Why did the Sigma 35 Art lost so much credit ? AF not durable ?

I had this one in past to replace the 35L and it was better in all cases.
Anyone has an idea why this Art (with best quality control) loses so much credit ?
Less scores on revieuw sites, sold more... could this be that the AF only works temporary or something and is not durable like the canon (with the dock Sigma released).
Strange why they couldn't make a durable AF then ? I don't understand...

I'm not quite sure as to what you are asking?

Because too many copies have broken AF. Its also pretty big and heavy.

My copy was great when it actually hit, but it missed MUCH more than it hit. I even spent hours trying to fix via dock, got to the point where everything was 100% perfect during tests, then the minute I take the lens out, its back to missing everything. Very frustrating.

My copy works perfect. weight no issue for me.

I've had both the 18-35 Art that I shot on a 7d for about 6 months, and the 50 Art that I shot on the 5d3 for about a year. The 18-35 needed a good bit of adjustment on the dock, but after that it was bang on. The 50 Art AF was nearly perfect right out of the box. And I used both of these for dimly lit moving subjects on a regular basis. Consider the source of the reviews you're looking at. Some are questionable. And opinions based on anecdotal accounts have a way of building up momentum. No doubt there are bad copies that get circulated, but as soon as someone utters the "lottery" jab it plants the seed in your head that only 1 in 1000s are useable, which is ridiculous. If someone says they get one bad copy after another, that signals to me the possibility of user error.

I do believe there is a statistically greater risk of getting a bad third-party lens rather than a bad OEM lens, but not even close to the epidemic scale some would have you believe. If you have any doubts, buy from a seller with a liberal return policy.

As for the weight issue, the 35L I is ~ 20 oz, the 35 Art is ~ 23 oz, and the new 35L II is ~ 26 oz.

Are these thorough reviews from serious sites/reviewers like www.photozone.de or www.the-digital-picture.com or customer reviews on shopping sites?

If the latter, I wouldn't give much weight to them: people are more likely to post 'reviews' when they've had problems, whereas quite a number of customers for whom the gear works fine will never post a review. Thus, such reviews are not a statistically sound quality measuring stick. Personally, I can't remember ever posting a review about my purchases, even though the sellers do send me their E-mails prompting me to do so.

I've got nothing but great things to say about it. Very sharp. Accurate focus. And seriously...big and heavy??? It's about the smallest lens I own besides the 50 1.8

You really need to examine the source of every review you read. The internet is full of poorly written reviews from people who have either spent 5mins with an item or worse, haven't used the item at all. There are also plenty of reviews out there that are published by people who "do product reviews" and having something to gain from it, whether it be monetary or social media exposure. For example, I watched a review on YouTube for the 50L done by a guy who also reviewed the Playstation 4, an Accu-rite Weather Station, some ugly and very expensive watch, a Toyota Rav4, and a Gilmore lawn sprinkler. The reviews were all about 5min long...5min for a sprinkler and 5 min for an SUV doesn't convey quality to me. Obviously, he can't be an expert on all of those products. I'm not suggesting a review is worthless if it isn't from a so-called expert, but I put more value if the person has some verifiable experience with the item.

Now onto the 35 Art; your use of the word "durable" seems like you're suggesting the AF mechanism becomes worse over time, or works well and then fails. I have not read anything consistent with that idea and I have not experienced that phenomenon myself. What does seem to be an issue is inconsistent AF accuracy at varying distances. In other words, some people are getting accurate AF with a 6-10ft target distance (just using those values as an example) and inaccurate results with targets outside of that range. I've also heard some say that results are inconsistent at any distance, but for the most part, the negative reviews cite the former example.

"I ordered the wrong thing for my other thing. One star."

I used the 50 Art, and I returned two copies. Both could not focus consistently using either static targets from a tripod or real world usage with my 70D. I was pretty disappointed as the lens when it nailed focus was unbelievably good. There is no shortage of idiots who don't understand how to use fast lenses and give lousy reviews. However, there is also a lot of evidence that suggests Sigma has had real trouble reverse engineering canon's AF on some cameras. Sigma's tend to either focus very well or very poorly on any particular lens/body combination, which is unfortunate. Because if they focused reliably I'd own pretty much every Art and fast zoom they make.

vengence wrote in post #18045435
Sigma's tend to either focus very well or very poorly on any particular lens/body combination, which is unfortunate.

This has been my experience too. I've found my Sigma 85mm f1.4 to be as accurate as all my Canon lenses in any lighting, but I had to go through a few copies of the original 50mm EX to get one that was usable.

I agree with if Sigmas did not have a big number of poor copies, I would probably own every Art series they made. But once you personally have a bad experience, its really bad.

I've found over the course of several months that it varies at the distance to subject, and also between bodies. On my 5D3, it hit up to about 15 feet, then would miss every time. I sold the 5D3 and picked up the 1DX Mark II, and I haven't noticed that same problem. It also seems ok on my 5Ds. I'm not sure of the technical reasons why it would change body to body, other than the body's AF system, but that definitely has been the case.

Sometimes I think Canon hires moles to go on line and spread Sigma AF hate and discontent to protect Canon lens sales...

I probably have more out of focus shots with my 70-200LII than my 35/1.4 art.

35 became my favorite lens I think.