[davef]

Peter,
I can understand your frustration. For the type of work you do, a reliable, fast focusing 16-50 class lens (for APS-C) or a ~24-70 on FF needs to be a workhorse. It pains me to say so, but it doesn't appear that Pentax is in this market. I guess that's why 5D's and D700/D3's are so popular with your competitors. Dave

[Ash]

Peter, I echo all your observations bar one, and that's the hunting you report of over 20 seconds in low light. My copy may hunt for 5-10 secs max, depending on how stationary the subject in low light is, but after that it will either give up with the blasted flashing hexagon or engage AF assist (usually from my 540's spotbeam) and try again with better success.

I suppose I'm not as disillusioned but share all your sentiments, mate, and would certainly expect better for a reasonably expensive lens that is top-of-the-line for Pentax.

[monochrome]

I hope some Pentax employees here are reading or paying attention to these SDM failure threads right now. this would definitely affect Pentax as a whole.

Just for grins I PM'ed JCPentax and linked this thread. Wonder what will ahppen?

[Class A]

Thanks for your elaborate reply, Peter.

It's not only my issues.

Sure, I know that this lens model has been problematic in various ways for a number of users but I didn't quite understand what your specific issues were.

I was in particular wondering whether you were arguing that the lens design needs an overhaul or you were unhappy with your particular copy and only demanded a redesign so that individual problems were less likely (but thought the lens is great if it only worked to specification).

Could it be that your copy has come somewhat out of alignment in a way that affects the camera's ability to focus? It may be an optical problem (regarding what the AF sensors sees) or a mechanical problem (regarding the actuation the motors are trying to achieve but not quite accomplish). The deterioration in AF performance you observed points to a problem of the copy, not a problem of the lens design as such.

I fully understand that you wish the lens would have better withstood your use which I fully believe would exclude any abuse of any sort.

Best of luck with your future developments.

Just for grins I PM'ed JCPentax and linked this thread. Wonder what will happen?

Don't hold your breath... :ugh:

[Class A]

Mine will go to service in a month or 2.

Fingers crossed they'll find something to address. This kind of issue with a lens is prone to not be diagnosed correctly and deemed to be "within specs". I truly hope your service experience will be positive.

2) that there needs to be a SDM<>SD electronic "switch" in a menu to choose the focus drive you want.

That would be great and has been suggested by many but I don't see Pentax implementing this. It would be dead easy/cheap to implement but it would also be an admission that SDM can fail or that there may be another reason as to why the old SD could be preferable to the super-duper SDM. I just can imagine Pentax making this admission,

Soon JCPentax will tell us all about it. Or not.

[PentaxPoke]

Soon JCPentax will tell us all about it. Or not.

I think your IM was a good attempt, but I can't imagine what he can say other than a company line "we don't see any widespread problem." Imagine the firestorm he would create if he came here and said that there was a problem with SDM. Pentax would be flooded with demands for returns to the point that it would possibly bankrupt them.

I think we are most likely to see the admission of "guilt" through positive marketing of an SDM mkII or something like that someday. Let's hope it is ring-SDM.

[lesmore49]

I've had my 16-45 for over two years, many thousands of exposure. It's a great lens, crisp, clear, etc.

The build quality...ie; plasticky parts concerns me, but so far I haven't dropped it and it keeps on working.

I do mostly outdoor photography with it and at F4 it's fine as I generally shoot at F8.

But I think it's slow for indoor natural light work...I tend to use my 50mm F1.4, 50 Macro F2.8 .

I have never read much good about the 16-50...concerns re; reliability problems.

Another good lens I've had for about the same time (6 months less) is the 55-300...great lens, very clear...sometimes hunts...then I switch on to manual focus.

[seacapt]

Soon JCPentax will tell us all about it. Or not.

One thing is for sure , no US employee of a Japanese maufacturer is going to make a statement on product issues without that statement being cleared by corperate in Japan! I say this from personal expeience.

[Urkeldaedalus]

Sorry to hear about your troubles, Peter Zack. I agree with you that Pentax would be wise to introduce Mark II versions of the DA*16-50 and DA*50-135 this year with faster, more reliable motors. Think about it: They could re-release basically the same lenses, charge more money, and recover some tarnished reputation for themselves and these lenses all in one stroke. What's to lose?

The only reason I can think of why this wouldn't be a great move for them is if they are working on a D-FA* 24-70 and 70-200 for an upcoming full frame camera. However, until that (full frame) materializes, I'm not going to count on it happening.

