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NO Focus lock, any other way?

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graph (g3)

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I read somewhere that the 300d cannot focus on a specific part of an image you want it to focus. I understand that the RB has 7 points on where you can assign it to focus but what if it is on the part of the shot where it doesnt land on the 7 points?

is manual focus the only way to do this? how will i know if its as sharp as it can get?

my understanding of a focus lock is that you point to something then it focuses, you press the lock button and the focus stays at that distance even if you let go of the shutter which was pressed halfway. then you can recompose and take dozens of shot with the same focus distance as long as the lock is still in place. am i correct? and the 300d doesnt have this lock button?

this is something i can probably live without since if im doing this im most likely to use a tripod, but i need to know if i can rely on the manul focus.
 
do you own a 300D yet?

yes it can do the focus/recompose technique.

you can also set it to center point af focus.
 
You can lock the focus in any of the modes, BUT ... in the full auto mode
cannot choose the number of focus points, I believe it always picks for you.

So ... you need to use the "P" or other "creative" modes to control which focus point you use. I always set it to the center point, and use focus lock to recompose my shot after focussing on the thing I want.
 
release focus and re-focus the next time to press the button.

As pointed out by the other replies, focus lock is maintained by keeping the button halfpressed.

--jalle
graph (g3) said:
I read somewhere that the 300d cannot focus on a specific part of
an image you want it to focus. I understand that the RB has 7
points on where you can assign it to focus but what if it is on the
part of the shot where it doesnt land on the 7 points?

is manual focus the only way to do this? how will i know if its as
sharp as it can get?

my understanding of a focus lock is that you point to something
then it focuses, you press the lock button and the focus stays at
that distance even if you let go of the shutter which was pressed
halfway. then you can recompose and take dozens of shot with the
same focus distance as long as the lock is still in place. am i
correct? and the 300d doesnt have this lock button?

this is something i can probably live without since if im doing
this im most likely to use a tripod, but i need to know if i can
rely on the manul focus.
Click to expand...
 
graph (g3) said:
my understanding of a focus lock is that you point to something
then it focuses, you press the lock button and the focus stays at
that distance even if you let go of the shutter which was pressed
halfway. then you can recompose and take dozens of shot with the
same focus distance as long as the lock is still in place. am i
correct? and the 300d doesnt have this lock button?
Click to expand...
Pressing the half shutter will lock the focus and allow you to recompose, AS LONG AS AiServo does not kick in when it detects movement of the object. When AiServo kicks in, the focus lock is lost, therefore the focus lock in 300D can be described as a "soft" lock...

The bad news is there is no way to dsiable AiServo, so a "hard" focus lock is one of the missing/crippled features in 300d

--
http://gallery29564.fotopic.net/

 
after you'd achieved the desired focal distance, and your focus will be 'locked' all the way till you swtich back or adjust the focus yourself.

Simple.
graph (g3) said:
I read somewhere that the 300d cannot focus on a specific part of
an image you want it to focus. I understand that the RB has 7
points on where you can assign it to focus but what if it is on the
part of the shot where it doesnt land on the 7 points?

is manual focus the only way to do this? how will i know if its as
sharp as it can get?

my understanding of a focus lock is that you point to something
then it focuses, you press the lock button and the focus stays at
that distance even if you let go of the shutter which was pressed
halfway. then you can recompose and take dozens of shot with the
same focus distance as long as the lock is still in place. am i
correct? and the 300d doesnt have this lock button?

this is something i can probably live without since if im doing
this im most likely to use a tripod, but i need to know if i can
rely on the manul focus.
Click to expand...
--
The Secret to Life is... Calcium!!
http://max-fun.fotopic.net
 
With Custom Function 04 you can set your * button to lock focus, and the shutter half press is AE only instead of both AE and AF. My 35mm Elan 7e has this.
graph (g3) said:
I read somewhere that the 300d cannot focus on a specific part of
an image you want it to focus. I understand that the RB has 7
points on where you can assign it to focus but what if it is on the
part of the shot where it doesnt land on the 7 points?

