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|Topic Review (Newest First)|
|05-23-2013 04:18 AM|
|e36||is anyone else having front focus issues with this lens?|
|05-07-2013 12:22 AM|
|05-02-2013 06:32 PM|
|05-02-2013 09:12 AM|
|GrendelKhan||Deal is dead...|
|04-26-2013 04:38 PM|
|04-25-2013 09:36 PM|
I tested using the battery test, as described here: http://cameralightlens
Of course I am testing with a single focus point. Every single test with all three Sigmas I got front focused. The Canon never misses. I didn't even bother to check for back focusing.
I may be screwing myself out of a fine lens because in real life I'm rarely going to replicate this scenario. But I'm not going to waste my time doing a bunch of tests to figure out where the problems lie. Especially when I have a Canon 50mm that works perfectly fine. I was going to sell the Canon after buying the Sigma but not anymore.
What's crazy is that this Sigma lens has been around a long time and the problems with it are well documented. You'd think that they'd fix the problem by now but they keep producing a flawed lens and people keep buying it. I guess at 1.4 your DOF is so narrow that when the focus misses most people probably blame themselves for soft focus, not realizing that the lens has a design flaw.
If anyone truly has a Sigma 50mm 1.4 that has perfect focus then what you have is a defective sample where the defect is an improvement.
|04-25-2013 08:31 PM|
|04-25-2013 06:06 PM|
|04-25-2013 06:00 PM|
That's exactly why my video showed. The lens in my video was back to Sigma 3 times, the last 2 times with the camera body in the video, to no avail. Canon vs Sigma on the same tripoded camera. Sigma fails.
|04-25-2013 05:30 PM|
AF is achieved by the camera in-conjunction with the lens motor. The body must be able to make small adjustments to the motor to lock down the focus perfectly. I know that some sigma lenses simply don't do well in this form of closed-loop control system as they dont provide the same level of motor accuracy/response as canons own lenses. But the lenses that I refer to are the cheap long range lenses. I would never imagine a modern lens (esp a prime with a fixed length) to have these issues.
Also I assuming you are doing all this with a single AF point. Could you also describe the subject, distance and lighting conditions. Sorry to sound so pedantic here but just wanted to know in what kind of situation the lens fails for you.
|04-25-2013 03:13 PM|
Late to the game but have to chime in here.
I've also heard of people sending the lens to Sigma for adjustment and having it come back in the same or worse condition.
I've come to believe that there is no such thing as a good copy of this lens. If you have the Sigma 50mm 1.4 and think it's tack sharp, it's because you haven't properly tested it for front focusing. There's no way three lenses in a row can have this exact same problem unless the problem is inherent in the design.
I also have the Canon 50mm 1.4 and conducting the exact same test with everything else being equal, the Canon focuses correctly every time. There is just no getting around the fact that the Canon AF works and the Sigma doesn't.
Now, the caveat is that this Sigma front focusing problem is only apparent in certain situations. I'd guess 90% of the time (or more) you will never know there is a problem. But I just don't trust the lens because I have no idea if/when the problem will rear its ugly head.
It pains me to return this lens because it is a superior lens to the Canon in many other ways, and I got it for the ridiculously low price of $359, and that's before whatever CB I got at the time. This lens is a steal at under $359 but sadly I have to send it back for the third time because accurate focusing is more important than anything else when it comes to lenses.
|04-22-2013 10:48 PM|
amazon just got them in stock.
|04-22-2013 09:03 PM|
|04-22-2013 08:40 PM|
|04-22-2013 08:27 PM|
had mine for about 6 years never had an issue.
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