Also, if they allowed the enabling of screwdrive AF with the 16-50 that would be a simple alternative. I'd probably just use that to take advantage of the K-7's (and future cameras) faster AF drive.

With all this said, I wanted to enter in a vote of confidence for my DA*16-50. It has yet to fail me when I needed it, even in challenging lighting situations, and it gave me my best pictures from the last wedding I shot. Overall I am very impressed with it, even though in general I favor prime lenses over zooms.

That doesn't invalidate any of the problems people have already had with the lens, and it doesn't mean mine won't fail at some point, but I wanted to add a positive critique to the thread. In true rebellious Pentax fashion, its new moniker "Piece 'O Crap" will probably make me want to shoot with it even more

[Ash]

I've had my 16-45 for over two years, many thousands of exposure. It's a great lens, crisp, clear, etc.

The build quality...ie; plasticky parts concerns me, but so far I haven't dropped it and it keeps on working.

I do mostly outdoor photography with it and at F4 it's fine as I generally shoot at F8.

But I think it's slow for indoor natural light work...I tend to use my 50mm F1.4, 50 Macro F2.8 .

I have never read much good about the 16-50...concerns re; reliability problems.

Another good lens I've had for about the same time (6 months less) is the 55-300...great lens, very clear...sometimes hunts...then I switch on to manual focus.

I'll disagree with you there.
I've gone from the 16-45 to the 16-50 and can admit a noticeable improvement in the quality of images beyond what MTF data report (https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/49602-da%2A-16...e-quality.html). The 16-45 was excellent for me as it is for you but once you shoot with the 16-50 you'll see the difference - 16-45 images, while sharp and reasonably contrasty, have less 'soul' and the colour/microcontrast X-factor the 16-50 seems to produce with its images.

The concerns are unfortunately going to come much more than the praise for this lens due to its high price tag and thus high expectations. For the initial QC issues of decentrering, which seemed to have been rectified (of course *without* an admission from Pentax that something was wrong), and now the SDM failures, the lens takes a further bad rap and and good that it may have is quickly forgotten.

Peter I do hope the service goes well for you and it significantly improves its reliability for you afterwards. I like you are eagerly awaiting Pentax's development in the new generation of SDM lenses.

[Pentaxor]

as far as comparison between 16-45 and 16-50 is concerned, I tend to agree with Ash. I saw some photo results comparing the two lenses side by side and unless you compare both results, you wont really see the difference. no matter how people say that the 16-45 is the cheaper and slower equal of the 16-50, and despite the fact that the 16-45 truly has a great sharpness and contrast, it is not as sharp and contrasty as the 16-50 as people hope to be. but it does the job extremely well. I would say that the 16-45 is the wide zoom partner of the 55-300, as the 55-300 is the budget equivalent of the 50-135, but with the advantage of additional range. that versatility would make the 55-300 an indispensable and better tool in most occasions. well, probably the 60-250 lens would be the more ideal equivalent.

the good thing about the 16-45 though, is it's reliability.

[Pentaxor]

Sorry to hear about your troubles, Peter Zack. I agree with you that Pentax would be wise to introduce Mark II versions of the DA*16-50 and DA*50-135 this year with faster, more reliable motors. Think about it: They could re-release basically the same lenses, charge more money, and recover some tarnished reputation for themselves and these lenses all in one stroke. What's to lose?

I dunno how much Pentax would lose if it initiates a massive recall of those lenses, but from what I have seen regarding product recalls, is that the companies, lose millions.

[asdf]

Instead of double-posting, I put a link to a summary of my DA* saga here:
https://www.pentaxforums.com/forums/877978-post36.html

I think the biggest problem here in Canada is that there is only one location (in Mississauga) that fixes these lenses. Canada is pretty big.

[Urkeldaedalus]

I dunno how much Pentax would lose if it initiates a massive recall of those lenses, but from what I have seen regarding product recalls, is that the companies, lose millions.

No need to recall the lenses. Just sell the Mark II zooms at an appropriately higher price and discontinue the Mark I zooms to phase them out. I don't know for certain, but I imagine this is how they have managed the multiple versions of the kit lens.

[Pentaxor]

No need to recall the lenses. Just sell the Mark II zooms at an appropriately higher price and discontinue the Mark I zooms to phase them out. I don't know for certain, but I imagine this is how they have managed the multiple versions of the kit lens.

which leads us to the question on how Pentax would handle warranty then? will Pentax be willing to replace the defective lenses with the new version or with the old discontinued ones? charging additional doesn't seem right because it is somehow a way of holding up a customer of having no choice.