November 22, 2014, 09:22:51 PM

Author Topic: Sigma 50mm Art 1.4 Focusing problems  (Read 20907 times)

NancyP

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #105 on: July 15, 2014, 11:46:52 AM »
I seriously doubt that Canon shares ALL of the details of autofocus protocols with Sigma. I am sure that Canon shares the basic protocols, but the tweaks made to adapt each motor- lens-AF protocol unit would not be given to Sigma, and in fact would not be pertinent. Sigma has to work out conditions for its own motor-lens combos. Canon may not have shared any of the AF protocols (and other lens communications, involving aperture stop-down) earlier on, given that there are Sigma lenses out there that will not function on newer Canon bodies.

I hardly think of Japan as "socialist". What baloney. American capitalists have learned a thing or two from Japanese businesses regarding production and innovation. A major difference is that the Japanese government openly supports early stage R and D, whereas the U.S. government hides its support of early R and D under a complicated grants and contracts system that doesn't get seen by the average citizen.

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #105 on: July 15, 2014, 11:46:52 AM »

mrsfotografie

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #106 on: July 15, 2014, 11:48:58 AM »
YuengLinger: I have a swedish friend who also got the 35 Art and 50 Art the other day, his 35 works flawless and is everything it should be, whilst the 50 is all over. I had the opposite experience and I had two 35's and two 50's, only one out of those 4 worked at all, and I have the docking.

Conclusion is, Sigma just can't do proper QC, it's just to many that doesn't work.... Lucikly I got a peeerfect 50 Art the second time.

Ok I'm sticking to my 35A and 50 EX, both are truly excellent copies (yes my 50 is spot on most of the time too).
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YuengLinger

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #107 on: July 15, 2014, 12:17:28 PM »
Just got my RMA from B&H.  Simply don't want to deal with the dock.  Also, just read on the lensrental site that they have had "multiple" problems with the lens locking up during adjustment on the dock.

And I don't play the "good copy" game.

Lovely bokeh, all around IQ, but I'm too spoiled by AF to give it up for MF!   :-X

GammyKnee

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #108 on: July 15, 2014, 12:48:22 PM »
Conclusion is, Sigma just can't do proper QC, it's just to many that doesn't work.... Lucikly I got a peeerfect 50 Art the second time.

I wish I could find out what the odds are in this Sigma QC lottery, 'cos this new 50 is even more appealing than its predecessor (got burned by that one myself).

Has anybody checked serial/batch numbers to see if there's any trend, e.g. are newer production runs any better than earlier ones?


sdsr

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #109 on: July 15, 2014, 03:32:33 PM »
Just got my RMA from B&H.  Simply don't want to deal with the dock.  Also, just read on the lensrental site that they have had "multiple" problems with the lens locking up during adjustment on the dock.

And I don't play the "good copy" game.

Lovely bokeh, all around IQ, but I'm too spoiled by AF to give it up for MF!   :-X

I expect that if I ever decide I want this lens I'll buy an EF mount but use it on my Sony A7r, where MF is easy. But it's annoying to buy a fairly expensive AF lens which you're expected to fiddle around with on a docking station and even then seems best used, in the case of many copies at any rate, in MF mode.  (Speaking of MF, I've recently been greatly enjoying a 50mm 1.4 Pentax/Takumar; excellent image quality, small, fairly light and, to these eyes, more attractive... and it just works.  All for c. $100.)

thestructured

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #110 on: July 21, 2014, 06:14:15 PM »
I feel so much better to have read this thread. I registered with this forum just to share my experiences. I'm soon to be on my fourth copy of the sigma 50 art. Copy #1 had the issue where center point focusing was fine, however outer points resulted in front focusing, and this was consistent. AFMA can't fix that because it will result in the center cluster (5d3) not working properly. Same issues on my 6d, to a lesser degree. Sigma said they can't fix it until new firmware comes out that addresses this problem. Onto copy #2; my second copy had no problems. It was a beautiful thing, not only because the optics are phenomenal but because it confirmed that I'm not insane and imagining that the first copy had a problem. It was a night and day difference. Then, like an idiot, I returned the second one (the dealer I got it from was selling them at an inflated price) and picked a third one up elsewhere since I found them at their normal price (put $200 back in my pocket). Well, I now regret that because the third one has the same exact outer point issue as copy #1 did. I am going to try for a 4th one, though it's hard to play this game because they are not consistently in stock anywhere.

