Weekend Photography Tips - zoom and lens distortion

Chances are good that if you have a compact or an entry level camera you have a zoom lens either built in or that came as part of your kit.  Most of us love the flexibility of a zoom lens.  It does a lot of legwork for us.  Understanding the perks and pitfalls of your zoom feature can really improve your photos. 

First let's address the two kinds of zoom on most compact cameras - digital and optical. One is good, the other is to be avoided.  When you use optical zoom, your camera lens is extending to its fullest focal length.  This is a good thing.  It can greatly improve the composition of your pictures, drawing attention to your subject and eliminating distracting backgrounds.

When you continue past that, the digital zoom kicks in.   This is a bad thing.  Digital zoom basically crops your image and enlarges part of it. You lose quality with every increment further you zoom in as seen here.  When you get that image onto your computer you will see more pixelation and less clarity.  You want to take advantage of your optical zoom and avoid the digital zoom. 

Here is another good reason to become familiar with the various lengths of your camera lens: lens distortion. The best example of this is found in self portraits, where the camera is held by the subject.  Things can appear a little wonky.  Noses become predominant.  You may notice this as well in pictures taken of children when mom gets too close with the camera.  

The reason for this is that most compact cameras and dslr kit lenses have a very wide angle at their low end.   Mine came with an 18-105 lens originally. 18mm, its widest focal length, is not much different from a fisheye lens if you are close to your subject.  You can see examples of that here. 

A wide angle is really nice for taking in a sweeping panorama.  It is really awful for taking a picture of a person within a few feet of your camera.  Better to back up and zoom in a bit than to be physically close when shooting wide.  

Weekend challenge:

Get a willing volunteer to sit for you take the same picture of him/her from very close and zoomed out.  Then step back and zoom in a bit more with each shot, trying to keep the same amount of person in the picture each time.  Got to the end of your optical zoom with this experiment.  Then upload your pictures and see what you get.  

 You may have heard that the camera doesn't lie.  Well, it does. In fact the camera records the same image quite differently at different lens settings.  

This page gives a good visual comparision of the effect of various focal lengths.  50mm is usually considered to be 'normal' perspective.  It is pretty darn close to what the naked eye perceives.  The further you zoom OUT (lower number, lens is pushed back to camera) the more pointy and narrow the face appears.  The further you zoom IN (higher number,lens protruding out of camera) the more the facial features flatten out and become more flattering to the subject.  Most zoom lenses perform best somewhere in the middle of their range. 

 

 

Comments

[Yvonne Rinaldi]

Kim,
Could you pass along the link and/or name of the card game your friend in Germany has marketed? I've got some mums here interested (note how I threw in a little Canadien?)

Thanks in advance ... and thank you for your photo tips. Your timing is perfect, as always. So glad you are gaining health back!

[Kim]

http://www.amazon.com/exec/obidos/ASIN/B005E8W36C/starryskyranc-20

Speed math link Yvonne : )

[Brianharig]

Thanks for the tips on zoom lenses. The newer lenses don't have a much distortion as old ones.
Thanks again,
Brian
travel-photo-tips.com