50mm focal length is "what the eye sees" for a 35mm film camera. Most digital cameras have sensors that are smaller than 35mm "full frame". So, for the same image size, the focal length will be shorter. Typical DSLRs these days have sensors that are 1.5x smaller than full frame 35mm. On these cameras, a 33mm focal length will give the same "frame" as a 50mm lens on a 35mm camera. (33 x 1.5 = 50)...

If you are talking 35mmfilm) then 50mm has been considered what the eye sees. not with standing the fact that the diagonal of 50 is closer to 43mm. why 43mm that is what pentax made for one of it's premium lenses in the original limited series. in any event, be 50 or 43 that was what is considered 1x..

But if you go to aps-c digital, then with a 1.5 crop factor a 35mm becomes 52.5mm the original 50mm or so standard lens..

Basically a standard lens is one that if you look through the lens and note the relative size and angles from each other and the distance a subject in the scene seems; then you take the camera away the scene relative to the above should seem the same. or the "normal" lens...

Thanks for the responses!.

So is a 50mm lens considered a zoom lens or is a 35mm focal length considered wide angle? I may be way off the mark with these questions..

The reason I'm asking is because if I'm going to buy a lens for an SLR (i.e. XTi) and one is 18-200 and the other is 28-200, will the 28-200 be the equivalent of 42-300 and therefore be zoomed in at the widest or will the 28-200 simply sacrifice the wide angle? Sorry if this doesn't make any sense. Thanks again.josh..

The 28-220 would start at 42(1.5 crop). while the 18 would start at 27(assuming same crop). 42 is not considered a wideangle; while 27 is..

If you want the total range then the answer is to get a 12-24zoom and either of the other 2 lenses. though if the other lens was the 18-something you could leave it on the camera unless you had a true wide angle scene...

Uyman wrote:.

Thanks for the responses!.

So is a 50mm lens considered a zoom lens or is a 35mm focal lengthconsidered wide angle? I may be way off the mark with thesequestions..

A zoom lens is one whose focal length can be varied (like an 18-200). Calling a lens a "50mm" implies that it is fixed at 50mm, not zoomable to other focal lengths..

On a 35mm film camera, 50mm is considered a "normal" focal length and 35mm considered wide angle. This is true whether you have a zoom lens set to those focal lengths or fixed focal length (also called "prime") lenses with those focal lengths..

On an APS digital SLR, 50mm is a "medium telephoto" focal length and 35mm is "normal"..

Where this gets confusing is that dSLR's take film lenses, and while they work fine the field of view is different. If you're used to a 50mm on film, the same lens on a dSLR is too tight and you keep backing into walls to get the right framing..

Leonard Migliore..

Thanks Leonard and everyone else. I really appreciate the replies and so quickly! I'm still learning a lot and this forum has been invaluable. Since I take a lot of pictures where I need things wider, I guess a 28mm wide end will be too narrow for me on a digital camera (42mm equivalent). In any case, I'm getting used to the terminology and reading on this forum is helping me a lot.josh..

Uyman wrote:.

Since I take a lot of pictures where I need thingswider, I guess a 28mm wide end will be too narrow for me on a digitalcamera (42mm equivalent)..

This is why you see so many kit zooms (or third-party zooms) that begin at 17mm or 18mm. This is the rough equivalent of 28mm (or a little wider) on a 35mm film SLR...