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First K-7 images with infrared filter
Posted By: HEEGZ, 08-02-2010, 05:48 PM

I have no experience with IR photography, so I decided to get a cheap Opteka R72 IR filter to try with my K-7 and 18-55 WR kit. The filter arrived today and I took a few test images in my backyard. Below are a normal image, a red-dominant image, the same image with a red-blue channel swap, and then two more images at longer focal lengths. EXIF data included.







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08-03-2010, 12:48 AM   #2
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I'm moving this to the PYP section. Definitely an interesting effect, and I like how you didn't go all-BW like most people do!

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08-03-2010, 12:51 AM   #3
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You got THAT out of K7? Nicely done. I've not had much luck using the Hoya R72, maybe it's the filter..

This is the best I could do in a short experiment, 10 seconds.



08-03-2010, 05:23 AM   #4
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QuoteOriginally posted by Adam Quote
I'm moving this to the PYP section. Definitely an interesting effect, and I like how you didn't go all-BW like most people do!
Sorry, I forgot this forum was here.

08-03-2010, 05:27 AM   #5
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QuoteOriginally posted by JeffJS Quote
You got THAT out of K7? Nicely done. I've not had much luck using the Hoya R72, maybe it's the filter..

This is the best I could do in a short experiment, 10 seconds.



After reading some of the posts on the forums I was ready to write off IR with my K-7. Instead I decided to try a cheap filter and see what sorts of results I could get. I started off with 10, 15, and 20 second over-exposures and quickly realized that I can have success at 4, 6, and 8 seconds. Next time I am going to see if I can get some good exposures at 1 second or less, to reduce motion blur.

There is a lot of wiggle room with Photoshop, and you can really make the image whatever you want since IR looks so surreal. I haven't done any noise reduction to these images because I haven't figured out how to do it really well in Photoshop. I'd like a stand alone noise reduction program, but not willing to buy one yet. The free versions strip EXIF data, and I'm not willing to do that.
08-03-2010, 05:36 AM   #6
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Well done impressive for the K7 I also like the color ! Perfer the blue as opposed to the red.
08-03-2010, 06:29 AM   #7
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Nice test shots. If you want to get serious about doing IR photography, you may want to convert a camera, and have the IR-cut filter in front of the sensor replaced with a clear filter. I have done that to my K10D and can now shoot IR as well as UV with the right filters and lenses.
Because a modified camera is so sensitive to IR, you and take photos using various color filters to mix IR to the visible colors, producing interesting color schemes.
08-03-2010, 08:06 AM   #8
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Conversion comment:

If you plan to have a dSLR converted for IR, I'd suggest that you have the internal IR-blocking hot-filter replaced with clear optical glass, rather than with an IR-pass filter. With an internal IR-pass filter installed, a cam can ONLY be used for IR, and only at one spectral frequency. With clear optical glass, the camera can be used for multiple purposes: for general photography, by screwing an IR-block filter onto the lens; or for IR, by using various IR-pass filters; or for any type of spectrum-slicing you want. With just optical glass, the camera's effective ISO increases by ~2x-3x.

I have two 5mpx P&S's I use for IR shooting. One is a Minolta Dimage F300 converted with a 720nm filter installed. The other is a Sony DSC-V1 'NightShot' with a lever that pulls the IR-block hot-filter away from the sensor. The Minolta is now IR-only, and decent for handheld shots down to modest light levels. The Sony is general-purpose (and quite nice), and very handy in NightShot mode, up to ISO 2500. With no filters, it can shoot in total darkness with its own IR light source or with an add-on IR light; or I use 780nm, 900nm, 930nm, 1000nm IR-pass filters, handheld or tripodded; or I use blue or violet filters for working with actininc (UV-violet-blue) light, as earliest photo emulsions saw; or I use B&W filters (yellow, orange, red, green, etc) for certain effects.

08-03-2010, 10:17 AM   #9
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Thank you for the comments. In regards to IR in general, my current setup will have to do, as I am already a few hundred dollars past my limit for the summer. Future purchases will be for more lenses, with the next one being the 10-17mm Fisheye for Christmas. Long term I would like to have a dedicated IR camera, but that will likely be years down the road.

If you have a K-7, I have worked up a rough guideline for daylight IR shooting with a 720nm filter. Using the Opteka filter that I linked to in the OP.

ISO 200, bracket 1-2 seconds for f/2-f/8
ISO 400, bracket 0.5-2 sec. for f/2-f/8

ISO 100 requires more fine tuning and so no easy guidelines. ISO 200 looks very comparable with minimal noise.
08-03-2010, 10:31 AM   #10
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I took a bunch of images today to come up with some guidelines, which I just posted above. Below are the first four exposures which I have processed. Note that these were taken with longer exposures before I realized that the ISO 200 and 400 images were nearly as good with much shorter exposure times. These were taken with the WR kit lens, which I've been really impressed with so far. Also, there is less vignetting at f/8, so my next batch will probably be ISO 200-400 at f/8-f/11 with exposure times between 1-6 seconds. EXIF data embedded.
1st image - normal visible spectrum photo

2nd image - approximation of the infrared RAW DNG file (converted to JPEG obviously)

3rd image - fully processed infrared image

4th image - the 3rd image with the red and blue channels swapped.



08-03-2010, 11:08 AM   #11
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Using your IR filter, try changing the white balance on the the camera and do a "white-click" on the grass....
08-03-2010, 12:20 PM   #12
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Wow HEEGZ, those look real nice.

I've been thinking about getting an IR filter but from the threads I read most indicated a Hoya or Cokin filter would work the best. But they are pricey. I was contemplating a cheaper Chinese version and your results with the Opteka IR filter gives me some sense of what can be accomplished.
Thanks for sharing.
08-03-2010, 01:03 PM   #13
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QuoteOriginally posted by Eric Seavey Quote
Using your IR filter, try changing the white balance on the the camera and do a "white-click" on the grass....
Thank you for this. I'm still new to photography and have never manually set a white balance before. When processing the RAW image, I set it to the daylight setting, maybe 5500K going off of memory. Learning to manually set WB is on my technique to-do list, and I've not made an attempt yet.

Also, the WB may be off because I was messing with the color balance and added in a bit of yellow/green so that it wasn't so stark white. Also, I messed with the levels and curves a bit, and I'm sure a auto-levels on these images would result in some changes. The amount of control you have with these IR alterations is almost overwhelming...
08-03-2010, 01:11 PM   #14
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QuoteOriginally posted by Jools Quote
Wow HEEGZ, those look real nice.

I've been thinking about getting an IR filter but from the threads I read most indicated a Hoya or Cokin filter would work the best. But they are pricey. I was contemplating a cheaper Chinese version and your results with the Opteka IR filter gives me some sense of what can be accomplished.
Thanks for sharing.
This was partly my purpose in buying the filter. I was curious if the K-7 could achieve decent results without spending almost $100 on a filter. First, I wasn't even sure that the IR could get pass the built in filter, so if it didn't work then I'd be out a bunch of money. Second, I wondered if the cheap filters work very well as most of the feedback is about Hoya, etc.

Since I'm using the kit lens, the cheap filter gives me a pretty good look at the minimum IR quality that the K-7 is capable of. If I were using a nice fast prime lens with a higher quality filter I am sure you could achieve some very nice results. It also helps if you know exactly what you are doing with Photoshop, as I am still in the learning phase with post-processing.

I have a 50mm 1:1.7 that I used briefly after I took the images above. At f/2 there was no vignetting and the overall images looked pretty good. However the wind had picked up and every image was pretty blurry, so I haven't processed them. Will try again next week when I get back from an out-of-state wedding.
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