Powershot G16: fast bracketing for handheld?

Question

I want to be able to take handheld shots at night. Often these shots involve high-contrast scenes, where a sign or something will be lit much more brightly than the surrounding environment. I want to capture the image as it appears to the eye, rather than having either a completely dark background or a completely blown-out subject (the brightly-lit sign). My research has led me to conclude that this effect must be achieved in post-processing with image stacking or similar techniques.

The Powershot G16 has exposure bracketing settings, but it takes a decent amount of time between exposures. This may be because it's defaulting to a longer shutter speed. The camera has an HDR feature that does well in some low-light settings and takes three exposures in very rapid succession, making handheld HDR shots possible. Is there a way to get that rapid exposure speed to occur automatically when the button is fully depressed in a bracketing context and not an HDR context? Is there a way to program AEB to use specific shutter speeds and aperture values? I want to be able to take these shots handheld and getting an image that has as little handheld shake as possible is paramount, which means exposures taken as closely together as possible.

Answer 1

I want to capture the image as it appears to the eye

If you make some research, you will find than the human eye as a very wide dynamic range compared to a camera. That means that an eye can see details in dark area and at the same time details in bright ones. As a camera sensor works somehow linearly, it can't do that. It is as if you were trying to measure 3 meters with a 1 meter rule.

I want to be able to take these shots handheld and getting an image that has as little handheld shake as possible is paramount, which means exposures taken as closely together as possible.

Taking shoot with close exposures won't help much if you want to capture scene with high dynamic range...

If you want to get the same level of details with a camera as with your eye, in my opinion you have two choices :

• take only pictures of scene with a limited dynamic range, so your camera will be able to take it all in one shot
• use HDR to get a high dynamic range

The HDR mod of the camera will do a computed bracketing of the scene to make the most of it : 3 shots, generally the first with a regular exposure, then underexposed to get details in bright area and finally an overexposed for low light areas. (You will make 3 measures of 1 meter with your 1 meter rule and then be able to measure 3 meters) If that mod doesn't give you the result you want, it's maybe because :

• there is to much movement in the scene (your subject moves too much between the first and the last shoot)
• the shutter speed required to get low light details (the underexposed shoot) is too low and your are moving while taking this picture.

You can try to use an higher shutter speed by selecting a lower mean exposure setting. I may work or not, I don't know the specifics of the Canon G16.

As a rule, if it's a moving scene and that the subject you want to photograph is on movement, it will be very difficult/impossible to achieve a photography with a high dynamic range (unless you want to use multiple cameras and fun 3d reconstruction).

You can still try to shoot in raw, manually underexpose and overexpose your picture and then use HDR technics to get a "better" picture...

If you really want a good level of details and that your subject isn't moving, use a tripod (or something stable to put your camera on). When shooting night urban scene, I have to use shutter speed of 0.1, 1, 10, 60 seconds or even more for my overexposed shot... At some point, even the wind is a problem with a tripod not stable enough.

Answer 2

Olivier's answer is great, but I'd like to provide my shorter one:

A rule of thumb is to never shoot handheld with shutter speed slower than 1/60th of a second. At night the shutter will almost certainly have to be slower than that so it is quite a bad idea to go handheld anyway. Use a tripod.
There probably is no way for you to reprogram the AEB on your camera. If this lag is really in between the exposures, you would have to either change the software or the hardware.