Chip Louie wrote:
>Well for me and almost everyone else, shooting wide open is very useful,
>personally I shoot WFO a lot. Don't be surprised at the Sigma lens'
>measured optical performance, they are quite good. But as much as Peter
>goes on about them they are not really better or even overall as good as
the
>data he is using indicates. The Sigma zoom using the data he has supplied
>from Photodo is less sharp overall. The real winner is the older Canon EF
>80-200 2.8L anyway you slice it based on this data anyway.
Gee Chip, when you say you and everyone else I did not realize that you
surveyed the entire global photographic community and found the vast
majority shoot wide open. How interesting. Can you provide the details of
how you did this? ;-)
Yes, the older Canon is an excellent optic. The rear element is almost flush
with the barrel so you cannot use the Canon TCs with it limiting its use (to
a degree). There is no USM so it is not fast like the Canon 70-200mm and
not silent like the Sigma. As to comparison, I did the chart and each has
its own advantages at various apertures. I also pulled out my old Pop
Photos tests (yes I saved many of them) and compared the newer Sigma to the
older Canon. In some instances the Canon is sharper such as at 200mm at
F2.8. Now that is providing you are blowing up your negative to 20x24 where
you will see about an 8% improvement at that specific aperture. While at
almost all others there is a 1% advantage to the Sigma except at 135 where
the Sigma is better by 13% but that again is if you enlarge to 20x24. Be
glad to provide the numbers to anyone if they would like.
>Before Peter gets all ballistic, chart it yourself and do an average of the
>data points and measure the area under the curve. It doesn't matter if you
>order the chart using focal length or apertures the Sigma is clearly not as
>good overall and this is reflected in the Photodo rating. The Sigma has
>other problems to go with the lower initial cost, which is very attractive
>to many people myself included. But the reality of it is that if you want
>to get a Canon lens fixed or serviced you will have an easier time of it
and
>the resale value of a Canon lens has been historically significantly higher
>than any of the third party lenses so. So in reality there is very little
>cost difference, a real difference in terms of performance optically and in
>terms of service and support.
No Chip, I am not going to go ballistic, I just state facts. You are
correct in saying the Canon has a better resale value, but then again it
costs twice the price of the Sigma so it would only stand to reason that it
would cost more used too.
Now, as to repair, what you are saying is something I have NEVER had a
problem with. All the 3rd party lens I have owned Sigma, Tamron, or others
are easily repaired by the manufacturer same as Canon. So before you use the
FUD (Fear Uncertainty and Doubt) factor, you should check for yourself. Have
you ever met a Canon lens you did not like?
Peter K
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