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04-10-2014, 01:08 AM   #16
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04-10-2014, 05:42 AM   #17
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QuoteOriginally posted by 13thmurder Quote
Any idea what wavelength i should go for with the k-30?

I really like the false color type infrared photos.

---------- Post added 04-09-14 at 10:26 PM ----------

I'm starting to wonder if the infrared filter i received was fake. Or could this just indicate that i'm doing something wrong? Have a look at this, a clearer image:


The leaves are all dark... why are the leaves dark? Is the filter i bought fake? Or am i doing something wrong?
Based on what I see yes, it is fake. If you had a real one the leaves would have a white or pink look to them. Here's one that is pretty much SOOC with using a red+IR filter on my K-01:

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Notice the color of the leaves? That's what you should get with one that has a good filter on it. You will need to cheat and use live view to set the white balance using grass or leaves, but then it's pretty much easy mode.
04-10-2014, 06:45 AM   #18
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QuoteOriginally posted by 13thmurder Quote
I recently got a k-30, and i bought a 720nm neewar infrared filter for it.

Anyway... the images it is producing are just awful. Here's a (bad) example. http://i.imgur.com/pchkQOe.jpg

That one was shot by hand, with a shutter speed of about 1/4 of a second, and 100 ISO... which seems a bit faster than i expected to be using with this filter.

Anyway, am i most likely doing something wrong, or does the pentax k-30 simply not work for infrared images? Or did i simply get a bad filter?
Isn't the glass in the lens opaque to infrared wavelengths? True infrared cameras use germanium instead of glass for the optical elements.
04-10-2014, 07:00 AM   #19
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The key to do what you want with what you've got (cheap*ish IR filter, medium Wavelength filter and an unmodded camera) will be trying to get the longest exposure time and having a tweaked white balance (in camera or in post, usually post is better) I would stack either a polarizer (~ND2) or a darker ND filter to try to increase exposure time as much as you can. And shoot RAW. This is all stuff that was mentioned. (be careful with cheap ND filters, some may block IR or cast odd colors in you shots)

As pete-tarmigan said, your lens might block IR but probably not. But it is in no way optimized for it.

I had better success with uncorrected lenses of simpler design (non-asp, minimum or no coating primes) I didn't bother analyzing this but I figured that the SMC would block some IR and that aspherical elements are optimized for visible light and might scatter IR. But this is just my guess. When I played around with IR before I got a P&S modified for it (filter removal) I had decent success with a Sony A33 and an old Minolta 50mm f/1.7. I was getting shitty shots with the kit zoom that came with the camera.

04-10-2014, 07:38 AM   #20
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QuoteOriginally posted by pete-tarmigan Quote
Isn't the glass in the lens opaque to infrared wavelengths? True infrared cameras use germanium instead of glass for the optical elements.
the near infrared frequencies we're dealing with here pass through glass just fine. the thermal imaging you're thinking of is something completely different.
04-10-2014, 08:44 AM   #21
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VOR is right. That is not a proper filter. The leaf color in the sun should be white with a high wavelength IR filter and pinkish with a lower wavelength filter. I've used 720nm and get white leaf color.

Shoot raw and convert to "the look" by changing the color temp during conversion in your normal photo editor. Use a tripod. You need to focus and then "back off" a bit. The older lenses have a red dot for IR focus. Look at one and you will understand.

Normal IR



Swap channel IR




These are from a converted K10. I've used a K10, K20, and film RF cameras with a 720 filter and get results like those pictures.
04-10-2014, 09:06 AM   #22
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One other tip, some lenses will "hotspot" like my Tamron 17-50 f/2.8 (see the middle of my pic) and cause a slight overexposure in the center. It gets more pronounced with longer exposures. Here's a good list of good and bad performers. Lens Hotspot Performance Database | Kolari Vision Infrared
04-10-2014, 12:01 PM   #23
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Another problem i've run into, when attempting to set the white point by photographing grass with the filter on, i get a message saying "could not complete the operation correctly".

It seems that the entire image just comes out monochrome red. I think i must have gotten a bad filter :/

04-10-2014, 02:34 PM   #24
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Try to do the adjustment in your photo editor of choice instead of in camera and see what kind of results you get. When shooting RAW, you're not going to degrade your image applying WB since the RAW file contains all the color information as the image was captured
04-13-2014, 09:21 AM - 1 Like   #25
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Hi 13thmurder,
I am in the same boat: K-30 with a Polaroid IR720 filter. Here is the work flow that I use... with random results.

1 Create a DNG profile with DNG profile editor, use the profile in Lightroom to cool down the photo. I guess Lightroom can be replaced with Raw The Rapee (RAW Therapy...Misread the name for a while)
2 Cool more the photo in lightroom and ajust color and saturation.
3 Swap red and blue channels with GIMP. Then Auto color ajustment.

---------- Post added 04-13-14 at 12:35 PM ----------

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