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Archive 2013 · Bad Sigma 35 1.4 copy?
  
 
stebesplace
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p.1 #1 · p.1 #1 · Bad Sigma 35 1.4 copy?


I've been testing over the last month or so, my copy of the Sigma 35 1.4. It's an amazing lens, and when it works, takes outstanding photos. I am shooting and testing with a 6D, 90% of the time with center point focus. But here are 3 things I've found that are bothering me:


  1. When I use live view, it takes a long time to focus, almost as though it's "ratcheting" itself into focus, if that makes sense.
  2. Often times, I get back focus, where a wall will come into focus before the subject in front of this. Mostly I've noticed this when there's some action/movement, and more so in the horizontal movement between the subject, and myself.
  3. And finally, focus speed in general is quite slow. Now, I don't have a 35L to compare to, but if I don't pre-focus, it often times will hunt more than my 85 1.8. The 85 snaps to focus extremely quick, even at infinity and back. The 35, easily 4-5x slower, if not more.


That's the short list. Often I find low contrast surfaces are nearly impossible for the Sigma to lock focus on. Anyone else running into these problems? Do I have a lemon? QC issues? What's the course of action for sending it back to get exchanged or calibrated? I purchased this lens over 30 days ago at Adorama. So at this point, assuming I'd have to send it to Sigma directly.

Now, don't get me wrong, this lens takes phenomenal images when it's working properly, or I pre-focus for some scenes. Just these potential QC issues are annoying. Build quality is also quite impressive.



Jun 14, 2013 at 11:53 PM
Volks1470
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p.1 #2 · p.1 #2 · Bad Sigma 35 1.4 copy?


stebesplace wrote:

  1. When I use live view, it takes a long time to focus, almost as though it's "ratcheting" itself into focus, if that makes sense.
  2. Often times, I get back focus, where a wall will come into focus before the subject in front of this. Mostly I've noticed this when there's some action/movement, and more so in the horizontal movement between the subject, and myself.
  3. And finally, focus speed in general is quite slow. Now, I don't have a 35L to compare to, but if I don't pre-focus, it often times will hunt more than my 85 1.8. The 85 snaps to focus
...Show more

1. That's normal for any Canon camera or lens. Live view focusing is just not very good.
2/3. For what Sigma lenses i've owned, they just can't compare to Canon's USM ring motor driven lenses.


That's the short list. Often I find low contrast surfaces are nearly impossible for the Sigma to lock focus on. Anyone else running into these problems? Do I have a lemon? QC issues? What's the course of action for sending it back to get exchanged or calibrated?


Were you able to focus using a Canon lens? If not, it's a limitation of the Camera.
One course of action would be to buy the USB dock and do some calibrations. It might work.




Jun 15, 2013 at 12:28 AM
marko1953
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p.1 #3 · p.1 #3 · Bad Sigma 35 1.4 copy?


Agree with above poster about live view being very slow to focus. The camera uses a different focus method with live view , it's not the sigma lens causing this problem

For me , I get about 95% good focus with the sigma 35mm, I spent a few hours micro adjusting the focus but found variable results with 5d3 but I am not an expert, will try again soon.the jury is still out for me, but I agree it is extremely sharp at 1.4 when it hits focus. Will have to read up about the USB dock ....what does it do that micro adjustment can't do?

I find the focus speed quite good, but not quite up to the 85 1.8 speed.



Jun 15, 2013 at 01:19 AM
stebesplace
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p.1 #4 · p.1 #4 · Bad Sigma 35 1.4 copy?


Good points about live view. I wasn't aware it was slower in general.

I think it's worth me sending back honestly, to see if they can calibrate it, or replace it with another copy. I'll be doing some more testing (in a scientific manner) on matched lighting, subjects, surfaces, etc., between both lenses to see what's up. I have not micro adjusted either, so that's an option too. I also may be too critical, having owned and used extensively a 70-200 2.8 IS II, this 85, and a few others that I felt were quite quick.

