PetKal
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 p.2 #4 · p.2 #4 · Camera Canada shipping the 7D Mark II on October 30th! | |
jjoejr wrote:
"Just read his review of it on this site. If I recall he gave it a 7/10, FWIW."
Looked at MTF charts and was surprised the 400/5.6 edged the expensive DO series I lens in resolution but contrast between the two was a virtual dead heat. 4 times the cost for a DO series one vs 400/5.6 for an extra stop and IS ? What am I missing?
Indeed, 400 DO MkI may not have the same sharpness as 400 f/5.6 or a good copy of 100-400. Granted, some 400 DO MkI copies are sharper than others, thus it is a bit tricky to draw a general rule in that regard. Furthermore, both 400 f/5.6 and 100-400 are significantly lighter and much less expensive than 400 DO MkI.
However, the obvious key advantage of 400 DO MkI over its f/5.6 cousins is a nominal aperture of f/4. That means one stop exposure advantage as well as an AF advantage. It doesn't take much of an ambient light loss (or target contrast loss) before f/5.6 lenses start to AF hunt, while 400 DO MkI still continues to focus well.
In addition, as it is to be expected, 400 DO MkI works much better with TCs than either 400 f/5.6 or 100-400.
One has to remember that the nominal aperture, for a given FL, is the most expensive lens design characteristic.
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