Lens Calibration

[returntovendor]

Hello,

I recently picked up a lens calibration target in the interest of sharpening the autofocus/calibration of my setup. I have a few lenses, but I wanted to start with my primary portrait lens, the Canon 70-200 2.8 IS II.

I've found that... at 2.8, this lens isn't looking as sharp as I expected it to in a "controlled" setting.

I've also found that it doesn't really seem to be in need of calibration. It appears that at the long end, it might be SLIGHTLY front focused? But I am having trouble discerning if that's the case.

The target I'm using: https://www.amazon.com/gp/product/B012F8G1DO/
The tutorial I'm following (per the target distributor's recommendation):

Camera: Canon 5D Mark IV
Lens: Canon 70-200 2.8 IS II
One speedlight camera left set to TTL to keep exposure constant for ease of use

The camera is setup on a tripod and locked into place, zoomed to 200mm at about 12 feet from the target.

Photos of my results as well as the setup: Sharpness Test - Google Drive

(The viewfinder aim appears off in the photo I shared because I was holding the camera steady to stabilize myself, the actual shooting alignment had the grid-line straight on with the 0 on the target.)

So my main questions/concerns are these:

1. Am I doing this right? Should I be changing my setup to properly execute this exercise?

2. Is the lens slightly front-focused, as it may or may not appear to be?

3. The loss of sharpness and contrast I'm seeing at f/2.8, is this expected for this lens? I feel a bit disappointed to pay so much for a lens only to see such a difference between 2.8 and 4, but perhaps my expectations are unrealistic.

Any help or advice is much appreciated.