----- Original Message -----
From: "Kotsinadelis, Peter (Peter)" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
> As to tests, I don't know about the way Practical Photographer does
> it ...
They don't give too much info, but they do say that they use real MTF and
average them for their figures.
As far as I could descern, all tests were done more or less in one period of
time and is therefore true comparisons. Again, as has been said before, a
lens sample and test of 1 probably doesn't say much. They normalized the
figures to 100%.
Their results (centre,edge at f2.8 f4 f8)
Canon: 73,74 80,75 84,80
Sigma: 74,65 76,74 79,74
Tamron: 77,65 82,71 83,78
As you can see, very close indeed.
I don't own any of the above (I still have the old EF 100mm macro) and what
I don't know:
Does the Sigma have an HSM?
Does any of the 3 have Full Time Manual Focus override?
Does any of the other two have internal focusing like the Canon?
> but I will say that Pop Photo also did some testing and the lenses
rated...
Now, IMO that is one bunch whose tests says allmost nothing at all :-)
> For half the price I put up
> with the Sigma. My only complaint is the screw in hood. Other than that,
the
> lens is terrific.
I think Sigma's optics are generally not bad, and they do offer good value
for money.
Regards
Thys
---------------------------------------------------------
Thys van der Merwe
Portfolio of African Images:
http://home.mweb.co.za/te/teknovis
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