AI Focus miss-focus sample

Ulysses · Sep 1, 2003

Justme said:
If I recall correctly (maybe not) didn't this BFS (I know it was
called something else as well but maybe it's an unrelated issue)
problem persist into the F717 as well (Brian Siverly rings a bell)
until a firmware fix?

The BFS was different in characteristic, cause and result. But Yes, it was quickly addressed by sending your camera into Sony for a parameter "realignment". This was not called a firmware update by Sony. I like Brian a lot. Brian was one who mentioned the issue, but he was not the "discoverer" per se. There were many who worked on this one for the F707

--

Ulysses

Frank B · Sep 1, 2003

I don't think I did that. I have been taking pictures using Single Focus and recomposing for many years without this problem and don't have it when I use Single focus with my 10D.

Frank B

DavidP said:
Especially when somebody else a day or two ago (wish I had the
link handy) showed similar tests where the camera didn't choose to
re-focus.

The one thing that comes to mind is the possibility that Frank let
off enough pressure on the shutter button and then re-pressed it,
so that the camera re-focused. I've certainly seen some finicky
shutter releases that might allow for that possibility to occur
without one knowing it.

Phil Askey said:

You have to move quite a bit...

Click to expand...

--
The Lowest Paid Concert Photographer Around
http://www.neonlightsimaging.com/artshow/final.htm
Photography -- just another word for compromise

'Since we can't keep crime in check, why don't we legalize it and
tax it out of business?' -- Will Rogers

DavidP #28649 · Sep 1, 2003

I don't really think so, either, given that you had multiple shots that showed this.

Do you have ANY situations where the camera decides NOT to refocus that are similar to these?

Frank B said:
I don't think I did that. I have been taking pictures using Single
Focus and recomposing for many years without this problem and don't
have it when I use Single focus with my 10D.

--
The Lowest Paid Concert Photographer Around
http://www.neonlightsimaging.com/artshow/final.htm
Photography -- just another word for compromise

'Since we can't keep crime in check, why don't we legalize it and tax it out of business?' -- Will Rogers

DavidP #28649 · Sep 1, 2003

Hmmm, sounds like they took a hammer upside the F707 body to me. LOL.

Ulysses said:
The BFS was different in characteristic, cause and result. But Yes,
it was quickly addressed by sending your camera into Sony for a
parameter "realignment". This was not called a firmware update by
Sony. I like Brian a lot. Brian was one who mentioned the issue,
but he was not the "discoverer" per se. There were many who worked
on this one for the F707

--
The Lowest Paid Concert Photographer Around
http://www.neonlightsimaging.com/artshow/final.htm
Photography -- just another word for compromise

'Since we can't keep crime in check, why don't we legalize it and tax it out of business?' -- Will Rogers

MAC · Sep 1, 2003

the 1.6 crop factor is "sucky" when shooting wide angle.......in comparison to the lower cost of full frame hardware for film. When you look at how much one must pay for quality wide angle glass to get even decent wide angle....."it is sucky". I have the 20 mm f2.8 BTW and it is an excellent lens but only 32 FOV

Again, the general public needs to know digital limitations with respect to film.

Digital Full frame costs and the limitations of the 1.6 crop factor needs stressed in these reviews for folks to clealy understand these are not tools that Ansel Adams would like.....and the upfront hardware costs are much more expensive than the film bodies, albeit I hate film

MAC

Ulysses said:
MAC said:

Make the comparisons to film capability please.

Click to expand...

--

Ulysses

--
MAC
http://www.digi-pictures.com

Phil Askey · Sep 1, 2003

David, you know as well as I do that I can't predict why someone else had a problem with one or two shots, all I can report is my own experience. It's like anything else, you have to understand it, allow for it and develop your technique. Overall I've had no problems with AI Focus on the 300D.

DavidP said:
Especially when somebody else a day or two ago (wish I had the
link handy) showed similar tests where the camera didn't choose to
re-focus.

