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I have two
lenses that I use with a Canon 1.4x crop
(Mark II) teleconverter, a Canon
300mm f2.8 IS L 'Prime' Lens
and a Canon 70-200mm f2.8 IS L 'Zoom' Lens.
 I
have been considering for some time a Canon 2x crop
(Mark
III) teleconverter to go with my 300mm lens,
which should provide me with a 'field of
view' of 600mm on a Canon 'Full Frame'
Sensor DSLR camera. Also if I used it on a 1.6x crop
sensor camera, like my Canon 450D DSLR, this
field of view would increase to 960mm.
The new Mark III converters appear to be a
vast improvement on the previous Mark II models and
I was pleasantly surprised when I read up on
my lenses and checked out their image
quality with and without the converters
fitted.
I am not into running image tests, especially when I don't have
some of the parts. However, I do know a
man that does and he has run extensive tests
which are more than good enough for me to
form a judgment, prior to purchase.
I visited
my favourite Canon Review website and
used the
ISO 12233 Resolution
Chart Tool
which is most excellent. You use it to
set-up the lenses of your choice, with or
without teleconverters and then you can
compare the resolutions at various
apertures.
Its terrific for comparing a Canon 300mm
with a converter against a 400mm lens or
even a 600mm lens to form an opinion
regarding image quality. When comparing the
two image charts it is important to check an
'entire image chart' resolution to make a
judgment as very often, certain areas are
sharper than others - for example the
numbers might match each other for image
quality on both charts but not necessarily
the squares or lines.
With a 'Full Frame' Sensor
DSLR my Canon 70-200mm f2.8 IS L Lens
and the 300mm f2.8 IS L lens both achieve
'optimum image' quality at aperture
f4 and on the 300mm the f5.6 aperture
appears just as good!
What I found interesting was that on both my lenses with either teleconverter fitted,
the best image quality is
achieved at f8.
Obviously the autofocus speed is not as fast
and the image quality is not as great
as it would be with the camera and lens only, but it still
appears reasonable. Certainly in good light
with excellent conditions, I would expect
the teleconverter combinations to work very
well.
There is no doubt that the Canon 2x crop
(Mark III) teleconverter could save me money
in gaining that extra 'field of view' and
reach.
For more information and reviews regarding
the Canon teleconverters, please click on
the
The-Digital-Picture.com
website!
To visit Canon's website, the link is -
Canon UK.
If you have enjoyed this article - please donate to my
Charity of Choice -
The Sick Kids
Richard Lawrence
Scotland
United Kingdom
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