About the number 10/ you listed. The reason is simple. AFAIK Sigme does not have any TC with SDM/Powerzoom power contacts. Stupid, heh ?
Thanks for the report, Stan. 2011/3/25 Stan Halpin <[email protected]>: > I was recently asking about this lens. Hearing no major horror stories about > this or similar lenses, and having some of my concerns about compatibility > put to rest by the Sigma technical folks (kudos to them for a quick, concise, > and on-target email response to my query), I bought one from Adorama. The > price was a couple hundred dollars higher than I had remembered from a few > weeks ago when I started looking. I don't know if that is poor memory or a > supply-demand adjustment. > > First impressions and observations: > > 1. Not as heavy as I feared. On the other hand, > 2. It is clear that plastic is well represented in the overall makeup of the > lens. Seems to be good quality plastic, but still. > 3. The in-lens AF system operates on HSM which is compatible with my K20 HSM. > Knowing nothing about the underlying technology, I consider this to be a > minor miracle. Multiple manufacturers are using the same technology in a way > that allows them to be cross compatible! Wow! > 4. The AF allows manual override if the body's AF is on AF-S. > 5. The AF is more of an AF-assisted MF. I.e., you could probably brew an > espresso in the time it takes to find focus if you start with the lens on > close-up and ask it to focus on something close to infinity. It reminds me of > using the Pentax F-1.7x extender with a manual lens, a similar need to > pre-focus the lens. > 6. However, if you have the lens zone-focused in the general neighborhood of > your subject, the AF seems quick and precise with no unseemly dithering. > 7. The lens has an Optical Stabilization (OS) system. > a. they say you can use the OS, or the camera's SR, but not both at > the same time. > b. the OS seems to work. I haven't really given it a workout yet. > c. it is nice to have an in-lens OS on a long lens; I have trouble > hand holding anything longer than a 250 or 300 because I can't get a good > sense of focus with the image in the viewfinder moving around so much. > 8. The OS has 3 modes: Off (recommended to avoid execess power consumption), > 1, and 2. The instructions are not clear on the difference between 1 and 2, > but I think 2 is for shooting race cars or speed skaters or other targets > moving horizontally while 1 is for general scenes where either nothing is > moving (other than the camera in the hands of the unsteady photographer who > had too much coffee) or the subject(s) exhibit random unpredictable movement > around the scene like in a hockey game or a kids soccer game. > 9. The lens is not weather proof. > 10. The Sigma web site, the Adorama and B&H descriptions of the lens, and the > generic instruction sheet that comes with the lens all mention the Sigma 1.4x > and 2.0x extenders which will work with this lens (though in manual focus > mode only.) However, we are special! Pentax users get an extra footnote: the > Pentax-mount Sigma tele-extenders are NOT compatible with this lens. I've > seen no explanation on what the incompatibility is. > 11. One other thing I almost forgot! The lens comes with a soft case which > has a shoulder strap; I have never understood why people would make cases > that are only good for storing lenses and don't have provision for carrying > them in the case. But Sigma goes a step further: they also have a shoulder > strap that attaches directly to the lens (on the tripod mount)! I don't know > that I would use it, but thanks Sigma for thinking of this. > > General comment - the lens is not magical. It does sometimes miss focus. My > handheld shots at 500mm show some signs of movement not overcome by the OS. > But a few quick shots this afternoon were far better than what I have been > able to do with similar subjects in similar lighting. It is a keeper until I > can find a Pentax counterpart that performs at least as well. > > For sample images (all birds) see my two blog posts from today: > http://smhalpin.posterous.com > > stan > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. > -- Thibault Massart aka Thibouille/Thibs ---------------------- Photo: K-7, Sigma 28/1.8 macro, FA50/1.4, DA40Ltd, K30/2.8, DA16-45, DA50-135, DA50-200, 360FGZ KX, MX, SuperA+Motor, Z1, P30 Mamiya C330+80/2.8 Sekonic L-208 FalconEyes TE300D x2 Studio flashes Laptop: Macbook 13" Unibody SnowLeo/Win7 Programing: Delphi 2009 -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
