's something external. Link to post Share on other sites More sharing options...
Timmyjoe Posted January 6, 2012 Author Share #4 Posted January 6, 2012 Yeah, I can't figure it out. Did a light leak test and that doesn't seem to be the issue. It's weird. Link to post Share on other sites More sharing options...
jaapv Posted January 6, 2012 Share #5 Posted January 6, 2012 It looks like one coma spot in an odd place. Weird indeed. I guess it is a flaw in the lens. Return it, I would say. Link to post Share on other sites More sharing options...
pgk Posted January 6, 2012 Share #6 Posted January 6, 2012 Given that its showing varying colours (prism pattern) I'd say that its been through glass as the light has been split - so not a light leak. As a guess I'd suggest it might just be reflected light from inside the lens - a bright spot or possibly even a minute chip on the periphery of one of the elements which has reflected a bright light source obliquely through one or more elements and onto the sensor. See if you can use a torch shining obliquely into the lens to recreate the effect and whether its only with light from one direction - this may give you a clue as to where to examine in more detail. Link to post Share on other sites More sharing options...
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