Tamron SP 90/2.5 vs Kiron 105/2.8 shootout

[chse]

As you might remember I was lucky to get the Kiron (Lester A Kine) at BH (see previous post) - it arrived Wednesday and I was eager to test it out. The contender is one of my favorites, the Tamron SP 90/2.5, I especially wanted to know if the Kirons legendary bokeh beats the Tamron. So here my 'ugly' bokeh test: I chose a contrasty background with lots of bright spots. The magnification was about 1:3.
The Kiron is a cheater! I set the aperture manually with the ring and used the same exposure; at f8 the Kiron was much brighter than the Tamron and the DOF was much more swallow. The Kiron matches the Tamron at f11 (!) - I wonder if this is done on purpose to suggest a smoother bokeh.
The Tamron images are first, followed by the Kiron. The Tamron images are slightly cropped (about 10%) to match the magnification.

Tamron f2.5

Kiron f2.5



Tamron f4

Kiron f4



Tamron f8

Kiron f11




The result are great since my heart beats for the tamron, there is nearly no difference between the 2 in contrast or sharpness. The bokeh is relatively smooth with both with no doughnuting. The Tamron is much smaller and lighter, though, and I like it as protrait lens. Next I will compare them as portrait lenses.
Please let me know what you think.

[lbam]

Hmm, it's tough to choose between them...
Maybe the Tamron is a little more contrasty (or is it just darker), but the Kiron a tad sharper...
It's hard to view matching pics on my monitor though...

Thanks anyway... seems you can't lose with either lens

[Nesster]

The thing I was trying to pay attention to - important in macro, imho - is the transition zone from focus to oof. Unfortunately, I can't see much to choose between the two there either.

These are great sample photos by the way

[Maple Wang]

where is the portrait comparison?