DJ Mills Loc: Idaho

Can someone tell me how to calculate the actual magnification power of a lens? Example: A Nikon 55-300 with a crop factor of 1.5 or a Canon 55-250 with a crop factor of 1.6. I know how to do the basic math and realize that 1.5 x 300 = 450 mm. What I don't know is how much magnification a 450 equivalent provides. Point & shoot cameras are big on saying "10 x zoom" etc. How does that work with a DSLR?

bobmielke Loc: Portland, OR

The multiplication factor listed on DX lenses is just a reference back to 35mm film camera lenses. Most folks getting excited about these numbers have never taken a single photo with a 35mm SLR. "Forgetta boutit".

SQUIRL033 Loc: Chehalis, WA

the "X" you see on compact zoom cameras refers to the base focal length. if, for example, the lens is a 30mm lens at its shortest focal length, and zooms to 150mm, it would be a 5x lens. if it zooms to 300, it'd be a 10x, and so on. while the calculation would be the same for a DSLR lens (i.e. a 100-400 zoom would be a "4X zoom" lens, this has nothing to do with the focal length of SLR lenses, and really isn't meaningful.

in rough numbers, a 50mm lens is about equivalent in FOV to the human eye. if you use that as a base, a 400mm lens becomes the rough equivalent of an 8-power telescope. is this a meaningful number? does it do you any good to know? probably not. as Bob said, "fugeddaboutit" and just enjoy the photos you get.

photocat Loc: Atlanta, Ga

Most makers have that information on their website, look for the type of lens and then check the specs.

Just Tami Loc: Long Island

Thanks Bob I hate having to think about math while just trying to enjoy my camera. I agree, just imagine what it you want it your photo and take it.