Camera Lenses ??

[The Trog]

Please excuse me but I am new to digital photography !!

Can anybody please explain to me, the logic in the numbers on my camera lens ?. My lens is an18-200mm. What does this actually mean and how in comparison does my magnification compare to something like an EF-600 ? What do the numbers actually mean in NOT too techinical language pleeeeeze?

Thank you very much.

The Trog

[rojash]

The 18-200mm means that it has a variable focal length of between 18mm (wide angle) and 200mm (telephoto), in other words it's a zoom lens.
I'm afraid the next bit is a weeny bit complicated. The field of view varies with the focal length, That is to say, at the 18mm setting, things look smaller, and the area covered is greater.
If you zoom in to the 200mm setting, things get bigger, so naturally, less gets included in the picture. Exactly how wide the field of view is at any particular focal length, will depend on how big the image sensor in your camera is. In the good old days of 35mm photography, this was easy. At a focal length of around 50-55mm the field of view was approximately the same as that of a human eye, so a 50mm lens was considered to be "normal", and anything shorter was wide-angle, while anything longer was telephoto.

BUT. The image sensor on a digital camera is considerably smaller than 35mm, and different from make to make and model to model, so either you need to know the sensor size and do a bit of math to calculate the equivalence between your lens and that on a 35mm camera, or (if you're lucky) the camera manufacture will somewhere specify the 35mm equivalence.

Have a look at the page below, and scroll down to the section "What about digital cameras?".

http://www.panoramafactory.com/equiv35/equiv35 .html

[heathfield]

Interesting link, Rojash. Ta!