Sorry John, but what these popphoto tests show me are subjective
grades. Where are the MTF curves? The MTF is not expressible as a
single number with any intelligibility. This is one of the reasons I
gave up reading the magazines on a regular basis. Too little useful
information, too much advertising and new equipment promotion articles.
Godfrey
On Mar 9, 2005, at 3:32 AM, John Whittingham wrote:
What are those sources? What are the testing methodologies? Where
are the charts and specifications of the tests? ...
Compiled from photographic publications such as Popular Photography
etc. I
would imagine they probably included Photodo MTF tests on earlier
equipment.
Cross-referenced the scores seem pretty reliable, as an example Popular
Photography tested the Tamron 28-75 f/2.8 XR Di and found it to be
comparable
in performance to the Canon L series glass:
http://www.popphoto.com/article.asp?section_id=2&article_id=711
http://www.popphoto.com/article.asp?section_id=2&article_id=663
In the listings on Photozone the Tamron scores very close to the top
wide to
standard zooms (Canon L):
http://www.photozone.de/2Equipment/easytxt.htm#Zstf
Yes it would be better to have the lens test in front of you with the
test
information etc. but MTF testing seems to be reasonably standardised
across
the photographic industry these days.
John
