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Canon 30D question

 
 
Eatmorepies
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      05-01-2007
Hello

I used my 30D with my 70-200mm f2.8L at a cycle race. The lens is usually
pin sharp.

My question is about servo focus.

I photogaphed riders coming towards me on servo focus at f3.5 with the lens
in the 140mm region. I took pictures at about 5 to 7m. The results were not
as sharp as I expected. I was under the impression that the camera had
predicitive autofocus and could take account of motion of the riders. If
this is not the case then I can understand why the pictures were less than
pin sharp, the riders could move a few centimetres in the time taken for the
mirror to move up. I didn't have camera shake as I was on about 1/1000s and
was leaning on a tree.

Is the problem as simple as riders coming closer in the 130ms or so for the
camera to respond to the shutter?

Regards

John


 
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=?ISO-8859-1?Q?J=F8rn?= Dahl-Stamnes
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      05-01-2007
Eatmorepies wrote:

> Hello
>
> I used my 30D with my 70-200mm f2.8L at a cycle race. The lens is usually
> pin sharp.
>
> My question is about servo focus.
>
> I photogaphed riders coming towards me on servo focus at f3.5 with the
> lens in the 140mm region. I took pictures at about 5 to 7m. The results
> were not as sharp as I expected. I was under the impression that the
> camera had predicitive autofocus and could take account of motion of the
> riders. If this is not the case then I can understand why the pictures
> were less than pin sharp, the riders could move a few centimetres in the
> time taken for the mirror to move up. I didn't have camera shake as I was
> on about 1/1000s and was leaning on a tree.


I do not know of any dSLR cameras that has such a predicitive autofocus
system as you describe... (correct me if I'm wrong). but I sure would have
liked to had one. I do a lof of this kind of shootings too:

http://www.dahl-stamnes.net/Foto/alb...p=Sykkel_stmbk

--
Jørn Dahl-Stamnes
http://www.dahl-stamnes.net/dahls/
 
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Keith Baird
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      05-01-2007
Jørn Dahl-Stamnes <(E-Mail Removed)> wrote:
> I do not know of any dSLR cameras that has such a predicitive autofocus
> system as you describe... (correct me if I'm wrong).


Of Canon's current lineup, it seems only the 1D Mk.3 has predictive
autofocus. It's not a feature I need much, but I'm surprised it hasn't
been carried over more from Canon's film SLRs.

--/<eith
 
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jdear64
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      05-01-2007

Keith Baird wrote:
> Jørn Dahl-Stamnes <(E-Mail Removed)> wrote:
> > I do not know of any dSLR cameras that has such a predicitive autofocus
> > system as you describe... (correct me if I'm wrong).

>
> Of Canon's current lineup, it seems only the 1D Mk.3 has predictive
> autofocus. It's not a feature I need much, but I'm surprised it hasn't
> been carried over more from Canon's film SLRs.
>
> --/<eith


>From Canon's website for the 30D:

http://www.usa.canon.com/consumer/co...&modelid=12929


Focusing Modes
Autofocus: One-Shot AF
Predictive AI Servo AF
AI Focus AF (automatic switching between One-Shot/Predictive AI
Servo AF)
Manual Focus (MF)

 
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Dave S
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      05-01-2007
Keith Baird wrote:
> Jørn Dahl-Stamnes <(E-Mail Removed)> wrote:
>> I do not know of any dSLR cameras that has such a predicitive autofocus
>> system as you describe... (correct me if I'm wrong).

>
> Of Canon's current lineup, it seems only the 1D Mk.3 has predictive
> autofocus. It's not a feature I need much, but I'm surprised it hasn't
> been carried over more from Canon's film SLRs.
>
> --/<eith


No one likes to be told to RTFM, but page 76 of the EOS30D Instruction
Manual says:

If the subject approaches or retreats from the camera at a constant
rate, the camera tracks the subject and predicts the focusing
distance immediately before the picture is taken. This is for
obtaining correct focus at the moment of exposure.

Dave S.
 
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Malcolm Stewart
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      05-02-2007
"Eatmorepies" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Hello
>
> I used my 30D with my 70-200mm f2.8L at a cycle race. The lens is usually
> pin sharp.
>
> My question is about servo focus.
>
> I photogaphed riders coming towards me on servo focus at f3.5 with the
> lens in the 140mm region. I took pictures at about 5 to 7m. The results
> were not as sharp as I expected. I was under the impression that the
> camera had predicitive autofocus and could take account of motion of the
> riders.


