Zoom

This feature is probably the most talked about property of a digital camera. From the 10x, 12x, 4x lenses to more traditional language like the "35 mm equivalent", the zoom of a particular lens is a subject of a lot of confusion.

To put things in order, let's start with the 10x, 4x expression of zoom. First of all, it appears to be a very good standard. A camera with 10x zoom can be seen as a far better one than a 4x. I mean, 10 is a larger number than 4; but there is a problem…

10x what?, 4x what?

This is the big problem with this system, you have no reference point. It simply tells you that a 10x zoom will give you a 10 x magnification of the image that you get at 1x zoom.

But how large is the field of view at 1x? Big question! You practically cannot compare two digital cameras this way because of the lack of a reference point.

So, how about the "35mm equivalent" system? Well, with this system, things get very tricky if explained properly. It involves a lot of technical things but I believe that you need a clear, simple answer!

The explanation starts with the understanding of the field of view. On lenses specifications you'll find something like 35-140 mm equivalent zoom. At 35 mm equivalent, on this particular lens, you get the largest field of view, you can put a lot of scenery in a photo. At 140 mm equivalent, the field of view shrinks by a factor of 4.

To simplify the problem, you will need to take a look at your feet:

As you see, it is an effort of imagination. At 25 mm equivalent, you get a field of view of 90°. At 50 mm equivalent, you get a field of view of 45°. Closing your feet even more, at half of 45° (22.5°), you get a 100 mm equivalent!