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09-04-2013, 06:52 AM   #421
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QuoteOriginally posted by IchabodCrane Quote
I would hope CDAF provides more consistent focusing but it's doubtful the lens would be used that way most of the time.
I had raised the topic in the comments section of the review and DPR staff responded they did not have a 70D ready when they tested the Sigma's AF. However, I got a comment from another photographer. Here it is:
QuoteQuote:
By CarstenKriegerPhotography (1 day ago)
I have been using the 70D and Sigma 18-35mm for about a week now and so far the live view AF is very consistent and accurate compared to the viewfinder AF. I haven't tried it out with fast moving subjects yet but so far it looks rather promising.
Note that with the 70D, CDAF is about same speed as PDAF.

09-04-2013, 07:12 AM   #422
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I'd like to know if the flare testing in the lenstip review was done with the hood on or off and what difference it would have made to those shots if it wasn't used.

With the dpr review, wouldn't poor focus accuracy at f1.8 be just as much the fault of the camera AF points not being made to deal with that aperture? I'm curious what the accuracy would be at f2.8 rather than f1.8?

I can't see myself shooting that wide open since I shoot live music and f1.8 doesn't work well with moving subjects. In theory, this lens will be perfect for small to medium gigs where I'd love to have wide to standard zoom range covered with the same sharpness that I love from my DA*55.
09-04-2013, 07:24 AM   #423
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Update today from B&H: " we haven't yet received the merchandise from our supplier."
09-04-2013, 08:35 PM   #424
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QuoteOriginally posted by dadipentak Quote
Update today from B&H: " we haven't yet received the merchandise from our supplier."
Same here

09-04-2013, 08:56 PM   #425
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I thought the deal was that Pentax and Sony versions were coming later in the year, as in, November or December. I wouldn't be surprised if it doesn't come until early next year. It's still not out for Nikon yet, or even Sigma's own mount. Only Canon.
09-04-2013, 11:16 PM   #426
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QuoteOriginally posted by Mistral75 Quote
Needs detailed AF microadjustment for best results Inconsistent autofocus in difficult conditions even after microadjustment
These reflect my own experiences with this lens on a Canon 7D, the AF would lock on without difficulty - exactly where the plane of focus was positioned was variable...sometimes by significant amounts, even with static subject matter. I personally think this is symptomatic of a lens with lowered contrast at wide apertures, which is one of the many reasons why AF systems are generally overly taxed by the use of fast lenses. There are also physical limitations of how heavy the lens elements in a lens can be because of the limited amount of torque AF motors can produce. The greater the weight the motors have to move the shorter the MTBF - I recall quite a few photographers complaining about the sigma 50mm f/1.4 HSM having a burnt out AF motor, there were also issues with the older version of the sigma 120-300mm f/2.8 APO EX DG HSM burning out AF motors as well.

Last edited by Digitalis; 09-06-2013 at 05:55 PM.
09-06-2013, 02:44 PM   #427
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QuoteOriginally posted by falconeye Quote
Note that with the 70D, CDAF is about same speed as PDAF.
Technically, isn't it it PDAF also now in liveview using their dual pixel system?
09-09-2013, 01:55 AM   #428
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QuoteOriginally posted by Mazhe Quote
Technically, isn't it it PDAF also now in liveview using their dual pixel system?
Some call it PDAF, some CDAF as both terms aren't really defined in an exact enough manner.

Technically, both, PDAF and CDAF, compute and maximize a correlation function. The dual pixel 70D AF produces two image signals which now can be both, cross-correlated as well as auto-correlated and the AF actually switches between both options (according to the patent). I foresee a better, future, version which combines both signals.

So, if you call it, at the end of the day, CDAF or PDAF, is a matter of taste. I called it CDAF because the 70D has another, classic PDAF module.

09-10-2013, 02:45 PM   #429
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The Sony people are saying the A-mount version of the lens has been delayed until November, so I don't see a K-mount hitting the market this year. Demand appears to be pretty strong for this lens.
09-10-2013, 03:04 PM   #430
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QuoteOriginally posted by Winder Quote
The Sony people are saying the A-mount version of the lens has been delayed until November, so I don't see a K-mount hitting the market this year. Demand appears to be pretty strong for this lens.
Actually, the response that the Sony people got specifically included Pentax in it, saying that the Sony and Pentax versions have both been delayed until mid-November (approximately and not guaranteed).

I guess that means the Nikon one is expected out before mid-November?
09-10-2013, 03:08 PM   #431
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QuoteOriginally posted by thornburg Quote
I guess that means the Nikon one is expected out before mid-November?
According to B&H, the Nikon version will be available at the end of September, though I'm sure it's backordered like crazy.

Sigma 18-35mm f/1.8 DC HSM Lens for Nikon 210-306 B&H Photo

QuoteQuote:
New Item, Available for pre-order
Expected availability: September 25 2013
09-10-2013, 03:09 PM - 2 Likes   #432
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QuoteOriginally posted by Winder Quote
The Sony people are saying
They have people? Lucky bastards.
09-11-2013, 02:51 PM   #433
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QuoteOriginally posted by Edgar_in_Indy Quote
They have people? Lucky bastards.


09-11-2013, 07:29 PM   #434
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QuoteOriginally posted by Edgar_in_Indy Quote
They have people? Lucky bastards.
Came from Minolta.

Poor bastards.
09-15-2013, 06:43 PM   #435
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So I've borrowed this lens for the weekend and I'm using it on a Rebel T4i I've also borrowed.
This is a delightful lens when it nails the focus, sharp from f/1.8 etc, but this combination of lens and camera I have needs a serious adjustment for front focus, of my shots at 18mm/infinity I'm lucky if 1/3 of them is in focus.
I'm not even referring to shots at f/1.8 either, it is off enough that shots taken at f/4 or f/5.6 supposedly focused at infinity are out of focus. It's unacceptable.
The T4i cannot be adjusted for focus in camera, and I don't have a USB dock to borrow with the lens, so I've taken to auto-focusing then turning the focus ring back in the right direction after AF has locked. This also wouldn't be such an issue if the lens didn't focus past infinity.

I think the camera body is mostly to blame, but I'm truly hoping the Pentax version will work better out of the box. If not, then at least I will be able to dial in a focus adjustment on my K-5.
I'll likely take the Nikon version for a spin too, when it is available.

btw: Flare is as bad as lenstip describes. I like to shoot towards the sun...haven't decided whether this is a deal-breaker yet, the lens does everything else right. :/

Here are some photos I've taken with it: Sigma 18-35mm f/1.8 - a set on Flickr

Last edited by Mock; 09-15-2013 at 07:36 PM.
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