The problem
A whole series of frog frames with the AF Region centred on the eye have the eye out-of-focus.

Background
I noticed an AF problem (on a night-time shoot) of a series of shots of the small Eastern Dwarf Tree Frog (Eastern Sedge Frog (Litoria fallax)). The AF was consistently missing the focus on the eye of the creature despite the AF Point being placed on the eye of these static frogs. The frogs are typically 20-25 mm long.

I was in Live View Mode with the AF Region placed on the frog’s eye and every shot (40-50) had the eye noticeably OOF, with nil shots of the eye in focus. Other parts of the frog are in sharp focus, so this is unlikely to be a “subject movement” issue, especially since I was using flash as the main light source.

Testing
To check the AF, I later took a couple of frames of the Canon User Manual on my PC Screen, at roughly the same subject to lens distance as the frogs and the focus was sharp. The image without the Red AF Rectangle is a Raw file crop, whereas the image displaying the Red AF Rectangle is from a screen capture in Canon’s DPP V4.

Settings
For the frog and test images, the Live View AF Method was “FlexiZone – Single” with “AF-Continuous” and “AF Mode – One Shot AF”

As you can see, other body parts in the same plane as the near-side eye are nicely in focus – does anyone have an explanation for all frames showing an OOF eye?

Possible cause?
These frogs inflate/deflate their throat sac generating a strikingly loud noise. I suspect the eye moves during this inflation/deflation process but was surprised that not one shot had the eye in focus.

Thanks

Dennis

Full res crop in Canon's DPP
7D Mark II IMG_0223 Crop 1024 AF Query.jpg

Shot of screen in Live View
7D Mark II IMG_0398 Crop 1200.jpg

Canon's DPP showing AF Region
Screen Capture Crop 1200.jpg