Da* 16-50

Hi
I have the chance to get a da* 16-50 at a good price but the sdm as failed but he as had it converted to screw drive
Am I right in thinking that the screw drive will
Work on my K5 and K3 or will I have to have
It set up to work on my cameras

It should work just fine. If purchasing locally take your cameras along and give it a try. If a distant sale from a dealer you'd be covered by the DSRs with the right to return it if it proves to be unsuitable. Make sure the conversion job hasn't caused other issues not mentioned, but I'd guess it ought to be fine if done competently!
If a private sale 'caveat emptor.'

The DA* 16-50 is a lovely lens but can be let down by failing or slow sdm. My copy never failed but would often require "warming-up" when first placed on the camera. i had to manually focus at both extremes, then get the camera to AF. After that it worked fine until the next time.

It was not fast focussing by any stretch of the imagination so I would expect the screw drive conversion to be an improvement

The "conversion" is purely a matter of changing a few lines in lenses data file. So it can be reversed by changing the figures back. As there is no hardware modification, it is very unlikely it has been done to "hide other issues".

It'll be perfectly fine if the screwdrive conversion has been done. I would ask that you check the zoom ring for stiffness as that is a fairly common point of failure. If there is excessive stiffness near 20mm then consider returning the lens. There is a small plastic part in the zoom mechanism which can break off and cause the zooming feature to fail.

I've come across a number of these lenses in varying conditions so have some idea of the main problems.

Hope this helps.

Maybe in theory. Changing the code values someone else has attempted may not have been made accurately and as a second user you may not be able to reverse the process. It isn't without possible pitfalls! You sound very trusting.

I do trust my own ability.
I have done several conversions. It is true each file is specific to the lens and I have taken backups to all the lenses so they can be put back. However, there are plenty of sources of which lines are changed on the net. Or if you need them, I can send you a copy.

It’s on eBay with no returns
So i think I will give it a miss

I take therefore that the purchaser is considering your lens, but this is an assumption. It might be another which wasn't converted by an expert such as yourself with the offer a reversal backup. Others have made the conversion and add an 'at your own risk' warning.
https://www.youtube.com/watch?v=gpfcEebrBSs
If you have a vested interest it wouldn't have hurt to say so as for all I know it might be a no returns sale off flea-bay for a knackered offering when my advice would still be valid. The OP didn't state the seller and there are some dubious practices on the auction sites as I'm sure you're aware (but not everyone is.)

No, I am not selling the lens. And no, I don't have a vested interest other than to try and help others and also perhaps to dispel some of the "myths" that sometimes get spread on the internet.

As far as eBay is concerned, even if there is "no return", you are protected by the eBay system. If the lens does not work or is not as described, you can ask for a return. The seller will have to take the return at their expense and give a full refund. If they refuse, eBay will always decide in the buyer's favour and will refund you if the seller doesn't.

FWIW and whether relevant or not I don't know, but there will be a return time limit and if the purchase is made outside PayPal eBay aren't always able to help. That's how scams are achieved. As I said earlier, caveat emptor!
Notwithstanding, the OP hasn't told us the source of the lens and only asked if it will work on certain named cameras. Nothing more.

Post

But for the Op's information. If the lens arrived and didn't work, it can be returned under the eBay system as long as it was paid for on Paypal. The time limit is usually 30 days. But that is better than many. True, operate out of the eBay system and you are on your own. If you want more piece of mind, SRS have a couple in with a one year warranty but at nearly twice the price albeit with the SDM "working".

With that whole series of lenses, it does very much appear that it is not a question of a good or bad one but rather if the SDM has failed or if not, when it is going to fail. Actually, I prefer using both the 16-50 and the 50-135 on screwdrive. As many have said, if anything the AF seems slightly quicker and the noise is not much more. Certainly quieter than the "clunky" F series lenses.

Agreed! It might be worth a punt if it's a lens you're after. Obviously you couldn't send it back because the SDM isn't working. that's clearly explained, but the seller has a 100% rating so should be reliable and should some other issue be found not mentioned, return the lens for a refund.