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D30s focus area on its screen

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Rob L

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Has anybody ever noticed this before?



The blue area represents the actual focus area of the D30s focus sensor.

You can see it when you look at a clear sky through the cameras view finder. If the focus sensor is this big its no wonder I get out of focus shots or the famous focus just in front or just behind focus effect. This would also explain the poor sports performance some people get. (I say some people because some people would flame me and say they do sports all the time with out problems, but based on the things I've read here the vast vast majority of people have a very high percentage of shots that are no good) Any way.....

With this in mind about the size of the focus sensor area it tells me a few things about my awesome D30 that I love and want to learn to use better.

1. Areas of contrast need to be large enough to fill this focus sensor area (from now on refered to as FSA) in order to get proper focus on what I want in focus.

2. My sports shots could get a lot better and a higher percentage of keepable shots if I can keep the FSA in mind as I pan the soccer field follow the players. I would need to fill the unmarked FSA with more contrasting elements of the player I want in focus.

3. I've noticed in portraits that if a persons face fills the FSA I get slightly unpredictable results. Sometimes with shallow depth of field the nose would be tack sharp and other times the eyes and other times the eyebrows or hair.

If this is old news to everyone else I'm sorry for the long wasted post.

If anyone has further knowledge, please share or set me striaght.--RobL
http://www.preflash.com
"Why doesn't the image I captured look like what eye saw?" me.
 
I'm probably just being dense, but how do you know that's the area of AF ?

Are you focusing on a tree branch that doesn't cross the central portion, but does cross the outer portion, and there's nothing else in the frame?

This certainly would explain the AF performance of the D-30.

I wonder if the other two sensors have similar "range" ?

And what about other EOS-cameras?

One thing, though -- I thought we'd established long ago that the small AF area (the rectangle) was what's driving the flash exposures bonkers -- Canon's emphasizing them too much. If the area was as large as that circle, you'd think it'd be less of a problem.
Rob L said:
Has anybody ever noticed this before?



The blue area represents the actual focus area of the D30s focus
sensor.
You can see it when you look at a clear sky through the cameras

view finder. --The Unofficial Photographer of The Wilkinsons http://thewilkinsons.crosswinds.netPhotography -- just another word for compromise
Click to expand...
 
Rob L said:
Has anybody ever noticed this before?
Click to expand...
Rob L said:
If anyone has further knowledge, please share or set me striaght.
Click to expand...
Yes, I can see it - against any plain surface. But what makes you think this is a focus area?

Try this. Set the camera to focus only on the center sensor. Put this over a uniform untextured area so that it cannot focus. Now move it so that there is a contrast edge just outside the rectangular focus area, but wll within your blue circle. It will STILL not focus. Now move it so the contrast area is just inside the rectangle - the camer will now focus.

This indicates to me that the focus area is just as described by Canon

--Tony [email protected] Photo website : http://www.digifotoinfo.co.uk
 
DavidP said:
Are you focusing on a tree branch that doesn't cross the central
portion, but does cross the outer portion, and there's nothing else
in the frame?

This certainly would explain the AF performance of the D-30.

I wonder if the other two sensors have similar "range" ?

And what about other EOS-cameras?

One thing, though -- I thought we'd established long ago that the
small AF area (the rectangle) was what's driving the flash
exposures bonkers -- Canon's emphasizing them too much. If the
area was as large as that circle, you'd think it'd be less of a
problem.
Rob L said:
Has anybody ever noticed this before?



The blue area represents the actual focus area of the D30s focus
sensor.
You can see it when you look at a clear sky through the cameras
view finder.
Click to expand...
--
The Unofficial Photographer of The Wilkinsons
http://thewilkinsons.crosswinds.net
Photography -- just another word for compromise
Click to expand...
 
I was just trying to determine what this was.

Even though I'm probably wrong here based on what you have pointed out it sure would be nice to know why the AF is so problamatic.

Anyway thats why at the end of my post I asked for more info or for someone to just plain set me striaght.

Thanks for the input.

RobL
Tony Collins said:
Rob L said:
Has anybody ever noticed this before?
Click to expand...
Member said:
If anyone has further knowledge, please share or set me striaght.
Click to expand...
Yes, I can see it - against any plain surface. But what makes you
think this is a focus area?

Try this. Set the camera to focus only on the center sensor. Put
this over a uniform untextured area so that it cannot focus. Now
move it so that there is a contrast edge just outside the
rectangular focus area, but wll within your blue circle. It will
STILL not focus. Now move it so the contrast area is just inside
the rectangle - the camer will now focus.

