pentax 17-70 sdm

I ordered a sigma 17-70 from srs on monday and the parcel arrived this morning when i open the box i noticed they had packed a pentax 17-70 instead of the sigma being an honest man i informed them and sent it back but i gave it a quick try on my k10 and the sdm focus is so quiet and quick i thoght about paying the extra but when i checked the pictures out on the screen i noticed a focus problem like if i focused on a object the object behind was in focus and the target subject was out of focus.I tried one of my other lenses and it was fine so they might of sent a dodgy copy out.Any one else had this problem...

At the time of your posting, I doubt many here had this lens. Maybe somebody has now.

If you can remember, where did you have the focus selector set, Auto, Sel, or centre?.

Which lens did you use which gave good focus? Some older lenses only use the centre spot, irrespective of where the selector is.

I f i can remember i had the focus selector set to center and the lens i used to test against was a tamron 18-250mm which was spot on.

This is a bit alarming, especially as I intend to upgrade some of my glass soon, I think I read that the 16-50 had similar problems when first relesed and I understand that ephotozine have not yet reviewed the lens because of that very problem.
You think Pentax would have learned from its mistakes.

As an aside to this post, why cant the focus point be displayed in the EXIF ? something for Pentax to think about maybe.

It is Use PhotoME - it'll show you tonnes of information (including the camera temperature !)
Matt

Just got a sigma 17/70 and had some lovely shots with it early days yet though .

This looks interesting

http://forums.dpreview.com/forums/read.asp?forum=1036&message=28805810

Comparison with 16 45 lower down.

Jim

I have just returned a Tamron SP AF70-200f2.8 as it had the same problem, It always focus beyond my selected area, (usually centre zone) in single, servo & manual modes on my K10D & 1*ist D.

I have one and am very happy with it. No focussing problems at all. This is purely from taking photos with it, I haven't used a focus test sheet with it or anything like that.

Has anyone else bought this lens since with good results?

I returned the first one I bought as, like the OP's, it would not focus on the point I was aiming at but went for the background every time and also was very soft at 70mm especially at longer focus distances.

I tried a couple more but the softness was still obvious.

I had to try a few 16-50's before I got one that wasnt wildly decentred so I was wondering if there was just an early batch glitch and they are OK now?

[IMG]http://i477.photobucket.com/albums/rr139/RobbieB_album/IMGP7269.jpg[/IMG]

This was taken the other day with the 17-70 SDM. It was taken with AF and I used the centre AF point but doesn't look quite sharp to me. Does this image show any signs of the lens being faulty?

Cheers

Rob

The pictures looks ok if you focused in the centre of the image has the bottle to right of centre looks nice and sharp.If you had a bad copy it would stand out that focus was well out.

I just got a Sigma 17-70mm and to be honest I think I prefer my DA 16-45mm therefore I will prob put it on the for sale bit soon.

Hi Rob - very hard to tell at that size. It looks a bit soft but its quite possibly the way the pic was resized for the web.

Youd need to post a 100% crop to show how sharp it was. Just crop a (roughly) 800X800 pixel square from the centre and save it without resizing.

Interesting, I have a Sigma 24-70mm F2.8 and I have the exact same problem with focusing on the K10D (focus point selected is out of focus and background is in focus)

Seems that the problem is not to do with the lenses, but the K10D itself.

I have tried the Sigma on my DS and K20D with no problems at all.

Seems that the K10d does have a focus problem from time to time, however it is only the last few months that it started occuring. I wonder if it something to do with the number of shots taken with it? I have taken 18000 so far, what has others who now have the focus problem taken with their K10D's?