Canon 20D Focus options

On Wed, 08 Dec 2004 21:27:12 -0700, "Roger N. Clark (change username
to rnclark)" wrote:

Bill,
On the 10D and D60 cameras, I never found the AI, or AI focus
were of much good for fast subjects, especially when unpredictable,
like birds at takeoff or landing. On the IDII, I've set the AI
to maximum rate and then it does real well (but my dogs playing are
still faster). Back to the 10D and D60: for fast action, I
learned to use single shot, and to lift my finger off the shutter
and then press it completely again.

I use AI nearly in 95% and Custrom Function for putting the AF to the
AE-Button on the back reachable easily with my thumb. If I am
following a subject and I think it is perfectly sharp I release the
AE-Button and press the shutter where no focussing is happening
anymore. When I have to recompose the frame a little bit and the AF
sensor normaly would be somewhere on the background and the subject
would have been out of focus this method works perfectly by dividing
AF and shutter!


Gruß
Stefan

--


People: http://www.stefanjondral.de/
Naturfotos: http://www.jondral-naturfoto.de/

Bill Hilton wrote:

Generally they recommend One Shot for stationary
subjects and AI for moving subjects


From: "N8urePix"

Bill, this is the mode I have been practicing with after reading the text in
the manual. I have not had much of an opportunity to try it on birds in
flight because of the weather


Bob, here's a link to a Canon publication by senior tech guru Chuck Westfall
describing the AF modes in detail ... it's written primarily for the 1D class
cameras so the custom function and 45 AF point info isn't applicable to the 20D
but most of it is useful for 20D owners too. For example I learned you're
supposed to run USM at 300/.3/0 to clean up after the anti-aliasing filter and
that the focus lock and recompose trick isn't recommended inside of 15 ft or
for portraits ... good reading.

http://www.photoworkshop.com/canon/EOS_Digital.pdf (a 35 pg 1 MB pdf so takes
a while to download ... I recommend saving it and reading it at your leisure)

There is something specifically for the 20D on this page ...
http://www.photoworkshop.com/canon/

Back to the AF modes and flight shots ... here are some sample images taken
with various AF modes which illustrate the problems ...

http://members.aol.com/bhilton665/T5220.jpg ... hand held with a 400 mm, the AF
mode isn't important here since there was a narrow orange patch of clouds in
the sky and I just wanted to freeze the birds while they were flying in it.
Hard part was getting a group of birds that weren't "touching" each other, and
getting a fast enough shutter speed, I think I went to iso 800 and then ran
Neat Image to clean up the noise artifacts. Either AI or OS would work here.

http://members.aol.com/bhilton665/T5314.jpg ... bird is just taxiing for
take-off, I'm in AI mode with the sensor on the neck ... so long as I keep the
sensor on the neck the head is in focus but if the wing gets in the way it will
shift focus to the wing, which is a problem. 500 mm f/4 on a Wimberly pivot
head ... I got about 8 frames of this guy.

http://members.aol.com/bhilton665/T4956.jpg ... different bird, same mode, same
problems ...

http://members.aol.com/bhilton665/T4897.jpg ... AI mode, in this one the wing
got in the way so the head/eye isn't sharp but the wing is ... this is the kind
of problem Roger avoids by using One Shot instead of AI ... so there are
advantages and disadvantages to each mode.

http://members.aol.com/hiltonfotogra...ff_feather.htm ... tough
problem here, the people beside me with 10D's (two) and a Nikon 1Dx couldn't
focus on these puffins but with the 1D Mark II I was able to catch them about
1/3 the time ... AI mode, 400 f/5.6 hand-held, 45 AF points ... small dark
target flying fast in bad weather ... tough conditions for flight photography.

http://members.aol.com/hiltonfotogra...tti_flight.htm ... same
trip but an easy bird to photograph in flight since it's white, flys slow and
is 4x bigger than a puffin ... piece of cake, even the 10D gets this one almost
every shot.

One more, this one sitting ...
http://members.aol.com/hiltonfotogra...ve_blossom.jpg ... if you use the
center focus point for a shot like this you'll get the breast sharp but the eye
isn't sharply focussed so I used one of the off-center focus points in One Shot
mode to lock on the neck, which is about on the same plane as the eye. This is
with the 500 f/4 and a 1.4x t/c on a Mark II and prints beautifully at 16x24"
... using the center point and recomposing would probably not work as well (see
the Westfall publication above) at this close range ... the problem with using
an off-center focus point is if the bird moves his head to the other side (for
example) and you no longer have a good composition ... I tried this several
times on a bear in Denali and when it worked it was perfect but the bear kept
swinging his head side to side sniffing the air so sometimes my focus point was
on the wrong side of the frame ...

