Fast Kids & Focus Points

[danny_bhoy]

Hi all,

I've got a party to shoot this weekend and the hosts have specifically requested loads of pictures of the various kids in attendance.

I'm just wondering what focus mode to use for best results. I'd normally use centre focus and recompose but I have a feeling that's not going to work with kids on the move.

Anyone have any advice?

Cheers,

Danny.

 

[Phil V]

I'd start with single point focus, AI servo and BBF.

You might also want to try the group of focus points, can't remember what it's called.
One of my favourite functions of the 7d is the way you can have different focus points selected for landscape and portrait. I often have the top right or top left point for people, and with the different points, that needs no adjustment as I turn the camera.

You've been wasting the best feature of the camera sticking with focus recompose.

 

[danny_bhoy]

Thanks Phil.

That's really interesting about the separate focus points. I'll delve into the manual and have a look for that.

One thing that really baffles me though is back button focusing. I can't get my head around why it's beneficial or what it's uses are (bare in mind that I rarely shoot anything but landscapes). Can you enlighten me?

 

[HoppyUK]

Thanks Phil.

That's really interesting about the separate focus points. I'll delve into the manual and have a look for that.

One thing that really baffles me though is back button focusing. I can't get my head around why it's beneficial or what it's uses are (bare in mind that I rarely shoot anything but landscapes). Can you enlighten me?

Back-button focus means that the camera focuses when you want it to, rather than always doing it when you happen to have half-pressure on the shutter release.

Try it. Most folks don't go back.

 

[Phil V]

Thanks Phil.

That's really interesting about the separate focus points. I'll delve into the manual and have a look for that.

One thing that really baffles me though is back button focusing. I can't get my head around why it's beneficial or what it's uses are (bare in mind that I rarely shoot anything but landscapes). Can you enlighten me?

Back-button focus means that the camera focuses when you want it to, rather than always doing it when you happen to have half-pressure on the shutter release.

Try it. Most folks don't go back.

This^

I used MF cameras for years after AF became the norm, when I got my first AF camera I hated the shutter half press, it seemed so counter intuitive. Using BBF means I use focus motors when I want, the focus ring when I want and can leave focus alone as much as I want.

 

[sk66]

IMO, BBF has two benefits and they both relate to being in a continuous/tracking focus mode.
When actually tracking a moving subject w/o BBF if you inadvertently release the shutter completely focus has to start all over again. Usually beginning with the central focus point, reacquiring the subject, focusing, and then you can start shooting again (slightly dependent on release priority). W/ BBF the camera continues to track focus regardless as long as the subject is under an enabled focus point (w/ button pressed).

The second is, in situations exactly like you will be in, it allows you to instantly switch between continuous tracking of a moving subject to focus/recompose for a stationary (relatively) subject, and not be forced into a centered composition. Just by releasing the button.

Unfortunately, Nikon has screwed it up on their newer bodies.

 

[Gary Coyle]

Actually the main benefit of using BBF is it seperates exposure from focus, if you just use the front focus/shutter button whatever the exposure for your first shot in a burst of photos is what you will get locked down until you release the shutter button

Using BBF the exposure is set differently for every single photo taken during a burst, very useful for moving subjects moving in and out of shady/bright areas as it will expose and meter for every single shot taken

Using the front shutter/focus button could well end up with a series of under and over exposed images as the exposure will be locked down to the first image taken, if the subject starts in good light then moves into shade you will get underexposed images

 

[Phil V]

Actually the main benefit of using BBF is it seperates exposure from focus, if you just use the front focus/shutter button whatever the exposure for your first shot in a burst of photos is what you will get locked down until you release the shutter button

Using BBF the exposure is set differently for every single photo taken during a burst, very useful for moving subjects moving in and out of shady/bright areas as it will expose and meter for every single shot taken

Using the front shutter/focus button could well end up with a series of under and over exposed images as the exposure will be locked down to the first image taken, if the subject starts in good light then moves into shade you will get underexposed images

I set my exp differently depending on the general situation, sometimes keeping it locked with the shutter button and sometimes not.

There are times it's an advantage to have it lock.ie where I might be shooting the same subject but change of camera position could include more sky or window. My general rule is to lock for portraits and not lock for Motorsport.

 

[danny_bhoy]

Thanks for the in-depth info guys. Really appreciate it.

Just to lay this down in pre-school terms: I can either use BBF for single shots with one press or I can keep the button depressed to continuously track a moving subject for multiple shots - the main benefit of this being that it meters each shot independently?

Again, please forgive me if I'm being a bit slow on the uptake. Focusing is always something that's always baffled me.

 

[Gary Coyle]

Correct

 

[danny_bhoy]

Correct

Magic. Cheers Gary.

 

[sk66]

Using the front shutter/focus button could well end up with a series of under and over exposed images as the exposure will be locked down to the first image taken,

Not with any Nikon I've ever used. 1/2 press locks focus, exposure is locked when the shutter releases each time. That's why there's an exposure lock button...which you might be using for BBF instead.

