Ashamed I dont know the answer to this question. AF related

[Matt57]

In machine gun mode, 3fps, 6fps, whatever- does the camera refocus in between shots or does it take the first shots focus and use it for the burst?

I think it refocuses but I cant be certain. Dont tell anybody I asked!! :o

[chauncey]

I think I know the answer but I'm not positive, so I will take the cowards way out and not answer.
Same question relating to IS.

[Matt57]

^ lol

So, some help people! Tons of views. I really dont think anybody knows?!!

[cdifoto]

If you want focus to track, use AI Servo. If you want focus to lock once and stay, use One Shot. Doesn't matter if you mash down on the shutter or take it easy.

[Matt57]

If you want focus to track, use AI Servo. If you want focus to lock once and stay, use One Shot. Doesn't matter if you mash down on the shutter or take it easy.

Ok, so in continuous mode (a "plethora" of pictures) with the shutter held down and the camera panning, it will refocus on every shot, right?

[cdifoto]

Ok, so in continuous mode (a "plethora" of pictures) with the shutter held down and the camera panning, it will refocus on every shot, right?

In a perfect world, yes focus will be maintained in AI Servo as you spray n pray. BUT AF systems aren't perfect and depending how fast your subject, camera, and lens are, you may or may not still have some misses in the series.

[primoz]

At least for EOS 1 series (film or digital) camera is tracking object even when shutter is open, and of course between the burst shoots too. But only in AI Servo mode of course.

[qtaran111]

It depends which AF Mode you are using (which is different to setting the Drive Mode).

You can set the Drive Mode to Single Shot, Continuous or Timer/Remote Control (I think these modes are self-explanatory).

You can then also independantly set the AF Mode to One-Shot AF, AI Focus AF or AI Servo AF.

One-Shot AF: The focus locks when shutter button pressed halfway

AI Focus AF: Similar to above, but if AF system detects movement, it will switch to AI Servo AF

AI Servo AF: Focus (and exposure) is continuously adjusted


So if you wanted to take several shots of a still subject, you could choose Continuous Drive Mode and One-Shot AF Mode (so every frame would have the focus/exposure fixed by the first shot).

If you want to take several shots of a moving subject (sports, flying birds etc) then choose Continuous Drive Mode and AI Servo AF Mode, so each frame's focus/exposure is adjusted before the shot is taken.

Also bear cdifoto's comments in mind: AI Servo AF isn't perfect and is limited by the lens, lighting conditions, shutter speed, speed of subject etc...

[Matt57]

Excellent. I knew there was a catch.

thanks!

[mhall711]

It depends which AF Mode you are using (which is different to setting the Drive Mode).

You can set the Drive Mode to Single Shot, Continuous or Timer/Remote Control (I think these modes are self-explanatory).

You can then also independantly set the AF Mode to One-Shot AF, AI Focus AF or AI Servo AF.

One-Shot AF: The focus locks when shutter button pressed halfway

AI Focus AF: Similar to above, but if AF system detects movement, it will switch to AI Servo AF

AI Servo AF: Focus (and exposure) is continuously adjusted


So if you wanted to take several shots of a still subject, you could choose Continuous Drive Mode and One-Shot AF Mode (so every frame would have the focus/exposure fixed by the first shot).

If you want to take several shots of a moving subject (sports, flying birds etc) then choose Continuous Drive Mode and AI Servo AF Mode, so each frame's focus/exposure is adjusted before the shot is taken.

Also bear cdifoto's comments in mind: AI Servo AF isn't perfect and is limited by the lens, lighting conditions, shutter speed, speed of subject etc...
How does safety shift effect this?( kinda off topic)

[PacAce]

How does safety shift effect this?( kinda off topic)

It's irrelevant. Safety shift is for exposure. This thread is about automatic focusing. Apples and oranges. :)

[mhall711]

It's irrelevant. Safety shift is for exposure. This thread is about automatic focusing. Apples and oranges. :)
So you are saying that AI servo does not effect expousre?

[mhall711]

Wait, thats not what i mean. After each shot the camera will refocus and re expose when in AI Servo ?

[qtaran111]

Yes, AI Servo will continuously adjust the focus and exposure whilst shooting.

Safety Shift is a feature that automatically compensates for exposure if there isn't enough latitude in the shutter speed/aperture settings to expose properly.

For example if you are in Tv mode and have set a shutter speed of 1/250 and the correct aperture is smaller than f/22 (which is beyond the smallest aperture for the lens) the camera will automatically shift the shutter speed down to 1/500 or 1/1000 so that the shot will expose correctly with f/22.

[Moppie]

At least for EOS 1 series (film or digital) camera is tracking object even when shutter is open, and of course between the burst shoots too. But only in AI Servo mode of course.


How?
I always thought SLR's focus using light reflected onto a sensor off the Mirror, which of course would be up when the shutter is open.

[cdifoto]

Exposure is unrelated to AF.

[qtaran111]

I think mhall711's question was whether exposure was adjusted in AI Servo AF mode, which it is.

[primoz]

How? The way ai servo works ;) Ai servo "predicts" where object will be when shutter will be pressed so you can actually call it front focus. And obviously processor is smart enough to calculate how much to turn lens in between. Otherwise you are right and standard focus can't be archived when mirror is up.
PS: This is no official Canon info, so details can easily be wrong, but it actually does track during exposure too.