My advice is to learn all the modes, practice with them and hope that you're in
the right one when something good happens

Bill,
These are great examples. With the 1-D Mark II, I work similarly to
they way you do. For flight images, the AI mode works well,
and I'm constantly shifting AF points for the specific scene
and desired focus point, all while working with AI mode.
For "portraits", I switch to one shot mode. Because I use a 10D
as backup, or with a shorter lens, it's hard remembering the
different button sequences between cameras ;-), especially in
the heat of action.

I was never satisfied with the AI mode on the 10D (or D60).
The manual says the camera will do its best effort to focus,
but will fire even if not in focus. With birds in flight action
(and my dogs at play), the 10D just usually never seemed to get
that great of focus in AI mode. The 1D Mark II does great
in this regard. So on the 10D I found I got a higher percentage
of critically sharp focused images with action shots in one shot mode,
rather than a higher number of images, but each slightly out of focus
with AI (by this I mean an OK 8x10 could be made, but looking a
little soft). I probably get 5 to 10 times as many critically
focused action shots with the 1DII as I did with the 10D,
given similar conditions, and with the 1DII it is usually my
fault for not keeping the sensor on the desired subject
during fast action that ruins focus. With the 10D it was
usually the camera failing to track and lock fast enough.
I suppose with "little brown birds" or fast birds like
puffins, the 1DII can be challenged as you say (with of course,
lenses being an issue too).

Roger

Bill Hilton wrote:

Generally they recommend One Shot for stationary
subjects and AI for moving subjects


From: "N8urePix"

Bill, this is the mode I have been practicing with after reading the text in
the manual. I have not had much of an opportunity to try it on birds in
flight because of the weather


Bob, here's a link to a Canon publication by senior tech guru Chuck Westfall
describing the AF modes in detail ... it's written primarily for the 1D class
cameras so the custom function and 45 AF point info isn't applicable to the 20D
but most of it is useful for 20D owners too. For example I learned you're
supposed to run USM at 300/.3/0 to clean up after the anti-aliasing filter and
that the focus lock and recompose trick isn't recommended inside of 15 ft or
for portraits ... good reading.

http://www.photoworkshop.com/canon/EOS_Digital.pdf (a 35 pg 1 MB pdf so takes
a while to download ... I recommend saving it and reading it at your leisure)

There is something specifically for the 20D on this page ...
http://www.photoworkshop.com/canon/

Back to the AF modes and flight shots ... here are some sample images taken
with various AF modes which illustrate the problems ...

http://members.aol.com/bhilton665/T5220.jpg ... hand held with a 400 mm, the AF
mode isn't important here since there was a narrow orange patch of clouds in
the sky and I just wanted to freeze the birds while they were flying in it.
Hard part was getting a group of birds that weren't "touching" each other, and
getting a fast enough shutter speed, I think I went to iso 800 and then ran
Neat Image to clean up the noise artifacts. Either AI or OS would work here.

http://members.aol.com/bhilton665/T5314.jpg ... bird is just taxiing for
take-off, I'm in AI mode with the sensor on the neck ... so long as I keep the
sensor on the neck the head is in focus but if the wing gets in the way it will
shift focus to the wing, which is a problem. 500 mm f/4 on a Wimberly pivot
head ... I got about 8 frames of this guy.

http://members.aol.com/bhilton665/T4956.jpg ... different bird, same mode, same
problems ...

http://members.aol.com/bhilton665/T4897.jpg ... AI mode, in this one the wing
got in the way so the head/eye isn't sharp but the wing is ... this is the kind
of problem Roger avoids by using One Shot instead of AI ... so there are
advantages and disadvantages to each mode.

http://members.aol.com/hiltonfotogra...ff_feather.htm ... tough
problem here, the people beside me with 10D's (two) and a Nikon 1Dx couldn't
focus on these puffins but with the 1D Mark II I was able to catch them about
1/3 the time ... AI mode, 400 f/5.6 hand-held, 45 AF points ... small dark
target flying fast in bad weather ... tough conditions for flight photography.

http://members.aol.com/hiltonfotogra...tti_flight.htm ... same
trip but an easy bird to photograph in flight since it's white, flys slow and
is 4x bigger than a puffin ... piece of cake, even the 10D gets this one almost
every shot.

