So, the "secret handshake" is pretty widely known in the A-mount world as being a stellar (if somewhat finicky) lens. After trying out just about every FF "walkaround" in the $100 - $400 USD range, I have essentially settled on this one. There is plenty to complain about with the lens: VERY long MFD, huge front element, fragile internal construction, hit-and-miss sample variation, and no first-party hood. So, after that list how could I possibly think this is a good walkaround lens?
Two words: image quality!
I tend to compare most lenses to my Minolta 50mm f/3.5 macro. It's a very unfair test as the 50mm has almost no faults. It's t-a-c-k sharp edge to edge, has zero distortion, and even has quite nice bokeh. The 28-135mm sits right beside this lens in sharpness, bokeh, and (for a zoom) distortion. There are few joys greater than zooming in to 1:1 and seeing what appears to be a fully composed shot. It is honestly breathtaking. I cannot imagine the A900 producing a more detailed image with any lens. It seems to take advantage of the sensor easily in a league with the CZ glass available. The only IQ knock I can think of is the somewhat low contrast it can produce. This is easily fixed with a small bump in PP, so I don't really regard it as an issue worth taking into consideration when purchasing. I'm really stretching for faults here...
The lens itself feels quite well balanced on the A900. The annoying "focus ring on the bottom" is another Minolta.... quirk. I'm used to holding lenses near the base, but I've had a few too many focus ring scrapes and now hold it smack dab in the center. To add to the "quirkiness" of the lens, how about some 28mm-only macro??? Yeah, it's not completely useless, but with the size of the lens and the front element, this should be called the "glass scratch" switch.
Focusing is incredibly quick on the A900. Perhaps it's a bi-product of the huge MFD (limited focus range), the rear-drive focus system, or the huge A900 AF motor, but this thing is f-a-s-t. By far the fastest focusing lens I've ever used. I had a guy at a photo gathering mess about with it (he shots a Canon 5D w/ 24-105mm L) and all he could say was "Wow!".
Here are 3 photos that I think show the characteristics of this lens:
1) 35mm @ f/9 showing distortion control and ridiculous resolving power. Click on pic for larger version.
2) 28mm @ f/9 showing distortion control, resolving power, and flare handling. Click on pic for larger version.
3) 100% crop of shot at 135mm @ f/7.1 showing (again) resolving power and portrait/studio/model possibilities, even with huge MFD. Click through for full size crop sample.
I have not had the chance (or money) to use the CZ 24-70mm. From everything I've heard and seen this lens is tremendous in almost every respect. However, it is $1700 USD and has some IQ issues (however overstated) with CA and corner sharpness (it's also rather enormous for the somewhat limited range).
All in all, I can't really think of anything that comes close to this lens for quality/price. You get the resolving power of a $1700 lens, the beautiful colors and bokeh of a classic Maxxum lens, and a phenomenal range for around $250-300 USD. These seem to be disappearing off the planet at a rather alarming rate, so if you own an A900 or plan on upgrading to FF in the future, I cannot recommend this lens enough.