is manual focus the only way to do this? how will i know if its as
sharp as it can get?

my understanding of a focus lock is that you point to something
then it focuses, you press the lock button and the focus stays at
that distance even if you let go of the shutter which was pressed
halfway. then you can recompose and take dozens of shot with the
same focus distance as long as the lock is still in place. am i
correct? and the 300d doesnt have this lock button?

this is something i can probably live without since if im doing
this im most likely to use a tripod, but i need to know if i can
rely on the manul focus.
Click to expand...
--
Shannon

 
This is exactly what happens for me, its not a REAL focus lock.

I thought I was going nutty, everyone keeps saying "its has FL it has FL" and my camera can change focus with the button half pressed, I was sure it was faulty or something, but it seems thats the way it is?
lasm said:
graph (g3) said:
my understanding of a focus lock is that you point to something
then it focuses, you press the lock button and the focus stays at
that distance even if you let go of the shutter which was pressed
halfway. then you can recompose and take dozens of shot with the
same focus distance as long as the lock is still in place. am i
correct? and the 300d doesnt have this lock button?
Click to expand...
Pressing the half shutter will lock the focus and allow you to
recompose, AS LONG AS AiServo does not kick in when it detects
movement of the object. When AiServo kicks in, the focus lock is
lost, therefore the focus lock in 300D can be described as a "soft"
lock...

The bad news is there is no way to dsiable AiServo, so a "hard"
focus lock is one of the missing/crippled features in 300d

--
http://gallery29564.fotopic.net/

Click to expand...
--
------------------------
http://www.absolv.com
 
300D * button does something similar I think.

Unless you got a dud set, you should be able to do focus/recompose .

How long are your lens? ai servo kicks in when it detects "significant" movement, on very long lens, it MAY be a problem . (no problem at 400mm for me)
shanstu70 said:
graph (g3) said:
I read somewhere that the 300d cannot focus on a specific part of
an image you want it to focus. I understand that the RB has 7
points on where you can assign it to focus but what if it is on the
part of the shot where it doesnt land on the 7 points?

is manual focus the only way to do this? how will i know if its as
sharp as it can get?

my understanding of a focus lock is that you point to something
then it focuses, you press the lock button and the focus stays at
that distance even if you let go of the shutter which was pressed
halfway. then you can recompose and take dozens of shot with the
same focus distance as long as the lock is still in place. am i
correct? and the 300d doesnt have this lock button?

this is something i can probably live without since if im doing
this im most likely to use a tripod, but i need to know if i can
rely on the manul focus.
Click to expand...
--
Shannon

Click to expand...
 
This is the most annoying/disappointing feature of the 300D.

However, you can prevent servo from kicking in by pressing and holding the depth of field preview button after focussing with a half press of the shutter button. You can even take the shot with the dof button still pressed.

Canon should hang its head in shame for imposing AI focus on its paying customers.
 
Presumably the camera can't tell the difference between the subject's moving across the view and our moving the camera to recompose the shot.

So is servo-focus an issue if you move the camera too fast while recomposing?

Chris
 
Michael Kilpatrick said:
This is the most annoying/disappointing feature of the 300D.
However, you can prevent servo from kicking in by pressing and
holding the depth of field preview button after focussing with a
half press of the shutter button. You can even take the shot with
the dof button still pressed.
Canon should hang its head in shame for imposing AI focus on its
paying customers.
Click to expand...
I was just checking out on the up-and-coming Nikon D70 specs, aimed to compete with the 300D users and reading in-between the lines, it won't surprise me if the Nikon D70 behaves exactly the same way, it has an AiServo mechanism which cannot be turned off..

