[cali92rs]

So my eternal search for a walk around zoom continues.
I indulged in a Sigma 18-35mm zoom. That range would cover about 75% of my shots.
The good: IQ is as good as advertised. When it nailed focus, it was as good or better than any prime i have (which includes the 31mm LTD).
The unacceptable: "when it nailed focus" is a huge caveat for my copy. I got the dock in anticipation of focus issues. The problem is that it was inconsistent. Sometimes it would front focus, sometimes it would back focus. Also, it is such a pain in the @ss to remove the lens, sticking it on the dock, making the changes, then put it back on the lens. Focus testing is iterative, so you are going to have repeat this process over and over. And because the problems were inconsistent, all this was a waste of time.
Also, it is a big lens. If i wanted a walk around kit this big, i would have just kept my 6D + 24-105L setup, because the Sigma is not much smaller, if at all

I really wanted this to work out for me because its specs fit me like a glove. Oh well.

[AldaCZ]

I fell you

[Adam]

I love how Sigma still denies any known issues with this lens. For a lens this expensive I would have expected a firmware fix or service advisory long ago...

[Madaboutpix]

Understandable woes ... even if they don't come as a complete surprise, given the well-documented AF issues troubling this lens. In fact, I increasingly take Sigma's USB dock approach as a somewhat pathetic admission that they're clueless about how to make the AF of some of their fast, more complex lenses work on a wide range of bodies, for which they can only be back-engineered.

You sound as if you have been on this search for quite a while, so I guess you have already looked at both the HD20-40 and the HD16-85 and felt they were not fast enough for what you shoot? IQ-wise, and provided good copies, I know I wouldn't have reservations about either of them.

[cali92rs]

Understandable woes ... even if they don't come as a complete surprise, given the well-documented AF issues troubling this lens. In fact, I increasingly take Sigma's USB dock approach as a somewhat pathetic admission that they're clueless about how to make the AF of some of their fast, more complex lenses work on a wide range of bodies, for which they can only be back-engineered.

You sound as if you have been on this search for quite a while, so I guess you have already looked at both the HD20-40 and the HD16-85 and felt they were not fast enough for what you shoot? IQ-wise, and provided good copies, I know I wouldn't have reservations about either of them.

Ok...this is a bit irrational so forgive me. But i had the 16-85mm for a while and actually liked it a lot. But (here is the irrational part ) the 16mm of that zoom made me not use my DA15mm, and i love that little lens (not to mention the fact that the used market is such that i can maybe get 50 cents on the dollar if i decided to sell it).

So, I decided to give the 20-40mm a shot. I figure that is a nice complement to the 15 and 70 i already have (and I can still break out the 31 and 50mm for lowlight/indoors situations).

[Outis]

I was thinking of getting an 18-35 for astrophotography, and was wondering whether the AF issue had been fixed. Good to know, thanks! Given the fact that the autofocus is basically useless, I'd be much happier if they just designated it as a manual-focus only lens and knocked $300 off the price or something. Or had a less expensive manual-focus version.

[Madaboutpix]

So, I decided to give the 20-40mm a shot. I figure that is a nice complement to the 15 and 70 i already have (and I can still break out the 31 and 50mm for lowlight/indoors situations).

Sounds like a plan. Still, owning and loving the DA15 myself, I'm reasonably sure the HD16-85 wouldn't give me that many headaches about no longer using the prime enough. The zoom for flexible yet high-quality imaging when changing lenses is not feasible, with the bonus of the WR, and the compact prime for low-profile portability as well as critical IQ.

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Last edited by Madaboutpix; 11-28-2015 at 12:40 PM.

[cali92rs]

I am not going to tell you not to get one, because there are those that do have good copies. However, it is an expensive piece of kit and even with the dock, it won't ensure that you get consistent results.
So, i am just submitting another datum point for those in the future that may be interested in this lens.

[Madaboutpix]

I am not going to tell you not to get one, because there are those that do have good copies. However, it is an expensive piece of kit and even with the dock, it won't ensure that you get consistent results. So, i am just submitting another datum point for those in the future that may be interested in this lens.

Which is commendable and much appreciated. Sharing experiences like yours remains one of the things that make this forum so useful.

[gfurm]

Mine nails focus every time (with K3 II) with no dock or in camera adjustments. I was a bit hesitant buying it but I have no regrets.

Greg

[interested_observer]

I was thinking of getting an 18-35 for astrophotography, and was wondering whether the AF issue had been fixed. Good to know, thanks! Given the fact that the autofocus is basically useless, I'd be much happier if they just designated it as a manual-focus only lens and knocked $300 off the price or something. Or had a less expensive manual-focus version.

I only shoot this lens on a tripod and with liveview - thus bypassing the autofocus issue (which is OVF related). I do wish that Sigma wold fix the issue.

[Digitalis]

Sorry to hear of your woes, but if you didn't read the pentax forums review, or my comparative review of the Sigma 18-35mm Vs the FA31 You would have known what to expect. There are some people who own copies of this lens that allegedly do not have any issues with using this lens with PDAF - call me prejudiced but with the increasing evidence of AF issues and their prevalence outside Pentax brand cameras I'm finding these positive reports extremely hard to believe.

i am just submitting another datum point for those in the future that may be interested in this lens.

It really can't be just a coincidence that Nikon* and Canon* photographers are experiencing identical issues with PDAF with this lens as well. Sigma photographers are being suspiciously quiet about it.

*And these people were using current camera bodies with advanced AF systems like the Canon 7DII and Nikon D7100.

[voy-tech]

I was debating the same thing last year, went with the Ltd 20-40 and couldn't have been happier. The lightweight size and impressive IQ is great if you don't need the huge aperture of Sigma (or primes).

[sholtzma]

My copy too has bizarre AF issues. Again, manual focus is fine, as is LiveView. It is like the little girl with the curl: when it is good, it is very, very good, but when it is bad, it is horrid. Have not had time yet to experiment with the dock, but I'm not holding out much hope.

I should add that I am shooting with a K5iis. Don't know if that matters to the stories of woe...

[Edgar_in_Indy]

manual focus is fine, as is LiveView.

If Pentax ever comes out with a hot mirrorless camera, then maybe these misbehaving 18-35's can get a second life...