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03-01-2014, 09:10 PM   #1
Edward Kay
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monochrome infrared with the K-3

all my monochrome infrared in the past has been taken, using my Mamiya 6x7 rangefinder camera...I am new at trying to get similar monochrome infrared on my new Pentax K-3.....do you have to use a R-72 filter on the front of the lens like I do on my film cameras...or can you get similar results, using camera only....do not really understand digital.....cheers Edward

03-01-2014, 09:15 PM   #2
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You would have to do a longer exposure, but you can do an IR filter ont eh lens.
03-02-2014, 12:12 AM   #3
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There are a variety of filters ranging from 670nm through 900+nm. The colors range from red through blue as the numbers go up. You might have to stack two filters to get the density you want.
03-02-2014, 05:43 PM   #4
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Post processing are amazing these days.

03-03-2014, 04:52 PM   #5
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The problem with ir on a digital camera is that, as with a film camera, you put a filter on the lens that theoretically lets only ir spectrum light pass through; but unlike on a film camera, that light then encounters a filter who's purpose is to stop ir light from reaching the sensor. It's a bit like trying to see through 2 polarizer filters turned 90 degrees to each other.
03-04-2014, 01:44 AM   #6
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QuoteOriginally posted by Parallax Quote
The problem with ir on a digital camera is that, as with a film camera, you put a filter on the lens that theoretically lets only ir spectrum light pass through; but unlike on a film camera, that light then encounters a filter who's purpose is to stop ir light from reaching the sensor. It's a bit like trying to see through 2 polarizer filters turned 90 degrees to each other.
True. With an unmodified camera, you need dense filters and long exposures.
I modified a Nikon D70 for full-spectrum. The camera was cheap. The replacement sensor-glass wasn't.
With a good neutral density filter and one of various IR spectrum filters, I get pretty good results in daylight.
The problem arises with getting the filter density you need and getting it with only one or two filters. That means getting all of your neutral density in one filter and all of your IR spectrum filtering in one filter. When you stack on the third or fourth filter, you get vignetting. You can get around this by using a zoom, but you still lose scenery.

If you have to stack a bunch of filters, just crop the image when you're done.
03-04-2014, 08:01 AM   #7
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I used to get okay results on my K5 with dropping the ISO and doing a longer exposure with a good IR filter. Watch which lenses you use because some get hotspots.
03-04-2014, 08:06 AM   #8
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Here's an example taken with the K5, and here is what I used for settings:

Shutter Speed -1/2 second
Aperture - F/8.0
Focal Length - 20 mm
ISO Speed - 1600
Name:  ohioriverir.jpg
Views: 273
Size:  198.3 KB


Last edited by VoiceOfReason; 03-04-2014 at 08:08 AM. Reason: formatting errors
03-30-2014, 06:09 AM   #9
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QuoteOriginally posted by Edward Kay Quote
all my monochrome infrared in the past has been taken, using my Mamiya 6x7 rangefinder camera...I am new at trying to get similar monochrome infrared on my new Pentax K-3.....do you have to use a R-72 filter on the front of the lens like I do on my film cameras...or can you get similar results, using camera only....do not really understand digital.....cheers Edward
I used to do infrared shots on my Pentax *ist and my Pentax K7 using R-72 filters. The difficulty came when composing the shot because absolutely nothing was visible in the viewfinder. I would either use a tripod and compose the shot without the filter, then screw it on and take the shot - OR just trust to luck and point the camera at the scene (ok with wide angle).

When I got the K7 the *ist was redundant so I sent it away to Advanced Camera Services in Norfolk to be modified for infrared exclusively. I'd read this artice Convert your Digital SLR to Infrared which went into the subject in more detail. I recently purchased a Tamron lens AF18-200 for 132 to use with the *ist body. There are shots taken with this kit on the following pages East Lothian page 13 and East Lothian page 14 - the second page is exclusively infrared with 26 photos at different focal lengths.

With the modified camera I can compose the shot in normal colour in the viewfinder. I use Program mode on the dial but I sometimes underexpose by a full stop. The preview image on the camera's LCD screen is monochrome red but it can tell me if I need to reshoot at a different exposure. Because foliage appears white it's often necessary to underexpose to get detail. Shooting in RAW mode is a big help later. I remove the saturation and adjust white and mid levels to get good contrast.

Sample picture from Aberlady Bay Nature Reserve

and one showing the Bass Rock, the beach at low tide and North Berwick Law
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