Zoom Lens For D3100
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11-09-11, 12:36 PM
Join Date: Feb 2011
Yes, sort of.
In the old days of film (yes, I'm that old) the 'Standard' lens on a 35mm Camera was 55mm (although most manufacturers settled for 50mm). This gave the perspective most like you would view the scene with the naked eye. If you fitted a Wide Angle lens (say 24mm) everything would appear further away and the distance between objects would appear greater. i.e. Something 10M away might look as if it was 20M, and something 20M away might appear 40M. The opposite effect is achieved with a long (Telephoto) lens where everything looks closer and more compressed.
The mathematics are simple. If 50mm is 'standard' then 100mm will make you subject appear half as close (twice the size). These simple sums tend to stick in the minds of us oldies and we still think of a 300mm as a 6x magnifier. However, there is a crop factor to consider because DX digital sensors are proportionally smaller than the 24mm x 36mm format of 35mm and you need to add a 1.5 multiplier (1.6 with Canon). So, the 300mm is the equivalent of a 450mm lens on a 35mm camera. In other words a 9x magnifier.
The tendency with Bridge cameras is they provide a zoom with 'equivalent 35mm' markings. Also their sensors are smaller still, so the effect is even greater. This is why you can get a "200mm" on a Bridge that is half the size of one on a DSLR. First of all, it's 'equivalent' focal length, so it's a 4x magnifier while the real 200mm on a DSLR will be a 6x.
Bridge manufacturers would be more honest if they just used magnifying indicators instead of the equivalents that they do use.
The day you think you've found perfection is the day you stop looking, then someone else will find it and move in front of you.
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