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12-03-2012, 08:43 PM   #136
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QuoteOriginally posted by oxidized Quote
I think I have read before about people having their SDM die and they tried their lens on a K10 with old firmware and the autofocus was brought back to life as a screwdrive.
Happens only with firmware 1.10 or lower...

Also, I think they're seeing that if a lens goes on a huge sale, regardless of "inherent flaws", it sells... just look at Black Friday's figures. I'm not sure for the later batches though. Those sold during BFriday were old stock, right? I hope there is a way to determine the production month/year of a lens through its serial number... because I'd really want to see how many of the 2012 production batch may fail within a year.

...otherwise I'll be shelving my budget for the DA*50-135 and get the elusive FA*85 f1.4 instead.

12-03-2012, 09:50 PM   #137
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QuoteOriginally posted by Alizarine Quote
Happens only with firmware 1.10 or lower...

Also, I think they're seeing that if a lens goes on a huge sale, regardless of "inherent flaws", it sells... just look at Black Friday's figures. I'm not sure for the later batches though. Those sold during BFriday were old stock, right? I hope there is a way to determine the production month/year of a lens through its serial number... because I'd really want to see how many of the 2012 production batch may fail within a year.

...otherwise I'll be shelving my budget for the DA*50-135 and get the elusive FA*85 f1.4 instead.
I just bought a DA*50-135 2 weeks back, don't know if it's from old stock or new batch manufactured this year. Its AF feels faster than I remembered, difference is quite obvious, at least I can't call it a slow AF lens anymore. My DA*16-50 was also bought in this year in May, and can't confirm its year of make. But I think its AF is a bit slower than another copy which I also had but with a replaced SDM (serviced in Japan a few months back), the difference is pretty obvious too. I know some dying SDM lenses have slow AF problem too.

So I guess there are some variations between SDM motors or Pentax tweaked somewhere in the SDM lenses.

The SDM lenses I have so far:
DA*16-50, 5 copies, 3 had SDM problem and serviced by Pentax, 2 copies okay so far (one is with me, one is w/ my friend).
DA*50-135, 3 copies, 1 had noisy and slow SDM problem, 1 had slower AF SDM than the other (which I'm using right now).
DA*55/1.4, 2 copies, all okay before I sold them.
DA*300/4, 1 copy, okay before I sold it.
DA17-70, 2 copies, one okay, one w/ noisy and slow SDM but still could AF, sold it for cheap.

One thing I found out is that all those lenses w/ SDM problems came from the US (yeah, I guess that's the price I have to pay for bargains from eBay), and all those w/o problems came from local (Singapore). Cosmetically all copies are in mint or near mint condition, never dropped (at least I couldn't see any sigh of drop) or damaged physically. Some how here in Singapore we have pretty low SDM failure ratio, some of my friends bought the DA*16-50 and 50135 as soon as they came to market, and they are still working fine after 5 years.

The only one I never had is the DA*60-250, mostly due to its super high price here in SG (retail for over $2k all these years ).

Last edited by frank; 12-03-2012 at 09:55 PM.
12-03-2012, 10:16 PM   #138
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QuoteOriginally posted by frank Quote
One thing I found out is that all those lenses w/ SDM problems came from the US (yeah, I guess that's the price I have to pay for bargains from eBay), and all those w/o problems came from local (Singapore). Cosmetically all copies are in mint or near mint condition, never dropped (at least I couldn't see any sigh of drop) or damaged physically. Some how here in Singapore we have pretty low SDM failure ratio, some of my friends bought the DA*16-50 and 50135 as soon as they came to market, and they are still working fine after 5 years.
I'm not surprised.
With the return laws in the US, some guy definitely ends up to be the 'sucker' with the lemon.

Plenty of loop holes in the system.
You hear of people using the video cam for daughter's b'day, then returning it;
Some bloke uses that nice suit for his annual dinner and dance and then returning it, etc.

My only problematic lens was a Sigma bought in the US.

Then there are so many compliants about focus issues with K5 and Kr which is again very low in Singapore.
Another suspect is that US lighting is still using non-energy efficient tungsten while Singapore and EU 'tungseten' are really CFLs.
12-04-2012, 07:54 AM   #139
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QuoteOriginally posted by frank Quote
I just bought a DA*50-135 2 weeks back, don't know if it's from old stock or new batch manufactured this year. Its AF feels faster than I remembered, difference is quite obvious, at least I can't call it a slow AF lens anymore. My DA*16-50 was also bought in this year in May, and can't confirm its year of make. But I think its AF is a bit slower than another copy which I also had but with a replaced SDM (serviced in Japan a few months back), the difference is pretty obvious too. I know some dying SDM lenses have slow AF problem too.

So I guess there are some variations between SDM motors or Pentax tweaked somewhere in the SDM lenses.

The SDM lenses I have so far:
DA*16-50, 5 copies, 3 had SDM problem and serviced by Pentax, 2 copies okay so far (one is with me, one is w/ my friend).
DA*50-135, 3 copies, 1 had noisy and slow SDM problem, 1 had slower AF SDM than the other (which I'm using right now).
DA*55/1.4, 2 copies, all okay before I sold them.
DA*300/4, 1 copy, okay before I sold it.
DA17-70, 2 copies, one okay, one w/ noisy and slow SDM but still could AF, sold it for cheap.

One thing I found out is that all those lenses w/ SDM problems came from the US (yeah, I guess that's the price I have to pay for bargains from eBay), and all those w/o problems came from local (Singapore). Cosmetically all copies are in mint or near mint condition, never dropped (at least I couldn't see any sigh of drop) or damaged physically. Some how here in Singapore we have pretty low SDM failure ratio, some of my friends bought the DA*16-50 and 50135 as soon as they came to market, and they are still working fine after 5 years.

