zoom vs mm

Discussion in 'Photography Forum' started by Shirleyshusband, Mar 5, 2010.

  1. Shirleyshusband

    Shirleyshusband Elite Refuge Member

    Messages:
    4,122
    Joined:
    Nov 16, 2003
    Location:
    Stitzer, WI
    Can someone explain/compare the zoom vs mm information given?

    On my old inexpensive digital camera, I have a 10x optical zoom and something like 3x digital zoom. I see that on some of the dslr cameras. But then on others it's something like 70-300 mm. I know what 10x does. Going by that, if I wanted a good picture of something 75 yards away I'd need around a 50x zoom-ish. So how do I compare the mm numbers???:scratch
     
  2. Diver-Down

    Diver-Down Elite Refuge Member

    Messages:
    1,537
    Joined:
    Feb 24, 2002
    Location:
    Bethlehem PA
    5X, 10X, ext. is only relative to that particular lens. If it's focal length goes from 37mm to 370 mm that would be a 10X zoom. If it goes from 100mm to 500mm that would be 5X zoom, the 5X would actually have more reach.

    Best way to compare would be to look at the "35mm equivalent" rating. You can compare that to an SLR lens only after you add in the crop factor of the SLR camera itself. Most Canon's have a 1.6 crop factor, Nikon 1.5x, so a 70-300mm lens on most Canon SLR's would have a 35mm equivalent of 112-480mm.

    50mm is equal to aprox. 1X when comparing something like binocular power. So 8x would be equal to about 400mm

    Make sense ?
     
  3. Shirleyshusband

    Shirleyshusband Elite Refuge Member

    Messages:
    4,122
    Joined:
    Nov 16, 2003
    Location:
    Stitzer, WI
    Hate to admit it but no. :scratch My scope is 3-9 power, my binocs are 10 power...

    Is there a website that might help me understand?

    thanks for the reply.
     
  4. Diver-Down

    Diver-Down Elite Refuge Member

    Messages:
    1,537
    Joined:
    Feb 24, 2002
    Location:
    Bethlehem PA
    You're scope is variable power, it zooms from 3 power to 9 power

    You're binocs are fixed at 10 power.

    mm relates to camera lenses, power (x) relates to scopes/binocs.

    A 70-300mm lens is aprox. 1.4 power to 6 power if you want to look at it like a scope, although it's really more complicated than that. 70/50= 1.4 and 300/50=6

    50mm= 1x which is how we see things
     
  5. Shirleyshusband

    Shirleyshusband Elite Refuge Member

    Messages:
    4,122
    Joined:
    Nov 16, 2003
    Location:
    Stitzer, WI
    That helps. So using a 70-300 mm increases size by 6 times. The reason I'm trying to figure this out is I'd like to be able to take some nice pics of wildlife, so I'm trying to guess/figure out what zoom/mm I need (and can afford).

    I'll be stopping at a camera shop next week to get a little better informed.

    Any suggestions and advise are appreciated. Thanks.
     
  6. teul2

    teul2 Senior Refuge Member

    Messages:
    469
    Joined:
    Oct 6, 2006
    Location:
    Carroll County, MS
    Find a Canon DSLR kit in your budget.
    You'll get more out of it than a fixed lens camera.
     
  7. Diver-Down

    Diver-Down Elite Refuge Member

    Messages:
    1,537
    Joined:
    Feb 24, 2002
    Location:
    Bethlehem PA
    That's probably easier to explain....Buy the least expensive camera and the most expensive telephoto lens you can afford.

    For birds/ducks 250-300mm would be the minimum. Buy 400mm if you can afford it. 500+ mm is ideal but very very expensive except for some 3rd party zoom lenses, still about 1k.
     
  8. Dizzy Duck

    Dizzy Duck Elite Refuge Member

    Messages:
    10,338
    Joined:
    Dec 9, 2000
    Location:
    Gettysburg, Pa and Southern MD

Share This Page