Using all autofocus points.

[Janice]

Are you all satisfied with using all your autofocus points most of the time? Its something Ive never done.

I either use manual focus... or the centre point on its own.

I cant get to grips with the fact that about 3 or more autofocus points go active (red dots light up on those points when they are in focus)

how does it focus on what you want then?? I gather the closest subject to you takes priority.. but what do the other focus points do then when they light up to say htey are in focus? They might be quite far back in the picture.

 

[Slapo]

I use either dynamic area AF (should be good for moving subjects, not sure about it), single area Af or MF (for close-ups).
The closest subject usually doesn't make sense for me (not in what I take photos of), but I think that would be a situation where all of the points could be used.

In dynamic area AF I select the main point and the camera should switch to a different one if needed. Needless to say I don't think it happened more than twice

In full auto mode, I have to idea how cameras tend to focus, but a logical solution would be dynamic area AF if the subject is restless or closest subject (cameras probably try this first in Auto mode) depending on the mode that is being used.

It doesn't really focus on what you want in auto mode, it focuses on what the people who created the algorithms thought you'd want to focus on... which means it's way off often

 

[RobertP]

When I first got the 20D 80% of my pictures were wrongly focussed. Not disastrously bad but not right. Took me a long time to find out about all focus points enabled and what that means. Never had them all active ever since. Not tried with the 5d to see if it is any cleverer.

Centre only for me too. Joystick button to choose another if need be.

 

[Slapo]

Centre only for me too. Joystick button to choose another if need be.

I'd guess it's like that with most people here.

 

[Steep]

Centre, I figure I want to focus on my subject which 95% of the time is in the centre, if I leave it up to the camera it will almost always focus on the wrong thing.

 

[mho]

I use a single AF point but may have it auto expand to the 7 or 13 around it for tracking once a lock has been made on the subject when in AIServo.

All other times its just one point selected by me for which is appropriate for the subject.

I never use Auto All Point AF

 

[RobertP]

Guess I could read the manual but I thought it switched itself to all points normally if you used AI servo focus?

 

[mho]

Guess I could read the manual but I thought it switched itself to all points normally if you used AI servo focus?

an easy answer no

its a bit more complicated than that.

Should add its related to certain custom function settings and focal length dependant in conjunction with custom function settings.

 

[magpieant]

I always use one point (only got 5 on my D50 ) - normally the centre one.

Anth

 

[cjnicolai]

Honestly, I've had lots of students who struggled with getting the focus points to work for them, and most of them have moved on to manual focus and never looked back. LOL. Sometimes a camera can just be too damn helpful.

I always use my 35mm film gear in manual focus. Even though I'm ridiculously blind, I still focus better and faster than autofocus does.

- CJ

 

[Janice]

Centre only for me too. Joystick button to choose another if need be.

Oh good. Thought it was just me!!

Although I think I am going to change the use of joystick to change the autofocus points in my custom functions... as during the wedding last weekend I was finding off-focus on faces and quickly switched to manual focus so only lost a couple of non-important shots......later I realized the joystick had been nudged and the top right focus point was the active one instead of the centre.. so I was getting a blurry face but a nice sharp tree, top right!!

 

[stevewestern]

Lord help me - I want to pay a blind woman to teach me how to take pictures...



..sadly, she takes much better pictures than I do despite that..

Hey, at least my Mum loves me !!

 

[Slapo]

...I still focus better and faster than autofocus does.

Ever tried to catch some swallows in flight that way?

You probably need a decently big and bright viewfinder for accurate manual focusing.
There's still focus lock in most dslrs of today for the rest of us.

 

[cjnicolai]

Ever tried to catch some swallows in flight that way?

You probably need a decently big and bright viewfinder for accurate manual focusing.
There's still focus lock in most dslrs of today for the rest of us.

Yes, I have, thank you. I've also manually focused an 400mm 2.8 with a doubler (yes, that's 800mm at 2.8 on a monopod with a glass element the size of a salad plate) on the sidelines in an NFL game.

And I've manually focused at 2.8 in low light to photograph 18-month-old triplets.

It's all in what you're used to.

And who exactly are "the rest of you"? LOL. Such a separatist.

- CJ

 

[Ally]

center point for me too, I use the jostick at my right thumb to change points for compisional values and so on

 

[cjnicolai]

Lord help me - I want to pay a blind woman to teach me how to take pictures...



..sadly, she takes much better pictures than I do despite that..

Hey, at least my Mum loves me !!

Steve, honey, it ain't what you got...it's how you use it.

Seriously, my vision is estimated at around 20/6000 and is only corrected to 20/40 on a good day. If I can manually focus, anybody can.

- CJ

 

[digitalfailure]

I use the center point too, but will sometimes scroll through the other points if i'm trying to be arty

 

[walls]

center one for me, a toe or a finger tends to get in the way using them all

 

[grumpybadger]

I never use auto select. I use the centre spot and recompose. I actually have my cameras set up so I can grab stop AI servo mode with the '*' button on the back of the camera so I can grab focus and reframe without moving to OneShot mode.

an easy answer no

its a bit more complicated than that.

