What is the main difference between a wide angle lens (28 mm) and just focusing a standard lens to 28mm?

Question

Thank you, I appreciate all your help, I'm obviously a newbie. I asked the question because I was looking into getting a wide angle lens but didn't want to get something I may already have had in a standard 18-55 lens. Thanks again.

Answer 1

I think you're talking about zooming, not focusing a standard lens (like an 18-55mm) to 28mm.

The difference is that a 28mm fixed (prime) lens usually is sharper and is almost always lighter.

Still, the vast majority of photographers utilize zoom lenses over primes because of the greater convenience and the ability to crop in the viewfinder to capture the perfect image.

Answer 2

George is correct. And I think I understood your question the same way, too. A "prime" lens (a non-zoom lens) is .. usually lighter, (because it can be made smaller), and it may have a larger aperture (to let more light in), and almost always sharper (there are exceptions).

For example, I have used three different Canon lenses that will work at 135 mm (Canon 70-200 mm f 4L, 100-400 mm f 4.5-5.6 L, and 135 mm f 2 L)--and I have to say that the 135 mm f 2 is the sharpest.

http://www.flickr.com/photos/little_pook...

http://www.flickr.com/photos/little_pook...

http://www.flickr.com/photos/little_pook...

Answer 3

By definition, there is no difference because there is no such thing as a 28mm "standard" lens.  Standard lenses are 50 mm to cover the 43.3 mm diagonal width of a 35mm film (or sensor).  

Wide angle lenses are (typically) 35, 28, 24, 21, 18 and 14 mm (again in 35 mm terms or Effective Focal Length).