This indicates to me that the focus area is just as described by Canon

--
Tony Collins
[email protected]

Digital Photo website :
http://www.digifotoinfo.co.uk
Click to expand...
 
That's what I thought, too.

But sometimes it DOES seem that the camera sneaks outside that rectangle, just to spoil a picture. ;)
Tony Collins said:
Yes, I can see it - against any plain surface. But what makes you
think this is a focus area?

Try this. Set the camera to focus only on the center sensor. Put
this over a uniform untextured area so that it cannot focus. Now
move it so that there is a contrast edge just outside the
rectangular focus area, but wll within your blue circle. It will
STILL not focus. Now move it so the contrast area is just inside
the rectangle - the camer will now focus.

This indicates to me that the focus area is just as described by Canon
Click to expand...
--The Unofficial Photographer of The Wilkinsons http://thewilkinsons.crosswinds.netPhotography -- just another word for compromise
 
Rob L said:
I was just trying to determine what this was.

Even though I'm probably wrong here based on what you have pointed
out it sure would be nice to know why the AF is so problamatic.

Anyway thats why at the end of my post I asked for more info or for
someone to just plain set me striaght.

Thanks for the input.

RobL
Click to expand...
Rob,

Could it be the partial metering area?

JC
 
JC said:
Rob L said:
I was just trying to determine what this was.

Even though I'm probably wrong here based on what you have pointed
out it sure would be nice to know why the AF is so problamatic.

Anyway thats why at the end of my post I asked for more info or for
someone to just plain set me striaght.

Thanks for the input.

RobL
Click to expand...
Rob,

Could it be the partial metering area?

JC
Click to expand...
 
i used to wonder about that but the marked ring looks about 105 of the overall frame which is what canon says partial metering is.

i have been trying to figure out the exposure algorithm within the partial area. if you take a reading with part of the area dark, part bright it seems that its either one or the other and not an average 9or any other algorithm0. anyone know how the d30 calculates the exposure when the partial metering zone varies like this ?
JC said:
Rob L said:
I was just trying to determine what this was.

Even though I'm probably wrong here based on what you have pointed
out it sure would be nice to know why the AF is so problamatic.

Anyway thats why at the end of my post I asked for more info or for
someone to just plain set me striaght.

Thanks for the input.

RobL
Click to expand...
Rob,

Could it be the partial metering area?

JC
Click to expand...
 
Hi Tony heres what I got when I tried what you did:



I took this picture of the moon in a clear blue sky here in michigan.

The camera would not focus on the clear part of the sky, but it would focus on the moon. The problem is it locked focus at the point you see the moon at in the picture. I think this could be a big part of the problem with the auto focus if the subject I wanted in focus was slightly less contrasty dead center of the middle square then the object (the moon in this case) just outside the focus sensor area. Imagine how screwed up your focusing could be if this was happening say 35% of the time coupled with the slow AF the D30 already has. So I was right to a certain degree. And I believe my findings about how to use this knowledge to improve my picture taking still stand.

By the way this happened no matter where the moon was, top, bottom, left or right of the square.

What do you or anyone else think?

RobL
Tony Collins said:
Rob L said:
Has anybody ever noticed this before?
Click to expand...
Member said:
If anyone has further knowledge, please share or set me striaght.
Click to expand...
Yes, I can see it - against any plain surface. But what makes you
think this is a focus area?

Try this. Set the camera to focus only on the center sensor. Put
this over a uniform untextured area so that it cannot focus. Now
move it so that there is a contrast edge just outside the
rectangular focus area, but wll within your blue circle. It will
STILL not focus. Now move it so the contrast area is just inside
the rectangle - the camer will now focus.

This indicates to me that the focus area is just as described by Canon

--
Tony Collins
[email protected]

Digital Photo website :
http://www.digifotoinfo.co.uk
Click to expand...
 
Rob L said:
Hi Tony heres what I got when I tried what you did:



I took this picture of the moon in a clear blue sky here in michigan.

The camera would not focus on the clear part of the sky, but it
would focus on the moon. The problem is it locked focus at the
point you see the moon at in the picture. I think this could be a
big part of the problem with the auto focus if the subject I wanted
in focus was slightly less contrasty dead center of the middle
square then the object (the moon in this case) just outside the
focus sensor area. Imagine how screwed up your focusing could be if
this was happening say 35% of the time coupled with the slow AF the
D30 already has. So I was right to a certain degree. And I believe
my findings about how to use this knowledge to improve my picture
taking still stand.

By the way this happened no matter where the moon was, top, bottom,
left or right of the square.

