Canon 5D mark IV + 35mm Sigma ART f/1.4 live view issue

[Patlezinc]

Sorry, perhaps I did not post the initial message at the right place.... :-[

I copy here :

Hi everyone.

I just bought a 5d IV and I have an issue with my 35mm.

I have calibrated the focus lens with the usb dock. That is ok.

But I have a problem in live view.
When I do the focus in live view, if i focus with a non-centered zone, for far objects (More than 1 meter), focus is blur.

I have disabled all corrections.

I thought it was impossible to miss a focus with live view...

Two more infos :

- my Canon 24-70 F4 at 35mm is working perfectly with the 5D
- the 35mm is working perfectly with the live view on the Canon 6D.

So the lens is ok i think, but not with the 5D.

The question is : can someone try to focus a far object with the live view on his 5D4, on the right or on the left with a 35mm ART?

Thanks.

Here an exemple :

Auto focus (impossible to do the focus) :

Manual focus:

 

[Mt Spokane Photography]

Sigma published a list of lenses that are incompatible with the 5D MK IV, they may need firmware, or features turned off in the 5D IV.

Sigma’s Statement:
<blockquote>Thank you for purchasing and using our products.
Please find the following notes on the usage of SIGMA interchangeable lenses for EOS, when attached to Canon EOS 5D Mark IV that is released on September 8th.

• MO (Manual Override) function is unavailable with this camera (Full-time Manual function can be offered).
• When using a SIGMA interchangeable lens for EOS, setting the corrections to [Disable] is recommended, as “Lens Correction” functions of the camera, such as Peripheral illumination correction, Chromatic aberration correction, Diffraction correction and Distortion correction are not supported.*

* If those functions are activated, the performance of lenses may not be accurate.
* This is not only for EOS 5D Mark IV, but also for other camera bodies with the same function.
We appreciate your continued support for our company and products.


https://www.youtube.com/watch?v=zIJ04LMJ3G8
</blockquote>

 

[Patlezinc]

Thanks, but it is not related to this at all

 

[Mt Spokane Photography]

The live view focus should work perfectly unless the camera is defective, or the lens has a issue. Since the camera works fine with other lenses, it points to a lens issue. I'd call or email Sigma and show them example photos.

 

[Patlezinc]

Done, and they don’t understand (or don’t admit the problem I think, they explained me how to setup the OVF focus... they did not know it was not the same focus system... oh my god...)
i simply think that the lens was made in 2012 and the first DPAF came in 2013 with the 70D.
They had no idea of DPAF process when they made the lens.
It is working perfectly on a 6D but it is not using a DPAF system so...

A simple way would be to find someone with a 5d4 and a 35 art. Test is quick.

 

[neuroanatomist]

Done, and they don’t understand (or don’t admit the problem I think, they explained me how to setup the OVF focus... they did not know it was not the same focus system... oh my god...)
i simply think that the lens was made in 2012 and the first DPAF came in 2013 with the 70D.
They had no idea of DPAF process when they made the lens.
It is working perfectly on a 6D but it is not using a DPAF system so...

A good example of why I won't buy a 3rd party AF lens.

 

[Valvebounce]

Hi Patlezinc.
I'm wondering if it is the settings you have added via the dock (which microadjust the lens for the phase detection sensor) throwing a spanner in the works? I believe it is possible to save the settings electronically, if not save them in analogue format (pencil and paper) and reset the lens to factory default and try the shot again.

Cheers, Graham.

 

[Patlezinc]

I can try, but I precise that the center focus zone of the live view is working perfectly. Only sides zones have. A problem.
Even if putting all AF setup at zero solve this, I can say goodbye to the OVF then.
Seems to be a retro-engineering problem from sigma. Why not doing a firmware update?

At this time I did not find anyone with the same configuration to do the same test...

 

[Valvebounce]

Hi Patlezinc.
Sorry, I hadn't realised that it was only peripheral focusing that was an issue.
Is this looking at the edges after focussing in the middle, or actually (what I now think) you are asking the camera to focus through the periphery?
Either way, it may be something to do with the focal plane shape (curvature seems incorrect after reading these articles!).
Have a look at this 3 part series from Roger at lens rentals for more info on my suggestion.

Part 1 Stopped Down MTF Curves.

Part 2 Best Individual MTF Curves.

Part 3 Best Average Focus Point.

Cheers, Graham.

 

[Patlezinc]

Thanks Graham.
I finally found someone who did the same test and... same failure.
I think Sigma engeneering doesn’t incorporate DPAF system correctly (canon glasses working perfectly all over the frame).

I think a firmware update could work but... not sure they will recognize this problem (sigma France doesn’t think there is an issue...)