On May 25, 2009, at 09:31 , Bran Everseeking wrote:
On Mon, 25 May 2009 16:01:59 +1000
Brian Walters <[email protected]> wrote:
The 35-70 will be
equivalent to about 52-105 due to the sensor being smaller than
24mm x
36mm size of 35mm film. If you need wide angle, you will need a new
lens.
the 35-70 will still be a 35-70. no extra reach is created
I know most know its a crop factor not a tele increase but it has
become a pet peeve. I think the delusion is a selling point.
Pet peeve or not, telephoto lenses are rated by their angle of view,
ie: 2°, 7°, which is based on the receiving end, in this particular
case, a 24 x 36 mm chunk o'film. IF you reduce the size of the
receiver, ie: APS-C sensor, you have used a portion of the angle of
acceptance (crop factor) and mathematically re-defined the lens's now
usable angle of view by a factor of 0.666, or 2/3rds. We think of that
as a 1.5x crop factor, when it in this case is a reduction in the
angle of view we are using, effectively narrowing the field, and
therefor increasing the telephoto filed of view properties by 1.5.
Telephoto lenses don't reach out, they narrow the usable field of view
at the same time increasing resolution to render that field sharp.
Where is my logic (not so clearly constructed) wrong here?
Or is this just all semantics?
If it doesn’t excite you,
This thing that you see,
Why in the world,
Would it excite me?
—Jay Maisel
Joseph McAllister
[email protected]
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