I do believe you can change these behaviors from their norm in the more advanced cameras.

 

[Phil V]

Thanks for the in-depth info guys. Really appreciate it.

Just to lay this down in pre-school terms: I can either use BBF for single shots with one press or I can keep the button depressed to continuously track a moving subject for multiple shots ...

Not quite.
You still need to use AI Servo focus mode.

There are reports that using BBF with AI Servo is slightly less accurate on static subjects, I use it personally, but I'm not convinced it's not contributing to my error rate.

(it could just be internet rumour.

...the main benefit of this being that it meters each shot independently? ...

Not necessarily:
As my post above - you can set AE lock on the shutter half press or have no lock, it's down to personal preference and conditions. when shooting portraits outside, I like to lock in an exposure (I'm not a manual shooter and this is my preferred working method with AV) when shooting rallying, the cars move in and out of shade so I don't want to lock in an exposure.

Again, please forgive me if I'm being a bit slow on the uptake. Focusing is always something that's always baffled me.

The only thing that baffles me is that you bought a 7d which is a camera famed for it's complex and highly customisable focussing. For landscapes a 5d classic or even a 60d is probably a better buy. But if you're going to be doing more of this type of stuff it'll come into it's own.

 

[danny_bhoy]

Not quite.
You still need to use AI Servo focus mode.

There are reports that using BBF with AI Servo is slightly less accurate on static subjects, I use it personally, but I'm not convinced it's not contributing to my error rate.

(it could just be internet rumour.

Not necessarily:
As my post above - you can set AE lock on the shutter half press or have no lock, it's down to personal preference and conditions. when shooting portraits outside, I like to lock in an exposure (I'm not a manual shooter and this is my preferred working method with AV) when shooting rallying, the cars move in and out of shade so I don't want to lock in an exposure.

The only thing that baffles me is that you bought a 7d which is a camera famed for it's complex and highly customisable focussing. For landscapes a 5d classic or even a 60d is probably a better buy. But if you're going to be doing more of this type of stuff it'll come into it's own.

Thanks Phil, still digesting all of the above. Going to need to get my hands on my camera and put it into practice for it to sink in.

As for the 7d, full frame was never and option (would require new lenses) and I though it was the best of the rest in terms of build quality. As you say, I'm sure I'll see the benefits of it's strongest points as I do more people orientated sort of work

 

[Phil V]

Thanks Phil, still digesting all of the above. Going to need to get my hands on my camera and put it into practice for it to sink in.

As for the 7d, full frame was never and option (would require new lenses) and I though it was the best of the rest in terms of build quality. As you say, I'm sure I'll see the benefits of it's strongest points as I do more people orientated sort of work

It's a great camera but lots of people have struggled with the complex focussing modes (it's hideously customisable) - good luck with it.

 

[Gary Coyle]

Not with any Nikon I've ever used. 1/2 press locks focus, exposure is locked when the shutter releases each time. That's why there's an exposure lock button...which you might be using for BBF instead.

I do believe you can change these behaviors from their norm in the more advanced cameras.

The OP is talking Canon not Nikon.

 

[Burry1]

Actually the main benefit of using BBF is it seperates exposure from focus, if you just use the front focus/shutter button whatever the exposure for your first shot in a burst of photos is what you will get locked down until you release the shutter button

Using BBF the exposure is set differently for every single photo taken during a burst, very useful for moving subjects moving in and out of shady/bright areas as it will expose and meter for every single shot taken

Anyone used Sony Alpha BBF? My A580 seems to lock exposure when I press the back button as well as focus, so if I press it and recompose I can get the exposure quite wrong at times. I would have thought I'd use the AEL button as well, if I wanted this to happen. Can't find any settings to change this behaviour.

Thanks, Burry1

 

[sk66]

The OP is talking Canon not Nikon.

Isn't the little button with an asterisk the exposure lock button?

I'm pretty familiar w/ Canons as well, just not *as familiar* so I left it as "Nikons."

I *believe* that with both Nikon and Canon bodies without a dedicated AF-On button; when you assign focus to the exposure lock button it defaults to assigning exposure lock to the shutter 1/2 press. Essentially, all you are doing is swapping the two functions.

 

[Phil V]

Isn't the little button with an asterisk the exposure lock button?

I'm pretty familiar w/ Canons as well, just not *as familiar* so I left it as "Nikons."

I *believe* that with both Nikon and Canon bodies without a dedicated AF-On button; when you assign focus to the exposure lock button it defaults to assigning exposure lock to the shutter 1/2 press. Essentially, all you are doing is swapping the two functions.

You assume incorrectly (for Canon) when assigning the focus to the back button, there is no default, there is a choice as you scroll to either assign AE lock or not. Now I'm not suggesting some people might not go beyond the first option that gives them focus on the * button, but the choice is there with no 'default' setting.

