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Note: this is a continuation of the discussion at
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/72242-sigma-70...ty-test-7.html regarding the older, non-HSM, non-Macro version of the Sigma 70-200/2.8.
Since that thread deals with the newer, Macro + HSM version of the Sigma 70-200/2.8, I thought it would be better to start a new thread rather than potentially confusing readers who aren't aware of the distinction between the two versions.
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This is my review of the Sigma 70-200/2.8 APO EX - this is the original incarnation of this lens, before the versions with DG coatings, "macro" designation, HSM, and now, OS and FLD. Like many "pro" lenses of that era, this lens feels solidly built (and comes with the associated heft).
I'll jump right to the "important" points (but if you have questions about any aspects of this lens, feel free to ask)...
Overall, performance is very good from 70 - 200mm, with perhaps the shorter end being a bit stronger. Wide-open at 70mm it's not as sharp as my DA70, but you wouldn't know it unless you directly compared the two. At 200mm, it gives my FA*200/2.8 a run for its money (in most situations). The Sigma has a lot less CA and I haven't noticed any PF so far - these were my biggest complaints about the FA*200. The bokeh is also quite nice, especially at 200mm.
The main weakness of the Sigma appears to be performance wide-open at MFD (minimum focusing distance). Here, things take on a "dreamy" look - by this I mean that there is haloing around high-contrast edges. Actually, it's only the OOF edges that do this - the in-focus edges seem to be fine. That said, stopped down a bit things do get much better. As is also the case once you back up.
This weakness is a bit surprising given the rather large MFD to begin with, but the newer "Macro" versions of this lens (which have a smaller MFD) are also not great up close so it must be a characteristic of this lens' fundamental design. The lesson here is if you need to shoot small things close-up, get a dedicated macro lens.
Thinking about it some more, I was using this lens with an old Hoya HMC UV filter that's not in the best shape (shows some fine scratches) and might've also needed a cleaning. This might have contributed to the problem, but I doubt it was 100% responsible
(*).
Here are some shots at 200mm to illustrate the points above. These are resized versions of the JPGs from the camera (natural tone setting and fine sharpness +1). These were resized using Irfanview and could probably use a bit more sharpening, but they should give you a good idea. I'll also provide links to the original versions for those of you who wish to take a critical look.
We'll start off with some shots at f2.8 and typical shooting distances.
A non-sharpened 100% crop of the above - what do you think?
And lastly (
click here for original):
The next set of shots illustrate the performance at MFD.
MFD and f5.6 - looks pretty good (
click here for original):
MFD and f2.8 - looking a bit dreamy (
click here for original):
Again, MFD and f2.8 (
click here for original):
One other thing - this lens back focuses on my K20D, like my FA*200 (however, my two DA lenses are spot-on). I've been fiddling with the AF adjust, as well as the adjustment in the debug menu (to go beyond +10), but I haven't found the optimum setting yet. It seems that the amount of adjustment needed varies with subject distance - if I optimize for portrait distances, infinity focus will be off. It's a bit frustrating - hopefully this issue will go away once I upgrade to the K-5 next year.
(see update below)
I also have the Sigma 1.4x matched converter, but I'll need to resolve the focus issues first before I can properly evaluate this.
Anyways, I'm still getting to know this lens so I'll be adding to this thread as time goes on.
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* on Mike's advice, I took the filter off and the BF issue has almost entirely gone away! It might still be BF slightly, but I need to do some more testing in order to be certain.
Last edited by photogerald; 10-01-2010 at 02:07 AM.
Reason: Updates and added more photos