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Title: Which Wide Angle Zoom Post by: klindup on August 08, 2009, 05:58:48 AM I am looking to buy a wide angle zoom to partner my 40D. I am considering the Sigma 10-20 but I am not sure whether to go for the f4-f5.6 or the f3.5. My thinking is that the extra aperture of the f3.5 over the f4-f5.6 can be addressed by upping the ISO. My reason for hesitating with the f-3.5 is that I have several P series Cokin filters and the physical diameter of the f.3.5 will result in vignetting and that I will have to buy the larger filters which is an added cost.
I would appreciate the opinions of the experts out there. Ken Lindup Title: Re: Which Wide Angle Zoom Post by: KeithB on August 10, 2009, 08:35:29 AM Are you trying for depth of field or motion-stopping with the wider aperture?
Because wide angle lenses already have a pretty deep depth of field at almost any aperature. Use Bob's calcluator to plug in some numbers and comapare against your needs. Title: Re: Which Wide Angle Zoom Post by: klindup on August 10, 2009, 10:41:26 AM Hi
Angle of view is my reason for buying the wide angle and I cannot see a reason for going for the f3.5. At those focal lengths depth of field will not be an issue and I guess that at f5.6 and certainly f8 the hyperfocal distance will be 5 or 6 feet. My concern was that there might be other differences such as differences in build quality or image quality that make the f3.5 a better lens. ken |