# Sigma 35mm F1.4 Art - Focus issues on D810



## aerodreamer (May 16, 2017)

Hey all. 

Was wondering if others have had focus issues (front) on the Sigma 35mm F1.4 Art and D810 combo. I would greatly appreciate some insight into the issue below with the Sigma 35mm F1.4 and D810. 
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SIGMA 35MM LENS 1 RESULTS
I've essentially maxed out the AF Fine tune and Focal Pro(calibration software) recommends a +32 AF fine tune (out of range). A friends D810 body yielded similar results of +35 (out of range). In real life, both bodies and lens were severely front focusing. 

Meanwhile, I was able to get the same lens perfectly calibrated on my D7000 at a value of +9.

This lens was returned to sigma for updates and realignment. 
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SIGMA 35MM LENS 2 RESULTS
I purchased a 2nd Sigma 35mm F1.4 Art to see if my numbers changed. The lens was calibrated on both my D810 and buddy's D810. Results were +17 and +20 respectively. In real life, this lens also front focused. 

The same lens on my D7000 yielded a fine tune of -1. No focusing issues were noted while taking pictures.
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Below is a link to the summary of my lens tuning results across all bodies and lenses. Tuning was performed under controlled lighting conditions and using a tripod and Focal Pro software. 

AF - Fine Tune Summary 

Any ideas on what might be going on? Do I have a dud camera or lens? Or the Sigma just does not like D810s? 

Would greatly appreciate your inputs. 

Thanks


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## Derrel (May 16, 2017)

Sounds to me like the D810 has an issue....while the D7000 body does very well.
It is not always "the lens" when there is a focusing issue...the camera itself needs to be operating properly, and within established tolerances.


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## aerodreamer (May 17, 2017)

Isnt it odd that two independent D810 bodies responded in the exact same manner. I mean the results are sooooo close.


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## Derrel (May 17, 2017)

Yes, seems very weird.


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## sloweddie (Jul 23, 2017)

Maybe the Sigma needs some tweaking via the Sigma USB Dock to bring its focus into the proper spec. My 50mm Art was more than +20, frustrating for such a sharp lens; using the USB Dock it got to zero.


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## benhasajeep (Jul 23, 2017)

sloweddie said:


> Maybe the Sigma needs some tweaking via the Sigma USB Dock to bring its focus into the proper spec. My 50mm Art was more than +20, frustrating for such a sharp lens; using the USB Dock it got to zero.



Have to remember the lens is talking to the camera and vice versa.  And Sigma backwards engineers the lenses to work with the cameras.  I suspect the lenses were not originally set up for D810's.  And in this case does have necessary info for D7000.  In the Past Sigma would update lenses for current bodies at the time.  Now I think they realized they needed to cut some costs and invented the dock.  Good idea on their part.  And for photographers too.  I suspect there needs to be an update to the lens to meet new specs for the D810.


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## aerodreamer (Apr 13, 2018)

Resolved!!! After not having used the lens in the last 2 years, I caved and bought a Sigma USB Dock.
Got my AF fine tune on camera to zero and its tack sharp using custom tuning via dock.

Still find it odd that a brand new lens can vary between the focal range so much.  

Thank all for the help. I just feel like I bought a new lens! (although I've had it in storage for the last 2 years )


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