We test an unmodified Sony A100 dSLR camera with a Hoya R72 IR filter to see how it performs for infrared photography.
The Sony A100 is an interesting camera in many ways. We wanted to see how it performed in the infrared part of the spectrum.
To do this we took a Sony A100 out with the standard kit lens and a heavy duty Manfrotto tripod. We used a Hoya R72 infrared filter to shoot a series of tests.
A RAW image, 30 seconds, f5.6 and 100ISO
The Red channel
The Green Channel
The Blue Channel
The obvious thing you can see from the above unprocessed channel images is that, compared to other cameras we have tested, the Sony A100’s Bayer filter (and perhaps the IR blocking filter) interact very differently with the Hoya R72’s filtration than we are used to seeing. The green channel is very underexposed, yet with most other digital cameras this is our preferred channel to use.
Below we show the above channels processed in Photoshop to stretch the exposure histogram as much as possible whilst minimising clipping.
Now to look at image noise we took a series of shots at varying ISO and show you the red channel. Please note that our favored test location has willow trees and in some shots becaus eof high winds at the time there are blurred willow branches in the shot. This doesn’t detract from the ability to judge image noise.
100ISO 15 sec f3.5
200ISO 8 sec f3.5
400ISO 4 sec f3.5
800ISO 2 sec f3.5
1600ISO 1 sec f3.5
As you can see, even though the exposure duration is reducing as we go to higher ISO settings, the noise level still ramps up very quickly. Now noise is not necessarily bad, and can be used for great creative effect, you just need to know how your camera behaves.
The Sony A100 is certainly capable for taking some interesting IR shots. Some of the following images were taken from the red channel and some from the green.