Hi-tech also have a REVERSE ND GRAD, what is that??? link

Never mind I found it.

Ah okay, you're worried about the transition.
It's actually the angle of view that matters the most not the front element.
So for wide angle lenses soft is most of the time better but for normal to long you can get hard ones, you can even special order ones with an razor edge for tele lenses.

I think it's quite hard to make a define line when to use which type of transition since also the type of photo matters.

Seascape for example hard ones are better but if you've hills and trees a soft one is better.

You're having the same problem if you go for smaller filters because it's the transition that matters and that's roughly the same on each size although just read it does differ from brand (didn't knew that).
Hi-tech hard are softer then lee hard I just discovered.

Thank you Glyn.

I'm glad Pentax have decided to make SDM lenses only so hopefully these problems are in the past.

It seems so John and Unlocker but this the problem that I mean, how can you point the finger to the SDM motor while you don't even know it's to blame?

Unlocker and Glyn I'm not saying that you're blaming the SDM for the problem or the opposite, your just reporting what is going wrong and how it looks like.

What does TA mean?

I find your list also a bit strange, it seems like a DA40mm would be your best choice since it's cheap very sharp wide open and it's precisely in the focal ranges you mentioned. Just step forward or backward to zoom

George, I doubt that the KAF3 lens (SDM only) is more complex then screw-driven lens, I even dare to say the opposite might be true.

Glyn your story is one off those I meant.
Is the SDM motor really to blame there or can it be a gear in the AF system that's not working well or maybe an O-ring that gets lose?

It depends on what holder you're using.

The cokin z-pro is a 100mm holder that holds 3 filters and is rated up to 20mm (35mm format) so 13mm APS-C so comparable holders might be the same.

The Z-pro holder can be adapted and it can then easily fit 10mm for APS-C and maybe even wider?

Simon define oddly?

The problem is I think with the KAF2 focus system inside the DA*16-50 lens that cause for a lot of problems.
The KAF2 lenses have Screw-driven focus, SDM and also quickshift all that makes the AF system inside the lens very complicated and no other lens maker even dared to make such a system in their lenses.
With the simpler design off prime lenses those does not seem to suffer but the complex design of the wide angle zoom seems to be too much.

The KAF3 mount lenses like the DA17-70 and DA*55 with only SDM will be far more reliable. Maybe even more reliable than screw-driven lenses because they have less mechanical components.

Unlocker, tough luck with your 50-135 hopefully they solve it properly for you
Do you think the SDM motor is at fault or is the AF system of the lens that's playing up?

Wondering what horror stories there are out there at first.
And now I'm also actually quite curious how bad the SDM failure might be under active members but mostly that's just too kill time though
Although if only one lens is very problematic that just proves that the design is not good rather that the SDM motor is at fails.

Indeed but at the moment the SDM motor is getting the blame for every AF failure of a lens that has one and the the trust in the SDM motor isn't very high under some members here and I wonder if the SDM motor deserve that?

DA 17-70 - 3 (0)
DA*16-50 - 3 (0)
DA*50-135 - 5 (1) sticky AF but the whole lens is faulty sdm problem???
DA*60-250 - 3 (0)
DA*55 - 1 (0)
DA*200 - 0 (0)
DA*300 - 2 (0)