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11-30-2014, 04:21 AM   #1
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Sigma 18-35mm

Amazon.com : Sigma 18-35mm F/1.8 DC HSM Lens for Pentax APS-C DSLRs : Camera Lenses : Electronics

Has anyone worked with this lens? I've been considering it for my K-5. Just wanting to know you guy's thoughts on its focusing performance in lower light settings and about how heavy is it for a carry around for long periods of time? Just as long as its much lighter than the 28-300mm usm from Canon...

11-30-2014, 06:07 AM   #3
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I have this lens and it works great w/ my k3. Here's a party I used that lens at:
https://www.flickr.com/photos/55038128@N00/sets/72157648740320699/
12-01-2014, 01:51 AM   #4
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While the sigma 18-35mm f/1.8 "ART" is certainly a good lens there are some substantial issues with autofocus - and there doesn't seem to be a predictable pattern to it from what I have seen.



My recommendation is to buy the lens dock so any systemic AF issues can be eliminated. Random AF issues regardless of light levels will still occur at the most unexpected of situations for no apparent reason*.



I also strongly recommend investing in a lens calibration chart so you can quickly and accurately asses the AF accuracy and adjust it accordingly. I also reccomend buying a O-ME3 viewfinder magnifier to increase the chance that you can spot any focus errors before you press the shutter.


The lens is also a brick:


Pentax K 24mm f/2.8, SMCP-FA31mm f/1.8 Limited, Sigma 15-30mm f/3.5-4.5, Sigma 18-35mm f/1.8

I have no real complaints about lens weight, but for some it can be a deal breaker. Even though it has an APS-C specific design, the Sigma 18-35mm is bigger and in some cases three times as heavy as full frame lenses that cover a similar range.


* "if anything can go wrong, it will."

12-01-2014, 02:19 AM   #5
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I could only justify buying such a huge lens for low-light events where reliable output is essential. Unfortunately reliable autofocus is its major weakness, so I will not be taking that risk.
12-01-2014, 09:52 AM   #6
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QuoteOriginally posted by Digitalis Quote
Even though it has an APS-C specific design, the Sigma 18-35mm is bigger and in some cases three times as heavy as full frame lenses that cover a similar range.
We should be thankful, I guess, that they didn't make it a f1.4 zoom
I bet they built some f1.4 prototypes though.
12-01-2014, 10:04 AM   #7
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Well, the Canon 28-300 is 3.67lbs and the Sigma 18-35 is 1.78lbs, so it's definitely lighter...

Any other lenses you have used to get a reference? When I saw it on my friend's 70D, it was a substantial lens - but not significantly larger or heavier than a DA*16-50 (well, .5lbs can be significant depending on who you are, but not to me).
12-01-2014, 04:09 PM   #8
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QuoteOriginally posted by rawr Quote
We should be thankful, I guess, that they didn't make it a f1.4 zoom
...the focus issues would have been worse than they already are.

12-01-2014, 06:43 PM   #9
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I have not had major trouble with my copy. I doubt I'm the only one because lots of people are likely not saying anything. Still, there are a number with issues.

As for weight, I find it to be not problematic at all. Pentax users complain that anything over 250g is too heavy, so take a lot of what you read with a gain of salt.


My collection of sample photos:
https://www.flickr.com/photos/127442034@N03/sets/72157649140156878/
12-01-2014, 11:19 PM   #10
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QuoteOriginally posted by MadMathMind Quote
Pentax users complain that anything over 250g is too heavy
I work with larger formats where a 250g lens is a real lightweight to me. But for what it is the Sigma 18-35mm f/1.8 is actually heavier than the full frame equivalents.
12-02-2014, 01:02 AM   #11
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It can't be heavier than whatever is equivalent, since theres nothing equivalent on aps-c
12-02-2014, 02:23 AM   #12
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QuoteOriginally posted by zitounae Quote
It can't be heavier than whatever is equivalent, since theres nothing equivalent on aps-c
The closest FX format equivalent are the professional 24-70mm constant f/2.8 class lenses, the 18-35mm f/1.8 lens has a smaller focal range but it still weighs more than some of these lenses.

Last edited by Digitalis; 12-02-2014 at 02:40 AM.
12-02-2014, 03:24 AM   #13
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QuoteOriginally posted by Digitalis Quote
The closest FX format equivalent are the professional 24-70mm constant f/2.8 class lenses, the 18-35mm f/1.8 lens has a smaller focal range but it still weighs more than some of these lenses.
Yup true some does significantly, some get also really close on the weight side. The 18-35 is also still wider and faster (would i dare to say overall sharper?)

Don't get me wrong i had a deep thinking about buying this lens, finnaly the significant weights and limited range for an all purpose lense made me skip that one (more than the eventual focus issues that should en up solved in some way).
But after all, the 18-35 is just unique and imho can't really be compared to anything yet.
12-02-2014, 03:38 AM   #14
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QuoteOriginally posted by zitounae Quote
But after all, the 18-35 is just unique and imho can't really be compared to anything yet.
In your opinion - I compared it to the SMCP-FA31mm f/1.8 limited and it was found wanting* - especially in the areas of focus precision, bokeh and to an extent resolution, at f/1.8 it is an excellent lens but at smaller apertures a prime will be just as good, if not better**. But if you need 18mm f/1.8 on APS-C format this is the only lens going that offers it with decent image quality.


* In my review the difference between the Zoom and the prime was in the end a matter of one stop, the FA31 wasn't as contrasty as the Sigma lens at f/1.8 but once it was stopped down to f/2.8 the prime matched it and at apertures of f/4 and up, the FA31 exceeded the performance of the sigma zoom across the frame.
** and significantly more compact as well.

Last edited by Digitalis; 12-02-2014 at 03:55 AM.
12-02-2014, 11:01 AM   #15
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Your choice to think it makes that much sense to compare a zoom with a prime that cost 200$ more - Can't blame, did it too! With the 200$ cheaper 30 art and there the prime won too (imho) because even if less sharp, was all around easier to carry for all purpose lens.
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