G
Guest
>>>>>>>>>>>> I've used a Cokin A system with an 85mm > portrait lens (67mm thread, stepped down to 62mm) and managed to scrape away > at f8... > any wider, I get pretty pictures of my filter holder>>>>>>>>>>>>> You can take photos at different apertures with a filter to determine if it vignettes.
I have placed some groundglass material (translucent--blank film with scotch magic tape (not clear) over it) in the film plane. Open the shutter and observe the effect with the lens stopped down. I have found that the vignetting is worse at the smaller apertures than wide open. This is more accurate than just looking at the finder, unless your SLR shows 100% of the film area. Most do not, to compensate for the masked off section of the slide mount. Doesn't the RTS III show 100% of the film area?
I have placed some groundglass material (translucent--blank film with scotch magic tape (not clear) over it) in the film plane. Open the shutter and observe the effect with the lens stopped down. I have found that the vignetting is worse at the smaller apertures than wide open. This is more accurate than just looking at the finder, unless your SLR shows 100% of the film area. Most do not, to compensate for the masked off section of the slide mount. Doesn't the RTS III show 100% of the film area?