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08-11-2009, 05:59 PM   #1
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k20d IR + sensor noise

I decided to do some IR photography with my new k20d. I know that the k20d is less IR sensitive than the k100d.

I noticed some horizontal bands (?) in the shots. Here is an example: link

There are no bands when taking normal photos, even at longer exposures (20-30 seconds). Any ideas whats happening?

note I am using a hoya r72 filter.

08-11-2009, 09:50 PM   #2
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What lens did you use to take this shot?
Some lenses are less amenable to IR photography.
I too have the R72 and have had reasonable success with getting decent IR shots in M mode and lots of PP work.
It's an art to work out with cams that are not designed to do it - but it's possible.
08-12-2009, 12:46 AM   #3
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I am using the kit lens that came with my k100d. I have used this lens + filter on my k100d for IR photography with much success. The bands that I am getting seem related somehow to the k20d body?
08-12-2009, 10:16 AM   #4
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Considering the Hoya is a high quality IR filter, and the K20d shouldn't exhibit this kind of streaking with longer exposures (what ISO were you set at?), I would have to vote for the kit lens being the culprit as well being the most likely culprit. Looking at the clouds they appear pretty over exposed, that may be another possiblity - did you bracket or have any shorter exposures to compare?

08-12-2009, 11:34 AM   #5
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@pxpaulx - the scene was defn unevenly lit. Could the banding be indicative of a channel being overloaded?

I guess it could be the kit lens? It worked fine for IR on my k100d. However, considering that the k100d is much more IR sensitive, it is possible that the banding due to over exposure would not have occurred.

The only real way to know whether it is the kit lens would be to try IR on another lens. However, I do not have an IR filter for my other lens =(
08-12-2009, 12:29 PM   #6
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I'm hoping to have enough money together to get the Hoya P72 filter by Christmas (I've just spent a small fortune on lenses - my last chance before pay cuts kick in). I've never done IR before and had been thinking of getting a larger filter then using step-up rings for most of my other lenses (I already have some rings for a circular polarizer). Is there some reason why this won't work? (thinking of slaw0710's other lens).
08-19-2009, 02:57 AM   #7
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k20 banding...

Hello Slaw, this is for sure problem with light entering camera from behind(through viewfinder). Use small cover supplied with package, or something else and you will take great shots. I had same problem with this, until I saw that problem dissappeared when I covered viewfinder by finger accidently

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