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Thread: Hoya R72 IR filter

  1. #1

    Default Hoya R72 IR filter

    I've recently acquired one of these and should be with me shortly. Can anyone advise the light loss in stops or is it a question of trial and error

    Any advice appreciated

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  2. #2
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    Default Re: Hoya R72 IR filter

    Trial and error dependant on many factors... a quick WWW search indicates anything between 5 and 15 stops!!! Good luck!
    Cheers;
    Lee
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    5D3, 80D, 40D (IR), G3X
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  3. #3

    Default Re: Hoya R72 IR filter

    Quote Originally Posted by EOS_User View Post
    Trial and error dependant on many factors... a quick WWW search indicates anything between 5 and 15 stops!!! Good luck!
    Thanks for that [emoji4]

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  4. #4

    Default Re: Hoya R72 IR filter

    Does your camera have live view? Since you will have to use a tripod live view is quite handy as it can work out the exposure for you and if you also have live view AF this will make focusing easier as it uses the sensor to focus rather than the normal AF detectors. This eliminates the problem with IR focusing at a different point to visible light. In the old days most manual lenses had an IR index so you could focus normally with the filter off then put the filter on and adjust the lens to move the focus distance from the visible index to the IR one. Even then it was better to avoid large apertures as the marks were not always that accurate. Unfortunately most modern lenses especially zooms lack the IR index so are tricky to focus accurately though for lenses in the 18-50mm range focus will probably be acceptable if you set the aperture to f8-11.

    In my experience Canon have rather effective anti-IR filters on their sensors so you will probably find your exposures need to be quite long. On a modern camera I suspect that exposure times of 20-30 seconds is likely even on a bright day. Duller days may require longer. Older cameras are a bit more IR sensitive and my D30 can manage 5-10 seconds or so.

    One useful thing about IR is that the required exposure doesn't seem to vary much even when visible light conditions change. Generally I use manual mode, take a couple of test shots to determine typical exposure and then use that varying it only if required and even then it doesn't usually require much tweaking on the fly.

    I do recommend setting a custom white balance though as this makes it much easier to assess the image and exposure after it's taken. If you use AWB or any fixed setting the image will come out bright red and not at all easy to assess whereas a custom white balance gives you a fairly neutral, almost monochrome, rendering. This makes the image easier to asses and the histogram a lot easier to interpret.

    Generally I set the custom white balance from a patch of grass photographed with the filter in place. Failing that a general scene that's reasonably illuminated will suffice.
    Nigel

    You may know me from Another Place....

    The new ElSid Photogallery...

    Equipment: Far too much to list - including lots of Nikon...

  5. #5

    Default Re: Hoya R72 IR filter

    Quote Originally Posted by El Sid View Post
    Does your camera have live view? Since you will have to use a tripod live view is quite handy as it can work out the exposure for you and if you also have live view AF this will make focusing easier as it uses the sensor to focus rather than the normal AF detectors. This eliminates the problem with IR focusing at a different point to visible light. In the old days most manual lenses had an IR index so you could focus normally with the filter off then put the filter on and adjust the lens to move the focus distance from the visible index to the IR one. Even then it was better to avoid large apertures as the marks were not always that accurate. Unfortunately most modern lenses especially zooms lack the IR index so are tricky to focus accurately though for lenses in the 18-50mm range focus will probably be acceptable if you set the aperture to f8-11.

    In my experience Canon have rather effective anti-IR filters on their sensors so you will probably find your exposures need to be quite long. On a modern camera I suspect that exposure times of 20-30 seconds is likely even on a bright day. Duller days may require longer. Older cameras are a bit more IR sensitive and my D30 can manage 5-10 seconds or so.

    One useful thing about IR is that the required exposure doesn't seem to vary much even when visible light conditions change. Generally I use manual mode, take a couple of test shots to determine typical exposure and then use that varying it only if required and even then it doesn't usually require much tweaking on the fly.

    I do recommend setting a custom white balance though as this makes it much easier to assess the image and exposure after it's taken. If you use AWB or any fixed setting the image will come out bright red and not at all easy to assess whereas a custom white balance gives you a fairly neutral, almost monochrome, rendering. This makes the image easier to asses and the histogram a lot easier to interpret.

    Generally I set the custom white balance from a patch of grass photographed with the filter in place. Failing that a general scene that's reasonably illuminated will suffice.
    Thanks for the great tips. Much appreciated. My camera is a 7D II and hopefully will be able to give this a go at the weekend

    Sent from my XT1032 using Tapatalk

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