[Toshi]

How bad are the AF failures for the DA* 50-135? Is it prevalent like the problems with the initial batch of the DA* 16-50? I was thinking of ordering the 50-135 in a week or so but reading some of the recent failures has me thinking twice. I am using a DS so it wouldn't be using the SDM but I'm looking into upgrading to the K20D in the near future and I wouldn't want it to fail on me later on down the road. Maybe I should opt for the Tamron 70-200 for now?

[Talisker]

The 50-135mm a cracking lens. I've had mine for 18 months, no problems, including down in the Antarctic on small boats (cold and damp). I haven't seen the reports of failures you refer to, but would suggest that: as the Tamron is a more recently released lens, the reports of durability aren't in yet; and you are more likely to see complaints about Pentax lenses on a Pentax forum than about third party lenses. That's not to denigrate the Tamron - I've never handled one - but as I said, the Pentax is a cracker.

[nostatic]

I would buy a 50-135* with no hesitation. The only other lens I can say that about is a 77ltd. Everything else has caveats imho. Not the 50-135*.

[cooldude14es]

Hi.

DA* 50-135mm is a wonderful lens. Obviously there are not so many failure reports as the DA* 16-50 but sadly some people have reported many problems, on this forum and on others.. just make a search on google and you will find them.

I have been using it for some time now and I think that my lens needs to visit de technical service since it has some focusing issues when wide open...

It is sad but true... anyway, I would recommend this lens to every pentax user.

Greetings.

[Aegon]

Mine has been working without problem for nearly a year. And I think everybody should own one.

[fsdogwood]

I had one in my hands (the 50-135mm), it won't focus in the 90-135mm range ...
a crippled lens. Had to send it back to the retailer ...

Ended up with the new Sigma 70-200mm HSM, at least Sigma has more experience
with the new HSM technology. Do miss the weatherseal on 50-135 though. Besides,
Sigma offers 4-yr warranty, as far as I know.

Go over to dpreview and see the 50-135 posts.

HTH.

[nostatic]

Go over to dpreview and see the 50-135 posts.

HTH.

Why? I would think that any rampant faults would show up here...the 16-50* ones sure did. I find the dp site to have a significant contingent of pixel peeping idiots and people who don't actually own the gear they claim.

Seems there have been a *very* small number of problems with the 50-135* lenses. From posts here, maybe could count on one hand the number of issues. And as always with the interwebs, you never know the circumstances around the failure. While I am sure that some are legit, I'm willing to bet that others are user error of some kind. I've seen this first-hand on other web forums for other stuff.

The bottom line is that *any* device can and will fail at some point. Just depends on when and under what circumstances.

[jsherman999]

There is no comparison between the two - the 16-50 has (had?) a relatively high failure rate, the 50-135 doesn't.

Every single lens line manufactured is going to have a few lemons, however, so that's probably what you're hearing about.

The Tamron 70-200 2.8, while exceptional, has it's share of QC issues too - I had to send one back because of AF problems myself.

Overall, the best guarantee, IMO, of exceptional IQ in currently-made K-mount s the DA* 50-135, DA 12-24, FA/DA 35's, DA 70ltd, DA 40ltd, FA 77ltd, FA 31ltd, and FA 43ltd.

Now, for the obligatory shot:



(he looks worried, but it's not about the 50-135 - he's worried about dying.)




.

[yeedub]

Thats an awesome picture of your son!

There is no comparison between the two - the 16-50 has (had?) a relatively high failure rate, the 50-135 doesn't.

Every single lens line manufactured is going to have a few lemons, however, so that's probably what you're hearing about.

The Tamron 70-200 2.8, while exceptional, has it's share of QC issues too - I had to send one back because of AF problems myself.

Overall, the best guarantee, IMO, of exceptional IQ in currently-made K-mount s the DA* 50-135, DA 12-24, FA/DA 35's, DA 70ltd, DA 40ltd, FA 77ltd, FA 31ltd, and FA 43ltd.

Now, for the obligatory shot:



(he looks worried, but it's not about the 50-135 - he's worried about dying.)




.

[sinus007]

Toshi,
Please, do yourself a favor - order 50-135!

Just my $0.02

[Toshi]

I guess I shouldn't worry too much. Everytime I see sample photos from the lens, I know I just have to have it . Plus I was able to pick up a brand new 1.4 Tamron TC last week so I could mount it to the 50-135 and roughly get the same focal range as the Tamron. Sample photos from this combo looked great and I think I can manage losing 1 stop for now.

[Canada_Rockies]

How bad are the AF failures for the DA* 50-135? Is it prevalent like the problems with the initial batch of the DA* 16-50? I was thinking of ordering the 50-135 in a week or so but reading some of the recent failures has me thinking twice. I am using a DS so it wouldn't be using the SDM but I'm looking into upgrading to the K20D in the near future and I wouldn't want it to fail on me later on down the road. Maybe I should opt for the Tamron 70-200 for now?

I have the 50-135, and the AF failures with my lens can be directly fixed by cleaning all the contacts very thoroughly. Some of the lenses seem to be just a tiny bit fussier than others about the contact cleanliness. Sometimes removing and replacing the lens is enough, at other times I have to use a micro fibre cloth and alcohol. It's worth the effort to have this superb lens in my arsenal.

[Edit] Here's an indoor shot - 1/125 @ f/4, ISO 1600 - multi point AF. My daughter's indoor soccer team, Les Gauloises, in the blue uniforms.

[K100Dave]

no, no, no.........This is next on the LBA list!

[Hannican]

Bring back MSN Cashback through eBay BIN!!!!

[blende8]

This post may be of interest to some:

Re: Just tested my new DA* 16-50 and boy does it stink: Pentax SLR Talk Forum: Digital Photography Review

My personal opinion is that these lenses are optical-wise extremly fine designed and are able to deliver excellent pictures (I know what I´m talking about because I earn my living with lens-design and have all the necessary equippment available to test lenses!).

But besides QC problems there seem to be mechanical flaws too (I really don´t want to bash Pentax, the grass isn´t greener elsewhere). E.g. my DA* 50-135 (which is a replacement from the 2nd batch, the 1st was a absolut lemon!) produced excellent results for the first 1000 shots and starts to deteriorate than continously. Because I was thick waiting another couple of month for a replacement I took it apart and figured out that the plastic pinch rollers which control the movement of focussing-lens inside the lens barrel are already worn out by 6/100mm. The resulting "play" of the otherwise backlash free focussing mechanism was absolutly intolerable, generating random focussing results.

I replaced the worn out "plastic" pinch rollers by new one´s which were made from higher grade plastics with tighter tolerances and smoothed the roller guidance inside the lens barrel. After that all focussing problems were gone! Even in "cold" environment (-5°C) the SDM-motor focusses properly (what wasn´t the case before).

Posted by Ralf Mayer

Read also the follow ups ...

The main reason for this wear-out is a not good enough surface finish of the guidance grooves in the anodized aluminium barrel. They are just to rough and wear the roller (which is actually not "roller" but a "slider") out by grinding of material. There is nothing wrong with the roller material iself which is made of a plastic called POM what is commonly (in most lenses) used for that purpose. This fast wear maybe specific for my lens and than it is clearly a QC issue with this lens!

So far my lens is flawless. I have it over a year now.
The results are fantastic.