One more, this one sitting ...
http://members.aol.com/hiltonfotogra...ve_blossom.jpg ... if you use the
center focus point for a shot like this you'll get the breast sharp but the eye
isn't sharply focussed so I used one of the off-center focus points in One Shot
mode to lock on the neck, which is about on the same plane as the eye. This is
with the 500 f/4 and a 1.4x t/c on a Mark II and prints beautifully at 16x24"
... using the center point and recomposing would probably not work as well (see
the Westfall publication above) at this close range ... the problem with using
an off-center focus point is if the bird moves his head to the other side (for
example) and you no longer have a good composition ... I tried this several
times on a bear in Denali and when it worked it was perfect but the bear kept
swinging his head side to side sniffing the air so sometimes my focus point was
on the wrong side of the frame ...

My advice is to learn all the modes, practice with them and hope that you're in
the right one when something good happens

Bill,
These are great examples. With the 1-D Mark II, I work similarly to
they way you do. For flight images, the AI mode works well,
and I'm constantly shifting AF points for the specific scene
and desired focus point, all while working with AI mode.
For "portraits", I switch to one shot mode. Because I use a 10D
as backup, or with a shorter lens, it's hard remembering the
different button sequences between cameras ;-), especially in
the heat of action.

I was never satisfied with the AI mode on the 10D (or D60).
The manual says the camera will do its best effort to focus,
but will fire even if not in focus. With birds in flight action
(and my dogs at play), the 10D just usually never seemed to get
that great of focus in AI mode. The 1D Mark II does great
in this regard. So on the 10D I found I got a higher percentage
of critically sharp focused images with action shots in one shot mode,
rather than a higher number of images, but each slightly out of focus
with AI (by this I mean an OK 8x10 could be made, but looking a
little soft). I probably get 5 to 10 times as many critically
focused action shots with the 1DII as I did with the 10D,
given similar conditions, and with the 1DII it is usually my
fault for not keeping the sensor on the desired subject
during fast action that ruins focus. With the 10D it was
usually the camera failing to track and lock fast enough.
I suppose with "little brown birds" or fast birds like
puffins, the 1DII can be challenged as you say (with of course,
lenses being an issue too).

Roger

Roger,

The 20D has two AI focus modes, one named "AI focus AF" the other named "AI
Servo AF". When you refer to the AI mode on your 1-D, I wonder which 20D
focus mode that is equivalent to. Since discussing this with Bill and
yourself, I have been doing some experimenting and find the AI Servo AF
works best in most of my applications even if it is following a subject on
the ground or in a tree. By depressing the shutter key half way and holding
it there, the camera will continue to refocus as I follow the bird, etc. I
find this to be very helpful and much more effective in most situations. I
can focus on a bird jumping from branch to branch, even if it locks on a
nearby twig a slight movement back onto the bird will cause the camera to
refocus. It also continues to refocus on a bird flying directly toward you
which on my 300D I would have to lift my finger from the shutter button and
refocus and in most cases lose the shot.
--
Bob

"Nature Photography by Bob Moul"
http://www.pbase.com/rcm1840


Bill,
These are great examples. With the 1-D Mark II, I work similarly to
they way you do. For flight images, the AI mode works well,
and I'm constantly shifting AF points for the specific scene
and desired focus point, all while working with AI mode.
For "portraits", I switch to one shot mode. Because I use a 10D
as backup, or with a shorter lens, it's hard remembering the
different button sequences between cameras ;-), especially in
the heat of action.

I was never satisfied with the AI mode on the 10D (or D60).
The manual says the camera will do its best effort to focus,
but will fire even if not in focus. With birds in flight action
(and my dogs at play), the 10D just usually never seemed to get
that great of focus in AI mode. The 1D Mark II does great
in this regard. So on the 10D I found I got a higher percentage
of critically sharp focused images with action shots in one shot mode,
rather than a higher number of images, but each slightly out of focus
with AI (by this I mean an OK 8x10 could be made, but looking a
little soft). I probably get 5 to 10 times as many critically
focused action shots with the 1DII as I did with the 10D,
given similar conditions, and with the 1DII it is usually my
fault for not keeping the sensor on the desired subject
during fast action that ruins focus. With the 10D it was
usually the camera failing to track and lock fast enough.
I suppose with "little brown birds" or fast birds like
puffins, the 1DII can be challenged as you say (with of course,
lenses being an issue too).

