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ISO Accuracy

The actual sensitivity of each indicated ISO is measured using the same shots as are used to measure ISO noise levels, we simply compare the exposure for each shot to the metered light level (using a calibrated Sekonic L-358), middle gray matched. We estimate the accuracy of these results to be +/- 1/6 EV (the margin of error given in the ISO specifications). Note that these tests are based on the sRGB JPEG output of the cameras, in accordance with ISO 12232:2006, the standard used by camera manufacturers.

By our tests, the G15's measured sensitivities are about 1/3 stop lower than indicated across the ISO range (i.e. images are fractionally darker than expected for any given set of exposure values). A discrepancy this small has little practical impact in real world use.

Noise and Noise Reduction (JPEG)

Note: this page features our interactive noise comparison widget. By default, we show you the default noise reduction settings of the camera tested, and three other models of the same class. You can select from all available NR options, and from other cameras. The 'tricolor' patches beneath the familiar gray/black/portrait images are taken from the same test chart, and show how noise impacts upon blue, green and red areas of a scene.

ISO range noise comparison

In terms of measured JPEG noise the Canon Powershot G15 maintains relatively low levels of both luminance and chroma noise up to ISO 1600 before increasing significantly at ISO 3200 and beyond. However, when looking at the sample shots it becomes obvious that some of this 'image cleanliness' is being paid for by a loss of detail at higher sensitivities. That said, Canon's approach to noise reduction if fairly well balanced. The images show comparatively little chroma noise up to higher sensitivities while some luminance noise is tolerated. This gives the G15 high-ISO output a grainy appearance that is not too dissimilar to film grain, and much preferable to the 'blotched' noise than can be seen on some other small-sensor cameras.

Overall the Canon performs very well for a camera with a 1/1.7" sensor. If you want visibly better high ISO results in a small package you'll have to invest in a compact camera with a larger sensor, such as the G1 X or Sony RX100. That said, both these cameras haven't got lenses as bright as the G15's, which means you can keep the ISO down for longer on the latter.

Raw noise (ACR 7.3 RC noise reduction set to zero)

As usual, looking at the Adobe Camera Raw results gives a pretty clear explanation of the JPEG results. With noise reduction in ACR set to zero the noise level curve is much steeper than for the out-of-camera JPEGs. Some noise is visible even at base ISO but both chroma and luminance noise become quite intrusive at ISO 400. Of course much cleaner results could be achieved by applying a customized noise reduction mix in your raw converter.

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Comments

Total comments: 4
BobFoster

I had an Oly XZ1 for about a year and then sold it. The IQ was good and the lens sharp but I found the sensor noise not good at high ISOs, the video awful, the handling a bit awkward (esp the lens cap and lack of grip), no viewfinder etc. I have just purchased the G15 at a considerably reduced sale price here in Oz and couldn’t be more delighted. It handles well, has great low light performance, bright sharp lens, good video and handling is good. As a complete package, it’s basically everything I wish the XZ1 could have been.

1 upvote
karlowac

I got myself one of these 3 months ago at a store sale. They were making room for G16 so the price was lowered to less than EUR300 (a bargain, compared to G16's EUR430). I had thrashed my old Canon P&S just two days prior so I was in the market for an inexpensive replacement (read EUR100 to EUR200 tops).
All I can say is: I payed a little bit more but got more than I ever expected.
It is an incredible little camera, I fell in love with it.
It is compact but beats my Canon 500D in some areas.
With quality lighting in place I can barely tell the IQ difference between those two physically totally different cameras.
I can't imagine anyone ending up disappointed with this little gem.

0 upvotes
Matte Steven

Have to say, G15 is a classic DC in last years.

0 upvotes
Gary R.

It's an interesting list of "cons" here. I've had cameras with articulating screens, and found I really didn't use them all that often, so really don't consider it much of an issue either way. "No automated panorama mode", again, is a plus to me. The stitch-assist features are very useful for producing high resolution panoramas with user control if things don't stitch perfectly the first time (where the 'auto' ones fail so often, I feel they belong on camera phones and low end point and shoots, not on enthusiast models...I really hate having only that automated option, forcing me to use manual settings, on my LX7).

I will often set my max. auto ISO to 1600 anyway, so that "con" really isn't much of one, and the HDR issue is of no concern for me.

So all in all, this is a very impressive list of 'cons'. If these are the worst faults of the camera, it sounds like Canon has done a very good job.

0 upvotes
Total comments: 4