Sigma 35mm f/1.4 user feedback needed

Started Jun 10, 2013 | Discussions thread
M J Valentine
Senior MemberPosts: 1,244
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Re: Outer points focus very innacurate
In reply to Mais78, Jul 7, 2013

Hi Mais78,

Thanks for the reply. I wonder if the 6D is part of the problem. I understand that the 6D's centre point focusing point (cross type) has a horizontal sensitivity of f/5.6 with vertical line sensitivity of f/2.8 whereas the 5D Mark III's 5 centre points have a horizontal and vertical sensitivity of f/2.8. Have you tried an another lens faster than f/2.8 with your 6D? I have a 40mm STM on my humble 650D which has so far focused accurately at all f-stops.

There's a USB calibration tool for the Sigma 35mm f/1.4 but the lens should be able to focus at f/1.4 out of the box and the fact that you've had to return two of these lenses is worrying. Using this lens at f/1.4 is the main reason why anyone would buy a fast prime over slower lenses.

I can't afford to buy a 5D Mark III so may need to re-think buying a Sigma 35mm and buy a Canon 35mm, provided that the Canon 6D is capable of focusing accurately with any lens faster than f/2.8.

Kind regards,

Martyn

Mais78 wrote:

M J Valentine wrote:

Hi,

I'm thinking of buying a Sigma 35mm f/1.4 to complement a Canon 24-105mm. I am selling my 650D and 15-85 to buy a 6D and plan to use the fast prime for low light and general photography.

I considered buying a Canon 40mm f/2.8 but I am concerned that the extending focusing action may cause dust to enter the camera body so the Sigma 35mm would seem to be a good candidate, especially as it is significantly faster. I have previously used a Canon 35mm f/1.4 but didn't like the purple fringing at f/1.4 which the 650D's Digic V processor couldn't resolve.

I have read many positive reviews about the Sigma 35mm f/1.4 and would be grateful for feedback from owners. Does the lens focus accurately wide open? Any other problems/issues/regrets?

Have you needed to send the lens to Sigma for repairs in the UK? In this regard I have been advised by a well informed source that Sigma UK can take weeks or months to service a lens. Has any other UK Sigma user experienced such delay? I wouldn't want to be without a lens for months while it is adjusted for front/back focusing.

Thanks,

Martyn

I have gone through two copies with same problems:

1. Inconsistent focus

2. On the 6D focusing withe the outer points at f1.4 is very inaccurate. I also did a comparison at f2.8 vs the 40mm pancake and can tell for sure it is an issue of the lens not the camera.

Unfortunately issue 2 makes it unusable, it might be the sharpest 35mm around in lab tests using live view, but if it cannot focus properly in real life what's the point?

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