Saturday, December 31, 2011

This blog is about extenders.  I own one, but rarely use it.  Rarely meaning about 5 times in 5 years, maybe not that often.  The purpose of an extender is to make your lens longer.  As an example they can double the size of your lens from 200 mm to 400 mm.  Some however increase the length only 1.4 or 1.5 times making a 200 mm lens 280 mm or the 300 mm respectively.  My extender is 1.4 and makes my 400 mm lens 560 mm.  Here is a pic of mine:

 That is an SD card to help get an idea of size.

 Here is a pic of the lens (400 mm, 5.6) I would usually attach it to:

Here is the lens with the extender attached.

One of the upsides of  extenders is they will bring the subject closer.  The next photograph is with just the lens attached.

This next pic is with the extender attached from about the same location.                                     

Another upside is extenders do not cost as much as lens does.  The 400 mm lens shown here costs about $1275, but the extender is only about $475.  To buy a 500 mm lens would cost about $10,000.  So the lens with extender is $1750 or the 500 mm lens at $10,000, the choice is yours.   The final upside is size.  THe 500 mm lens weighs 7 pounds and is over 15 inches long.   I don't know the weight of the lens with the extender, but it is significantly lighter.  

You had to know it was coming, yes the downsides.  First the optics are never as good as using just the lens.  If your lens is marginal the extender will cause it be worse.  You will almost certainly need a tripod.  THe extended length with the extender will exaggerate motion.  The final downside is it will slow the lens.  My lens is a 400 mm 5.6 lens, but with the extender attached is a 560 mm 8.0 lens.  If it was a 2 x extender the lens would be 800 mm but at an f-stop of 11.  

There is one last consideration.  Some extenders do not work with some cameras so (Old extenders versus new camera).  Some extenders will not meter (measure light) with all cameras, and some will not autofocus.  Mine will not auto focus with my XTI but will with the two 1D's.  Do the research before buying. 

The first photograph is without the extender.  There were several without the extender that were sharp. (both photographs have been cropped)

This second shot with an extender and was of two that I consider useable, and even this one is not as sharp as the first.

I have just one more point to make.  The more mega-pixels the camera has the more you can crop without the loss of detail or having the detail of the photograph suffer.   So I would suggest get a camera with more pixels.  There are plenty of them between $500 and $1000 by Sony, Nikon, Canon, Pentax.  They really aren't that much more expensive than an extender. 

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