[panoguy]

I can't believe that the company would hold that position. Sigma's own cameras don't have some revolutionary technology on them.

Foveon - it solves all your problems.

Just FYI to the OP: the Sigma tech was blowing hot air about "ancient DSLR systems." I have an SD1 Merrill, and their AF module is the same vintage as the one in the K10D (PDAF-only, since the SD1 doesn't even have live view CDAF).

You can bet that Sigma tested their 18-35 on the SD1 before rolling it out. In fact, my copy focuses just fine on my Sigma body, but I personally suspect the later manufacturing runs are not as tightly constructed as my very early 18-35.

[bdery]

I am paraphrasing, but he told me that DSLR cameras are using an “ancient" focusing system and are often not able to handle new “esoteric” lenses, such as the 18-35.

Technically true, but other lenses still manage to perform well. Even fast aperture lenses.

He mentioned, though I did not quite grasp it all, the difficulty the mirror in a traditional DSLR system introduces to focusing

Also theoretically true, but not backed up by experience.

He also noted, after I mentioned that I turned shake reduction off, that the sensor assembly due to its shake reduction capability still causes a problem.

It shouldn't have any impact.

I was specifically told to set the lens up at 1 meter distance at 35mm, at 1.8 and focus on a 3D item, not a chart. This sounds much like the follow-up testing pentaxforums did, but I will give it a try.

A 3D object introduces a new variable in the equation.

The Pentaxforums tests are rigorous, well detailed, and as an optical designer often responsible for products qualifications, I find no significant faul with it. It documents and demonstrates the problem without doubt.

[candgpics]

Hi:

Thank you all for your comments and thank you Digitalis for the follow-up.

I adjusted the lens for 35 mm to (-1) and took some pictures of my children last night and it seems to be working well at 35 mm (I thought I might get some random, but regular, out of focus images and from my small sample I did not.

Tonight if I have some time I will play around at other focal lengths at the global (-1), fully expecting a low keeper rate, but we'll see.

Then I will decide whether to get the dock. I am swamped at work over the next few weeks and will not have the time to devote to using the USB dock before my return window closes. I would hate to return a lens that can be made to work with an acceptable rate of focus success simply because I do not have the time at the moment to adjust it. Though, I still am not happy that an apparently needed accessory is not included.

If the lens does in fact focus accurately about 80% of the time I would be happy with that, given its utility and great performance at f1.8. I have learned to deal with "work arounds," much as I imagine everyone has to some extent with lenses and camera bodies.

To the forum members who have the 18-35--have you found it to be as useful/worthwhile as you initially thought it would be, particularly when (some of you) are experiencing some focus issues?

[Digitalis]

To the forum members who have the 18-35--have you found it to be as useful/worthwhile as you initially thought it would be

To be perfectly blunt: no. It does not outperform the FA31, the bokeh can be atrocious at longer focus distances. For me its greatest utility lies in the fact that it fills in the focal length gap that exists between the Sigma 8-16mm f/4.5-5.6 and the Pentax FA31mm f/1.8. Though I'm finding the Sigma 15-30mm f/3.5-4.5 to be of more use in that regard, 15-30mm on APS-C is a very useful focal range.

[candgpics]

Hi, thank you again Digitalis.

I'll play with the lens for a bit more, but all of this discussion seems to be pointing me in one direction (kind of like.....I know what to do, but do not yet want to admit it; oh well).

Thank you, as well as to everyone else, for your comments

[aaronhbridges]

I was having serious issues with the new Sigma and ditching the half-press in favor of the rear AF button has changed its performance completely, if you haven't tried this out check it: https://www.pentaxforums.com/forums/38-photographic-technique/236970-perfect-...everytime.html