The one thing that comes to mind is the possibility that Frank let
off enough pressure on the shutter button and then re-pressed it,
so that the camera re-focused. I've certainly seen some finicky
shutter releases that might allow for that possibility to occur
without one knowing it.

Phil Askey said:

You have to move quite a bit...

Click to expand...

--
The Lowest Paid Concert Photographer Around
http://www.neonlightsimaging.com/artshow/final.htm
Photography -- just another word for compromise

'Since we can't keep crime in check, why don't we legalize it and
tax it out of business?' -- Will Rogers

--
Phil Askey
Editor / Owner, dpreview.com

Ulysses · Sep 1, 2003

For all I know, they may have had the Berstein Bears knocking the camera around back there. Whatever it was that they did, it worked. Usually. :-]

DavidP said:
Hmmm, sounds like they took a hammer upside the F707 body to me. LOL.

--

Ulysses

Travis · Sep 1, 2003

Member said:
David, you know as well as I do that I can't predict why someone
else had a problem with one or two shots, all I can report is my
own experience. It's like anything else, you have to understand
it, allow for it and develop your technique. Overall I've had no
problems with AI Focus on the 300D.

Phil, in your testing does the camera STAY in Servo mode for a few successive shots if you are shooting action, or is there a delay for every shot you take? For example, there's another thread where some photos of a rodeo were posted. If I wanted to take a bunch of shots of the rodeo (where everything is moving all the time), will the camera introduce a delay for EACH photo I take? OR.... if I am aiming the camera the moving subjects will it switch to Servo and STAY there for a few successive shots?

Obviously, this may be something you have been able (or not enough time) to test, but could be an important distinction between using AI Focus or being able to switch to Servo on the 10d.

Travis

Ulysses · Sep 1, 2003

These things get mentioned in the review.

And for those aspects and details that don't really need to have an entire page devoted to them (like the 1.6x FOV crop), you have the Learn center here at DPReview.com.

What folks need to learn is how to do their research. The info is all there, and it's easy pickings. There's no need for unnecessary redundancy.

--

Ulysses

Ulysses · Sep 1, 2003

Hey there, Travis. I'm not sure if this answers your question, but Phil commented:

"As far as AI Focus introducing a 1 to 2 second delay, I can assure you that this is not the case, AI Focus works by using One Shot AF first. It assumes One Shot AF by default and then monitors the focus point to see if it moves, thus there is no difference in focus speed between AI Focus and One Shot."
http://forums.dpreview.com/forums/read.asp?forum=1010&message=5920772

Travis said:
Travis said:

David, you know as well as I do that I can't predict why someone
else had a problem with one or two shots, all I can report is my
own experience. It's like anything else, you have to understand
it, allow for it and develop your technique. Overall I've had no
problems with AI Focus on the 300D.

Click to expand...

Phil, in your testing does the camera STAY in Servo mode for a few
successive shots if you are shooting action, or is there a delay
for every shot you take? For example, there's another thread where
some photos of a rodeo were posted. If I wanted to take a bunch of
shots of the rodeo (where everything is moving all the time), will
the camera introduce a delay for EACH photo I take? OR.... if I am
aiming the camera the moving subjects will it switch to Servo and
STAY there for a few successive shots?

Obviously, this may be something you have been able (or not enough
time) to test, but could be an important distinction between using
AI Focus or being able to switch to Servo on the 10d.

Travis

--

Ulysses

MAC · Sep 1, 2003

and bandwidth that could be saved though if Phil just spent some time telling the consumer straight away that digicams are not good action shooting equipment and that much cheaper film SLR gear can do a much better job because of low noise at high ISO.

Then all those Matthew C. etc. discussions could be avoided. We'd have it straight away in balck and white without the research.

Also some controlled gallery samples of Phil's wife driving a car at 60 mph and Phil testing these cams with this test, how much better does the science get??

MAC

Ulysses said:
These things get mentioned in the review.

And for those aspects and details that don't really need to have
an entire page devoted to them (like the 1.6x FOV crop), you have
the Learn center here at DPReview.com.

What folks need to learn is how to do their research. The info is
all there, and it's easy pickings. There's no need for unnecessary
redundancy.

