View Full Version : infrared filter
FocusOn
05-03-2014, 8:59am
Hello!
I'm thinking about buying an infrared filter but there are so many choices available!
Does anyone know if the IR IR720 give me the snow covered woods type look?
Thankyou!
I'm not thinking of doing it yet, but it is on my mind possibly in the future, with a second hand cheap DSLR and wondering about the sensor if there are changes at that level as well. from what I've read there is a filter to be removed and or replaced and so I am intrigued with this thread as well.
arthurking83
05-03-2014, 10:51am
You don't need to remove the internal IR filter for IR captures.
The only reason for removing it, is for shorter exposure times. That is IR at handheld shutter speeds.
The internal IR filter simply acts as a blocking filter, and if you use an IR(pass) filter like an r72, then you're in a fighting match between the pass filter and the blocking filter. It still works, but just needs more time to expose. The internal IR block filter has a blue appearance. Unless you're a dedicated tinkerer, just leave it.
If your plan is to remove the camera's IR block filter, two options for this process are:
1. replace the filter with a dedicated IR filter, which makes the camera permanently IR only(I'm thinking of doing this to my D70s)
2. replace the filter with a clear glass filter, which makes it broad spectrum! If you do this, you may then need added filters on your lens to eliminate wavelength contamination for exposures.
*note! if you do decide to remove the filter in the camera, a replacement must be installed, otherwise you won't achieve any focus with your normal lenses! This filter is part of the optical path to the sensor.
R72(or any 720nm) pass filter will give you that while foliage look in your images.
BUT!! note that it is a process look. You won't really ever see it straight from the camera, unless your camera has the ability to process images in a specific manner.
Tutes abound on the net for how to get this snow look ... it's about colour channel swapping or some other photoshop processes.
I think what they generally tend to do is to slide the channel sliders from red to blue and blue to red .. or variances within those two steps.
Note that when you shoot IR on a colour capable medium, it basically is just red! .. once it's whitebalanced properly. if you camera is set to auto WB, the camera may respond to the all red filter, by adjusting WB which then makes the image look a bit brownish or mauve. This effect is basically inconsistent. It could depend on the camera being used and how it's AWB system works.
But for best results, don't worry too much about WB, shoot raw and WB later in your raw convertor.
Some foliage may come out looking snow white in a simple edit of the image, but this is no guarantee. it depends on the foliage, it's condition and the exposure made.
FocusOn
05-03-2014, 12:04pm
Thankyou arthurking83!
I'll muck about in photoshop for a bit and see how it goes!
Warbler
05-03-2014, 1:19pm
These folks do very good work:
http://www.lifepixel.com/
I've used them personally to replace a damaged High Pass Filter with a standard one, and another photographer here has ab old Canon 10D converted by them. They do various types of conversion, but once you've settled on one, you can't change your mind. You can of course simply convert to B&W to remove "false colour".
Click on the embedded video:
http://www.lifepixel.com/infrared-filters-choices
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