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05-05-2012, 02:20 AM   #31
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QuoteOriginally posted by Chaos_Realm Quote
I don't understand why pentax doesn't just scrap SDM, and use DC. It's only drawback is noise... Edit: actually just found out its quiet too. Hmmm
IMO they will. Simply SDM is possible at the same time as screwdrive. DC probably is not. So now they have to (and already did) make a choice, either screw AF or motor (whatever the type) AF but not both. I think a big part of theses problems came because Pentax wanted to offer combo AF to its customers.

This is one example where compatibility sometimes hurts more than anything else.

05-05-2012, 02:26 AM   #32
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QuoteOriginally posted by thibs Quote
IMO they will. Simply SDM is possible at the same time as screwdrive. DC probably is not. So now they have to (and already did) make a choice, either screw AF or motor (whatever the type) AF but not both. I think a big part of theses problems came because Pentax wanted to offer combo AF to its customers.

This is one example where compatibility sometimes hurts more than anything else.
is that because the screw drive would induce a "feedback" current through the DC motor as it rotates?
05-05-2012, 02:35 AM   #33
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QuoteOriginally posted by Chaos_Realm Quote
is that because the screw drive would induce a "feedback" current through the DC motor as it rotates?
Dunno. Or maybe this is 'simply' that you need to (electronically) flip the AF from screw to SDM and that doesn't work correctly.
The 17-70 was the next SDM lens and the first SDM-only lens. It seems it got its number of problem although a lot less.
DA*55 AFAIK has none out of the ordinary. Still an SDM lens though.
05-06-2012, 04:38 PM   #34
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QuoteOriginally posted by philbaum Quote
From your poll on the 17-70 sdm:
2310: 12 failures
2311: 4 failures
2312: 2 failures (normalized to 12 months, that would equate to 5 failures)

Interestingly enough, regards the failures on the 16-50: the high point was in 2009, and then in 2010 the failure rate started falling.

Those failure numbers wouldn't have fallen like that across the board unless Pentax had taken some action to fix the problem.
There have been several folks around here with 16-50 and 50-135 failures recently with the usual 6 week turn around from CRIS. I don't think everyone particiopated in that poll. Plus, SDM lenses come with a 1 year warranty. What is the warranty for the Sigma lenses? I never got one of the DA* 16-50mm because the started out with the decenter issue then the SDM. Now they are priced by folks at an opium den. That said, I am not all that crazy about most Sigma and Tamron zooms. The exceptions were the Sigma 15-30 and 20-40/2.8.

05-06-2012, 04:49 PM   #35
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QuoteOriginally posted by Blue Quote
There have been several folks around here with 16-50 and 50-135 failures recently with the usual 6 week turn around from CRIS. I don't think everyone particiopated in that poll. Plus, SDM lenses come with a 1 year warranty. What is the warranty for the Sigma lenses? I never got one of the DA* 16-50mm because the started out with the decenter issue then the SDM. Now they are priced by folks at an opium den. That said, I am not all that crazy about most Sigma and Tamron zooms. The exceptions were the Sigma 15-30 and 20-40/2.8.
6 weeks is not a reasonable turn around, thats for sure. guess i missed the recent reports on sdm problems. I've been very fortunate on my 3 sdm lenses, knock on wood. If i've had problems with them, i'd be a lot less objective about it, i'm sure.

I think sigma lenses have a 2 year warranty but i may be wrong. the only sigma i have is the 10-20 which arrived with no problems. I've been tempted by some of their fast primes, like the 30 f1.4 but haven't bought any yet. Too many lenses to try, to little time
05-06-2012, 05:04 PM   #36
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QuoteOriginally posted by philbaum Quote
6 weeks is not a reasonable turn around, thats for sure. guess i missed the recent reports on sdm problems. I've been very fortunate on my 3 sdm lenses, knock on wood. If i've had problems with them, i'd be a lot less objective about it, i'm sure.

