« [DECK THE HALLS WITH PHOTO GADGETS] | Main | [ REVIEW–KAISERBAAS 37cm Digital Photo Frame ] »

December 12, 2007

[ Faster, Sharper and Better… ]

DIGITAL CAMERAS HAVE PUSHED OUT THE BOUNDARIES of the possible in photography in all directions. One of the most interesting differences between digital and film is the possibility of photographing in low, artificial light without using a flash.

Many cameras can have the sensor sensitivity (equivalent to film speed) cranked up to ISO1600 – and some even boast ISO3200. On small compact cameras these speeds are virtually unusable because of picture noise (grain), but with SLRs the high speeds can be used and in many circumstances flash can be dispensed with.

What are the considerations involved?

First, even the best sensors set to ISO1600 will show image noise. Most cameras have noise reduction functions built in that be turned on in the menu. The problem with noise reduction is that in removing the noise speckles it also removes some fine detail from the picture. In the worst cases the NR makes skin, unnaturally smooth and plasticky.

Getting correct exposure reduces the appearance of noise in the best lit areas of the photograph. Noise is always more of a problem in the shadows than in the highlights. Using the exposure compensation judiciously or bracketing shots increases the likelihood of getting a clean picture.

Second, white balance – correct colour – is an important issue with photos taken under low level artificial light. Auto white balance rarely gets the colour right and it is often worth trying the incandescent or manual settings.

Third, even at ISO1600 and with a fast lens it is still likely that the shutter speed will be slow. This is where image stabilisation or vibration reduction is a boon. Image stabilisation works either in the lens, by shifting an element to counteract photographer’s shake, or in the body of the camera by moving the sensor itself. The most effective stabilisation systems make it possible to hand-hold a camera down to speeds of 1/15 second and still get sharp shots.

We conducted a spectacularly un-scientific comparison of four DSLRs – a Nikon D80 with no IS; a Canon 40D and a Panasonic L10 with in-lens IS and an Olympus E-3 with in-body IS. Each was fitted with its kit lens. We were looking at image sharpness, colour and noise. We set up an object under a single incandescent lamp and set all cameras to ISO1600 and set the exposure manually to be the same on all. We hand-held each camera at 1/15 second at f8 with the zoom at 70mm focal length (film equivalent) and framed all shots the same.

What we discovered, for the little that it’s worth, is that the Panasonic is the sharpest but also the noisiest – the penalty of the smaller sensor. The Olympus, with similar sensor but different image processor, is sharp and exhibits well controlled noise. The Canon is astonishingly free of noise and just about as sharp. The Nikon has the most accurate colour and is almost as noise-free as the Canon but it falls short on sharpness, suggesting that image stabilisation matters. With a Nikkor VR lens the Nikon and the Canon would be equal.

In real life all of these cameras have excellent high ISO performance, but in low light the camera to have is the Canon 40D with an IS lens.

*

Posted by terry at December 12, 2007 10:18 PM

Trackback Pings

TrackBack URL for this entry:
http://bleedingedge.com.au/cgi-bin/mt/mt-tb.cgi/1402

Comments

Posted by: con at December 13, 2007 11:27 PM

Posted by: Anonymous at February 4, 2008 01:46 PM

Posted by: Terry at February 5, 2008 12:07 AM

Post a comment

Name:

Email Address:

URL:
Remember Me? YesNo

Security Code:

Comments: (you may use HTML tags for style)