You might also change from RAW to JPG to see if that makes a difference, it did for me. That affected the results more than I expected when I changed lights and forgot to reset it.
I assume you 've got the correct color temp. Reikan Technology Ltd FoCal 2.6.0 Introduction 11 1 Introduction FoCal is a software utility designed to control a Canon or Nikon DSLR camera and automate the process of choosing the perfect AF Microadjustment/Fine Tune value for the attached lens. I used a mirror lockup delay of 3 seconds which s the default in Focal 2. For a stable platform and no windage I use the cafeteria at work on a weekend (120ft/36m on a slab floor). I tried outdoors but found results inconsistent. Reikan Technology Ltd FoCal 2.3.0 Introduction 10 1 Introduction FoCal is a software utility designed to control a Canon or Nikon DSLR camera and automate the process of choosing the perfect AF Microadjustment/Fine Tune value for the attached lens.
In addition to sufficient light for fast shutter speed some of the key things I found at longer focal lengths are a stable indoor platform (no windage), no image stabilization, and a longer mirror lockup. I did my 600 at 24m and got the same results at 30m, probably because my lights covered a broad enough area around the target to fill the spot metering window. So the 30m distance is a bit long for 600, at the upper limit for 840, and well within the range for 1200. Based on the formulas the analysis ranges for a 1DX are:
The analysis distances are within the target search so those are the more important ones. Buy Reikan FoCal Pro Lens Calibration featuring Pro Calibration Software License, Includes Standard Hard Target 150mm, Windows and Mac Compatible, Works with Most Canon Cameras & Lenses, Works with Most Nikon Cameras & Lenses, Register up to 5 Cameras Simultaneously. Its a good read if you haven't already looked at it. Once you get the combo MFA then you transfer the values to the dock. I think these are the same focal settings on the dock. I started at 600mm then worked my way back to 4 different focal settings. Follow the basic setup (tripod, target position, camera setup). The formulas given on the second page let you compute analysis and target search distances for arbitrary focal lengths. I used Reikan Focal Pro with my D810 and Sigma 150-600 S. The tool on the web page provides distance guidelines specific to the Focal implementation based on camera characteristics and target size. The target needs to be evenly lit and completely fill the spot metering area for Focal to get the exposure right. You can't go by Canon's 25x/50x recommendations with Focal if you want the analysis to work. I just redid some tests after installing Focal 2.