Here I present the initial test results of shooting infrared with a Sony a77 dSLR camera, using a Hoya R72 IR filter.
The Sony is a nice camera for shooting IR, with the tilting screen.
Leaving the camera in Program mode it gave an exposure of 20 seconds, f5.6 and 100ISO in a part cloudy situation but with much of the view in full, though late in the day, sun. You can see the unprocessed result below:
By doing Levels in Photoshop produces a better result:
Lastly a return to Adobe Camera RAW to adjust the settings produces the image below:
If we examine the individual colour channels of this time you can see that the Sony a77 gives a vastly different exposure to the three channels, suggesting the blue filter on the sensor cuts out much deeper into the infrared than I have found common on most cameras recently.
I next switched to manual mode, which I generally prefer for infrared photography with most unconverted cameras. The reason for this is that the metering sensors in most cameras do not have an IR blocking filter, unlike the imaging sensor. Thus the camera always under-exposes in any auto exposure mode.
In manual I tried f4.5, 30 seconds and 100ISO. The lens in these shots in the Sony 11-18mm f4.5 lens:
and switching to 800ISO:
giving a much better result.
Below is a 100% section from the centre of the image so we can just image noise:
We can see noise but it is not too bad considering the ISO and length of the exposure. There was no noise reduction done in ACR.
Switching to the Sony 16-50mm f2.8 lens, here is a shot at f2.8, 30 seconds and 100ISO:
and the individual colour channels:
Again these show the substantial exposure difference between the channels. This means that if you are shooting to do a mono conversion from just one channel you will need to make substantial exposure changes depending on the channel you intend to use.
Below is another shot, this time done at f2.8, 30 seconds and 100ISO:
and a 100% centre section so you can judge noise:
Lastly here is a monochrome image produced from the red channel only after adjustments in ACR:
While this was only initial testing and I will follow up with a full infrared review shortly, I found the a77 to be quite suitable for infrared photography.
In the area around Creswick in central Victoria there are the often large remains of tailings from the gold mines that dotted the area in the 19th Century. These are called Mullock Heaps and mainly consist of overlying rock and quartz.
While to some these are a blot on the rural landscape, to a photographer they present many opportunities for photography. A recent trip there with my converted for infrared photography Canon 350D and a selection of lenses produced the images below. The camera used a custom white balance and I shot in RAW. These were processed in Adobe Camera RAW and then in Photoshop. Most had levels adjusted individually in each colour channel, a slight contrast improving curve and an increase in colour vibrancy.