This problem is very real. If you're lucky enough to get a copy without issues, (and they DO exist), do. not. sell. it.

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dilbert

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #111 on: July 21, 2014, 07:56:40 PM »
...
But it's annoying to buy a fairly expensive AF lens which you're expected to fiddle around with on a docking station and even then seems best used, in the case of many copies at any rate, in MF mode.
...

Why do you think AFMA exists on Canon cameras? To address the same problem that the docking station is for.

The problem isn't QC it is engineering tolerances and the fact that neither camera nor lens are all made the same. There is copy variation between each camera and lens. This means that whilst AFMA might be +5 for a given lens on your camera, that same lens might be -5 on my camera and that same lens might be +0 on someone else's camera.

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #111 on: July 21, 2014, 07:56:40 PM »

IsaacImage

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #112 on: July 22, 2014, 01:02:50 AM »
I feel so much better to have read this thread. I registered with this forum just to share my experiences. I'm soon to be on my fourth copy of the sigma 50 art. Copy #1 had the issue where center point focusing was fine, however outer points resulted in front focusing, and this was consistent. AFMA can't fix that because it will result in the center cluster (5d3) not working properly. Same issues on my 6d, to a lesser degree. Sigma said they can't fix it until new firmware comes out that addresses this problem. Onto copy #2; my second copy had no problems. It was a beautiful thing, not only because the optics are phenomenal but because it confirmed that I'm not insane and imagining that the first copy had a problem. It was a night and day difference. Then, like an idiot, I returned the second one (the dealer I got it from was selling them at an inflated price) and picked a third one up elsewhere since I found them at their normal price (put $200 back in my pocket). Well, I now regret that because the third one has the same exact outer point issue as copy #1 did. I am going to try for a 4th one, though it's hard to play this game because they are not consistently in stock anywhere.

This problem is very real. If you're lucky enough to get a copy without issues, (and they DO exist), do. not. sell. it.

Sorry to hear that , but you brought me smile ;)
Yes, I remember that once I had great D800 without any AF points issues …. well almost .. well just the left one ;)
and I return it and got even worst one ;)

Viggo

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #113 on: July 22, 2014, 02:47:15 AM »
...
But it's annoying to buy a fairly expensive AF lens which you're expected to fiddle around with on a docking station and even then seems best used, in the case of many copies at any rate, in MF mode.
...

Why do you think AFMA exists on Canon cameras? To address the same problem that the docking station is for.

The problem isn't QC it is engineering tolerances and the fact that neither camera nor lens are all made the same. There is copy variation between each camera and lens. This means that whilst AFMA might be +5 for a given lens on your camera, that same lens might be -5 on my camera and that same lens might be +0 on someone else's camera.

Like we've said soo many times before, it's NOT about afma ... Sigh, it's the  inconsistency ! Please print this message and tape it on your fridge.
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fotonunta

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #114 on: July 22, 2014, 06:54:59 AM »
All Sigma lenses have focusing problems! I had two of the a 24-700 and 70-200 last versions - I sent them to be calibrated with my body and then everything was ok.
« Last Edit: July 22, 2014, 06:56:34 AM by fotonunta »

dilbert

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #115 on: July 22, 2014, 07:15:41 AM »
...
But it's annoying to buy a fairly expensive AF lens which you're expected to fiddle around with on a docking station and even then seems best used, in the case of many copies at any rate, in MF mode.
...

Why do you think AFMA exists on Canon cameras? To address the same problem that the docking station is for.

The problem isn't QC it is engineering tolerances and the fact that neither camera nor lens are all made the same. There is copy variation between each camera and lens. This means that whilst AFMA might be +5 for a given lens on your camera, that same lens might be -5 on my camera and that same lens might be +0 on someone else's camera.

Like we've said soo many times before, it's NOT about afma ... Sigh, it's the  inconsistency ! Please print this message and tape it on your fridge.

