Does anyone know how the Sigma HSM compares to Pentax SDM with reagrd to reliability and MTF? I am not sure if the HSM uses the same contacts as the SDM or use the screw? I am looking at getting the Sigma 18-125 lens but not sure how well it will work with my K200D.
Thanks in advance for any thoughts or comments about them
I have seen complaints with the Sigma 70-200mm f/2.8 HSM not focusing, but I haven't noticed any complaints with the others. It is hard to say if there aren't as many of the Sigma's around, or if they are more reliable. If they did fail would people post about it here? etc.
Sigma is big manufacturer (if not largest of the planet) and make a lot of HSM lenses to other brands. HSM motor itself must be same motor-type than with all sigma's HSM lenses across different mount/brand versions.
They are, but let me clarify. Pentax is a small company. There are a lot of Sigma lenses for Pentax mount, but I think there are more Pentax SDM Lenses for K mount than there are HSM Sigma lenses for K mount.
For example, I notice on Amazon (for USA) that the Pentax 50-135mm is the #86 best selling SLR lens for all mounts. The Sigma 50-150mm is not in the best seller list at all. That doesn't mean anything, but the Pentax 16-50 (#71 on the list) and 50-135mm are strong selling lenses.
At least one review for the Sigma 50-150mm on Amazon stated "Would not autofocus". That is only 1 review, but there are only 10. 2 others had issues with front/rear focus. That is 30% of the lens reviewers who had issues. I know this number doesn't mean much as we don't know if only people with problems are leaving reviews, etc. But still, that doesn't sound promising.
I do not know if the HSM in Pentax is the same as in other brands (there are no guarantees that it is, but I imagine they would try to keep it that way to keep costs down).
HSM motors of sigma lenses may not be very bad, otherwise sigma would be ex lens-manufacturer pretty soon.
I still see lots of failures among all lens mounts, but I imagine they are acceptable overall. People will be more tolerant of failures due to the low initial cost and long warranty.
Quite another story with Pentax, BTW...We faithful pentaxian buy whatever Pentax offer, no matter how long stuff works ;-D ..Oh, just kidding (or then not).
Nikon and Canon buyers do the same. I know my L lens is way better than that Sigma that cost half as much...
I am not defending Pentax, as I do think there is an issue with SDM. I haven't had any failures yet, but I haven't had SDM lenses that long. Is the issue worse than with Sigma's HSM? Maybe, maybe not.
Eric
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