Teleconverters for wildlife photography

Replies to This Discussion

Permalink Reply by Howard Kennedy on May 14, 2011 at 11:46

Yes and no.

 

A teleconverter does increase the focal length of the lens but it also reduces the maximum aperture size too, which can make autofocus slow or impossible.  You need a lens with a wide maximum aperture (f4 or preferably f2.8) to get the real benefit of a teleconverter.  You lose the equivalent in maximum aperture "stops" to the magnification factor of the teleconverter, so a 2x converter will reduce the maximum aperture available by two stops and a 1.4x converter will reduce it by 1.4 (in practice 1.5) stops.

 

As your camera's autofocus needs the maximum amount of light available to operate, it needs to be able to let as much light in as possible during focusing.  In almost all light conditions, it is impossible for autofocus to function with an aperture smaller than f8.  If your lens has a maximum aperture of f5.6 and you attach a 2x converter, this will reduce the maximum available aperture to f11 and it will be unable to autofocus.

 

Even if you are happy to forego autofocus and do all your focusing manually, you will find that all but the best quality teleconverters will have a detrimental effect on image quality.  You may get the animal bigger in the frame but fine detail in fur or feather may be disappointingly soft.

 

In conclusion, a teleconverter is only worth adding if you have a really good lens to attach it to and the teleconverter is as good in optical quality as the lens.  A teleconverter is not a cheap option to make a medium quality mid-range lens better.

Permalink Reply by Myles Storey on May 15, 2011 at 11:50

OKey...Thanks Howard. Maybe it's better getting a lens with a longer zoom.

Permalink Reply by Peter Sims on October 28, 2011 at 18:14

Try out the new Canon 1.4 mk 111 converter, it is very good. I usualy use a Kenko 1.4 Pro, but the Canon Mk3 blows it away. It goes without saying if you are using these sort of magnifications then you need a good tripod.

Permalink Reply by Ian Cook on October 28, 2011 at 18:20

with a good lens, a converter is an absolute dream, ive got 300 2.8 and 600 F4 and always use them with converters on, the 300 even takes a 2x converter really well, the 600 not so much !

Permalink Reply by Peter Sims on October 28, 2011 at 18:30

I use mine on Canon 400 f2.8 and yes they really are made for those lenses. Alas these converters will only work on certain lenses, so if you are thinking of getting one, check out Canon's website first.

Ian Cook said:

with a good lens, a converter is an absolute dream, ive got 300 2.8 and 600 F4 and always use them with converters on, the 300 even takes a 2x converter really well, the 600 not so much !

Permalink Reply by Ian Cook on October 28, 2011 at 20:54

this is how sharp the 300 2.8 with a 2x converter on is ! Taken from a stone hide on a Bulgarian Mountain, so this is a wild bird, not captive ! The 2x can be challenging on anything but the 300 and 400 2.8, to get the images sharp !

Permalink Reply by Peter Sims on October 28, 2011 at 21:09

That is a stunning pic Ian, well done mate. Off to try and get some Kingfisher shots tomorrow and use the 1.4