Sigma 18-35mm f1.8 DC HSM Lens


philstaff

Link Posted 21/10/2015 - 14:57
I have been looking at some reviews recently on this lens all really rate it. Does any forum member have a copy and if so could you give me a little feed back.

Regards Ian

philstaff

smudge

Link Posted 21/10/2015 - 18:13
It is an excellent lens and I use it a lot for events and parties. Some complain about the size and weight but it feels about the same as a 16-50 on the camera, so not bad at all. The other frequent complaint is that the Pentax version does not focus well. My copy performs very well on my K5ii but on the few occasions I have tried it on my K5 backup body it has struggled to lock focus in low light.
Regards, Philip

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Algernon

Link Posted 21/10/2015 - 18:27
There are reports of focussing problems on other mounts as well as Pentax

It's not a problem for Pentax users they don't buy lenses to take photographs

See.....

http://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/277499-sigma-18...

--
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi

StephenHampshire

Link Posted 21/10/2015 - 18:59
I recently acquired one from a ember here. I am pleased to report that I have not encountered major focussing problems with my K3, although in really low light it can be a little slow.


England Expects.... by Arle Images, on Flickr

ISO 8000 1/80th f2.2


Steam Fair at night by Arle Images, on Flickr

ISO 640 1/20th f3.2


Growth and Decay () by Arle Images, on Flickr

ISO 500 1/100th f2.2
Everything Changes
http://www.flickr.com/photos/arleimages/

philstaff

Link Posted 21/10/2015 - 20:26
Thanks for the feed back all. I have not seen any issues with focusing on the video reviews. However I will dig into the issue and see if I can find out more.

Regards Ian

50mpCMOS

Link Posted 21/10/2015 - 23:00
I own the Sigma 18-35mm (constant aperture) f 1.8

One of my most frequently used lenses, and never have experienced one single issue with it. Out of every currently lens for sale in PK it's one of the fastest focusing, and also most accurate focusing. The only single (pk) lens that focuses faster is the Sigma 35mm f1.4 .

Other comparisons... Technically the Sigma 24-70 DG f2.8 is somehow able to focus more accurately, doesn't quite have the aperture of the 18-35, but for all of the eventual PK full-frame fans out there, it does not get any better with full frame zoom for PK.

Have tried it on most every digital Pentax camera body, even the K-01, also both versions of the K3. Not one single item I'd change about the 18-35 except that it is not full-frame. One of the best choices for aspc though

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johnha

Link Posted 22/10/2015 - 01:23
When a reputable camera magazine reviewed some of the very wide, very fast lenses they commented that camera manufacturers would not offer them. The reason was that focusing them is a challenge for the body and only the very best pro bodies had enough accurate AF points to do so (even on full-fat pro bodies only a handful of the most sensitive 'centre' AF points could handle it). Whilst an independent lens manufacturer would be happy to sell them, camera manufacturers would not want to sell a lens that didn't focus well on their best pro body.

I'd assume that given correct focus calibration (via the AF dock or whatever they call it), with centre-point AF in the right (or slightly less than ideal) conditions with good technique would work well. Beyond that there's a likelihood that AF performance will drop off for each sub-optimal factor at play (up until the point where the increased DoF inherent in wide-angles starts to make up the difference).

John.
PPG Flickr

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Spider-Man

Link Posted 20/11/2015 - 14:01
Ian, I have the Sigma 18-35mm F1.8 & use it with my K3, the image quality this combination delivers is simply outstanding.

The 18-35mm might not be a great zoom range but, what I like about this lens apart from the great quality feel, weight and light gathering ability of the lens, is the fact that with such a sharp lens you can crop the images quite dramatically and still produce good quality results. I'll try and add some images later, when I'm at my computer.

Peter P.
It's not the strongest species that survive, nor is it the most intelligent. It is those most adaptable to change.

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derek897

Link Posted 29/11/2015 - 02:19
philstaff wrote:
Thanks for the feed back all. I have not seen any issues with focusing on the video reviews. However I will dig into the issue and see if I can find out more.

Regards Ian

Hi Ian, I'm also looking at this lens amongst others, and I think the reason that the focusing issues don't come up at all in any videos is because there only seems to be an issue through the viewfinder, as that uses a different type of auto focus than live view. I think it's phase detection as opposed to contrast detection.
Have you purchased one yet or gone down a different route ?
Derek
I know what i like, If not always why.

philstaff

Link Posted 07/04/2016 - 14:37
derek897 wrote:
philstaff wrote:
Thanks for the feed back all. I have not seen any issues with focusing on the video reviews. However I will dig into the issue and see if I can find out more.

Regards Ian

Hi Ian, I'm also looking at this lens amongst others, and I think the reason that the focusing issues don't come up at all in any videos is because there only seems to be an issue through the viewfinder, as that uses a different type of auto focus than live view. I think it's phase detection as opposed to contrast detection.
Have you purchased one yet or gone down a different route ?
Derek

Not as yet Derek sorry for the delay.
Regards Ian

Blythman

Link Posted 07/04/2016 - 17:26
These were with the K5iis and 18-35 at f2.5. and 1/40 to 1/50 sec. So not the best of conditions, but hope it helps.

Badgers 1 of 5 by Alan Wennington, on Flickr


Badgers 2 of 5 by Alan Wennington, on Flickr


Badgers 3 of 5 by Alan Wennington, on Flickr
Alan


PPG
Flickr

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