John Hudson
2nd of February 2009 (Mon), 15:21
Hi everyone,
I've been considering buying a new circular polarising filter principally for use with three lenses:
Sigma 10-20mm, Canon 17-40mm and Canon 70-200mm. All of these lenses have a 77mm thread and so the choice would appear to be easy, get a 77mm filter.
However 10-11mm on the Sigma ultrawide actually puts my current filter holder into the frame (Cokin filter system). So I started wondering, would buying an 82 or 86mm filter and using a step up ring avoid this problem. I understand that standard sized screw in filters can also show up at ultra wide angles. <aybe the step up ring would be visible, but I'm thinking as they have to angle outwards, maybe they are wider than the 10mm field ov view.
Having an 86mm filter would also be of some occasional use as I use a Sigma 50-500mm for motorsport photography and this has an 86mm thread. Currently I have no polarising option for this lens as Cokin P stops at 82mm. It would be an occasional use item as with it being an f6.3 lens at 500mm, the opportunities to darken further with a CP and yet retain useful shutter speeds would be restricted to only the brightest of days.
The CP filter I'm thinking about is rather expensive and I'd appreciate your comments and experience before deciding on which filter to pursue.
thanks
John.
I've been considering buying a new circular polarising filter principally for use with three lenses:
Sigma 10-20mm, Canon 17-40mm and Canon 70-200mm. All of these lenses have a 77mm thread and so the choice would appear to be easy, get a 77mm filter.
However 10-11mm on the Sigma ultrawide actually puts my current filter holder into the frame (Cokin filter system). So I started wondering, would buying an 82 or 86mm filter and using a step up ring avoid this problem. I understand that standard sized screw in filters can also show up at ultra wide angles. <aybe the step up ring would be visible, but I'm thinking as they have to angle outwards, maybe they are wider than the 10mm field ov view.
Having an 86mm filter would also be of some occasional use as I use a Sigma 50-500mm for motorsport photography and this has an 86mm thread. Currently I have no polarising option for this lens as Cokin P stops at 82mm. It would be an occasional use item as with it being an f6.3 lens at 500mm, the opportunities to darken further with a CP and yet retain useful shutter speeds would be restricted to only the brightest of days.
The CP filter I'm thinking about is rather expensive and I'd appreciate your comments and experience before deciding on which filter to pursue.
thanks
John.