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Shooting an Infrared Image

Corker2211
Posted 07/06/2011 - 12:39 Link
Greetings from the USA.

Without going into a whole lot of detail, I tried using a cheap IR Filter with my K100D a while back. Never could get the hang of it. Pictures came out darn stupid, so I stopped trying.

Would using a Hoya R72 Filter make any difference with my K100D or do you have to have it modified for that, which I don't want to do. Infrared has always been an interest for me, but just never could get it right.

Regards,
Les
"Those who do nothing . . . make no mistakes in Life"

http://s404.Photobucket.com/home/Corker2/index

I'm just full of questions . . . It's the only way I learn anything! I have so, so, much to learn using my Pentax K100D DSLR
grahamwalton
Posted 07/06/2011 - 13:02 - Helpful Comment Link
I would guess that the K100d would be partially sensitive to infrared.
To use an unmodified camera for infrared, mount the camera on a tripod and frame and focus the subject. Set f8 at 1/8 sec, screw on the infrared filter and take an exposure. Repeat taking exposures at different shutter speeds until you get an image that is red but detailed.
On your computer, convert the image to monochrome and adjust levels and brightness until you are pleased with the result.
You are taking the image blind and the whole process is hit and miss. However, the results can be rewarding.
Friendly Regards
Graham
Edited by grahamwalton: 07/06/2011 - 13:02
Posted 07/06/2011 - 13:34 - Helpful Comment Link
Also bear in mind that the focus will be different with IR light so if you are relying on autofocus it will be out. Some older lenses have an IR focus scale but otherwise you might want to manually adjust the focus by trial and error after you have the exposure right.
You will only prise my 43Ltd from my cold, dead hands...
johnriley
Posted 07/06/2011 - 13:35 - Helpful Comment Link
With Photoshop you can make a pseudo-infrared image out of any file.

Use Channel Mixer. Selecte Monochrome. Increase red and green, reduce blue to virtually nothing and tweak the red and green to get the contrast right.

Here's an example from my EPZ K-r review:
http://www.ephotozine.com/articles/pentax-k-r-14989/images/pentax_kr_pseudo_IR.j...
Best regards, John
grahamwalton
Posted 07/06/2011 - 15:05 - Helpful Comment Link
This photo is an example of infrared photography on an unmodified Pentax DSLR, using an R72 filter.
https://www.pentaxuser.com/images/gallery/2010/03/normal/blowing-in-the-wind_126...
Friendly Regards
Graham
Anvh
Posted 07/06/2011 - 19:18 Link
grahamwalton wrote:
I would guess that the K100d would be partially sensitive to infrared.

There is a filter infront of the sensor that filter IR out sadly

I've the same problem with the K10D but if it's a sunny day and you got a tripod you can do IR photography but it takes quite some long shutter times.

This an IR i'm happy with.
http://fc04.deviantart.net/fs40/i/2009/359/2/a/A_Differend_View_by_Anvh.jpg
Stefan
Comment Image

K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
johnriley
Posted 07/06/2011 - 22:11 Link
The IR blocking filter is stronger on some cameras than others. The K-r and K-5 seem to be better for pseudo-IR images than the K10D or K20D.
Best regards, John
petrochemist
Posted 07/06/2011 - 23:00 - Helpful Comment Link
Anvh wrote:
grahamwalton wrote:
I would guess that the K100d would be partially sensitive to infrared.

There is a filter infront of the sensor that filter IR out sadly

I've the same problem with the K10D but if it's a sunny day and you got a tripod you can do IR photography but it takes quite some long shutter times.

The K100d has quite a weak hot filter (the one in front of the sensor) It's not difficult to get shutter speeds that can be hand held even with the kit lens. (Playing around last week I took an indoor 720nm IR portrait at 0.7s f5.6 200ASA that was reasonably exposed - slight camera shake, but that would have been fine at 800ASA)
Getting them properly in focus is more of a problem, as IR focuses at a different point then visible light. This difference varies considerably from lens to lens
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.

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Anvh
Posted 08/06/2011 - 18:39 Link
That's great to hear then, i'm curious how it is with the K5....
Stefan
Comment Image

K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
johnriley
Posted 08/06/2011 - 18:46 Link
Both the K-r and K-5 seem to be better for IR-like images than the K10D/K20D.
Best regards, John
Anvh
Posted 08/06/2011 - 19:21 Link
johnriley wrote:
Both the K-r and K-5 seem to be better for IR-like images than the K10D/K20D.

johnriley wrote:
The IR blocking filter is stronger on some cameras than others. The K-r and K-5 seem to be better for pseudo-IR images than the K10D or K20D.

Double post John?

But in all seriousness i'm curious about how much better it is.
Stefan
Comment Image

K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
Edited by Anvh: 08/06/2011 - 19:21
johnriley
Posted 08/06/2011 - 22:42 Link
You asked the question again Stefan, so I answered it again....
Best regards, John
Anvh
Posted 08/06/2011 - 23:09 Link
johnriley wrote:
You asked the question again Stefan, so I answered it again....

Not really it's just that i missed a word and we can't edit these days anymore...
Behind how it was the idea to put much but i forgot that so the question indented was different, the same item but more specific.
Just need to try it out i guess...

Anvh wrote:
That's great to hear then, i'm curious how it is with the K5....

Stefan
Comment Image

K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
Edited by Anvh: 08/06/2011 - 23:10
Anvh
Posted 08/06/2011 - 23:11 Link
petrochemist wrote:

Getting them properly in focus is more of a problem, as IR focuses at a different point then visible light. This difference varies considerably from lens to lens

I thought you could just focus through the filter now that i think about it?
Stefan
Comment Image

K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
johnriley
Posted 08/06/2011 - 23:19 Link
OK, K10D and K20D - very poor for IR. K-r and K-5 very good for IR. This of course relates to using the cameras as-is and creating the IR effect in Photoshop.

As for focusing proper IR through an R72 filter, lenses are not corrected for IR so the focus will be quite some way out. IR correction markes on older lenses are for 720nm films and still need further correction if 950nm films are used with an R95 filter. How this relates to digital I'm not sure, but using manual focus and LiveView could be the answer.
Best regards, John

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