The Tamron is the other alternative but it also supposedly has focus issues (random focusing sometimes) and is slower at focusing than the Sigma (though it probably won't break down and die like the Sigma :-)
im leaning toward the tamron myself, i've heard bad things about the HSM version and quality control of the sigma however the older non hsm version was better.
the goods,
fast and quiet focus,
sharp,
solid build,
Constant 2.8
Full frame
instant focus adjustment
the bads
heavy,
some CA at 200mm
The CA is minor and easily removed with software.
Overall a very good lens. HSM is excellent.
As for sharpness, it is hard for me to see the difference. Remember the number of factors involved in focusing. If your system is slightly off, camera sensor and selection, your eye... and many more. Best is to test it prior to purchase and make sure you can return it if not satisfied. Anything can break down but with a 10 year warranty, I feel fairly confident.
As for the review which was written in the early release of this lens, I have not experienced these problems. He even admitted that the CA is present in Canon and Tamron lenses but not as bad. My experience is CA to be minor at the100 to 200mm setting. You may have to pay 3 times the price to reduce this effect slighly. You get what you pay for, perfection comes in at a high cost in optical performance. Something that bothers me in this review is the testing on Canon bodies. The Pentax version may not have the focus issues encountered.
I use mine on a K10D and for the money I am very satified with the results.
I picked up one and ended up returning it for a couple of different reasons. First, I had the older non HSM/non Macro version and it was much sharper wide open then the new one. I just couldn't let that go . I also ran into the problem of it not focusing correctly at short distances (see the review of the lens at dpreview for details).
I picked up one and ended up returning it for a couple of different reasons. First, I had the older non HSM/non Macro version and it was much sharper wide open then the new one. I just couldn't let that go . I also ran into the problem of it not focusing correctly at short distances (see the review of the lens at dpreview for details).
John
I have not encountered any focusing problems even at shortest distance. I can not comment on sharpness at the wide open but my results are quite satisfactory.
What is the difference between a macro and non-macro version of a lens?
In general, a "non-macro" lens has minimal focusing distance about 10X focal length, e.g. 1 meter or 3 ft. for a 100mm lens. The maximum magnification ratio is about 1:8.
A "macro" lens can focus much closer. For most "macro" zoom lenses, the magnification ratio of 1:4 is common. Some can even do 1:2.
Note: I'm using the work "macro" with the loose usage commonly seen these days. Strictly speaking, "macro" means magnification ratio of at least 1:2.
The only thing the Tamron can claim is a slight bump in IQ but I have no idea if you can see it anywhere other than a test chart. At least I'm not aware of Sigma users complaining about IQ. I'm sure not.
What the Sigma does have:
Great build quality
Silent Focussing
The action on the focus and zoom rings is silky smooth. I one finger the zoom on mine and never does it feel stiff or too loose.
I get great pics from my copy and wouldn't trade it for anything.
The look and feel of a lens is very important to me and the Sigma is a sexy lens.
The biggest problem you'll have with the Tamron is the manual focussing. With the Sigma it is a instant shift from AF to manual Focus. Just give the focus ring the lightest touch and we are in manual focus. If you want to do the same with the tamron you have to engage the lens clutch by push-pulling the focus ring and then take your hand off the lens to shift to manual focus on the camera body. If you are the kind of photographer that likes to touch up focus the tamron would be a real pain.
I'm obviously biased towards Sigma. I have the 70-200 and the 18-50 2.8 constant aperture lenses but I believe all the above to be true.
What I should say is the finish on the Sigma lens is a love-it or hate-it thing so be sure to get your hands on both lenses before you buy.
In the end it's personal. Except for the manual focus thing you couldn't go wrong either lens.
so I could use this to lens to shoot my kids hockey games?
Yes, you'll have better luck shooting sports w/ the Sigma than the Tamron. Someone on DPR said the Sigma 70-200 HSM was the first lens he used that worked w/ AF-C (was fast enough) mode.
If the hockey games are indoors, don't get the Tamron.
I'm itching to try HSM so I'll probably get a Sigma as well...just that those HSM failure reports are disturbing
I use the 70-200 HSM version on the K20 and haven't found any issues taking motorsport photos. It's quick in focusing especially when I'm panning and taking bursts.
I've got the Sigma. It took some getting used to--the AF is busy so you have to pay attention and get the right shot. When you do, the IQ will blow you away. Noticeably soft wide open but good by 3.5 and dynamite sharp on up. Good bokeh & solid build. That said, I've heard very good reports on the Tamron, too.