Jul

24

How to choose Digital Camera – Part 2

Filed Under Digital camera, Howto, Series 

Now more about “other” specifications for a Digital Camera.

Angle of view

When photographing a group of people sometimes you need to take them closer together or step back to put all of them in a photo. This is called angle of view it depends on the ratio between the focal length and the film size.

As 35 mm cameras were professional standard, lenses are often described in terms of their “35 mm equivalent” fields of view. This is the difference between a normal lens (e.g. 50 mm), wide-angle lens (e.g. 24 mm), and telephoto lens (e.g. 500 mm). And is particularly common for digital cameras.

Mean values are 30-90mm for 3x zoom cameras.

Noise

The noise in the picture is one of most important parameters, but usually the one than is often omitted in characteristics of the camera.

Probably you’ve already seen that on some solid color areas you have dots or lines with different color just like when watching bad videotape on old VCR. This is called “noise”.

Theoretically if camera matrix is bigger there is less noise, but the size is not the only factor, the others like technology, thermal processes even electricity consumption are in play. So the best way of seeing the quality is to make test pictures. As a guide you can use camera sensitivity – usually measured in ISO. Camera with 50 ISO will be not so good as one with 800 ISO. In addition some professional cameras have noise reduction system.

Optic

The optic is one of the most important components for a camera. Low quality optic is usually seen when you take pictures with contrasting areas at the edge you could see colorful areas.

The only way to verify is to take test pictures.

Autofocus precision and speed

The precision and speed of autofocus differ from old 35mm cameras. On new digital cameras autofocus could take a second which could be crucial if you are going to take a picture of moving object, but is OK when taking static pictures. In addition autofocus could work properly when you have good lighting(such as taking picture outside), but poorly in low light (like taking picture at home).

Some cameras have low light indication and that is very useful, because in those conditions shutter is in 1/30 s and you need to keep camera steady – not a problem when light is good and shutter is 1/100 s.

to be continued…

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