Roger

Roger,

The 20D has two AI focus modes, one named "AI focus AF" the other named "AI
Servo AF". When you refer to the AI mode on your 1-D, I wonder which 20D
focus mode that is equivalent to. Since discussing this with Bill and
yourself, I have been doing some experimenting and find the AI Servo AF
works best in most of my applications even if it is following a subject on
the ground or in a tree. By depressing the shutter key half way and holding
it there, the camera will continue to refocus as I follow the bird, etc. I
find this to be very helpful and much more effective in most situations. I
can focus on a bird jumping from branch to branch, even if it locks on a
nearby twig a slight movement back onto the bird will cause the camera to
refocus. It also continues to refocus on a bird flying directly toward you
which on my 300D I would have to lift my finger from the shutter button and
refocus and in most cases lose the shot.
--
Bob

"Nature Photography by Bob Moul"
http://www.pbase.com/rcm1840


Bill,
These are great examples. With the 1-D Mark II, I work similarly to
they way you do. For flight images, the AI mode works well,
and I'm constantly shifting AF points for the specific scene
and desired focus point, all while working with AI mode.
For "portraits", I switch to one shot mode. Because I use a 10D
as backup, or with a shorter lens, it's hard remembering the
different button sequences between cameras ;-), especially in
the heat of action.

I was never satisfied with the AI mode on the 10D (or D60).
The manual says the camera will do its best effort to focus,
but will fire even if not in focus. With birds in flight action
(and my dogs at play), the 10D just usually never seemed to get
that great of focus in AI mode. The 1D Mark II does great
in this regard. So on the 10D I found I got a higher percentage
of critically sharp focused images with action shots in one shot mode,
rather than a higher number of images, but each slightly out of focus
with AI (by this I mean an OK 8x10 could be made, but looking a
little soft). I probably get 5 to 10 times as many critically
focused action shots with the 1DII as I did with the 10D,
given similar conditions, and with the 1DII it is usually my
fault for not keeping the sensor on the desired subject
during fast action that ruins focus. With the 10D it was
usually the camera failing to track and lock fast enough.
I suppose with "little brown birds" or fast birds like
puffins, the 1DII can be challenged as you say (with of course,
lenses being an issue too).

Roger

From: "N8urePix"

The 20D has two AI focus modes, one named "AI focus AF" the other named "AI
Servo AF". When you refer to the AI mode on your 1-D, I wonder which 20D
focus mode that is equivalent to.

AI Servo ... the "AI Focus" mode is new with the 20D, even the expensive 1D
series pro models don't have it yet (maybe the 1Ds Mark II but not the 1D, 1D
Mark II and 1Ds).

From: "N8urePix"

The 20D has two AI focus modes, one named "AI focus AF" the other named "AI
Servo AF". When you refer to the AI mode on your 1-D, I wonder which 20D
focus mode that is equivalent to.

AI Servo ... the "AI Focus" mode is new with the 20D, even the expensive 1D
series pro models don't have it yet (maybe the 1Ds Mark II but not the 1D, 1D
Mark II and 1Ds).

Bill Hilton wrote:

From: "N8urePix"


The 20D has two AI focus modes, one named "AI focus AF" the other named "AI
Servo AF". When you refer to the AI mode on your 1-D, I wonder which 20D
focus mode that is equivalent to.


AI Servo ... the "AI Focus" mode is new with the 20D, even the expensive 1D
series pro models don't have it yet (maybe the 1Ds Mark II but not the 1D, 1D
Mark II and 1Ds).

The 10D, D60, and (if I remember correctly) Elan (film) series
all had the AI focus mode. It means the camera "watched" the
focus and if focus point started to move, the camera would shift
from one shot to AI servo mode. I never found that it worked
very well on these cameras, as it always seemed to lag behind
the best focus in my experience.

Roger

AI Servo ... the "AI Focus" mode is new with the 20D

From: "Roger N. Clark

The 10D, D60, and (if I remember correctly) Elan (film) series
all had the AI focus mode.

Roger, I "borrowed" my wife's 10D for a year and never knew it had this mode,
though it's right there in the Spanish novella "Manual" shipped with the camera
Next you're going to tell me it's on the 1D Mark II? Gotta re-read the
guide now ...

Bill

Bill Hilton wrote:
AI Servo ... the "AI Focus" mode is new with the 20D


From: "Roger N. Clark

The 10D, D60, and (if I remember correctly) Elan (film) series
all had the AI focus mode.


Roger, I "borrowed" my wife's 10D for a year and never knew it had this mode,
though it's right there in the Spanish novella "Manual" shipped with the camera
Next you're going to tell me it's on the 1D Mark II? Gotta re-read the
guide now ...

Bill


Bill,
Since it was on all the other cameras I had, I was surprised
to see it was not on the 1D Mark II. But then I didn't care,
since I never use it.

Roger