Hi.
I had a 50 1.8 with a Hoya R72 IR filter that I used for infra red on my 20D.
My 50 broke about the time I started doing IR photos, so I was wondering if I could use my 70-200 f4 for infra red. I have read that the lens can do it, I was just wondering if the difference in apertures between the 2 lenses (f1.8 VS f4)would be really bad since IR on a 20D requires a long exposure.
A new Hoya R72 sized for my 70-200 is about the same price as buying another 50 1.8 lens. I don't really want another 1.8 because it only lasted 4 months (going to go with the 50 1.4).
Any advice would help. thanks, Richard


