Infinity focus calibration distance

How would you determine distance to calibrate infinity using Sigma dock?

With long tele lenses would you just focus on something in far distance and adjust by trial and error?

Wait for a clear night and focus on the moon.

Ramon-uk wrote in post #18063732
Wait for a clear night and focus on the moon.

I guess a quarter million miles might just count as close to infinity.

Looking at the app I have on my phone, Hyperfocal distance on APS-C at 600mm/f:6.4 is 9922 feet, or 1.9 miles, with the near limit at half that. So I would suggest that you would want to be focusing on a subject at about 4 miles to ensure true infinity focus.

Given the other distances that the Sigma program offers I would suggest that you use either the average approx distance to your usual furthest subject. Or a hunderd yards or so. I shoot airshows where I'm normally shooting at between 400 and 800 yards, and set the infinity MFA at about 600 yards. You will of course need to do the MFA at these sorts of distances whan the weather conditions are optimal. Early in the morning before the ground starts to warm up creating mirage effects would be best. I'm using the 150-600C.

Alan.

I figured it'd be the hyperfocal plus a bit but the distances required had me thinking 'their must be an easier way!'. Usually shoot at f/8 which came to 1.5km at 600mm.

Emailed Sigma.

'Hello,

I am emailing asking for help calibrating my 150-600 Contemporary lens using the dock.

How do I determine distance for infinity calibration?

Regards

Mr Gungnir'


'Dear Mr Gungnir,
Thank you for your email reading your 150-600mm lens.
We would suggest you star with a target at forty times the focal length you are working on i.e. 24 meters at 600mm

Kind regards
Sigma Imaging (UK) Ltd'

Gungnir wrote in post #18064901
Emailed Sigma.

'Dear Mr Gungnir,
Thank you for your email reading your 150-600mm lens.
We would suggest you star with a target at forty times the focal length you are working on i.e. 24 meters at 600mm

Kind regards
Sigma Imaging (UK) Ltd'

Not too different from Canon recommendation to calibrate at 50 * FL distance