Assist points visible in the viewfinder?

I think I saw this once but haven't seen it since - was I imagining it or is there a setting I've yet to understand that shows these points?

You mean the 6 assist points mentioned here:
• 9-point TTL CMOS sensor
• 6 "Invisible Assist AF points"

Well if they are invisible, you can't see them. They are to assist in a higher local density of AF points about the center for AI servo use. In AI servo you can't see any of the AF points, as the AF gets handed off from point to point.

I'm assuming you are talking about 5D series cameras.... In which case Mike is correct. You can't see those assist points at all in the viewfinder... They aren't indicated on the focus screen, are simply clustered close around the center point only and are only functional in AI Servo and when you have manually selected the center point. They are only used when a moving subject is "passed off" to them from the visible center point. According to Canon, this is most useful when tracking an erratically moving subject that's difficult to keep the center AF on. In other words, it's sort of like increasing the size of the center point a lot.

Keep in mind that on the 5D series only the center AF point is the faster and more sensitive "cross type". All the others, including the hidden assist points, are not.

You probably already know, the assist points are enabled through a Custom Function. On 5DII it's C.Fn III - 7: Autofocus/Drive - AF point area expansion. I am not sure if it's the same on 5D classic.

If using Canon DPP or Zoombrowser to view your images, you can see what AF point was used in any particular image, including the "hidden assist" points. You have to enable "show AF point(s)" in the software, if I recall correctly (I no longer use either of the Canon softwares very much.... I mostly use Lightroom and Photoshop, neither of which can display the active AF point).

On the 1D3 they will light up when the camera uses them. If you select a dingle point and the camera uses an assist point near it, the selected point will light up and also assist point will light when focus is confirmed. You can test this to see what I mean by selecting a point and aiming at a line with the selected point just off the line. The neareset assist point to the line will be used and light up.

Sorry I wasn't clear - yep it was on the 1DIII

I'll try out zoom browser (at the mo I'm just using a reader and hen straight to lightroom), that will be interesting to see where the AF points were when I missed focus and could figure out why.

Thanks kawi_200 - so I'm not going mad

You can also turn a function on to display the AF points on the playback screen too. I forget where it is, but it's not in the custom functions menu.

Not those in 5D or 5DII

kawi_200 wrote in post #13848717
You can also turn a function on to display the AF points on the playback screen too. I forget where it is, but it's not in the custom functions menu.

That sounds handy