Live View AF on 7D (1 Viewer)

Just wondering what people think about live view AF as opposed to normal AF on the 7D. I know that LV AF is slower but how about accuracy - anyone got any thoughts? (I know that it employs two different methods to AF).

I have been trying Live view AF lately just for the mirror lock-up but cannot make my mind up if the AF accuracy is any better than normal AF.
What I have tried a few times (with camera/lens locked on a tripod) is to AF normally and then switch to live view at 5x zoom - I have noticed a few times that this shows the normal AF to be a bit oof - performing AF via LV seemed to correct the problem.

I use liveview quite a lot when the camera is tripod mounted. I find autofocus works better in liveview than normal AF when using teleconverters but mostly I use manual focus with liveview due to being able to magnify the image either 5x or 10x.

It doesn't have a spot focus but if the subject is large enough in the frame then it's usually pretty accurate even with multiple converters and the screen magnified. Personally due to the slowness of operation I find manual focus much quicker/more effective for my needs.

I have been trying Live view AF lately just for the mirror lock-up

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This isn't meant to sound facetious, but any reason you can't use mirror lock-up on normal AF?

Yeah, you could surely use MLU with normal AF, but it's buried in the menus. In Liveview it's in MLU automatically.

Keith Reeder said:

Yeah, you could surely use MLU with normal AF, but it's buried in the menus. In Liveview it's in MLU automatically.

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Spot on Keith - its a quick and easy way to go in or out of mirror lock-up.

IanF said:

I use liveview quite a lot when the camera is tripod mounted. I find autofocus works better in liveview than normal AF when using teleconverters but mostly I use manual focus with liveview due to being able to magnify the image either 5x or 10x.

It doesn't have a spot focus but if the subject is large enough in the frame then it's usually pretty accurate even with multiple converters and the screen magnified. Personally due to the slowness of operation I find manual focus much quicker/more effective for my needs.

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That's interesting Ian, I am guessing that you use it with the 400/5.6 + tc which will give you AF even with a reporting tc.

Where I am experimenting with it is for long distance shots with my 300/2.8 + 2x tc and also stacked 1.4x and 2x - it seems to me that when shooting at infinity distances (about 50 mtrs + I think with my set-up) then the LV AF seems to be more accurate. You do need a tripod like you say and no good for action shots of course due to not having AI Servo mode available.

I have also been playing around with my 70-200/4 with a 2x tc, it reports 400mm and f8 but AF's surprisingly decent especially if you are very roughly in focus to start with.

Yes I'm using the Canon 400mm f5,6 with a combination of converters. Sometimes I'll stack four together but usually it's three at most. I find you get decent enough results with stacked converters when taking HD video.

Actually I find in liveview with teleconverters autofocus works better than with normal AF. I've occasionally managed autofocus with three teleconverters - Kenko 2x, Kenko 1.5x and Canon 1.4x in tandem but mostly using just two. The Kenko 2x isn't great quality so lately I've been using two Kenko 1.5x in tandem with a Canon 1.4x. Of course you need pretty good light and contrast and a bird that will stand still long enough for focus to lock on. Works well with waders sometimes but really manual focus is much more practical.

Also when using a remote shutter release and autofcus there's more misses than hits when using more than one teleconverter.