How to shoot IR with K-x, K-5.

Started Mar 21, 2012 | Discussions thread
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SRT201
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How to shoot IR with K-x, K-5.
Mar 21, 2012

I recently figured out how to optimize my K-x settings for shooting IR using a standard R72 filter. I have always used my Olympus E-420 for IR as the 420 brightens it's liveview making it easy to frame shots without all the fuss of removing the filter, re-focusing, etc. You can probably use very similar settings on a K-5. I don't know how sensitive the K-5 imager is to IR though.

For shooting IR all that is required is a decent R72 filter that blocks almost all visible light and a camera that is reasonably sensitive to IR. Once that filter is on though your viewfinder becomes black and useless. NEVER look at the sun through the VF!

Here's how I setup the K-x with Liveview to compose my IR shots WITH an IR filter attached.

Using the Custom Image settings, you can coax the K-x into giving you a useful Liveview image. Also, the K-x Liveview CDAF system works rather well with an R72 filter. This is very important as IR light focuses differently than visible. If you focus your camera and then place an R72 filter over the lens the resulting shot will be significantly out of focus!

If you just pop an R72 on the front of your K-x and turn on Liveview all you will see is a very dark red image that is next to impossible to use in outdoor lighting for framing a shot.

So, here's the setup that will make things easier.

  • Set the camera for RAW+JPG. You HAVE to shoot RAW for IR.

  • Set the Liveview focus mode to CDAF (the B&W circle icon)

  • Set the LCD brightness to full

  • Set the AF to single center point

  • Set the AF/AE-L button to mode 2 in the Custom Settings Menu. This turns off AF for the shutter release button and uses the AF/AE-L button for locking focus.

  • Turn SR off as you will be using Liveview for framing and SR really chews up the batteries.

  • Shut off most of the liveview information like histograms as they are useless for shooting IR and make it more difficult to see the LCD image.

  • Set the drive mode to 2 second delay which locks up the mirror before shooting. You can also use the remote but make sure you are using the mirror lockup to avoid any loss of detail due to mirror vibrations.

  • Set your image preview time for a few seconds with the histogram. Having the image pop up immediately with the histogram saves a lot of time finding the proper exposure.

  • Pick the B&W Custom Image mode and make the following adjustments to it. These changes are designed to optimize the live image on the LCD for framing while shooting.

1 - Color filter set to Red. This is done to emphasize the red channel in the live image (that's where almost all of the information is being recorded anyhow). You can also try the simulated IR filter setting as well to see which gives you a brighter LCD image.

2 - Hi-key adjustment should be set to FULL Hi-Key (+4 all the way to the right).

3 - Contrast set to lowest setting (-4). Again this is to optimize the brightness of the liveview image.

You may be questioning how these adjustments will end up creating a decent JPG file. They won't. The JPG's will be throw-aways BUT the whole point here is to make the Liveview image on your LCD bright enough to frame and focus WITH the IR filter mounted.

Once you've done this you should get a usable Liveview image on your LCD so that you can see and frame your scene. In many cases you will need to help the AF system by pre-focusing on a high contrast target. Point the center focus point at something at your chosen focus distance with high enough contrast that it can easily be seen on the LCD. Press the INFO button to zoom in a few times. Press the AF/AE-L button to allow the CDAF system to lock focus. In most cases it will lock but you may have to try a few targets if your light is marginal. Once your target is locked, recompose as usual. Having a nice ball head on your tripod is handy.

When shooting in IR your red color channel is the most important since almost all the exposure takes place in red. You should never allow the red channel to clip when shooting IR (or any other time for that matter). When the K-x combines all channels to get the final B&W luminance histogram your peak values will still be those produced originally in the red channel so the luminance histogram should give you all the information you need to avoid clipping (blown highlights).

As for exposure... you are going to have to go manual. The AE system will NOT work. Set your aperture for desired DOF and adjust your shutter speed until you get the histogram of your last shot bumping up against the right side of the graph without hitting it.

Yes, you can actually get some handheld IR shots with the K-x if you push the ISO up to 400 and beyond but really... IR requires a tripod. Plan on using one to get the best results.

After this of course you have to do some work on your VERY red raw file to come up with either an interesting false color or B&W image. It's well worth it and isn't difficult once you get the hang of working with IR.

This works for an R72 filter that starts to roll off around 720nm. If you go with a deeper infrared filter like an 87 I really don't know if this will work as there is an even heavier cutoff to visible and deep red. The image on the LCD would likely be much harder to see and the AF might not work at all.

For more info... Here's an excellent source
http://www.wrotniak.net/photo/infrared/

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Life is NOT measured by the "moments that take your breath away" anymore than books are measured by the number of exclamation marks. The whole picture matters.

Olympus E-420 Pentax K-5 Pentax K-x Ricoh Caplio R7
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