IR Filters and Lens Sizes

Soldato
Joined
26 Nov 2003
Posts
6,674
Location
East Sussex
Is there any adverse effect of having larger diameter IR filters? Thinking of how larger CP filters lose effect as they reach 70mm ish.
Basically, should I get an IR filter for my 77mm 10-20, or 67mm 18-70?
Thanks muchly :)

There arent any further modifications needed for IR effect are there? Just the filter and longer exposures?
 
IR work nomatter what size they are. As long as its lighttight your good to go. The reason why CPL filters go weird at large sizes is because of the width of field of view of some lenses. With superwide lenses you are covering such a wide angle that the direction the light is coming from varies across the frame, and as CPL filters rely on being at a certain angle to the light it can cause weirdness. and yup, all you need is a filter, and a tripod for the long exposures. I remote shutter might be usefull as well if you have to use the bulb setting to get a long enough exposure. :)
 
with realtion to cpl am i going to have a problem on my 72 mm sigma- was interested in the cokin poloriser to use with their filter system
 
with realtion to cpl am i going to have a problem on my 72 mm sigma- was interested in the cokin poloriser to use with their filter system

Its not the filter size that's the problem, its the width of the lens. What lens is it? And if you did have a problem, then a Cokin filter system wouldn't fix it im afraid.
 
thanks MK thats re-assured me as it was in my letter to santa thats all!
 
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