What do you or anyone else think?
Click to expand...
You have to be carefull that the "out of focus" or blurred version of the moon (bigger than the focussed version) does not stray into the small rectangle. If it does, then the camera can detect the contrast change and still focus.--Tony [email protected] Photo website : http://www.digifotoinfo.co.uk
 
I guess I'm not sure I understand what you are saying. The new digram a posted represents exactaly what I saw as the camera locked focus. The moon was not in the square and yet it locked on. The digram isn't perfect but it does give you the idea. So if the moon caused a focus lock by just getting barely getting near the square, doesn't that make you wonder how many times a photo that you thought you had a lock on with focus set for a certain subject was out of focus when you looked at it on your monitor or printed it. Maybe even just a little out of focus as with the moon here. If the square was over my intended subject but the other object like the moon here was just a little more contrasty, then the shot could be ruined depending on depth of field and/or the distance the 2 objects were apart.

RobL
http://www.preflash.com
"Why doesn't the image I captured look like what eye saw?" me
Tony Collins said:
Rob L said:
Hi Tony heres what I got when I tried what you did:



I took this picture of the moon in a clear blue sky here in michigan.

The camera would not focus on the clear part of the sky, but it
would focus on the moon. The problem is it locked focus at the
point you see the moon at in the picture. I think this could be a
big part of the problem with the auto focus if the subject I wanted
in focus was slightly less contrasty dead center of the middle
square then the object (the moon in this case) just outside the
focus sensor area. Imagine how screwed up your focusing could be if
this was happening say 35% of the time coupled with the slow AF the
D30 already has. So I was right to a certain degree. And I believe
my findings about how to use this knowledge to improve my picture
taking still stand.

By the way this happened no matter where the moon was, top, bottom,
left or right of the square.

What do you or anyone else think?
Click to expand...
You have to be carefull that the "out of focus" or blurred version
of the moon (bigger than the focussed version) does not stray into
the small rectangle. If it does, then the camera can detect the
contrast change and still focus.
--
Tony Collins
[email protected]

Digital Photo website :
http://www.digifotoinfo.co.uk
Click to expand...
 
Rob L said:
Has anybody ever noticed this before?



The blue area represents the actual focus area of the D30s focus
sensor.
You can see it when you look at a clear sky through the cameras
view finder. If the focus sensor is this big its no wonder I get
out of focus shots or the famous focus just in front or just behind
focus effect. This would also explain the poor sports performance
some people get. (I say some people because some people would flame
me and say they do sports all the time with out problems, but based
on the things I've read here the vast vast majority of people have
a very high percentage of shots that are no good) Any way.....

With this in mind about the size of the focus sensor area it tells
me a few things about my awesome D30 that I love and want to learn
to use better.

1. Areas of contrast need to be large enough to fill this focus
sensor area (from now on refered to as FSA) in order to get proper
focus on what I want in focus.

2. My sports shots could get a lot better and a higher percentage
of keepable shots if I can keep the FSA in mind as I pan the soccer
field follow the players. I would need to fill the unmarked FSA
with more contrasting elements of the player I want in focus.

3. I've noticed in portraits that if a persons face fills the FSA I
get slightly unpredictable results. Sometimes with shallow depth of
field the nose would be tack sharp and other times the eyes and
other times the eyebrows or hair.

If this is old news to everyone else I'm sorry for the long wasted
post.

If anyone has further knowledge, please share or set me striaght.
--
RobL
http://www.preflash.com
"Why doesn't the image I captured look like what eye saw?" me.
Click to expand...
 
I think what he's saying is that the glow from the moon (extending in all directions, including the right -- towards the rectangle) may have given just enough contrast for the AF to start working.
Rob L said:
RobL
http://www.preflash.com
"Why doesn't the image I captured look like what eye saw?" me
Tony Collins said:
Rob L said:
Hi Tony heres what I got when I tried what you did:



I took this picture of the moon in a clear blue sky here in michigan.

The camera would not focus on the clear part of the sky, but it
would focus on the moon. The problem is it locked focus at the
point you see the moon at in the picture. I think this could be a
big part of the problem with the auto focus if the subject I wanted
in focus was slightly less contrasty dead center of the middle
square then the object (the moon in this case) just outside the
focus sensor area. Imagine how screwed up your focusing could be if
this was happening say 35% of the time coupled with the slow AF the
D30 already has. So I was right to a certain degree. And I believe
my findings about how to use this knowledge to improve my picture
taking still stand.

By the way this happened no matter where the moon was, top, bottom,
left or right of the square.

