Camera sensor noise profile of a Canon Powershot G12

I was recently reading the article The Truth about Digital ISO in Digital PhotoPro magazine, and decided to investigate the camera sensor noise profile of the Canon Powershot G12 I use for underwater photography.

Noise plays a big part in underwater photography. Available light levels are lower underwater,with less available the deeper you go. Knowing the noise performance of your camera allows you to push the ISO and get maximum performance.

I started looking at noise in the Canon Powershot series of cameras in my previous post Noise Comparison – Canon Powershot G11 vs G10.

There has been some recent talk on the web about “native ISO”, where the lower ISO of a camera is not necessarily the best for noise performance due to in-camera amplification methods. I have always thought the underwater photos taken with my Canon G12 at ISO160 were better than ISO80 or ISO100, and thought this might have been the effect of native ISO.

After reading the article The Truth about Digital ISO in Digital PhotoPro magazine, I decided to test my theory.

I setup the camera in manual mode, with a shutter speed of 1/60 sec, aperture of f2.8, and fixed white balance. A fixed white balance is required so the camera does not try and change the colour tints of the high ISO noise, giving you an incorrect result.

I placed a filter barrel and cap over the lens to block out all light, and shot a sequence of RAW images at different ISO settings from 80 to 3200.

File Size

The first interesting thing I noticed was the size of the RAW files.

canon g12 raw files

The size of the file increased as the ISO increased with more sensor noise. The ISO3200 RAW file is nearly twice the size of the ISO80 file.

Continue reading Camera sensor noise profile of a Canon Powershot G12

46 Secrets to Improving your Underwater Photography

I recently received the following question via my website asking for some secrets to improving underwater photography, and as I started to compile the list, I thought that I would share a few of my secrets with you.

…” I just purchased a Canon G12 and the WP-DC34 underwater housing for it. I am an experienced diver, I have decided to get into underwater photography and was amazed by your photos and video with the Canon G12.. I was wondering if you could share some secrets and pointers for my upcoming trip to Belize. I would love to return with some quality video and photos…. hoping your insight could give me an edge. Thanks, Lowell”…..

Thanks Lowell for the great question.

I sat down and started to make a list. It got quite long (some people have written whole books on this subject), so I have tried not to get too carried away.

Some of these secrets are scattered around in previous posts, and I have tried to keep my list to a few key points. Some points relate specifically to the Canon Powershot G12 (which I also own), but most points are general and relate to all cameras that can be used for underwater photography.

Canon Powershot G11 inside wp-dc34 underwater housing

Before the Dive

My list starts before the dive, as I am a big believer in preparing things correctly allows you to be more relaxed during the dive, which in turn allows you to take better pictures.
Continue reading 46 Secrets to Improving your Underwater Photography