POTD 14 May 2014 - What Lies Within

[Mike Farley]

We're into May and I have not done any infrared so far this year, until now.

[Sam,anthaBriscoe]

Hi Mike,

I enjoy the infrared images you produce, I loved the trees you had in the annual exhibition.

How do you do these images? Do you have special dedicated camera or some kind of add on for your regular kit?

[Mike Farley]

Hi Sam

Thanks for the feedback. Naturally I am delighted that you are enjoying my IR work.

I use two cameras, with the main one being a modified Canon EOS 450D with a 720 nm filter. with which this image was made. The advantage being that I can shoot normally as exposure times are comparable with a conventional camera and AF is adjusted for IR during the conversion process. 720 nm is the Goldilocks option for IR filters as it is just above the upper limit of the visible spectrum.

The other camera I use is one where the manufacturer messed up and did not fit a sufficiently strong IR blocking filter. This means that I can put an IR filter on the lens without having too much of an adverse effect on exposure times and can still handhold. Being a rangefinder rather than a DSLR, there is a separate viewing system and I can frame my shot with the filter attached. Everything is manual focus and I make an adjustment before shooting. This how I started with IR as I already had the camera and only needed to purchase the filter when I wanted to experiment.

At some point, I will be converting my Panasonic G3 so that it has a clear full pass filter which will mean it can natively record all parts of the spectrum of which the sensor is capable. It's more flexible than modifying a DSLR which has to have the IR filter permanently in position as I can put appropriate pass and block filters on the lens to achieve the effect I want, with the EVF giving a preview. Fitting a UV/IR block filter, I can even use the camera normally. The G3 has contrast detect AF via the sensor which means focussing adjustments for different wavelengths are applied automatically. I will be using Protech to undertake the modification.

It is possible to use an IR filter with a normal camera, but exposure times will be long due to the IR blocking filter in front of the sensor. A tripod will be necessary and using a higher ISO also helps. Although I have not tried it myself, it should be possible to compose and focus using liveview, avoiding the necessity to remove the filter to frame the scene and then replace it to make the shot. This is a good option for occasional use or anyone interested in trying IR photography without too much financial outlay.

A while back I did a presentation at the club about infrared and there is a follow up thread on the forum which has some further information.

viewtopic.php?f=2&t=243

[Nina]

Like this one a lot Mike. Reminds me that I haven't done anything about converting my old Sony 717 for infrared. I must remind myself what I need to do and try it out.