Photography question

To: "Birding-aus" <>
Subject: Photography question
From: "Peter Shute (NUW)" <>
Date: Fri, 22 Sep 2006 08:55:48 +1000
On Thursday, September 21, 2006 10:31 AM Peter Shute wrote:

Also use the least
digital zoom as possible.

My camera (Canon Powershot A40) appears to do the digital zoom
using the raw image before saving it as a jpg.  I've proven it to
myself by
taking a photo of a newspaper at a distance where the writing was
legible on the final image.  Taking another photo from twice as far,
with 2x digital zoom, resulted in an image that was noticeably easier
to read.

Sorry, I've just realised that this is just nonsense. What I actually did (several years ago, so I forgot the details) was to take a photo at maximum optical zoom (3x) at a distance where the text could barely be read in the final photo. Then, without moving the camera, I took another photo at maximum digital zoom (3x optical and 2.5x digital = 7.5x). Then I downloaded the photos and enlarged the first photo by 2.5x to make them the same scale. The text in the digitally zoomed photo was noticeably more readable, e.g. the enclosed part of e's was not filled in. My conclusion was that digital zoom on my camera was a useful feature.

I think the distain for digital zoom comes from the fact that it's often used deceptively in advertising. However, if you understand what you're getting, the feature often isn't useless.

Another point: the value of this marginally useful feature may also be negated by the fact that you lose croppable area. E.g. a subject hopping from branch to branch might be best photographed with less zoom, simply to ensure that it's in the frame when you press the shutter.

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