So When I was looking at lenses I see things like 18mm - 55mm or 70mm - 400mm. And when I look at my cam the builting lens says 35mm - 436mm would these be the same thing? Or would the lenses be the same as the reading that appears on my pics once downloaded ie if I'm at normal view on zoom the focal length comes up as 6mm, but then what is the 35mm? I'd like to get some idea of what the mm on the lenses mean so I don't get something that's crap... And is the mm the focusing distance or is it just how far the lens can see?

Yes they are the same thing. The numbers tell you the focal length of the lens in millimetres. lenses with two numbers are zoom lenses and they tell you the mimimum and maximum focal lengths of the lens. The smaller the number the wider the field of view and vice versa, the larger the number the smaller the field of view.

Attached Link: http://www.dpreview.com/learn/?/key=focal+length

Keep in mind that the confusing "zoom ratio" advertised with some point and shoot cams is not the same thing as magnification, as magnification with binoculars, for instance.

Magnification is not the same as Zoom Ratio. Generally, a lens of about 50mm in a 35mm cam will show the same view as the eye, not magnified and not reduced. Go to a 100mm and you have a 2x magnification. Go to an 18mm lens, and you have a smaller image in the viewfinder than the eyes see but a wider angle in the viewfinder than the 50mm.

This stuff can be confusing. I use an 18mm to 120mm zoom, a 55mm prime lens and a 100-300mm zoom. For most of my images, the first one listed does most of the work. For macros, etc., the 55mm and the 100-300 for wildlife shots but almost always on the 300 mm. I could have used a 300mm prime lens just as easily, looking back at my shooting habits with the lens. I hope this helps. Others know much more that I do on this stuff. Tom.

Message edited on: 02/21/2006 19:00

Tx for the link, at least I'll know what I'm looking at now when I've saved up some cash and go to buy... One thing I tend to do is not enough research and after I've brought an item find that there is something better...