I saw an 77mm Opteka R72 filter on my local classifieds for $5, so I had to buy it. I plan to use it on a tripod for landscapes. Taking handheld shots on the way back to the office was an adventure, because the viewfinder is essentially blacked out. I have seen some cool pinhole escalator shots, so I tried one using the new filter. I am not expecting anything special from this particular filter, but I'd like to have fun with it. Maybe I will get my D200 converted to IR. If anyone has experience using an R72 filter: 1. Do you have advice re any focus shift? 2. Any other tips or comments re metering tricks, etc? 3. Bad idea to use it on D300?