sigma 18-35 f/1.8 review


Smeggypants

Link Posted 02/09/2013 - 18:22
http://www.dpreview.com/lensreviews/sigma-18-35-1-8/6
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283

Gamka

Link Posted 02/09/2013 - 20:54
One of the cons ... Restricted Zoom Range

Surely, if it zooms from 18 to 35 mm it cannot be restricted and performs as advertised.

johnriley

Link Posted 02/09/2013 - 21:19
That's really an argument about the language used though rather than the statement. We know they mean that 18-35mm isn't much of a zoom range.

Of more concern would be the erratic AF performance, which is probably the last thing we need in such a wide aperture lens.
Best regards, John

Smeggypants

Link Posted 02/09/2013 - 22:10
I think the AF performance is simply being more heavily scrutinised because of the Sigma USB Dock allowing the AF tweaking at different focal lengths and different distances.

I bet if you analysed the AF performance of any lens the compensation required would change for f length and f distance
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283

johnriley

Link Posted 02/09/2013 - 22:14
I'm sure it does, which is one of the reasons that adjusting zoom lenses can be fraught with difficulty.
Best regards, John

cabstar

Link Posted 02/09/2013 - 23:29
Could be down to the body used to test it on, at 18mm wide its a going to be a small point in the scene that gets focussed on.

Still an amazing feat of lens engineering.
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Currently on a Pentax hiatus until an FF Pentax is released

johnha

Link Posted 03/09/2013 - 00:34
I read in one of the magazines some months ago that big camera manufacturers are unlikely to make similar lenses partly because they might demonstrate focus issues with the cameras. Particularly as most cameras only have limited numbers of suitable AF points for accuracy at wide apertures, losing a gazillion of AF points or AF modes in the process. AF performance to the uninitiated could look quite poor depending on shooting style or subject matter.
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Pentaxophile

Link Posted 03/09/2013 - 15:54
The main thing that gives me pause is the price - for that cost you're well on the way to the cost of a used FF camera, which should give similar results with a cheaper f2.8 zoom like the Tamron 28-75mm.
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cabstar

Link Posted 03/09/2013 - 17:29
Pentaxophile wrote:
The main thing that gives me pause is the price - for that cost you're well on the way to the cost of a used FF camera, which should give similar results with a cheaper f2.8 zoom like the Tamron 28-75mm.

I have actually been looking at this scenario and recently launched FF DSLR by other brands are less than a 1000 now, definitely pause for thought...
PPG Wedding photography Flickr
Concert photography

Currently on a Pentax hiatus until an FF Pentax is released

Algernon

Link Posted 03/09/2013 - 17:55
f/1.8 lets about 1 and a 1/3rd more stops of light though
than f/2.8 which was the main reason they made the lens
Half Man... Half Pentax ... Half Cucumber

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

Algi

johnriley

Link Posted 03/09/2013 - 18:49
But not a thought for Pentax User...however, there are always a few purchasers who sell on very quickly. It seems odd, but maybe they don't get what they want or expect out of their new purchases. Amateur photographers can be very fickle!
Best regards, John
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