> Regards
> John


I've done numerous checks on this using an EOS 10D, and lately using a 5D.
My subjects have been motorway traffic approaching me at around 55-60mph. I
used EF135 f2, 200 f2.8 and 300 f2.8 USM lenses, and was by an overbridge.
Tracking using AIServo and the central focus point was in general,
excellent, unless the subject was a bland fronted coach with little detail
for the AF to latch on to. I also noted that the 1st. shot of a series was
quite often less sharp than later shots. Probably because I didn't give the
camera enough time to measure the speed of the vehicle, with the shutter
release half-pressed.
I also use a 30D for bird photography, and have great difficulty keeping the
central spot on any rapidly moving bird, so occasionally I get a really
sharp shot, but not that often! (I think my EOS3 is better with its top of
the range AF... but then I can't afford a 1 D series yet.)
(You might do better raising the ISO and using f5.6 to f8.)

--
M Stewart
Milton Keynes, UK



--
Posted via a free Usenet account from http://www.teranews.com

 
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=?ISO-8859-1?Q?J=F8rn?= Dahl-Stamnes
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      05-02-2007
Keith Baird wrote:

> Jørn Dahl-Stamnes <(E-Mail Removed)> wrote:
>> I do not know of any dSLR cameras that has such a predicitive autofocus
>> system as you describe... (correct me if I'm wrong).

>
> Of Canon's current lineup, it seems only the 1D Mk.3 has predictive
> autofocus. It's not a feature I need much, but I'm surprised it hasn't
> been carried over more from Canon's film SLRs.


I shall check that... WHEN my KmII arrive...
--
Jørn Dahl-Stamnes
http://www.dahl-stamnes.net/dahls/
 
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=?ISO-8859-1?Q?J=F8rn?= Dahl-Stamnes
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      05-02-2007
Dave S wrote:

> Keith Baird wrote:
>> Jørn Dahl-Stamnes <(E-Mail Removed)> wrote:
>>> I do not know of any dSLR cameras that has such a predicitive autofocus
>>> system as you describe... (correct me if I'm wrong).

>>
>> Of Canon's current lineup, it seems only the 1D Mk.3 has predictive
>> autofocus. It's not a feature I need much, but I'm surprised it hasn't
>> been carried over more from Canon's film SLRs.
>>
>> --/<eith

>
> No one likes to be told to RTFM, but page 76 of the EOS30D Instruction
> Manual says:
>
> If the subject approaches or retreats from the camera at a constant
> rate, the camera tracks the subject and predicts the focusing
> distance immediately before the picture is taken. This is for
> obtaining correct focus at the moment of exposure.


You're right. That was a part of the, so called, instruction manual that I
have missed.
--
Jørn Dahl-Stamnes
http://www.dahl-stamnes.net/dahls/
 
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Roger N. Clark (change username to rnclark)
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      05-03-2007
Keith Baird wrote:
> Jørn Dahl-Stamnes <(E-Mail Removed)> wrote:
>> I do not know of any dSLR cameras that has such a predicitive autofocus
>> system as you describe... (correct me if I'm wrong).

>
> Of Canon's current lineup, it seems only the 1D Mk.3 has predictive
> autofocus. It's not a feature I need much, but I'm surprised it hasn't
> been carried over more from Canon's film SLRs.


All modern SLR cameras that I am aware of have predictive
autofocus. It was introduced in film cameras in the
late 1980s/early 1990s. All canon's DSLR I believe have
it (I've used it on D60, 10D, 20D, 30D, 1D Mark II).

Roger
 
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Roger N. Clark (change username to rnclark)
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      05-03-2007
Eatmorepies wrote:
> Hello
>
> I used my 30D with my 70-200mm f2.8L at a cycle race. The lens is usually
> pin sharp.
>
> My question is about servo focus.
>
> I photogaphed riders coming towards me on servo focus at f3.5 with the lens
> in the 140mm region. I took pictures at about 5 to 7m. The results were not
> as sharp as I expected. I was under the impression that the camera had
> predicitive autofocus and could take account of motion of the riders. If
> this is not the case then I can understand why the pictures were less than
> pin sharp, the riders could move a few centimetres in the time taken for the
> mirror to move up. I didn't have camera shake as I was on about 1/1000s and
> was leaning on a tree.
>
> Is the problem as simple as riders coming closer in the 130ms or so for the
> camera to respond to the shutter?


John,

Are you using a single autofocus sensor, or all AF points at once?
I think multiple sensors can get confused by static background
spots versus moving spots. I have found I get better
tracking when I use 1 AF point. I have used a D60,
10D, and 1D Mark II for wildlife action photography.
I have found the 1DII is much much better at predictive
autofocus than the 10D or D60. I now also have a 30D but I
have not had a chance to use it yet for moving subjects
(maybe this weekend).

Roger
http://www.clarkvision.com
 
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