What do you or anyone else think?
Click to expand...
You have to be carefull that the "out of focus" or blurred version
of the moon (bigger than the focussed version) does not stray into
the small rectangle. If it does, then the camera can detect the
contrast change and still focus.
--
Tony Collins
[email protected]

Digital Photo website :
http://www.digifotoinfo.co.uk
Click to expand...
Click to expand...
--The Unofficial Photographer of The Wilkinsons http://thewilkinsons.crosswinds.netPhotography -- just another word for compromise
 
Thats the whole problem. I'm not sure I'm explaining myself well enough here. The fact that the moon had enough contrast that far from the square to cause a focus lock could also ruin a photo you try to shot in difficult contrasting situations. A situation where mulitiple subjects would ditract the AF from center square to wander around the edge if a more contrasy subject got its attention first.

I hope I'm being clear, because with all the people who have worries and complaints about the D30 AF it seems this topic would be on fire with people flaming me for being an idiot or people thanking me for pointing out something that may explain alot of "Why does a $3000 dollar camera have a $200 cameras AF?" Maybe its just plain bad design in that area. (Shhh or on purpose from an evil agreement with Kodak) ;).

RobL
http://www.preflash.com
"Why doesn't the image I captured look like what eye saw?" me
DavidP said:
Rob L said:
RobL
http://www.preflash.com
"Why doesn't the image I captured look like what eye saw?" me
Tony Collins said:
Rob L said:
Hi Tony heres what I got when I tried what you did:



I took this picture of the moon in a clear blue sky here in michigan.

The camera would not focus on the clear part of the sky, but it
would focus on the moon. The problem is it locked focus at the
point you see the moon at in the picture. I think this could be a
big part of the problem with the auto focus if the subject I wanted
in focus was slightly less contrasty dead center of the middle
square then the object (the moon in this case) just outside the
focus sensor area. Imagine how screwed up your focusing could be if
this was happening say 35% of the time coupled with the slow AF the
D30 already has. So I was right to a certain degree. And I believe
my findings about how to use this knowledge to improve my picture
taking still stand.

By the way this happened no matter where the moon was, top, bottom,
left or right of the square.

What do you or anyone else think?
Click to expand...
You have to be carefull that the "out of focus" or blurred version
of the moon (bigger than the focussed version) does not stray into
the small rectangle. If it does, then the camera can detect the
contrast change and still focus.
--
Tony Collins
[email protected]

Digital Photo website :
http://www.digifotoinfo.co.uk
Click to expand...
Click to expand...
--
The Unofficial Photographer of The Wilkinsons
http://thewilkinsons.crosswinds.net
Photography -- just another word for compromise
Click to expand...
 
Using the moon right at the edge of the rectangle is not a good test subject. If it is the least bit out of focus it spills over into the rectangle and triggers the AF system. The AF system will extend to infinity which removes all moonlight from within the rectangle and it locks.

For a better test subject, try focusing on a brightly lit black horizontal or vertical line on a white background at mid distance. This removes the confusion of getting an infinity lock and is a more deterministic subject to experiement with than the moon with the aforementioned moon glow/halo.

Personally I don't find the AF of the D30 slow at all, except in really low light. What happens to me, for example when shooting soccer at mid day, is that it focuses on whatever is in the rectangle. If I let the rectangle slip away from the player I'm shooting, my focus immediately changes from the player to the background, which comes out in excellent focus. The change in focus from the player to the background happens faster than I can take my finger off the * button.

Having a cluster of focus points for improved tracking is what the D30 needs, not faster AF of of only 1 or 3 points. Canon clearly wouldn't put their high end AF system in the D60 because they already have that in the 1D. But I as at least hoping for one of the mid-range AF systems.
Rob L said:
Rob L said:
Has anybody ever noticed this before?



The blue area represents the actual focus area of the D30s focus
sensor.
You can see it when you look at a clear sky through the cameras
view finder. If the focus sensor is this big its no wonder I get
out of focus shots or the famous focus just in front or just behind
focus effect. This would also explain the poor sports performance
some people get. (I say some people because some people would flame
me and say they do sports all the time with out problems, but based
on the things I've read here the vast vast majority of people have
a very high percentage of shots that are no good) Any way.....

With this in mind about the size of the focus sensor area it tells
me a few things about my awesome D30 that I love and want to learn
to use better.

1. Areas of contrast need to be large enough to fill this focus
sensor area (from now on refered to as FSA) in order to get proper
focus on what I want in focus.

