Canon PowerShot A650 Infrared Samples

We’ve gotten some requests to test the A650 for its infrared capabilities. Though not as sensitive as some older cameras to infrared, the A650s image stabilization and improved higher iso combined create the possibility of handheld infrared using an R72 filter.

With the A650s IS gaining 2-3 or more stops (IS continuous mode) it's possible to get by without a tripod using a Hoya R72 filter in bright sunlight. The settings used for the fastest shutter speeds are f2.8, iso200. This will yield approximately .3 sec shutter speed. You could turn up the iso to 400 or even 800 if you need faster shutter speeds – when you have moving subjects or wind for instance. You can always do some noise reduction in post processing too. When using marginal shutter speeds like this, it’s best to take at least a few shots to improve your chances of getting a crisp one.

The depth of field at f2.8 is surprisingly deep on the A650, though there may be times when you might want to stop down to F4 or 5.6 (when you have objects very close to the camera, as well as distant, and you want everything in focus).

When using a tripod, turn off the IS. I found that about 50% of the time the focus was missed when the IS was activated using a tripod. Once turned off, focus was achieved 100% of the time.

Interestingly, white balance settings have a dramatic effect on sensitivity. When I did a custom WB on some clouds in order to obtain a more B&W look, the shutter speeds were exactly double that of the “sunny” setting. After comparing greyscaled versions of the same image taken with both WB settings at 100%, it appears that the custom WB resolves a little more detail than the sunny WB. If I had a tripod and there was no wind, I would use the custom WB, otherwise I’d use the sunny setting and just post process to the look I wanted.

There’s no apparent central hot spot which affects many modern digital cameras at any aperture.

I know there’s a glitch in the pano – you might have to look at the larger version to find it. My pano bracket wasn’t set up quite perfectly, but considering how close the branches of the camperdown elm were to the camera, Canon Photostitch did a good job of putting 6 vertical images together.

I experimented with the Raynox HD7000Pro too – I sandwiched the 58mm R72 filter between the lens adapter and wide conversion lens. There was a bit of vignetting at full wide, but at one zoom step it was almost gone. (You could also select the “widescreen” aspect ratio to eliminate the vignetting). Even if you could find an 82mm R72 to place on the outside of the wide converter, it would still vignette and the cost would be astronomical. Focus seems to be unaffected in this configuration.

These samples were taken with the Canon G7 since the Canon A650IS and the Canon G7/9 have identical built-in lenses.

Tony

These two samples show different white balance settings.
Sunny WB setting (left) and Custom (right) before processing.