 

[sk66]

You assume incorrectly (for Canon) when assigning the focus to the back button, there is no default, there is a choice as you scroll to either assign AE lock or not. Now I'm not suggesting some people might not go beyond the first option that gives them focus on the * button, but the choice is there with no 'default' setting.

I haven't used a DSLR w/o a dedicated AF-On in quite a while.
So, when you assign only focus to the EL button you have no exposure lock? That makes more sense really.... (for continuous shooting/tracking)

(I know with most cameras you could assign EL to somewhere else like a fn button or whatever. Heck, with my camera I can assign AF-On to the Fn button if I wanted)

 

[Phil V]

I haven't used a DSLR w/o a dedicated AF-On in quite a while.
So, when you assign only focus to the EL button you have no exposure lock? ...

No. I can choose whether to assign exp lock, on the older bodies just to the shutter button half press but the newer bodies, just about anywhere.

Oddly I only have one 'older' body without an AF On button, but all the cameras are set up to copy the functions so they all work the same. When the 20d gets retired, we might even keep the buttons as they are (old dog - new tricks).

 

[sk66]

No. I can choose whether to assign exp lock, on the older bodies just to the shutter button half press but the newer bodies, just about anywhere.

Oddly I only have one 'older' body without an AF On button, but all the cameras are set up to copy the functions so they all work the same. When the 20d gets retired, we might even keep the buttons as they are (old dog - new tricks).

You "have to choose?" (I understand that "you can.") If you don't "have to" assign it somewhere, and you don't, then what happens? No EL I would hope. I wouldn't want it on the 1/2 press for this kind of use.

 

[Phil V]

You "have to choose?" (I understand that "you can.") If you don't "have to" assign it somewhere, and you don't, then what happens? No EL I would hope. I wouldn't want it on the 1/2 press for this kind of use.

(this from the 40d - there's similarities between them all and it was the nearest)

Shutter button + AF On(or *) button
CFn IV - 0 Metering + AF Start
CFn IV - 1 Metering + AF Start / AF Stop
CFn IV - 2 Metering Start/Meter + AF Start
CFn IV - 3 AE Lock/Metering + AF Start
CFn IV - 4 Metering + AF Start / Disable

So there's no 'default' there's a bunch of options, you 'have to' choose 1 of them.

I use 0 for motorsport and 3 for general photography because I like to select what I'm metering.

 

[sk66]

So it never goes to the shutter 1/2 press, and if you select anything but 0 AF and metering are coupled...

Isn't what you're metering based on the active focus point? (when not in matrix/cw) Can't you move the initial focus point to where you want it in AI? That's how I did it with the D3 and others w/o AF-on button. And that's how I "have to" do it w/ the D4/800. Unless I can recompose/trigger before the focus re-centers (or I have to dive into the menus).

I ask because I hate diving into menus to change things....but you have the C1/2 settings/dial.

 

[Phil V]

This is getting a bit tricky because the functions are clearly different on Nikon / Canon so:

So it never goes to the shutter 1/2 press, and if you select anything but 0 AF and metering are coupled...
.

No - you may have misunderstood the + on the menu detail:
the left of the + is the shutter button, the right of it is the * button (or AF On if available)

So the custom functions give a choice of metering behaviour and focus behaviour, some of the AF functions are for fairly specialist lenses, the long tele's have focus stop functions not available on lesser lenses (I have no idea what it does, sorry).

Isn't what you're metering based on the active focus point? (when not in matrix/cw) Can't you move the initial focus point to where you want it in AI?

The active focus point makes up some of the weighting in Eval mode, yes we can choose the focus point in AI servo.

 

[sk66]

No - you may have misunderstood the + on the menu detail:
the left of the + is the shutter button, the right of it is the * button (or AF On if available)

Got it. Actually, not quite so different. You just have more options.

 

[Phil V]

Got it. Actually, not quite so different. You just have more options.

Like I said, some of those options are for only a few lenses though.

Glad I managed to explain it. I might bookmark this for next time it crops up.

 

[Hedgehogfromhell]

I've just read through this and had a play with my 7D midway.. Thanks Phil! But i foresee a sleepless night playing with configs!

 

[Phil V]

I've just read through this and had a play with my 7D midway.. Thanks Phil! But i foresee a sleepless night playing with configs!

Sorry!

There's a post on here somewhere that describes how to get the immediate choice of 7 focus points on a 7d

Deadly serious, it's mindblowing. Not to mention the choice of spot focus / single point focus, group (or whatever it's called) focus. Focus priority / shutter priority, panning sensitivity. You can see why some people end up with a camera they can't get to focus accurately.

 

[Gary Coyle]

Canon totally screwed up the AF system with the ID MKIII, the MKIIN was superb and should have been left as it was.

 

[Durbs]

Personally, I disabled all but single-point, expanded point and spot AF modes.
Auto- and zone- AF just takes too much control out of your hands.