MTF's Lens Reviews

For those interested in comparing sharpness of lenses, I found an
interesting site:
http://www.photodo.com/nav/prodindex.html

Tien

 

Useful for those who may not have seen it; it's been around a while.
Problem is, "This page was last updated 5 juni 2000."

 

Frank ess a écrit :

Yah, most of my lenses are from before that era. I find it interesting
that a lot of the old AI manual focus lenses are just as good if not
better than their AF counterparts. Where there seems to have been
improvement is with the zooms.

Tien

 

It's been a favourite reference for many photographers for a long time.
Regrettably, it is poorly maintained (although they seem to have
fixed most of the link problems) and not up to date with lens releases
of the past few years.

When comparing lenses at this site it is most important to ignore the
"weighted" score for each lens.

Instead, compare lenses by looking at the graphs at wide open and
stopped down (usually f/8). If the sagital and tangential sharpness
lines are realtively smooth and close together (for each pair at
differing resolution tests), then it is a good indication of smooth
bokeh performance. Of course, the "higher" the curve the better, and
esp. a lower rolloff of the curve are indicative of better, usually
sharper glass.

Such sites are good in the sense of their independance and that they use
a randomly selected lens. OTOH, they only test one sample of each lens
so you have no idea if the presented lens is an exceptionally good one
or an exceptionally poor one ... or representative of what you might
acquire.

Cheers,
Alan

 

I guess one of the reasons that the site is not maintained / updated is
related to the demise of 35mm film.
There is a site at:
http://www.photozone.de/
Lenses are compared on a specific dslr body - it seems usually Nikon
D200 and Canon 350d on the few reviews I looked at. Most data is for
Canon, some Nikkor, and a few Olympus lenses, but the list is growing
quite fast. You can't compare data such as MTF "cross-system" because of
influence of anti-aliasing and in-camera processing, noise reduction
etc, even if the sensor size and pixel count was the same, so there is
little point using for example results of a Tamron lens reviewed on a
Canon system against a Nikkor tested on a Nikon dslr. The reviews refer
to testing of one sample - opening the doors to disputing this data
based on sample variation. There is also some user-survey based data on
this site - unscientific and probably subjective, but perhaps of some
interest.

 

If the sensor delivers less than stellar performance that is a problem
with the sensor, filters, processing, etc. No different than testing
with film rather than an optical bench. The film / sensor is a limiting
factor.

Chasseur D'Images, a french photo magazine, does test various sensors
(body models) with various lenses and does get differing results for a
given lens. But again, that's the sensor data doing it.

What they are doing is turning the individual body models into impromptu
optical benches when used with their test software (DxO Analyzer).

A lens is just a lens. Better lenses always give better results.
"Better" is not just sharpness.

Cheers,
Alan