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03-11-2013, 04:06 PM   #1
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K-5 + Lee 87 Infrared Polyester Technical Filter?

I picked up the Lee 87 Infrared polyester filter to try with my K-5 knowing full well that exposures would be very long. However, when I tried out the filter today I was unable to get a decent exposure after 4 full minutes for a scene that metered at 1/125 sec. without the filter. This exposure decrease is way more severe than even the Lee Big Stopper (10-stop ND filter). Anyone else have any experience with this filter on a K-5? Is there an alternative for the Lee system that might be more reasonable in terms of shorter exposure times?

03-13-2013, 08:25 AM   #2
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I would think they will all be like that, or thereabouts.

Best way to do IR is, if you have an old body, get in converted to IR and it will work as if it were an ordinary camera.

The mod is to remove the IR filter infront of the sensor and shim the sensor to allow for the shrter focal length of the IR light.

Bill
03-14-2013, 06:53 AM   #3
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I remember my early attempts at IR photography years ago with a K10D and a Canon XTi. The K10D had a very strong IR blocking filter compared to the Canon. If the K5 has an IR blocking filter anything like the K10D, then multiple minute exposure makes sense. I took a shot in bright sunlight at f/5.6 and ISO 400 for 15 seconds. Luckily the K5 has much lower noise at high ISO settings, so I would suggest bumping up the ISO to 3200.
Still adding a IR pass filter to an unmodified camera usually yields to long exposures. So a tripod is always necessary and any wind will cause trees and other moving objects to be blurry.
The first 11 photos I took in my flickr account were taken with an unmodified K10D. Infrared Photography - a set on Flickr
03-14-2013, 12:33 PM   #4
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QuoteOriginally posted by Eric Seavey Quote
I remember my early attempts at IR photography years ago with a K10D and a Canon XTi. The K10D had a very strong IR blocking filter compared to the Canon. If the K5 has an IR blocking filter anything like the K10D, then multiple minute exposure makes sense. I took a shot in bright sunlight at f/5.6 and ISO 400 for 15 seconds. Luckily the K5 has much lower noise at high ISO settings, so I would suggest bumping up the ISO to 3200.
Still adding a IR pass filter to an unmodified camera usually yields to long exposures. So a tripod is always necessary and any wind will cause trees and other moving objects to be blurry.
The first 11 photos I took in my flickr account were taken with an unmodified K10D. Infrared Photography - a set on Flickr
Very helpful, thanks. Your IR photos are quite impressive. What kind of IR filter did you use? I'm guessing that is was not as strong as the Lee 87.

03-15-2013, 07:32 AM   #5
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The "early attempts" were taken using a Hoya R72 (720nm pass). Actually, the K10D with the CCD sensor was pretty sensitive to UV light, so I was able to just screw on the B+W 403 filter to the lens. The inexpensive Sigma 18-50mm has not much coatings on the glass, that made it possible to get reasonable UV shots without the concern of IR leakage. These are my UV shots: Ultraviolet Photography - a set on Flickr
03-16-2013, 01:05 AM   #6
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QuoteOriginally posted by wjax Quote
I picked up the Lee 87 Infrared polyester filter to try with my K-5 knowing full well that exposures would be very long. However, when I tried out the filter today I was unable to get a decent exposure after 4 full minutes for a scene that metered at 1/125 sec. without the filter. This exposure decrease is way more severe than even the Lee Big Stopper (10-stop ND filter). Anyone else have any experience with this filter on a K-5? Is there an alternative for the Lee system that might be more reasonable in terms of shorter exposure times?
I had only one opportunity to test IR on my K-5 and I was very surprised with the results... especially considering the poor performance with my K20D.

I have successfully tested the K-5 with a 720nm filter (best results) and a 850nm IR filter (needed a longer exposure but still surprising results). Absolutely no modifications are required to capture IR on the Pentax K-5 (unless you need faster exposures).


Here are two examples (note: these are experimental photos and are not considered 'art' by any stretch! LOL):

IR 720nm:

Anyone know why I cannot post Flickr inline image attachments here?



http://www.flickr.com/photos/9776782@N02/8018117889/in/set-72157631608601333/

IR 850nm:



http://www.flickr.com/photos/9776782@N02/8018121470/in/set-72157631608601333/
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