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Apologies if this has been asked before, but I have searched and found nothing.
I have had a Pentax 17-70 f4 since new, and it has been a fantastic lens, significantly sharper than the 16-50 f2.8, which I also have.... but the 17-70 started having AF issues a few years back which is no doubt the SDM dying, and is now unreliable, leaving me with the 16-50 as my main lens in that focal length area on a K3.
As I am now doing an increasing amount of photography for a local newspaper the 17-70 range is better than 16-50 and I am missing it.
I can buy a brand new 17-70 but I am wondering if anyone has any information on the SDM ? I have heard / read somewhere that the SDM issue " has been solved" on later models of the 17-70 f4, but how do you know which is a "later model/version" , as far as I am aware there was no official release of an updated version. If the serial numbers are an indicator, does anyone know from where the (lets call it "updated") model/version starts ?
Yes, I know I can buy a 18-135, or 16-85 or 28-105 to replace it but already have the 24-70 on the K1ii, great lens, which is a bit short, and I mainly use a Sig 70-200 f2.8 on that body. Other bodies are K3 (i, ii & iii).
I also have a Tamron 28-300 which I used on the weekend but was disappointed with the results, also have a Sigma 18-250 but that wont be any better.
The sort of shooting situations I find myself in vary a lot, indoors, outdoors, good light, poor light, and flash is not always an option, sometimes ISO 400 or 800 is better and thats where the lens' ability in low light starts to come into play.
So I have a dilemna. I know the 17-70 can give me the results I need & want, but not interested if the SDM thing is unsolved. The 16-50 is a second best option based on image quality and range. I do not know the 18-135, 16-85 or 28-105 at all and reviews / reports are so varied I am not convinced on any of them.
Look forward to your replies.
Cheers