I wanted to try some IR photography and my largest lens is 77mm. The hoya 77mm rm-72 is $250, thats a lot of money just to try it out, then I came across the cokin for less than $50 so I thought I would give it a try sense I already had the P series holder. Recieved the filter, wanted to try some wide angle landscapes so I fitted it to my sigma 10-20 on a canon 20D, the results were terable, for some reason I got a reflection of the front of the lens in all the images like the filter was a translucent IR mirror, I even places the filter in the closest slot but that didnt help at all. I think the problem is the side light getting between the filter and the front element of the lens but there is no way to preven this with the cokin system. Im thinking about sending it back and getting a smaller 58mm hoya to use with a few of my lenses. What do you guys think, is the cokin junk or am I doing something wrong?
Thanks,
Adrian
Forums
Adrian,
The 89B filter blocks a lot of infrared light and all of the visible spectrum so any light leaking in from the sides will be significant as compared to the IR that you are trying to catch. You might want to tape the sides to prevent this. Moreover, many people don't like the infrared effects of the 87C which cuts off below 870nm, let alone the 89B which cuts off below 890nm, but now we are talking about personal preferences. I'm particularly happy with the effects of the Hoya RM72, which cuts off below 720nm, but again that is highly personal. If you have a "smaller" lens with sufficient focal length range, then you could use a smaller, lower cost RM72. I have the feeling (without having tried it) that on a very wide lens like your 10-20mm the IR effects may vary much across such a wide area and become noticeably different, especially in blue sky areas, like polarizing effects under those conditions.
Frans Waterlander
pixographer
I had a similar problem, and resolved it by putting something between the sun and the back of the filter (my hand was the easiest thing to use, but I have also used a gray card as a sunblock.) Since the camera is on a tripod, it is a simple matter of putting that part of the lens/filter assembly into shadow.
I have also sometimes had to block the viewfinder, as light leaks through gaps in the mirror assembly can cause a similar problem.
Site Map / Direct Links| Cameras Other | |
Techniques Site Features | |
Blogs Archived Blogs Refreshers | |
More Articles | |
Columns eCommerce | |
News Resources |
