A week or so ago I said I intended to test my new Tokina 28-80/2.8 on my
5D against OM mount lenses. The test chart was a color map of Florida
taped onto the wall of my house on the back deck in open shade. In some
cases I tested the Tokina in both autofocus and manual focus modes.
Where possible I checked every stop from f/2.8 to f/16.
The other lenses tested were a Kiron 28-70/4, Kiron 28-105/3.2-4.5 and a
Zuiko 28/2.8. It's a blacknose and may be MC but it doesn't say so. I
also discovered much to my chagrin that the diaphragm ring on this
almost never used lens won't open up past f/5.6. Feels like the detent
ball is getting stuck. Gotta check that out.
So far I've only analyzed the results for 28mm but here's what I've seen
so far. The first startling observation is that every single autofocus
shot on the Tokina looks better than the corresponding manual focus
shots on the same lens. Not by a great deal but enough so that you'd
readily pick one over the other. That was a bit of a shock. I don't
know if it's my eyes or the screen but it's a fact.
The next shock was that I rated the performance of the Kiron 28-70/4 as
"unacceptable" at center from f/4 thru f/8 and "poor" at the edges
through f/8. It didn't produce what I'd call a decent image until f/11
and was still performing better at the edges than center.
Then, the next shock after that was that the 28/2.8 Zuiko wasn't much
better than the Kiron 28-70. I rated it "poor" at f/5.6-f/8 and, like
the Kiron it didn't produce something decent until f/11.
The last on the test list was the Kiron 28-105/3.2-4.5. This lens did a
pretty fair job. It totally outshone the Zuiko 28 and Kiron 28-70 at
all apertures and would be the clear winner... if it weren't for the
Tokina 28-80/2.8 in the mix. I ranked the Tokina as the best performer
at both center and edge at every aperture. The Kiron 28-105 came close
in a few places but there was never any real difficulty picking out the
winner.
Now some comments: Test results described as "unnacceptable" and "poor"
are highly technical terms for looking at the images in comparison and
saying "That looks gawd awful" or "That doesn't look so hot". Don't
expect any quantifiable numbers.
The results with the Zuiko 28 and the 28-70 Kiron almost lead me to
believe that I'm looking at bad focus instead of lens performance. Note
that they didn't get better until f/11 and f/16 and then the edges got
better than the centers. On the other hand, I had to manually focus the
Kiron 28-105 as well. I don't know why I'd do OK on that lens and not
on the others. Anyhow, a little double checking might be in order later on.
But so far I'm really, really happy with the Tokina. I have glanced at
the results at 35 and 50mm and haven't seen anything to change my mind
yet. I haven't shot the 80mm test yet.
The Tokina is a really nice piece of glass with heavy duty mechanicals.
More later.
Chuck Norcutt
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