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Old Mar 3, 2008, 6:17 PM   #1
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I'd be interested to hear if the K20d's Live View LCD can be used for framing with a Hoya R72 IR filter in place. IR with the LCD is a real benefit of Live View.

Has anybody tried? Or could somebody try?

Any comments are highly appreciated.

PS: I'm not talking about the in-camera PP filter called "infrared"
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Old Mar 3, 2008, 8:03 PM   #2
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chip_de wrote:
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I'd be interested to hear if the K20d's Live View LCD can be used for framing with a Hoya R72 IR filter in place. IR with the LCD is a real benefit of Live View.

Has anybody tried? Or could somebody try?

Any comments are highly appreciated.

PS: I'm not talking about the in-camera PP filter called "infrared"
Hi chip_de,

This is a really good idea! I've got a 55mm R72, and I'll see about digging out a step adapter to fit it to one of my faster lenses and give it a try tomorrow if the weather cooperates.

I've only played with IR a little, mostly with the Panny FZ1, which has a relatively weak IR filter. I also did try it with the DS, and while the images were okay, in use, it was a pain because the VF was so dark, even in the brightest sunlight. I was surprised that the AF worked okay, but composing the frame was almost impossible without removing the filter.

We'll see how the K20 works tomorrow. I'm very interested to see how this works. . .

Scott
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Old Mar 4, 2008, 11:41 AM   #3
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Hi chip_de,

Went out today with the R72, K20, and F 50 1.7. Unfortunately, the K20's sensor does not seem to have much in the way of useable IR sensitivity. I tried all WB settings in case that might have any bearing, and all ISO sensitivities. At 6400, I could barely see the shadows of an image on the LCD in LV, and the actual exposure came out almost totally black, though I tried a long exposure in Manual exposure mode.

Too bad, that would have been a potential feather in Pentax's cap. . .

Scott
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Old Mar 4, 2008, 3:58 PM   #4
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snostorm wrote:
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Hi chip_de,

Went out today with the R72, K20, and F 50 1.7. Unfortunately, the K20's sensor does not seem to have much in the way of useable IR sensitivity. I tried all WB settings in case that might have any bearing, and all ISO sensitivities. At 6400, I could barely see the shadows of an image on the LCD in LV, and the actual exposure came out almost totally black, though I tried a long exposure in Manual exposure mode.

Too bad, that would have been a potential feather in Pentax's cap. . .

Scott
Thanks a lot for trying, snostorm!

Anyway, that's bad news. Although I wasn't expecting the K20 to be super-sensitive to IR, this is a bit of a disappointment. :sad:

I actually don't understand why the aren't just boosting the signal more for the LCD at least. This would be great in simply very dark environments as well. I assume they could even do that in the firmware. :?

A camera that needs several seconds if not minutes for an IR exposure and an LCD that is virtually unusable for IR is a pretty bad combination - it would just be trial-and-error framing and exposure, with minutes for every step.

Is there any DSLR available at all that can handle this? Beeing at least _either_ sensitive to IR _or_ having a usable LCD for IR?

For me, that's another expectation that I have to "uncheck" for the K20d, sadly.





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Old Mar 4, 2008, 6:12 PM   #5
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If I am not mistaken, all digital cameras have a built-in IR blocking filter because the chips are sensitive to that wave length. I read an article not long ago about a company that removes the filter from the camera so that it becomes a dedicated IR camera, not useable for general photography any more. Serious IR photographers are willing to dedicate a body to that purpose. Speaking of which. when is the last time you saw an IR correction mark on a focusing scale? Some digital lenses don't even have a focusing scale!
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Old Mar 4, 2008, 6:16 PM   #6
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From what I understand you don't do long exposures. You do very long exposures. I read someplace about a guy doing IR with K10D (very similar IR response as the K20D) by doing 30 minute to one hour exposures.

Frankly, I don't have enough life left to waste it with exposures like that. Add to that that you have to sit there and old the button down for that length of time (you would have to use Bulb mode) and the usefulness of this would be very limited. You couldn't do outdoors because of movement caused by wind.

I have looked and looked trying to find someone that will convert a Pentax to IR only and have only found one possibility. The gentlemen said he was looking at doing it. I may have to sacrafice my old *ist and send it to him to try with. With any luck he will be able to do it. He has done Canon and Nikon and some point and shoots. If I learn anything about converting Pentax I will post.

In the mean time I bought a Fuji A900 point and shoot converted for IR only. 9MP, 4X optical zoom, nothing fancy, but it has very nice image quality for a point and shoot and the price was right $400 converted. I got it from Maxmax.com.

Robert
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Old Mar 5, 2008, 11:06 AM   #7
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MaxMax.com where I bought the IR-Only Fuji A900 adjusts the position of the sensor to compentsate for the change in focus area. The information sheet they included with the camera talks about the change in focus and what they do to adjust for it. They do this too for dSLR's. My only complaint about them is they won't touch Pentax cameras and I would really like to convert my old *ist to IR-Only. I don't want to buy a Canon or Nikon because that would mean a whole new set of lenses. I really like the idea of being able to use the 10-17 fisheye or the 18-250 or the 50 f1.4 that I already have.

Robert
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