--
http://gallery29564.fotopic.net/

 
Thanks Max - I was reading this thread wondering if anyone was going to state the obvious. People - it is a different way of doing things but if you're going to spend that kind of money you might as well learn to do it the Rebel way. it may seem kludgy at first, but through repetition it becomes second nature. ~ m²
Max Fun said:
after you'd achieved the desired focal distance, and your focus
will be 'locked' all the way till you swtich back or adjust the
focus yourself.
Simple.
Click to expand...
--

'Brothers and sisters, we've learned that there's some bad bokeh going around out there. So like, just be careful man, alright?' (If Wavy Gravy emceed PMA) http://rhodeymark.instantlogic.com

 
Chris Wyles said:
Presumably the camera can't tell the difference between the
subject's moving across the view and our moving the camera to
recompose the shot.

So is servo-focus an issue if you move the camera too fast while
recomposing?
Click to expand...
The problem is more evident with longer zoom ranges, such as 200mm and above...

Anything below that, it is generally quite safe and predictable when using the focus-recompose technique..

--
http://gallery29564.fotopic.net/

 
Hi Chris - apparently different cameras have different sensitivities in this area. Daniella had Canon turn her AI Focus sensitivity up, as it wasn't going into Servo easy enough. I usually have to trick mine into Servo as well, but like it that way. Some users report Servo engaging on just about every attempt to recompose. The AI Focus is supposed to be more sensitive to subjects moving closer/further (out of focus) than moving laterally within the focus distance/DOF. If it doesn't work that way, I'd say it needs calibrated (or a different camera bought off the shelf). ~ m²
Chris Wyles said:
Presumably the camera can't tell the difference between the
subject's moving across the view and our moving the camera to
recompose the shot.

So is servo-focus an issue if you move the camera too fast while
recomposing?

Chris
Click to expand...
--

'Brothers and sisters, we've learned that there's some bad bokeh going around out there. So like, just be careful man, alright?' (If Wavy Gravy emceed PMA) http://rhodeymark.instantlogic.com

 
You might be right, but I suppose it depends on how well it works.

It seems as though the algorithm in the 300D is very unsophisticated and makes no allowance for focal length or aperture.

I find my 300D almost never kicks into servo with the kit lens, but if I use either my 75 - 300 IS or my 50 mm/1.8, both of which have limited depth of field, it switches to servo all the time during a normal half press/recompose.

Using the depth of field preview button stops this, but I would rather not have to do it.

I have no problem with the genuine cost saving features of the 300D (plastic body, 4 shot buffer etc), but AI focus simply doesn't work for me and I think it is mean spirited of Canon to inflict it on people who, in many cases, have just bought the most expensive camera they have ever owned (A$2000 - hardly a budget camera).
It still takes sensational photographs though.
 
focus points meaning the 7 points aligned in a form of a cross?

its just weird that my g3 can scroll to any space in the image for focusing (but then focusing is a weak point of my g3)
 
I would probably use it for still lifes (product shots for catalog) and will be in a tripod so it would be really difficult for me to more the thing just to focus.

usually i take a dozen shot of a single setup with different cam settings and it would be really hard to refocus/recompose on each shot.
lasm said:
graph (g3) said:
my understanding of a focus lock is that you point to something
then it focuses, you press the lock button and the focus stays at
that distance even if you let go of the shutter which was pressed
halfway. then you can recompose and take dozens of shot with the
same focus distance as long as the lock is still in place. am i
correct? and the 300d doesnt have this lock button?
Click to expand...
Pressing the half shutter will lock the focus and allow you to
recompose, AS LONG AS AiServo does not kick in when it detects
movement of the object. When AiServo kicks in, the focus lock is
lost, therefore the focus lock in 300D can be described as a "soft"
lock...

The bad news is there is no way to dsiable AiServo, so a "hard"
focus lock is one of the missing/crippled features in 300d

--
http://gallery29564.fotopic.net/

Click to expand...
--
[email protected]
 
so by switching to Manual focus after a desired focus on auto, it maintains its current focus? what about soft lock or when the subject moves on manual (i know its a lame question but i just need all the right info and not assume the simple answers)
 
when you recompose while holding the shutter halfpressed, is it annoying when it still refocuses?
 
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