--

Ulysses

--
MAC
http://www.digi-pictures.com

Frank B · Sep 1, 2003

If you assume that my 10D is not defective and that I did not mess up the test and that AI Focus does sometimes switch to servo when recomposing then the question is how often will it make a difference. Maybe not too often.

1. I suspect it only switches to servo when the center focus point after re-focus is either closer or further away and it does that only occasionally.

2. If it does switch to servo and the two focus points are within depth of field the subject will still be sharp, although not quite as sharp as it would be if the camera had focuses accurately.

I need to test further whether when it switches to servo mode it has trouble switching back to Single Focus when you half press the shutter for the next picture (as reported in the Luminous Landscape review). If it does not switch back to Single Focus that is another a problem. I think my camera switches back without a problem, but I am not sure.

Frank B

Michael Louis · Sep 1, 2003

is just how good the 10d tracks a subject in dedicated Al Servo.

I only have experience with my old beat up yet reliable Rebel X so I only know AI Focus.

What's the action/sports advantage if the 10d is only So-So with dedicated Al Servo.
Michael

Ulysses said:
These things get mentioned in the review.

And for those aspects and details that don't really need to have
an entire page devoted to them (like the 1.6x FOV crop), you have
the Learn center here at DPReview.com.

What folks need to learn is how to do their research. The info is
all there, and it's easy pickings. There's no need for unnecessary
redundancy.

--

Ulysses

Travis · Sep 1, 2003

Member said:
Hey there, Travis. I'm not sure if this answers your question, but
Phil commented:
"As far as AI Focus introducing a 1 to 2 second delay, I can assure
you that this is not the case, AI Focus works by using One Shot AF
first. It assumes One Shot AF by default and then monitors the
focus point to see if it moves, thus there is no difference in
focus speed between AI Focus and One Shot."

Thanks Uly, but I already knew that. What I'm asking is this: if the camera does detect movement (if you're shooting sports, for example) and switches to Servo mode, will it STAY in Servo mode for a few successive shots, or will it default back to One Shot after every shot?

Here could be an example.

1) You aim the camera at a bull rider (referring to the other thread where the rodeo pics were posted) and half-press. The camera switches to Servo since the subject is moving. After the slight delay for the camera to switch, you take the shot.

2) You still have the camera aimed at the bull-rider and you half-press again. Will the camera still be in Servo mode to track the subject, or will you need to wait again for it to switch to Servo? Meaning, will it default back to One Shot for every photo, or will it be smart enough to know you are still tracking the moving subject even after you have snapped the first photo?

Travis

Justme · Sep 1, 2003

Ulysses said:
Justme said:

If I recall correctly (maybe not) didn't this BFS (I know it was
called something else as well but maybe it's an unrelated issue)
problem persist into the F717 as well (Brian Siverly rings a bell)
until a firmware fix?

Click to expand...

The BFS was different in characteristic, cause and result. But Yes,
it was quickly addressed by sending your camera into Sony for a
parameter "realignment". This was not called a firmware update by
Sony. I like Brian a lot. Brian was one who mentioned the issue,
but he was not the "discoverer" per se. There were many who worked
on this one for the F707

For those who don't know, BFS stood for Blue Flash Syndrome (you'll have to do a search when it's working). I do know that Brian took the issue to the fore-front, raising awareness of it. Quite a few people in the Sony forum at the time, knocked him for it but they ended up benefiting when it eventually caught the eye of Sony.

Member said:
--

Ulysses

Ulysses · Sep 1, 2003

Travis said:
Thanks Uly, but I already knew that.

I took the easy route, since your question could have been taken both ways.

)

Travis said:
If the camera does detect movement (if you're shooting sports, for
example) and switches to Servo mode, will it STAY in Servo mode for
a few successive shots, or will it default back to One Shot after
every shot?

You're probably getting the feeling that I do, from the available info, that the camera defaults to its DEFAULT position in AI Focus of resorting to One Shot FIRST, and then if it judges the subject to move towards or away from the camera, then rapidly switching into AI Servo. Isn't that how you're reading it? It's not as if it locks into AI Servo by default.

