[e_honda]

Bought a used copy from BH. Called them up today and they accepted a return (was pretty much at the end of the 30 day policy).

Couple weeks back noticed that the AF simply didn't turn on when I turned my K5 on. Neeedd a few minutes to "warm up". At first I thought it was because of a low battery, then I noticed this happening more and more. Then I read up that this was a problem on a lot of SDM AFs. I had to part ways with this thing, as much as I liked the image quality. Couldn't take the chance that the AF would just die completely one day.

So what next? Is this a problem that has been dealt with by Pentax and does buying a new/newer copy reduce the risk of the same problem? I probably can't run the risk of buying another used one, as I'm scared this problem might show up after the limited return/warranty policies run out on used items. Is the Sigma 50-150 a viable alternative or does it have issues of its own? Would appreciate any advice. Thanks.

[Adam]

Pentax's old SDM system unfortunately isn't very reliable (let alone fast), so you'd probably be better off with the sigma.

I could also recommend the Sigma 70-200mm or Tamron 70-200mm (the first one doesn't have SDM, so it won't ever break ).

Tamron 70-200mm f/2.8 Di LD (IF) Macro AF Lens AF001C-700 B&H
Sigma 70-200mm f/2.8 EX DG APO OS HSM for Pentax 589109 B&H

[psychdoc]

I have had mine without problems. But that in itself does not mean anything. I bought mine from from Adorama where they were also selling a warranty for 7 years; Try the 70-200 and if you dont like it, the extended warranty is one way to go about it. This was well over a year ago.


SKU Brand Product Qty Price Total
-------------------- ---------------------------------------- --- ----------- -----------
PX50135AFD Pentax SMCP-DA 50-135mm f/2.8 ED (IF) SD 1 $799.95 $799.95
CZW7L29 Mack 7 Year Warranty for Lenses Valued $ 1 $34.95 $34.95
----------------------------------------------------------------- ----------- -----------
Subtotal: $834.90

Advantagesof Pentax 50-135:
Much smaller than 70-200. Big deal for me. Not so much for others.
I have only tried a Tamron 70-200 that belonged to a friend. It was too tiring to carry it around. Plus the colors and IQ seemed better with the Pentax.

[pop4]

Is this a problem that has been dealt with by Pentax and does buying a new/newer copy reduce the risk of the same problem?

What problem? To the best of my knowledge, to this day, Pentax has never officially acknowledged that there have been any problems with the design and reliablity of SDM in their lenses.

So what next? ... Is the Sigma 50-150 a viable alternative or does it have issues of its own? Would appreciate any advice. Thanks.

If I'm not wrong, the Sigma 50-150/2.8 has been discontinued, so it may not be the easiest lens to get your hands on; however, what I've read about it seems to indicated that it would be a very good choice. Otherwise, I'd suggest looking at the Sigma 70-200/2.8 lenses (there's a few versions out there), or the Tamron 70-200/2.8, if you don't mind a screw driven lens.

[twitch]

The 70-200's are almost twice the weight and size of the 50-135. If you need the 50-135 then buy a DA*50-135 and an extended warranty. If you need a longer lens look at the 70-200's but ..... the size!!

[Frogfish]

The Sigma 50-150/2.8 is an excellent lens. Very sharp, much faster AF than the 50-135 and no HSM/SDM issues, a much sought after lens amongst Pentaxians. Keep an eye for one - they do come up from time to time and you shouldn't have to wait long. The Tamron/Sigma 70-200/2.8 are both excellent lenses but are proportionally bigger/heavier than the 50-150/50-135 lenses.

[e_honda]

Thanks guys for the suggestions. I was able to find a Sigma 50-150 II online at Fumfie. Looks like they are the last ones to carry this. I'm just hoping it delivers something close to the IQ of the Pentax with better AF reliability.

[liukaitc]

so what is the chance u geting a bad SDM............
as for sigma 50-150 u also need to pay attention to the front/back focus issue...

[Yukoner777]

You would think that considering the thousands of members here who are specifically interested in Pentax equipment that Pentax would be concerned about the SDM issues, especially since it is a much talked about issue and the issue affects their high end lenses. I, for one, am steering clear of these until Pentax admits there is a problem and deals with it. Their sales of those lenses must be hurting.

[Frogfish]

so what is the chance u geting a bad SDM............
as for sigma 50-150 u also need to pay attention to the front/back focus issue...

Quite high. The 16-50 seems to have the most SDM issues followed by the 50-135 and these can often appear when the lenses are out of guarantee. The biggest problem of course is Pentax's pathetic one year guarantee when Sigma offer 2 to 3 years (depending on location) and Tamron 2 to 6 years (in USA) !

[Edgar_in_Indy]

Good job finding the 50-150mm still in stock somewhere. All of the big online stores have been out of it for months now.

[JHD]

Quite high. The 16-50 seems to have the most SDM issues followed by the 50-135 and these can often appear when the lenses are out of guarantee. The biggest problem of course is Pentax's pathetic one year guarantee when Sigma offer 2 to 3 years (depending on location)...

I have a Sigma 10-20 and the 50-150. Both come with a 10 year manufacturer's warranty here in Canada.

Something else to ponder... Sigma sells far more lenses than Pentax and yet I don't recall reading one instance of a failed HSM in the past year. Conversely SDM problems are just the norm; hardly a month goes by and you don't hear of at least one.

[e_honda]

Good job finding the 50-150mm still in stock somewhere. All of the big online stores have been out of it for months now.

Update on this: Turns out Fumfie didn't have any 50-150s in stock after all . They punked me sort of. Charged my credit card almost immediately, had me call them to sell me on accessories (the customer rep said they had about 50 of these in stock, BTW) and then never gave me a shipping notice for about two weeks.

Finally called them up to check on my order. Turns out they didn't have any of these in stock. Then the guy tried to upsell me on the 70-200. I said no thanks, as I could buy from somewhere else for the same price that would also be an authorized dealer (because Fumfie isn't). Just had them cancel my order. Appears now that they removed the 50-150 page from their site.

My solution: Found a Tokina 50-135 on Craigslist for my Canon 7D for basically half the price of the used DA* 50-135 I originally got. Sharp lens. In fact I was surprised to find that it has the same glass/optics as the Pentax DA*, but it doesn't have SDM (thus no SDM issues) and it's AF is faster/better in general. Only quibbles are it has an irremovable tripod caller and doesn't have IS. I'm extremely happy with this but I'll patiently be on the lookout for a used 50-150 (for Pentax). if I ever get ahold of one, I'll compare.

[rawr]

I was surprised to find that it has the same glass/optics as the Pentax DA*

It is the same lens. The Pentax version has SMC and SDM and WR, but that's the only difference. I can't recall whether Pentax licensed the Tokina design, or vice versa. Same with the Pentax/Tokina 16-50.

[Kanner]

Get the 18-135, I have one, great walk around lens, sharp too.