Can someone school me on live view

I have never ever used it. I will use a 5Dmk3 and a 7Dmk2. Is there any special settings in the menu's I should have selected? Is there different focusing modes for it? Better settings? The 5Dmk3 for portraits and the 7Dmk2 for nature

Live-view uses the same auto-focus control options in the camera menu as regular viewfinder auto-focus. However what changes is that when it uses live-view it uses a different set of internal sensors to detect the focusing point.

In practice this means that because the light is not being reflected and split (one to the mirror box and viewfinder - and one to the AF sensors) the live-view AF sensor system gets more light. This is why you have cameras like the 7D which can auto-focus with a lens maximum aperture of down to f5.6; but can use a maximum aperture of down to f8 in liveview.

Live view AF sensors are typically not as fast as those through the viewfinder - as such for action you will typically find most still use the viewfinder. For hand-holding the viewfinder is also superior in most situations.

Live-view comes into its own when tripod mounted and also for situations where you want to do very fine focusing; especially manual focusing. This is because you can magnify the live-view image on the back of the camera - so you can "zoom in" on the critical area to ensure that the focus is really where you want it to be (your manual should detail the + and - buttons for magnification in live-view mode)

Your 5D3 will use "contrast detection" for live-view AF, and as mentioned above it is generally slower than the phase detection AF you get through the viewfinder. The camera will "rock" the lens on either side of critical focus and find the point of highest contrast which is usually the point of focus.

This is not true of your 7D2 however. The 7D2 has Canon's unique dual pixel AF system for live view, where ever pixel in the sensor is essentially a phase detection point. This allows for AF that is nearly as fast a through the view finder. Since the sensor pane itself is doing the focusing, this can actually be more accurate than the viewfinder phase detect array because there is no variance between the detection array and the sensor plane (when the mirror is down and sending light to the phase detection sensor there can be a slight variance between the distances to the detection sensor and the main imaging sensor, which is why you have MFA. The 7D2 can also AF all the way down to f/11 using the dual pixel AF system.

Thank you for the explanation. I can see how for tripod it would work. Thanks again! So more for landscapes and static subjects then.
Can I use live view for action shots of dogs? With the 7Dmk2 that is?

Keyan - thanks for the reminder - I forgot that the 7DM2 did some new fancy tricks!

007 - just because its not "as fast" doesn't mean you can't shoot action with it. You might find that sometimes its not as good; such as for sudden grab-shots or the subject moving toward/away from the camera; but you can certainly still use live-view in either camera for action.

It's more a case of what is suitable for the situation - live-view has the problem that if you;re holding the camera in your hands you have to move it out infront of you to see the screen; that is instantly moving the centre of gravity of camera, lens and arms out away from your core body centre of gravity. That puts more strain on your hands and arms; increases fatigue and makes it more likely to induce hand/camera shake.

So many times the choice will be made for you by the situation.

Overread wrote in post #17637981
Live-view uses the same auto-focus control options in the camera menu as regular viewfinder auto-focus.

Usually not.

True. Normal AF has a dedicated sensor. Live view AF uses the image sensor.

That is not at all why standard AF is limited to f/5.6 for many cameras, or f/8 for some AF points in some cameras (the two mentioned here included).

Contrast detect AF is typically not as fast as the phase detect AF you utilize when shooting with the normal viewfinder. But now some cameras, like the 7D Mark II, have phase detect AF in live-view too.

Exactly!

I only use Live View when shooting from a tripod and manual focusing. I don't do much video, thought.

gqllc007 wrote in post #17638004
Thank you for the explanation. I can see how for tripod it would work. Thanks again! So more for landscapes and static subjects then.
Can I use live view for action shots of dogs? With the 7Dmk2 that is?

It will focus lock quickly. I find it great for video and/or off angle shooting. For action shots of dogs....the biggest issue is that the dual pixel AF system doesn't seem to be able to burst shoot or track shot to shot, and the 7D2's OVF AF system is built for high speed action shooting and subject tracking, so you will probably get better results using that.

GeoKras1989 wrote in post #17638026
I only use Live View when shooting from a tripod and manual focusing. I don't do much video, thought.

Same here. It's quite helpful when you zoom in the LCD screen on the area you want in focus.

I do not shoot much video, either.

Keyan wrote in post #17638831
It will focus lock quickly. I find it great for video and/or off angle shooting. For action shots of dogs....the biggest issue is that the dual pixel AF system doesn't seem to be able to burst shoot or track shot to shot, and the 7D2's OVF AF system is built for high speed action shooting and subject tracking, so you will probably get better results using that.

I'll add that shooting action shots of anything using live view can be fairly clumsy. You'll be holding the camera and lens out in front of you and YOU may not be very accurate...