pentax kr and a Hoya R72 InfraRed filter


jkdlee

Link Posted 02/04/2011 - 22:46
hello guys. i would really like to have a go at infrared photography and create those dream like pictures like this image here.
link
ive seen tutorials on youtube on how to create these images which is fine but all i want to know is that if the pentax kr is sensitive to infrared light and capable of taking these pics? is the hoya r72 filter a good choice? and does anyone have any experience with infrared photography using pentax dslr's?

(image removed and replaced with a link to avoid copyright imfringement)
just a newbie with a good eye
Last Edited by the Moderator Team on 04/04/2011 - 10:55

karma mechanic

Link Posted 02/04/2011 - 23:08
Regarding IR sensitivity the sad truth is that older is better. The generation of cameras that includes the *ist DS allows IR shots to be handheld, while the K10D needs many seconds exposure. In each generation of camera the strength of IR filtering tended to be greater and the exposures got longer.

The K-5 can just about do it handheld, but using very high ISO speeds to overcome the insensitivity. I don't know specifically how the k-r gets on, but it is unlikely to be feasible without a tripod. The R72 filter does let a small amount of visible light through, so works well on an insensitive camera.

The picture you showed may well be done using a modified camera, in which case relatively normal exposures can be used without a tripod. These are cameras where the filter that normally blocks the IR has been removed. That picture looks like the sort where the 'false colour' IR picture is rendered more lifelike by swapping certain colours. Personally I favour rendering it as monochrome, all of mine are taken on a Sony camera which I modified myself, using normal shutter speeds. I have yet to get anything worth keeping from the Pentaxes, but then I already have a suitable tool with the Sony...

With a good tripod it is certainly worth experimenting. You'll get pictures that are very red, but adjusting for a more lifelike balance or converting to monochrome is easy. Definitely worth a try, just determine the exposure using trial and error and the histogram. Grass and leaves give lots of IR, while stone gives very little. Sunshine is good. Palm trees give the most pronounced effect. Shadows tend to be very dark since they are lit mainly by the blue sky which has almost no IR.

Some of mine are here: http://www.infrared.webspace.virginmedia.com/Infra-Red/index.html
My own website is www.richardgaddphotography.com

Also on 500px

jkdlee

Link Posted 02/04/2011 - 23:37
thanks for the helpful advice. yeah i have read that u need long exposures with these new generation of cameras unless u modify it. nonetheless i will still buy the filter and just experiment with it. i dont mind using a tripod nice pictures btw. i like the black and white versions too. cheers
just a newbie with a good eye

johnriley

Link Posted 03/04/2011 - 01:38
I tested the K-r for |EPZ and the IR perfomance looked encouraging. I only tries using Channel Mixer inb Photoshop, but it looked as though there was some potential for IR phgotography.
Best regards, John

jkdlee

Link Posted 03/04/2011 - 20:26
johnriley wrote:
I tested the K-r for |EPZ and the IR perfomance looked encouraging. I only tries using Channel Mixer inb Photoshop, but it looked as though there was some potential for IR phgotography.

thats good to know. thanks
just a newbie with a good eye

karma mechanic

Link Posted 03/04/2011 - 21:41
Here's a test shot on the K-5 and R72 filter to give an idea. Overcast, exposure was 8 sec at f/5.6, ISO 800:



Same thing without the filter, 1/200th at f/5.6, ISO 800:



For the IR one I used 'click white' in Bibble to get the white balance from the old sink in the background, it gave a colour temp of 1666K to render it the way you see. Apart from changing the colour temp it is just the raw file, no other modification. For the unfiltered one the temp came out as 5338K.

Exposure difference due to the filter is a factor of 1600, so between 10 and 11 stops.

Ok, they aren't very dreamy, but they do show the effect...
My own website is www.richardgaddphotography.com

Also on 500px

jkdlee

Link Posted 04/04/2011 - 23:43
thanks for that karma! hopefully the kr will produce near similar results. ill post again wen i receive my filter

cheers
just a newbie with a good eye

petrochemist

Link Posted 05/04/2011 - 10:32
One quick check you can do to investigate IR sensitivity of a camera is photographing a TV remote (being used)
If the camera is sensitve you see a bright spot where the remote is sending it's signal.
I checked my K100d with this before splashing out 10 for a R72 clone.
Mike
.
Pentax:K5ii, K7, K100D, DA18-55, DA10-17, DA55-300, DA50-200, F100-300, F50, DA35 AL, 4* M50, 2* M135, Helicoid extension, Tak 300 f4 (& 6 film bodies)
3rd Party: Bigmos (Sigma 150-500mm OS HSM),2* 28mm, 100mm macro, 28-200 zoom, 35-80 zoom, 80-200 zoom, 80-210 zoom, 300mm M42, 600 mirror, 1000-4000 scope, 50mm M42, enlarger lenses, Sony & micro 4/3 cameras with various PK mounts, Zenit E...
Far to many tele-converters, adapters, project parts & extension tubes etc.

.[size=11:].Flickr WPF Panoramio

jkdlee

Link Posted 05/04/2011 - 12:22
petrochemist wrote:
One quick check you can do to investigate IR sensitivity of a camera is photographing a TV remote (being used)
If the camera is sensitve you see a bright spot where the remote is sending it's signal.
I checked my K100d with this before splashing out 10 for a R72 clone.

too late! the filter came in today! hehe. thanks anyway will try it on asap but the weathers not looking good today..
just a newbie with a good eye

jkdlee

Link Posted 07/04/2011 - 00:25
the weather looked good today no??
so i went to regents park and finally tried out infrared photography.. boy its addictive! here are my first attempts






i am happy that the kr is capable of taking decent inrared pics but not so happy about the horizontal/vertical streaks u can see. all the pics i took had these streaks in it and all in the same position. it really affects the picture does anyone have a clue what causes this? the filter? the lens? the sensor??
just a newbie with a good eye
Last Edited by jkdlee on 07/04/2011 - 00:27

karma mechanic

Link Posted 07/04/2011 - 07:14
The streaks are caused by the light that comes in via the eyepiece. This has an effect because the exposure is so long for the light that comes in through the lens, the tiny amount of light that leaks through the eyepiece gets to make an exposure.

You can either use the little slide-in eyepiece cover, or just shade the eyepiece with your hand.

Apart from that little glitch you appear to be getting the hang of it - very impressive!
My own website is www.richardgaddphotography.com

Also on 500px

johnriley

Link Posted 07/04/2011 - 09:02
The second shot has great potential but could do with being sharper.

Black and white IR images are more usual, but in this case the colour makes for an attractive shot.
Best regards, John

jkdlee

Link Posted 07/04/2011 - 15:23
thanks for the comments! i will try that. much appreciated
just a newbie with a good eye
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