[Bob 256]

I just got my K-1 and want to explore some IR photography. Although the K-1 sensitivity to IR is low, it does produce pretty usable imaging with fast lenses and a time exposure. My main question is however, what is a good source for IR filters? I would like to get a source for thin film filters since one of my lenses requires a behind the lens filter and only a thin film would work. In looking at Wratten filters, I got sticker shock since my last purchase quite some time ago when they could be had for not that much. The 3 inch is going for almost $100US now!! I've got front-of-the-lens filters pretty much covered.

Anyway, suggestions would be appreciated.

[Medex]

I just got my K-1 and want to explore some IR photography. Although the K-1 sensitivity to IR is low, it does produce pretty usable imaging with fast lenses and a time exposure. My main question is however, what is a good source for IR filters? I would like to get a source for thin film filters since one of my lenses requires a behind the lens filter and only a thin film would work. In looking at Wratten filters, I got sticker shock since my last purchase quite some time ago when they could be had for not that much. The 3 inch is going for almost $100US now!! I've got front-of-the-lens filters pretty much covered.

Anyway, suggestions would be appreciated.

I did try IR photography with IR72 filter on the lens and K-1. You allways need tripod, higher ISO, e.g. ISO 3200, f2,5 to acquire 1/13 second exposure time (not reasonable for mooving objects or mooving trees) and you can't see nothing through viewfinder. Just using LiveView. Quality of Live view picture is not good - too much noise. Pictures are little bit grainy.
The best way is converted Pentax APS-C camera. I did it by my self (K-30) - 640 nm filter. Simple glass filter costs about 20 euro S(tock Optics). If you are not able to do conversion yourself, there are servises available (about 150 euro maybe).
Here are some samples made with K-1:
http://www.efoto.lt/node/1185737
http://www.efoto.lt/node/1192454 (manipulation)
and witk converted K-30:
http://www.efoto.lt/user/56297/nuotraukos/serijos?serija=barcelona_infrared

[TER-OR]

If you do the conversion, keep in mind that not all lenses perform equally in IR. Some cause hotspots. There's a little information about this online.
If I had an extra couple thousand laying around I'd get a full-spectrum or UV converted camera and have some fun with flowers etc. I wonder how a K-01 would do in that role?

[Yoda boy]

I did try IR photography with IR72 filter on the lens and K-1. You allways need tripod, higher ISO, e.g. ISO 3200, f2,5 to acquire 1/13 second exposure time (not reasonable for mooving objects or mooving trees) and you can't see nothing through viewfinder. Just using LiveView. Quality of Live view picture is not good - too much noise. Pictures are little bit grainy.
The best way is converted Pentax APS-C camera. I did it by my self (K-30) - 640 nm filter. Simple glass filter costs about 20 euro S(tock Optics). If you are not able to do conversion yourself, there are servises available (about 150 euro maybe).
Here are some samples made with K-1:
Infrared - Baluo?o gl?byje
Infrared - Ruoniukai (manipulation)
and witk converted K-30:
_«M.G»_

I would like to see an article on taking IR photos. Likelihood would be with a common lens and either a K3 or K1 camera. I suspect that a lot of readers would be interested in this.

[pcrichmond]

You can find 3x3 or 4x4 polyester sheet by LEE at BH for between 16 & 30/US. Only comes in 87 or 87C. I use a full spectrum converted K-01 for IR and love it. Mostly use screw on filters for 720 or below. I do have the LEE 87 in sheet with Cokin setup for B/W work. I have seen some Wrattan 70 on ebay for around 40US. Enjoy, IR is such a fun world.

[Bob 256]

Many thanks prichmond - that's what I was looking for - will check out the LEE filters at BH. I considered making my own gelatin filter material as I have the dyes for IR but not the knowledge on making the hardened gelatin. I vaguely remember something about pouring the gelatin onto a sheet of glass but nothing else technical about their production. That might be fun if anyone knows where I can get that info. Apparently Tiffen has taken over the old Kodak Wratten business, but they have priced their product into the stratosphere.

I used one of the K-1 digital "filters" to convert a regular photo to "IR" and it did amazingly well - skies came out dark and vegetation came out whitish just like an IR photo (although I know it is in no way a true IR rendering). It might fool some people at first look.

I did a fair amount of IR photography back when IR film was readily available from Kodak and others. It was sensitive enough to use with conventional exposures but pretty grainy and low resolution. Having an IR photo with the resolution of the K-1 should look great but there are compromises I know. At this point, I lack the funds for a converted camera but I would like to see what the K-1 can do given its limitations.

I'll post some K-1 IR photos here when I get them.

Thanks folks.

[pcrichmond]

If I had the funds, I would probably buy a separate K1 just for a conversion also. Just doesn't feel right to convert the one I have. Being able to see and focus in IR via liveview on the K-01 is such an advantage over the old film days, let alone the faster exposures possible. Perhaps if Pentax comes out with a full frame mirror-less, I might have to reconsider.
Let us know if you make any of your filters, sounds like a great DIY. I would love to have a few 720 sheets for behind the lens filtration also.

[Bob 256]

If I had the funds, I would probably buy a separate K1 just for a conversion also. Just doesn't feel right to convert the one I have. Being able to see and focus in IR via liveview on the K-01 is such an advantage over the old film days, let alone the faster exposures possible. Perhaps if Pentax comes out with a full frame mirror-less, I might have to reconsider.
Let us know if you make any of your filters, sounds like a great DIY. I would love to have a few 720 sheets for behind the lens filtration also.

Ditto. IR can produce some striking images which would be even more striking if done with 36 M pixels.

I'm going to play around when I get a little time, and try to make a gelatin filter. I have an IR spectrophotometer to check the transmission and will see if I can get close to the 87 or 87C IR filter curves. As I mentioned, I'm not sure about casting the filters and hardening them so they can be lifted off a glass substrate - will go with some trial and error methods to begin unless some one in the know chimes in. I'll be glad to post some notes if I'm successful - might be a month or so.