| Re: infrared photography questions |
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Group: rec.photo.digital.slrsystems · Group Profile
Author: Alan HoyleAlan Hoyle Date: Apr 2, 2008 14:02
On Wed, 02 Apr 2008 11:19:18, Neil Harrington wrote:
>>A friend of mine wrote and asked:
>>
>> I have recently become interested in infrared photography. I'm using
>> a Sony Cybershot DSC-H5 with a Hoya R72 IR lens filter (I've attached
>> a couple of shots just taken in Charlotte).
>>
>> I am considering buying a dedicated IR digital camera (professionally
>> converted) in the near future....which would mean no need for tripods
>> or, I assume, R72 lens filters. Just point and shoot with fast
>> shutter speeds. I would also think that this means having the
>> ability of shooting in lower light scenarios since there is no need
>> for a dark IR lens filter.
> To your friend:
> You'd still need an IR filter like the R72 to do infrared photography.
> AFAIK, the professional conversions you're talking consist mainly of
> removing the low-pass filter from inside the camera that keeps the IR from
> reaching the sensor. They don't add the necessary filtration to hold back
> visible light, and without that you'll just be shooting visible light with
> considerable IR corruption, probably causing problems with sharp focus --
> the reason for the camera having the low-pass filter in the first place.
That is not universally true.
A friend of mine has an Olympus E-500 DSLR that he had professionally
modified. Instead of simply removing IR/UV filter from the sensor,
they replaced it with custom-cut glass that's the functional
equivalent of an R-72. The TTL VF looks normal, but the sensor only
gets IR. He can't use it as a normal visible light camera anymore
though. Since the camera is from the generation before live-view
became standard, he doesn't get a preview of what the actual shot will
look like, but he can hand-hold and take reasonable IR images. The
E-500 also has a useful "focus bracketing" feature, but he also stops
down the aperture to get extra DoF and make focus less important.
-alan
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