I need to pick up a 35L at some point to compare the two personally, though as I mentioned, the images coming from the Sigma 35 are pretty remarkable.



Jun 15, 2013 at 02:25 AM
marko1953
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p.1 #5 · p.1 #5 · Bad Sigma 35 1.4 copy?


Update on my testing. I just switched from single point to expanded point AF. It works so much better. I just spent about an hour shooting around the house at 1.4 trying to get it to miss focus and I couldn't. Much happier, I will leave it on that setting. Very sharp lens.


Jun 15, 2013 at 04:16 AM
splathrop
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p.1 #6 · p.1 #6 · Bad Sigma 35 1.4 copy?


marko1953, could you try using expanded point AF to take some portraits, wide open, focusing on one eye? I'm having a hard time imagining that would work as well as single point, but if that's the solution it would move me toward the Sigma camp.


Jun 15, 2013 at 08:22 AM
Lars Johnsson
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p.1 #7 · p.1 #7 · Bad Sigma 35 1.4 copy?


Have you done MA on your lens?


Jun 15, 2013 at 08:32 AM
stebesplace
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p.1 #8 · p.1 #8 · Bad Sigma 35 1.4 copy?


Lars, no MA yet. I thought about picking up the Sigma USB Dock since it's cheap and trying that out. I've never had a camera that can do MA, as i've come from a 1D2 to a 6D (change of pace). I'm not even sure what MA would do to correct things like back focus, but I'll do some research today on that.

I think part of the problem is my expectation coming from a lens like the 70-200 II. My old 85 1.2 II was slow to focus (to a degree), so I figured this lens would fit between the two of those lenses speed wise. Since it's falling more towards the 85, I guess I'm just a little disappointed.

MA and more testing is on the docket this weekend. I've never had to return a lens for service, so assuming I need to do that with Sigma directly, and not Adorama at this point since it's past the 30 day period, should it come to this.



Jun 15, 2013 at 09:44 PM
stebesplace
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p.1 #9 · p.1 #9 · Bad Sigma 35 1.4 copy?


You know, the thing that kills me, is that when the focus is on, it's friggin on. Sharpest lens in that FL I've ever used.

I just did a series of shots compared to my 85 1.8.

Off white wall, grey breaker box just left of center. Light source is natural from a window to the right out of frame. Wall fills frame edge to edge.

I took 50 shots on the 35, and 50 on the 85. Focus was on the edge of the breaker box flat against the wall. The first 25 shots were with a colored 3x5 card clipped to a tripod to fit in the middle of the frame (taking up approximately 20% of the total frame). Last we're just the background. Further, I set focus before each shot to be at the closest distance, then let AF handle the rest. Long process, but I am a numbers guy, and wanted to see the results.

35
5 (Yellow Card): 100%
5 (Green Card): 100%
5 (Grey 18% Card): 40%
5 (Blue Card): 100%
5 (Red Card): 80%
25 (No Card): 75%

85
5 (Yellow Card): 100%
5 (Green Card): 80%
5 (Grey 18% Card): 100%
5 (Blue Card): 100%
5 (Red Card): 100%
25 (No Card): 90%

* Percentages refer to number of shots that were in focus. No card shots that were out of focus refer to "low contrast" shooting situations.

The Sigma didn't do well with the grey card, and interestingly, the Canon didn't do well with the green card. In these examples, there was back focussing occurring, which is represented by the %'s.

So I guess what I'm saying is, the lens seems to perform fairly well stationary, and the back focus seems to occur only when I'm moving around trying to get a shot (again, panning more so than anything else). I'll look at MA adjustments next.



Jun 15, 2013 at 10:09 PM
stebesplace
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p.1 #10 · p.1 #10 · Bad Sigma 35 1.4 copy?


marko1953 wrote:
Update on my testing. I just switched from single point to expanded point AF. It works so much better. I just spent about an hour shooting around the house at 1.4 trying to get it to miss focus and I couldn't. Much happier, I will leave it on that setting. Very sharp lens.