I think sigma lenses have a 2 year warranty but i may be wrong. the only sigma i have is the 10-20 which arrived with no problems. I've been tempted by some of their fast primes, like the 30 f1.4 but haven't bought any yet. Too many lenses to try, to little time
I currently have 1 sdm lens, a DA* 300mm. I had a 17-70 for a while but I sold it because it wasn't getting used much. I added a 3 year warranty to my 300 when I got it. The data is not tabulated anywhere to make a true assessment on the DA* zoom, 17-70 failures, but given there price point, it still appears to be too high. Pentax/Hoya made a mistake by trying to officially deny the problem imho how ever low or wide spread the problem was coupled with the turn around on servicing them. I think the poll was active for a while and then went inactive and it was also unclear if everyone was aware of the poll.

I agree with you about the too many lenses to try, and too little time. bigthumbsup
05-06-2012, 05:52 PM   #37
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Sigma have a 5 years warranty in Canada and on some lenses 10 years
05-06-2012, 09:43 PM   #38
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1 year in Benelux, 1 free year if registered to sigma. Which is no better than any other

05-06-2012, 10:59 PM   #39
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QuoteOriginally posted by monochrome Quote
Many on this Forum have lamented of late the dearth of Thrid-Party lenses in K-mount. May I gently observe that this is a possible side benefit of the new Unilateral Pricing Policy? Third-Party lens makers will hopefully be more likely to release lenses in K-mount if the price competition from Pentax-native lenses at their price points is diminshed.

Just sayin'. I'm going to duck now.
Definitely! Pentax's strategy of abandoning % of Pentax-mount lens sales is pretty much assured of success.
05-09-2012, 05:07 PM   #40
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QuoteOriginally posted by philbaum Quote
I think sigma lenses have a 2 year warranty but i may be wrong. the only sigma i have is the 10-20 which arrived with no problems. I've been tempted by some of their fast primes, like the 30 f1.4 but haven't bought any yet. Too many lenses to try, to little time
I often took delight in the fact that one could buy Sigma-rebadged lenses at Ritz with the Quantaray label, and get five years of warranty on the identical lens. Of course my local Ritz has departed, so maybe that wasn't a great payoff strategy for them.
05-09-2012, 05:59 PM   #41
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QuoteOriginally posted by bobmaxja Quote
Sigma have a 5 years warranty in Canada and on some lenses 10 years
It varies depending on the lens. The Sigma 70mm/2.8 EX DG macro and 30/1.4 have a 1 year + 3 year extended warranty for the lens in k-mount. The 8-16mm has a 3 and new version of the 50-500 have a 3 year warranty.
05-09-2012, 07:27 PM   #42
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I dont know where you take that info
The Sigma 70mm/2.8 EX DG macro and 30/1.4 are 10 years
Product
05-09-2012, 08:09 PM   #43
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QuoteOriginally posted by bobmaxja Quote
Blue
I dont know where you take that info
The Sigma 70mm/2.8 EX DG macro and 30/1.4 are 10 years
Product
That is a Canadian link. My information came from B&H and Adorama descriptions of those lenses and are specifically U.S.A. warranties. I think some of the Sigma warranties were longer here at one point. The Tamron 90mm macro currently has a 6 year U.S.A. warranty for comparison to the Sigma 70 macro.
05-09-2012, 09:11 PM   #44
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Why not include the Sigma 18-250 f3.5-6.3 as it is only priced at $479.99 and might be worth the extra $80.00? Too bad tamron doesn't make the 18-270 in the Pentax mount..
05-13-2012, 08:16 PM   #45
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How soon on the comparison test between the Pentax 18-135, Sigma 18-135,18-200 (new) and Sigma 18-250? Wonder if Tamron will ever produce an 18-270 Pentax mount or maybe Pentax might 'borrow it" from Tamron and label it as their own. It has happened before.........
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