09-20-2010, 10:50 PM
[quote name='Birefringent' timestamp='1285020769' post='3015']
I mean that there is still some gradual fall of in image intensity at the corners when the lens is at 17mm and the aperture is wide open. Perhaps this should not be called vignetting, but rather spherical aberation due to using a larger extent of the lens. As you suggest, the effect is minimized as I zoom in a bit or if the aperture is stopped down a bit. I am not 100% convinced that one filter and no filter are any different. Probably the best way to determine that would be to shoot a wall of uniform color and illumination with and without a filter. At any rate, the sharp mechanical vignetting is no longer present, and I am very glad for that!
All the best.
[/quote]
Actually, what you describe is the optical vignetting I was referring to, and I do expect a single filter or the absence of a filter not to have any effect on this either, as a lens normally is designed to take at least 1 filter of a standard size and thickness, without causing mechanical vignetting. You can read a little on optical vignetting here:
[url="http://www.opticallimits.com/lens-terminology"]http://www.photozone...ens-terminology[/url]
Spherical aberration is something completely different; you can read more about it here:
[url="http://toothwalker.org/optics/spherical.html"]http://toothwalker.o.../spherical.html[/url]
Kind regards, Wim
I mean that there is still some gradual fall of in image intensity at the corners when the lens is at 17mm and the aperture is wide open. Perhaps this should not be called vignetting, but rather spherical aberation due to using a larger extent of the lens. As you suggest, the effect is minimized as I zoom in a bit or if the aperture is stopped down a bit. I am not 100% convinced that one filter and no filter are any different. Probably the best way to determine that would be to shoot a wall of uniform color and illumination with and without a filter. At any rate, the sharp mechanical vignetting is no longer present, and I am very glad for that!
All the best.
[/quote]
Actually, what you describe is the optical vignetting I was referring to, and I do expect a single filter or the absence of a filter not to have any effect on this either, as a lens normally is designed to take at least 1 filter of a standard size and thickness, without causing mechanical vignetting. You can read a little on optical vignetting here:
[url="http://www.opticallimits.com/lens-terminology"]http://www.photozone...ens-terminology[/url]
Spherical aberration is something completely different; you can read more about it here:
[url="http://toothwalker.org/optics/spherical.html"]http://toothwalker.o.../spherical.html[/url]
Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