Should add its related to certain custom function settings and focal length dependant in conjunction with custom function settings.

I think that is only true for the 1 series and not the 20D/5D based interface

Yes, I have, thank you. I've also manually focused an 400mm 2.8 with a doubler (yes, that's 800mm at 2.8 on a monopod with a glass element the size of a salad plate) on the sidelines in an NFL game.

Surely that makes it an 800 f/5.6?

Guess I could read the manual but I thought it switched itself to all points normally if you used AI servo focus?

I don't believe so. I found the 5D worked much better with all points selected for AI Servo (think that enables the "hidden" 6) but the '1' works better with just the one and the additionals added automatically - as described by mho.

 

[whitewash]

i have never let my camera decide what to focus on, ive always used just one spot and thats usually the centre one

 

[cjnicolai]

No, grumpy, it makes it an 800mm 2.8.

CJ

 

[digitalfailure]

I don't believe so. I found the 5D worked much better with all points selected for AI Servo (think that enables the "hidden" 6) but the '1' works better with just the one and the additionals added automatically - as described by mho.

The hidden 6 points become active in A1 servo on the 5d when you go into the custom functions and enable them. I use the centre point only and reviewing images on the lcd shows the center and 6 hidden points.

 

[Slapo]

Yes, I have, thank you. I've also manually focused an 400mm 2.8 with a doubler (yes, that's 800mm at 2.8 on a monopod with a glass element the size of a salad plate) on the sidelines in an NFL game.

And I've manually focused at 2.8 in low light to photograph 18-month-old triplets.

It's all in what you're used to.

And who exactly are "the rest of you"? LOL. Such a separatist.

- CJ

In that case, I wouldn't want to be near you when you furiously chop vegetables... them cut pieces could fly into me and knock me out for good

How come the lens came out unharmed?

I mean, I have almost damaged the lens as I was trying to manually focus fast on them once or twice.
Not to mention I wasn't sure I have them in focus as I could barely keep them in the viewfinder

If there's a secret technique of your how to to that safely and fairly accurately, feel free to share it (accepting PMs all the time as well)

 

[mole2k]

No, grumpy, it makes it an 800mm 2.8.

CJ

The increase in focal length given by the 2x converter will mean you would need twice as large an aperture to maintain the f2.8. Aperture isnt just physical size of the hole the blades make, its linked to the focal length. Thats why consumer lenses often have apertures that change throughout their range.

 

[cjnicolai]

OK, yes, correct. However the practical difference between 2.8 and 5.6 at 800 mm is pretty much nada.

(Using a DOF calculator, 800 at 2.8 from 50 feet away gives a total DOF of 0.19 feet. At 5.6, total DOF is 0.38 feet.)

 

[cjnicolai]

Slapo, not sure why quick manually focusing would cause that much equipment damage? That said, the key for me is anticipation and keeping both eyes open so I'm a step ahead of the action.

 

[Slapo]

Slapo, not sure why quick manually focusing would cause that much equipment damage? That said, the key for me is anticipation and keeping both eyes open so I'm a step ahead of the action.

Well, when I tried it, I got from one 'edge' to another very quickly. Might be the lens in some way, though.

I still can't figure out how you can anticipate movements of a swallow when they always change their direction quite suddenly here.

I could try again tomorrow if it's not raining, though. I might need a better spot for them first.

 

[cjnicolai]

Slapo, I was referring to the football game and the triplets. Still, slowing down and keeping both eyes open when you shoot is very helpful.

Please note that I'm not saying autofocus isn't good or shouldn't be used. I'm simply saying that there are times when manually focus makes a lot of sense and can be faster than auto -- and I'm also saying that manual focus is a lot easier than a lot of people think. Frankly, as a medium format shooter, I don't have the option of autofocus, so I've learned to be very good with manual.

 

[mole2k]

I manually focus a lot, quite often while shooting motorsport too. I taught myself to track a car at 300mm tracking it and taking shots as it gets closer while zooming out and maintaining focus. It isnt nearly as hard as you might think. A bit of practice and you can get there.

 

[cjnicolai]

Mole, absolutely.

 

[grumpybadger]

OK, yes, correct. However the practical difference between 2.8 and 5.6 at 800 mm is pretty much nada.

(Using a DOF calculator, 800 at 2.8 from 50 feet away gives a total DOF of 0.19 feet. At 5.6, total DOF is 0.38 feet.)

So I can't get a 600 2.8 by using a 2x on a 300?

I wasn't arguing that 800 f/5.6 is hard or not, I was arguing that it wasn't a 2.8 lens with the extender. I'm not saying that you don't have a good skill with manual focus and that going to f/5.6 suddenly makes it easy, I'm just saying that your initial statement broke the laws of physics.

I've been taking pictures long enough to remember the days when cameras didn't/couldn't focus for you and it was all manual focus. I still manual focus myself sometimes, but I find the modern screens without the split prism make it harder. For birds in flight, I have found that prefocussing can also be a good way of working.