Custom Function Question - Focusing/AE Lock

[Slea]

Hi Jared, I use this facility a lot when shooting wildlife. Take Birds in Flight, you press the * button to focus on the bird, also having AI focus enabled to enable the focus to keep tracking the moving subject, the bird may pass through different backgrounds e.g. sky, bushes etc but ONLY when you press the shutter release will the exposure actually be measured. If you do not separate these 2 functions then the exposure will be calculated by the camera as soon as you half depress the shutter to focus but that may not be correct for when you actually take the shot. I haven't explained that very well but I think you can get the gist from my ramblings

HTH

Slea.

[Slea]

Hi Jared, thanks for the welcome

'Kamel Karma' I know roughly what that is but I will have to read a little more to make sure I am correct - but thanks anyway, it is appreciated

I keep the * button pressed to focus and then just fully depress the shutter release whenever I want to take an image, sometimes I will keep both depressed to take multiple exposures and sometimes I will release the shutter button (but keep the * button depressed) and recompose the shot and then fully depress the shutter again to take the next shot. Only when I stop taking shots of that particular subject and take the camera away from my eye will I release the * button. Its actually harder to explain than do so just experiment and all will become clear

Slea

[Slea]

Thanks for the explanation re Karma Jared

Originally Posted by bauerman

so even though in my example the shutter buttons function has been changed to the AE lock function – fully depressing that shutter button will take the shot? I guess that I really just need to go home tonight and play around with this…….
Jared

Got it in 1 When you have that sorted out you may find Custom Function 16 also interesting, I also have this enabled for flight shots and it means that I can even half press the shutter button ready to take a shot and the camera wont take that as an instruction to calculate the exposure which will only be done when you actually finally fully depress the shutter button, depending how you work you may or may not find it useful

Slea

[metalstorm]

It also works in servo mode where you can stop it's focus mechanism and still release the shutter with the release button. I don't use 1 shot on mine because the consistency isn't very good for me. I get better results using * to focus and use ai servo.

[Rense]

It would be my first advice advice to anyone:

* Get the focuslock on * ASAP.

Rense

[Mr. Pickles]

Don't ask questions man, just do it >

I better go figure out how and what to do too. Maybe it is a D60 thing? Maybe use D60ers are all behind the times? Better upgrade to a less colorful image Canon, eh

[Mr. Pickles]

You could practice the technique on a "Pair" image. Or do it on more than one. Go do it quick and avoid the badgering later

I would think the feature of button switching is on most of the DSLRs. Wonder about the 300 or 350 though...?

[cyclohexane]

I'm pretty sure the 1.6x bodies that came after the 10D do not have the capability to use the * button to focus, as there are now only two buttons on the back versus the 3 on the 10D and before.* I know that I've searched the 300D and 350D for a custom function like that without success, and everyone tells me that the 20D can't do it either.

Of course, I don't own any Canons, so all my experience is from using other people's cameras.* I do use rear-button focusing on my Nikons though.* If another player moves in front of the one I'm tracking, I can simply let go of the focus button to maintain focus on the original player- it's a lot quicker than trying to grab focus lock buttons on the end of a telephoto zoom lens or pushing a lock button.* Also, I can engage VR/IS without initiating focus, should I ever want to do that.

[cyclohexane]

I just checked dpreview's reviews of the 350D and 20D, and it seems like they can indeed perform rear button focusing- I guess whoever told me that was misinformed. The next time I handle one of those bodies, I'll check it out. It appears to be Custom Function Number 4 for both, so the next time I grab ahold of a Canon I'll look for it.

[Rense]

Originally Posted by bauerman

What are your particular reasons for saying that - just curious as to your view of the advantages....

Jared

Jared,
Think of the following situation:
* you see an object you want to focus on, but is is rather dark and not in the right position.
* Without having focuslock on * you press halfway the shutterbutton which focusses but also calculates the exposure (so you* *
* now have a wrong exposure, and no good composition).
* So you want to recompose. After recomposing pressing the shutter halfways gives you a new focuslock
* and exposure. But you don't want this new focuslock (and exposure) ...
* So the only way out is: focuslock on *, lock the focus, oriented the camera to the right exposure object, press the shutter
* halfways giving you the right exposure and then recompose for the perfect picture (good focus, good exposure, good
* composition)
Rense

[Mr. Pickles]

So you keep the * button pressed in (locks focus), push the shutter down, which locks exposure and takes the shot, and then release the * button...right?

[metalstorm]

Yes the 20D definitely has this function since I have a 20D and I use the function.

Originally Posted by cyclohexane

I'm pretty sure the 1.6x bodies that came after the 10D do not have the capability to use the * button to focus, as there are now only two buttons on the back versus the 3 on the 10D and before.* I know that I've searched the 300D and 350D for a custom function like that without success, and everyone tells me that the 20D can't do it either.

Of course, I don't own any Canons, so all my experience is from using other people's cameras.* I do use rear-button focusing on my Nikons though.* If another player moves in front of the one I'm tracking, I can simply let go of the focus button to maintain focus on the original player- it's a lot quicker than trying to grab focus lock buttons on the end of a telephoto zoom lens or pushing a lock button.* Also, I can engage VR/IS without initiating focus, should I ever want to do that.

[Rense]

Originally Posted by Mr. Pickles

So you keep the * button pressed in (locks focus), push the shutter down, which locks exposure and takes the shot, and then release the * button...right?

No need to: just press the * once release it and then press the shutterbutton halfways.
Rense

[metalstorm]

You never have to release the * button if you wish. *I can make the continuous ai servo focus stop focusing when I release the * button(it lets you FR if you wish in this mode). *You cannot do that you are controling focus from the release button. *The release button will fire regardless of what you do with the * button.

Originally Posted by Mr. Pickles

So you keep the * button pressed in (locks focus), push the shutter down, which locks exposure and takes the shot, and then release the * button...right?

[craig waller]

i have both my 20D and my 1Ds MK2 set up like that . . . its all what you are comfortable with... if you are tracking something like a race car, football, or birds mentioned earlier, for me its easier to hold that * button to track focusing then to hold the shutter release half way down, . . . . i have been working like that for 8 years, back to my A2 and 1N film bodies...

cw

www.craigwaller.com

[JohnC]

I'm not familiar with the Nikons, but some Canon bodies have a Custom Function 20 that sets the sensitivity of AI Server focusing. It adjusts the length of time the system is programmed to stay at the most recently focused distance. The default setting is 0.5 seconds, but you can make that slower or faster if you are in a situation where you sometimes have another object crossing in front of the one you are tracking focus on.

CFN 20-0 is normal
20-1 and -2 are slow (remain focused for 1 second and 0.75 second) The focus stays on the original object
20-3 and 20-4 are fast (0.25 and 0.125 seconds) The focus will jump to the new subject

John

Originally Posted by cyclohexane

I do use rear-button focusing on my Nikons though.* If another player moves in front of the one I'm tracking, I can simply let go of the focus button to maintain focus on the original player- it's a lot quicker than trying to grab focus lock buttons on the end of a telephoto zoom lens or pushing a lock button.*