I'm not sure I'd be able to always shoot on multi-point focus, simply given the character of the lens. Many times, I'd want to be able to focus on a single point, such as an eye, or ring, etc.



Jun 15, 2013 at 10:11 PM
 

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marko1953
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p.1 #11 · p.1 #11 · Bad Sigma 35 1.4 copy?


Yes I get what you are saying splathrop and stebesplace, yet to do real portrait testing. Will be doing a big school musical shoot this week, will know much more in a few days. Single point expansion is not really multiple focus points it's just like an enlargement of the single point if the single point can't find focus or if something moves.


Jun 16, 2013 at 12:56 AM
stebesplace
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p.1 #12 · p.1 #12 · Bad Sigma 35 1.4 copy?


Yeah, I plan on playing with the single point expansion a bit more too, will post back on my findings. I haven't seen many complaints about this lens, which makes me think their QC has improved big time with these new series of lenses however, I may have to tweak mine with MA / potential calibration, etc.


Jun 16, 2013 at 06:26 PM
stebesplace
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p.1 #13 · p.1 #13 · Bad Sigma 35 1.4 copy?


I got a chance to test some of the MA on my 6D with the Sigma. These are 100% out-of-camera crops, no processing other than the initial import into LR4 with 2012 processing.

Tripod mounted, center focus, EV metering, ISO 100 @ 1.4, 1/80s. Focus on the basket back pane, which has a slight curve to it, about 4.5' from the sensor plane.

0 MA Note the candle on the right is slightly more in focus indicating the focal plane is not where it should be


-5 MA


Doing a -5 changed things dramatically. Focus is right on, and where it should be for this lens, IMHO. When the focus is right, it's impressive. There's some CA here with the lens, but easily fixed in post. Still need to do some back focus testing and see if I need to adjust some more, but it's a start!



Jun 16, 2013 at 07:32 PM
trenchmonkey
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p.1 #14 · p.1 #14 · Bad Sigma 35 1.4 copy?


1st shot with mine impressive hardly covers it. Make the adjustments, love the results.




Jun 16, 2013 at 07:54 PM
RCicala
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p.1 #15 · p.1 #15 · Bad Sigma 35 1.4 copy?


I really recommend getting the Sigma dock to fine tune adjustments. Mine was perfect up to about 15 feet, then started backfocusing. With camera MA that wasn't correctable, but the Sigma adjustment at 0,0,0,-8 has it perfect throughout the zoom range.


Jun 16, 2013 at 08:14 PM
stebesplace
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p.1 #16 · p.1 #16 · Bad Sigma 35 1.4 copy?


RCicala wrote:
I really recommend getting the Sigma dock to fine tune adjustments. Mine was perfect up to about 15 feet, then started backfocusing. With camera MA that wasn't correctable, but the Sigma adjustment at 0,0,0,-8 has it perfect throughout the zoom range.


Good to know! I know MA can't really do much for the back focus from what I can tell, other than adjust the focal plane to be more accurate, which it has for me, but yeah, that Sigma Dock will be ordered later today to try out.



Jun 16, 2013 at 08:20 PM
trenchmonkey
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p.1 #17 · p.1 #17 · Bad Sigma 35 1.4 copy?


That's really good to hear, Roger



Jun 16, 2013 at 08:20 PM
stebesplace
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p.1 #18 · p.1 #18 · Bad Sigma 35 1.4 copy?


trenchmonkey wrote:
1st shot with mine impressive hardly covers it. Make the adjustments, love the results.

http://i244.photobucket.com/albums/gg31/rvrsbnd/D7H_8067_zps5450ddaf.jpg


Very nice! Glad you like it. I love the lens, really do, just want to make sure it's in good shape.



Jun 16, 2013 at 08:21 PM
trenchmonkey
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p.1 #19 · p.1 #19 · Bad Sigma 35 1.4 copy?


Thanks, Steve. Understand. That shot was on full frame but I'm lovin' it on croppers too!





Jun 16, 2013 at 09:11 PM





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