2. My sports shots could get a lot better and a higher percentage
of keepable shots if I can keep the FSA in mind as I pan the soccer
field follow the players. I would need to fill the unmarked FSA
with more contrasting elements of the player I want in focus.

3. I've noticed in portraits that if a persons face fills the FSA I
get slightly unpredictable results. Sometimes with shallow depth of
field the nose would be tack sharp and other times the eyes and
other times the eyebrows or hair.

If this is old news to everyone else I'm sorry for the long wasted
post.

If anyone has further knowledge, please share or set me striaght.
--
RobL
http://www.preflash.com
"Why doesn't the image I captured look like what eye saw?" me.
Click to expand...
Click to expand...
 
Lock up your mirrior and look at the sensor. It's below the mirror. See if the sensor is a rectangle or a circle.
Rob L said:
I hope I'm being clear, because with all the people who have
worries and complaints about the D30 AF it seems this topic would
be on fire with people flaming me for being an idiot or people
thanking me for pointing out something that may explain alot of
"Why does a $3000 dollar camera have a $200 cameras AF?" Maybe its
just plain bad design in that area. (Shhh or on purpose from an
evil agreement with Kodak) ;).

RobL
http://www.preflash.com
"Why doesn't the image I captured look like what eye saw?" me
DavidP said:
Rob L said:
RobL
http://www.preflash.com
"Why doesn't the image I captured look like what eye saw?" me
Tony Collins said:
Rob L said:
Hi Tony heres what I got when I tried what you did:



I took this picture of the moon in a clear blue sky here in michigan.

The camera would not focus on the clear part of the sky, but it
would focus on the moon. The problem is it locked focus at the
point you see the moon at in the picture. I think this could be a
big part of the problem with the auto focus if the subject I wanted
in focus was slightly less contrasty dead center of the middle
square then the object (the moon in this case) just outside the
focus sensor area. Imagine how screwed up your focusing could be if
this was happening say 35% of the time coupled with the slow AF the
D30 already has. So I was right to a certain degree. And I believe
my findings about how to use this knowledge to improve my picture
taking still stand.

By the way this happened no matter where the moon was, top, bottom,
left or right of the square.

What do you or anyone else think?
Click to expand...
You have to be carefull that the "out of focus" or blurred version
of the moon (bigger than the focussed version) does not stray into
the small rectangle. If it does, then the camera can detect the
contrast change and still focus.
--
Tony Collins
[email protected]

Digital Photo website :
http://www.digifotoinfo.co.uk
Click to expand...
Click to expand...
--
The Unofficial Photographer of The Wilkinsons
http://thewilkinsons.crosswinds.net
Photography -- just another word for compromise
Click to expand...
Click to expand...
 
Exactly.

One thing I will say. If the focus is WAY off when you point the lens, it's very easy NOT to have the AF sensor on something contrasty, and the lens may zoom right past what you want to focus on, before you can properly point the camera at something with contrast.

The 1-D (in multi-point mode) has less of this problem, because SOMEWHERE, an AF sensor is bound to find SOMETHING to focus on. (Maybe not the right thing, though).

To get optimum performance out of the D-30, I manually focus (it helps to have a lens that supports FTM for this) first to get it close, then I can see where to put the AF sensor. Then I press the shutter (or * button), and whammo! Lock. (Usually -- except in EV 2 or so light).

Keeping it ON the subject is somewhat difficult, though, if they're moving fast. Once again, the EOS-1D would solve that problem.

But an Elan-II AF wouldn't.
Jay Bean said:
Personally I don't find the AF of the D30 slow at all, except in
really low light. What happens to me, for example when shooting
soccer at mid day, is that it focuses on whatever is in the
rectangle. If I let the rectangle slip away from the player I'm
shooting, my focus immediately changes from the player to the
background, which comes out in excellent focus. The change in
focus from the player to the background happens faster than I can

take my finger off the * button.--The Unofficial Photographer of The Wilkinsons http://thewilkinsons.crosswinds.netPhotography -- just another word for compromise
Click to expand...
 
you made it better and worse :-). The center focus sensor is not only rectangle its 2 rectangles (see image) this makes things worse and proves me even more right. look how the sensor sees things. This is why the moon snapped into focus on the side. This is also why this could deffinetly be a bad thing.

Or am I looking at this wrong. The D30 is my first SLR so maybe all 3 point focus systems are this way on all SLRs?



Oh well I least I now know what I am up against. Also I misspoke when I said the AF was slow. I meant compared to the AF systems with many many points to choose from as you mentioned.

RobL
http://www.preflash.com
"Why doesn't the image I captured look like what eye saw?" me.
 
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