Travis said:
Here could be an example.

1) You aim the camera at a bull rider (referring to the other
thread where the rodeo pics were posted) and half-press. The
camera switches to Servo since the subject is moving. After the
slight delay for the camera to switch, you take the shot.

2) You still have the camera aimed at the bull-rider and you
half-press again. Will the camera still be in Servo mode to track
the subject, or will you need to wait again for it to switch to
Servo? Meaning, will it default back to One Shot for every photo,
or will it be smart enough to know you are still tracking the
moving subject even after you have snapped the first photo?

If the switch is fast enough (and Phil already indicated that there is no real "delay" as such), then it doesn't matter a whole lot whether it 'locks' into AI Servo, right?

--

Ulysses

Michael Louis · Sep 1, 2003

Frank,

If you have a second can you try this. Having the old Rebel X with fixed AI Focus I have noticed that the Al Servo is active and kicks in fast in TV mode, but not hardly in AV mode; it usually needs a lot of camera movement and moderate contrast change in this mode.

Is this true with the 10d? It could be a Rebel X peculiarity as it is 10 years old, and Canon has made a lot of changes in the mean time.

Frank B said:
If you assume that my 10D is not defective and that I did not mess
up the test and that AI Focus does sometimes switch to servo when
recomposing then the question is how often will it make a
difference. Maybe not too often.

1. I suspect it only switches to servo when the center focus point
after re-focus is either closer or further away and it does that
only occasionally.

2. If it does switch to servo and the two focus points are within
depth of field the subject will still be sharp, although not quite
as sharp as it would be if the camera had focuses accurately.

I need to test further whether when it switches to servo mode it
has trouble switching back to Single Focus when you half press the
shutter for the next picture (as reported in the Luminous Landscape
review). If it does not switch back to Single Focus that is
another a problem. I think my camera switches back without a
problem, but I am not sure.

Frank B

Ulysses · Sep 1, 2003

Justme said:
For those who don't know, BFS stood for Blue Flash Syndrome (you'll
have to do a search when it's working). I do know that Brian took
the issue to the fore-front, raising awareness of it.

Yes. Brian took credit for it. But the point being that the issue was brought to the attention of Sony well before it was actually a major conversation point in the forum.

Justme said:
Quite a few
people in the Sony forum at the time, knocked him for it but they
ended up benefiting when it eventually caught the eye of Sony.

This is true. But Brian wasn't taken to task for that by some of the forum members. What happened is that several folks allowed their pride to get in the way of working together on it, including Brian's. That was a loss for everyone. Still, the issue of BFS was addressed and fixed for most that took advantage of it.

--

Ulysses

Ulysses · Sep 1, 2003

Would Phil really allow her to drive the Beemer at 60+ MPH???

MAC said:
Also some controlled gallery samples of Phil's wife driving a car
at 60 mph and Phil testing these cams with this test, how much
better does the science get??

--

Ulysses

Ulysses · Sep 1, 2003

Don't forget to check that EXIF data. As far as I can tell, you ought to be able to read in the Maker Notes whether the camera actually USED the AI Servo focus or not.

Then again, probably everyone will tire of all of this and move on to just taking pictures sometime soon.

Frank B said:
If you assume that my 10D is not defective and that I did not mess
up the test and that AI Focus does sometimes switch to servo when
recomposing then the question is how often will it make a
difference. Maybe not too often.

1. I suspect it only switches to servo when the center focus point
after re-focus is either closer or further away and it does that
only occasionally.

2. If it does switch to servo and the two focus points are within
depth of field the subject will still be sharp, although not quite
as sharp as it would be if the camera had focuses accurately.

I need to test further whether when it switches to servo mode it
has trouble switching back to Single Focus when you half press the
shutter for the next picture (as reported in the Luminous Landscape
review). If it does not switch back to Single Focus that is
another a problem. I think my camera switches back without a
problem, but I am not sure.

Frank B

--

Ulysses

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