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View Full Version : Jeff Keller, remember that thread about IR photography?



ReF
01-28-2005, 03:23 AM
in case you haven't already tried Infrared photos and are still interested:

Since no one here seems to have tried infrared photography on a D-SLR, i though you might be glad to know that I tried it on the D-Rebel with the HOYA R72 filter(only one i have) and it work out pretty good. it's not a D30 but it should be close enough. a pleasant little bonus is that with the large CMOS sensor, the detail-eating graininess(even at ISO 50 on the A80)that is common in IR photography is gone. i also should mention that I was using my old 58mm filter on a 50mm lens with 52mm thread and on a 17-85mm lens that has a 67mm thread. of course there was some vignetting on at 17mm with such a small filter, but i did not notice "hot spots" in any of the photos. as far as I know, a hot spot is a discolored/slightly bright patch in the center of an IR photo when too large of an IR filter is used. The 58mm filter caused hot spots when used with the tiny lens on the A80, but i do not know of any guidelines for avoiding hot spot other than to use as small a filter as you can.

the only other thing i have to mention are: you need to use shorter focus lengths for IR so use a small aperture, focusing is a bit hit and miss.

in post processing to convert to B & W and adjust the contrast if you don't like what you get straight from the camera. converting to B & W also dramatically reduces the appearance of hot spots.

sherlock
01-28-2005, 04:40 AM
Hi Ref,


I am interested in where someone would use infrared photography? Thanks for answering a dummy's question!!!


Andrew S.

Rhys
01-28-2005, 09:23 AM
I am interested in where someone would use infrared photography? Thanks for answering a dummy's question!!!

Lots of people use IR photography. It's good at masking vegetation (which comes up lighter-coloured) and emphasising structures. As it shows heat, hotter things tend to come out lighter and cooler things, darker. It's not something that's very useful for seeing in the dark but it's useful for artistic purposes, medical purposes (checking on blood flows etc) and for archaeology - seeing what's under the ground by emphesising the differences in the vegetation etc.

sherlock
01-28-2005, 03:04 PM
Hey Rhys,


Thanks, I was just curious what the applications were for IR photography. Man, you know a lot! Are you a pro photographer, because I want to become a landscape photographer (I'm only 16, SORRY JEFF!!). Thanks!!



Andrew S.

D70FAN
01-28-2005, 03:16 PM
Hey Rhys,


Thanks, I was just curious what the applications were for IR photography. Man, you know a lot! Are you a pro photographer, because I want to become a landscape photographer (I'm only 16, SORRY JEFF!!). Thanks!!



Andrew S.

Want to know more? Google on IR Photograpy, or dSLR IR photography.

Rhys
01-28-2005, 04:55 PM
Thanks, I was just curious what the applications were for IR photography. Man, you know a lot! Are you a pro photographer, because I want to become a landscape photographer (I'm only 16, SORRY JEFF!!). Thanks!!

I understood that photographers are born rather than something one becomes. The skill is either there or it's not. I have always loved photography and I think I'm reasonably good at it. What I suggest is that if you want to do landscape photography, look at landscape photos, pinch ideas and try to design your own landscape photos. Use a throwaway camera or a digital and experiment.

ReF
01-28-2005, 10:59 PM
well, i really only use IR photography for "artistic" purposes, or if I want to cut through haze on long distant shots. IR waves pass through haze, smog, atmospheric scatter, etc, so it looks as though it was never there. one of the older threads in "D-slr chat" is also about IR photography if you are looking for more info.

ktixx
01-29-2005, 12:14 AM
From the brief research I have done, I was under the impression that the Canon 20d was unable to do IR photography due to a filter that removes the IR light from being captured by the CMOS. I also thought that the Rebel had the same filter to remove the IR light. I have seen threads on this forum about how to remove the filter and replace it with a clear piece of glass. Does anyone know any more on the subject? Is it impossible to shoot IR photo's with the 20D? Any input is much appreciated.
Ken

ReF
01-29-2005, 06:36 PM
From the brief research I have done, I was under the impression that the Canon 20d was unable to do IR photography due to a filter that removes the IR light from being captured by the CMOS. I also thought that the Rebel had the same filter to remove the IR light. I have seen threads on this forum about how to remove the filter and replace it with a clear piece of glass. Does anyone know any more on the subject? Is it impossible to shoot IR photo's with the 20D? Any input is much appreciated.
Ken

before i actually tried IR on the d-Rebel i was also under the impression that IR wouldn't work on it without removal of the filter. the literature on the web certainly makes it seem this way.

removing the IR cut filter increases the sensitivitly to IR so that faster shutter speeds can be used. clouds and foliage usually aren't in sharp focus because of long exposure times and wind. IR actions shots are very rare and can only be done if the filter is removed. this also allows you to use filters that block out more visible light than the HOYA R72. removing the filter makes it more suitable for astrophotography but i really don't know much about that subject. i don't think there are any filters that block out IR 100% so i think that IR photos will still work on the 20D. you can still use the "Remote control test" to see if your camera is sensitive to IR. since there is no live preview on the lcd, point the remote at the lens and hold down any button. shoot a series of burst shots or one .5 sec shot (the reason for this is because the light from the remote blinks, so you can miss it severa times shooting standard speed single frames) and see if there is tiny light coming from the remote.