AFMA is there because there is inconsistency. Canon recognizes that there is inconsistency in camera/lens manufacture and thus introduced that feature to allow people to tune their own camera. If every lens was the same, AFMA wouldn't be needed.

rs

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #116 on: July 22, 2014, 07:23:17 AM »
...
But it's annoying to buy a fairly expensive AF lens which you're expected to fiddle around with on a docking station and even then seems best used, in the case of many copies at any rate, in MF mode.
...

Why do you think AFMA exists on Canon cameras? To address the same problem that the docking station is for.

The problem isn't QC it is engineering tolerances and the fact that neither camera nor lens are all made the same. There is copy variation between each camera and lens. This means that whilst AFMA might be +5 for a given lens on your camera, that same lens might be -5 on my camera and that same lens might be +0 on someone else's camera.

Like we've said soo many times before, it's NOT about afma ... Sigh, it's the  inconsistency ! Please print this message and tape it on your fridge.

AFMA is there because there is inconsistency. Canon recognizes that there is inconsistency in camera/lens manufacture and thus introduced that feature to allow people to tune their own camera. If every lens was the same, AFMA wouldn't be needed.

AFMA is there for consistent errors. Inconsistent errors cannot be corrected with a simple offset.
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YuengLinger

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #117 on: July 22, 2014, 07:25:49 AM »
Dilbert, you are misunderstanding "inconsistency."

The 50 Art can be perfectly calibrated, yet still misses focus on too many shots. 

You get your AFMA perfect, then you get into a shooting situation, and one shot will be just right, then the next three will be terribly front or back focused.  I know--that is exactly why I sent mine back.

After trying for 10 days to get the 50 Art to function properly, I went back to using lenses that do work, such as the ef 85mm 1.2 L (so I know all about shallow DoF) and the ef 24-70mm 2.8 II L.  WHAT a FREAKING relief to have sharp, accurate, 95% successful AF!!!

Dilbert, do you understand now?  The 50 Art, for whatever reason, can be perfectly "tuned" to match a body, and still be all over the place.  If you happened to get a copy that does not exhibit such behavior, stop trying to tell others that there is some kind of user error or misunderstanding.

And, btw, I have a 35 Art that is almost as reliable with AF as my 24-70 (the best AF I've ever seen), and a Sigma 15mm 2.8 fisheye that is spectacular.  Those work.  I think I made a mistake buying the 50 Art before Sigma, using its customers as testers, figured out what is wrong with their production. 

As for the USB dock, it might make things worse for Sigma customers, because now there is this extra level of trouble-shooting Sigma tech support can use to delay actually finding out the true problems with their lenses.  Customer calls Sigma complaining about erratic AF, Sigma asks, "Have you used the dock?"  Customer buys dock, gets frustrated, return time to merchant has expired...Seems like it will cause more problems than it fixes FOR THOSE CUSTOMERs WHO KNOW HOW TO AFMA IN CAMERA. 
« Last Edit: July 22, 2014, 07:34:54 AM by YuengLinger »

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #117 on: July 22, 2014, 07:25:49 AM »

YuengLinger

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #118 on: July 22, 2014, 07:38:51 AM »
All Sigma lenses have focusing problems! I had two of the a 24-700 and 70-200 last versions - I sent them to be calibrated with my body and then everything was ok.

This is FALSE.  I have two Sigma lenses that have had no focusing problems.  (I don't consider improving AF accuracy with in-camera AFMA to be part of a "problem.")

But the 50 Art that I received did have erratic, unreliable AF that could not be helped with AFMA.

So, if online chatter can lead to Sigma fixing the problem, we aren't helping by using sweeping, ranting statements such as "All Sigma lenses have focusing problems!"
« Last Edit: July 22, 2014, 07:43:08 AM by YuengLinger »

infared

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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #119 on: July 22, 2014, 08:02:50 AM »
I have an original Sigma 5Omm f/1.4 and it focuses just fine on my 5DIII. Out of the box no adjustments.
I also own a Sigma 35mm Art  and it performed just fine right out of the box as well. No adjustments.
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Re: Sigma 50mm Art 1.4 Focusing problems
« Reply #119 on: July 22, 2014, 08:02:50 AM »