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15 mm fisheye wants filters

Ralph Honsbeek

New member
Hello there ,

I have Canon 15mm 2.8 Fisheye on a Canon 5D , I want to use filter to cover the whole area , rather not have any vignetting. I was hoping to use ND filter, I was looking at Cokin's P series and Z series , I wasn't sure if the P series of Cokin would interfere with the ultra wide angle of the 15mm on a fullframe, maybe the Z series . I would love to have some feedback , I heard about gelatin filter but not sure how to use them ,

Thanks a lot

Ralph
 

Anil Mungal

New member
Ralph,

There is a rear gel filter holder on the lens. Take a look at the lens mount, you'll see a square u-shaped groove that you can slide a filter into. I have not used it, so I cannot comment on usefulness, performance, etc; but this would definitely cover the full frame and avoid vignetting.
 
Hello there ,

I have Canon 15mm 2.8 Fisheye on a Canon 5D , I want to use filter to cover the whole area , rather not have any vignetting. I was hoping to use ND filter, I was looking at Cokin's P series and Z series , I wasn't sure if the P series of Cokin would interfere with the ultra wide angle of the 15mm on a fullframe, maybe the Z series . I would love to have some feedback , I heard about gelatin filter but not sure how to use them ,

Hi Ralph,

As Anil already mentioned, a gelatin filter has to be cut to fit at the rear of the lens. A filter on the front would seriously degrade the image quality and a flat filter that's not extremely thin will cause light fall off due to the longer light path through the medium at oblique angles.

In theory, a dome with exactly the right radius could be used, but it would need to be of extremely high quality to not cause distortions/blur, due to the huge DOF. Any irregularity, including dust will show as a blurred structure/object.

At the rear of the lens you'll see a marked square frame of approx. 30 millimetres, which is the size to which the gelatin filter needs to be cut, after which it can be slid into the grooves at the rear and where it should stay fixated.

Cheers,
Bart
 

Ralph Honsbeek

New member
Thanks a lot you guys , I am gonna give it a try ,

By the way , Cokin make a Adaptor holder for lenses like fishe , where then the cokin filter holder ring can be attached so that the cokin filter can still be used . no idea about the vignetting .

Do you know if Gelatin gels come in ND as well ,

Ralph
 
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