Tech Talk
By

Timothy Culp /

CNET/ March 13, 2007, 3:17 PM

The Trouble With Today's Digital Still Cameras

Timothy Culp is an electronic graphics technician who works on Special News Events and the CBS Evening News with Katie Couric.


(Kodak)
The camera manufacturers continue to seduce the public with ever-increasing megapixel counts. It is now common for consumer cameras to have 7, 8 and even 10 megapixel sensors, resolutions comparable to top of the line pro cameras. On the surface, what could be better. We can all now make huge 16 x 20" prints from a camera that will fit comfortably in our shirt pockets. It is, however, that very small camera size which is the cause of the problem we're tackling in this article.

A tiny camera by design must contain a tiny sensor. It is the resolution of the sensor which determines how large a print you can make. A 10 megapixel sensor can produce a much larger print than a 3 megapixel sensor can. An old world analogy is comparing a print from a 4x5" negative to that from a 35mm negative.

Technology is capable of producing huge numbers of pixels, but not capable of producing a small cost-effective sensor on which to record them. The result is a tiny sensor with way-too-many pixels crammed onto it. This results in very noisy images above ISO 200, and sometimes above ISO 100. Noise, as we are discussing it , is visible, not audible, noise. It shows up as clumps of pixels, color fringing, loss of contrast, etc. Manufacturers' claims of noise reduction technology are just that, claims. In today's consumer cameras, this technology is ineffective. Also be aware that this is a physics issue. ALL manufacturers currently have their backs against the wall with noisy, small sensors.

What good are all those pixels if the quality of the image is poor?

There are some workarounds. The first is to shoot at lower resolution, for example 5mp. A second option is to shoot only at the slowest ISO, usually 100 on most cameras. This will keep noise to a minimum.

I wish it were this simple. Consumer cameras are used in the automatic modes by most people, which means that the camera selects an appropriate ISO speed depending on light levels. When your child is having a birthday party and the lights are dimmed to enhance the cake candles, the camera automatically boosts the ISO up to 400 or even 800, and you end up with wonderful photos of your family with big clumps of noise all over their faces.

An obvious question is, if the pros don't have noise problems, why should the consumer? The answer is that the sensors inside professional cameras are much larger than those in consumer cameras, and these larger sensors handle noise very well. They also carry a considerably higher cost.

I recommend buying a camera with no more than 5 megapixels of resolution. This will produce prints worthy of framing up to 11 x 14". This should be more than big enough for most of us, who own printers with maximum print sizes of 8.5 x 11". Also, make every attempt to set the ISO to 100 on your camera and leave it there whenever possible. These two solutions will keep the noise to a minimum, and result in prints you can be proud of. Resist the huge megapixel seduction, and save $100 or more on the price of the camera!
© 2007 CBS Interactive Inc.. All Rights Reserved.
4 Comments Add a Comment
linkicon reporticon emailicon
janus_nyc says:
I'm going to try setting my camera to iso 100 instead of automatic . I have a new panasonic lumic 6 megapixel, but i take the pictures at 3 megapixels, which is pleant for e-mailing, etc. ...too big even for that ... it takews pretty good pictgures but i have seen noise in lowlight conditions
reply
linkicon reporticon emailicon
mja721 says:
It's about time someone said it! Most people don't even know what a pixel is and they get taken in by salespeople who also know little about cameras but can make big claims, like a camera can shoot images that can be blown up into posters.
reply
linkicon reporticon emailicon
editzero-2009 says:
I totally agree. I have a 8 megapixel camera that I normally shoot in the wide aspect ratio format that totals around 4 megapixels. the problem isn't the sensor, it's glass or plastic in front of it. It is similar to Prosumer DV cameras that have the recording capability of 550 lines horizontal, but the sensors do maybe 320 at best. I have a Olympus 500 and my main complaint there is that the focus ring isn't really attached to the lens, but is only a electronic device that sends a voltage to the camera, and when I turned it off and back on it resets to another setting so if you are trying to save batteries and turn off, you have to reset focus every time.
reply
linkicon reporticon emailicon
jimbo505 says:
with a 6 megapixel camera you should be ok

but with a higher selection of like 8 megapixel then you can really see detail on the photos
reply