The only one I never had is the DA*60-250, mostly due to its super high price here in SG (retail for over $2k all these years ).
Frank, out of curiosity, how would you rate the DA* 16-50 with the 17-70 optically?

12-04-2012, 07:56 AM   #140
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QuoteOriginally posted by pinholecam Quote
I'm not surprised.
With the return laws in the US, some guy definitely ends up to be the 'sucker' with the lemon.

Plenty of loop holes in the system.
You hear of people using the video cam for daughter's b'day, then returning it;
Some bloke uses that nice suit for his annual dinner and dance and then returning it, etc.

My only problematic lens was a Sigma bought in the US.

Then there are so many compliants about focus issues with K5 and Kr which is again very low in Singapore.
Another suspect is that US lighting is still using non-energy efficient tungsten while Singapore and EU 'tungseten' are really CFLs.
I actually have more problems with sodium-vapor and mercury-vapor lights at events than I do with lighting anywhere else. Those venues have rendered my m4/3 cameras as worthless as tits on a boar hog and can be a challenge with a dSLR.
12-04-2012, 09:47 AM   #141
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QuoteOriginally posted by Blue Quote
rendered my m4/3 cameras as worthless as tits on a boar hog and can be a challenge with a dSLR
No manual W/B options??
12-04-2012, 09:57 AM   #142
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QuoteOriginally posted by Medium FormatPro Quote
No manual W/B options??
When I need photos from an event, I would rather not be messing with manual w/b options. However, the wb on my GF2 and e-p1 can't fix crap lighting in these venues. Serious flash seems to be the only good solution to sodium and mercury vapor lights but isn't always an option.

Last edited by Blue; 12-04-2012 at 10:05 AM.
12-04-2012, 10:34 AM   #143
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QuoteOriginally posted by frank Quote
DA*50-135, 3 copies, 1 had noisy and slow SDM problem, 1 had slower AF SDM than the other (which I'm using right now).
I am curious, did you use the same camera with all of them. One possible reason for the faster autofocus could be a newer camera with improved focusing system.

12-04-2012, 12:54 PM   #144
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Here's a somewhat more expensive option for finding color temperature…

Sekonic Prodigi Color C-500R Color Meter with Built-in 401-501

Or one could almost experiment with color correcting filters - but those same filters frequently kill the optics on quality lens'

Then there's always post processing of raw files and the like.


I'm frequently good at guessing out most light sources. Unfortunately there are also those times when there is more than one color temp source
12-04-2012, 03:07 PM   #145
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QuoteOriginally posted by Blue Quote
Frank, out of curiosity, how would you rate the DA* 16-50 with the 17-70 optically?
Between these two, I definitely like the DA*1650 better, optically. The only thing I don't like on DA*1650 is its narrow zoom ring, which should be much wider and further away from the camera body, like the one on DA*50135.
12-04-2012, 03:10 PM   #146
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QuoteOriginally posted by oxidized Quote
I am curious, did you use the same camera with all of them. One possible reason for the faster autofocus could be a newer camera with improved focusing system.
You might be right. I didn't/couldn't use them all on the same camera 'cause I changed cameras along the way. But from what I experienced, K5 and K5IIs have pretty much similar AF speed under bright light environment.
12-04-2012, 03:13 PM   #147
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QuoteOriginally posted by pinholecam Quote
I'm not surprised.
With the return laws in the US, some guy definitely ends up to be the 'sucker' with the lemon.
You might be right on this one. No wonder there are so many refurbished goods sold in the US, far more than elsewhere.

Here in SG we are on the other extreme end: whence we walk out of the shop, we can't return the goods just bought
12-04-2012, 06:50 PM   #148
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QuoteOriginally posted by frank Quote
I just bought a DA*50-135 2 weeks back, don't know if it's from old stock or new batch manufactured this year. Its AF feels faster than I remembered, difference is quite obvious, at least I can't call it a slow AF lens anymore. My DA*16-50 was also bought in this year in May, and can't confirm its year of make. But I think its AF is a bit slower than another copy which I also had but with a replaced SDM (serviced in Japan a few months back), the difference is pretty obvious too. I know some dying SDM lenses have slow AF problem too. So I guess there are some variations between SDM motors or Pentax tweaked somewhere in the SDM lenses.
Those variations between copies are a little too varied don't you think? For a manufactured item to be somewhat so... "individual' in terms of the motor's condition.

A friend of mine also has the DA*50-135 whose SDM was out, at least on his K-01 and K10 (upgraded fw), but worked on another friend's K-30. Made things even more confusing to me actually =))
12-04-2012, 08:52 PM   #149
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QuoteOriginally posted by Alizarine Quote
Those variations between copies are a little too varied don't you think? For a manufactured item to be somewhat so... "individual' in terms of the motor's condition.

A friend of mine also has the DA*50-135 whose SDM was out, at least on his K-01 and K10 (upgraded fw), but worked on another friend's K-30. Made things even more confusing to me actually =))
I'm a mechanical engineer, part of my job requires me to deal with motors, step motors, DC motors, servo motors, big ones, tiny ones... Never used super sonic motors, but I know how hard to get all same motors perform the same in different 'bodies'. Most time it's not the motor, but those parts/gears connected to the motor that cause the variations. That's why some SDM lenses never had problem, while some had failed SDM motor replaced but the same problem came back again after a while.
12-04-2012, 08:55 PM   #150
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Let's not forget the Pentax ZX (MZ) series film cameras with the gear on the mirror motor that shrinks and splits. The gears and clutches are much more likely to be the trouble than the motor.
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