9 point focus or focus-recompose

[SFishy]

Coming from the Sony 707 I am VERY used-to the focus-recompose technique. I would use it all the time.

In reading around here, and on the web, "focus-recompose" doesn't appear to be the best method with the 20D (or other dSLRs), especially at wider apertures. I've been reading about the 9-point focusing, and how to select the best point.

So I have some questions

First -- do a lot of you still use center-point focus and then do focus-recompose, and how are your results?

Second -- for those of you using the 9-point focus... do you find you can do so quickly? Was it just a matter of getting used to doing it?

I illustrated more of my questions about 9-point focus below...

Look at the drawings below... tell me if I have the right focus point selected...



and



Those are pretty straight forward (assuming I have it right...)

But what happens when the object you want to focus on is somewhere in between? Like...



Any input on this would be helpful!

Thanks

Amy
--

Creativity is allowing yourself to make mistakes. Art is knowing which ones to keep.
http://www.something-fishy.com/photography

 

[SFishy]

...just a bump...

 

[Shutter.]

Hi Aim,

I have never used my 10d or 20d on anything but center-point focusing. I mean, I guess I did when I first got my 10D but I found it a real pain. You cannot switch if ast enough to react to situations. Then there's the auto setting which selects the "right" point for you. Well, you and I don't always shoot what the camera might think is "right".

Basically, I think it's a marketing gimmick for than anything. I'd just as soon manually focus that switch my focusing points around.

As far as your diagram questions, I have no idea. lol

Jim

Coming from the Sony 707 I am VERY used-to the focus-recompose
technique. I would use it all the time.

In reading around here, and on the web, "focus-recompose" doesn't
appear to be the best method with the 20D (or other dSLRs),
especially at wider apertures. I've been reading about the 9-point
focusing, and how to select the best point.

So I have some questions

First -- do a lot of you still use center-point focus and then do
focus-recompose, and how are your results?

Second -- for those of you using the 9-point focus... do you find
you can do so quickly? Was it just a matter of getting used to
doing it?

I illustrated more of my questions about 9-point focus below...

Look at the drawings below... tell me if I have the right focus
point selected...



and



Those are pretty straight forward (assuming I have it right...)

But what happens when the object you want to focus on is somewhere
in between? Like...



Any input on this would be helpful!

Thanks

Amy
--
Creativity is allowing yourself to make mistakes. Art is knowing
which ones to keep.
http://www.something-fishy.com/photography

--
Jim Fuglestad
http://www.fuglestadphotography.com
http://www.pbase.com/jfuglestad/galleries
http://www.pbase.com/jfuglestad/366

• You're not in third grade anymore. Take as many recesses as you want!
• Why simply live and let live? Live and help live.

 

[Shutter.]

... the focus-recompose technique is what I use exclusively, but it can get you in a bit of trouble when shooting wide open because technically it does change the focal distance of what you focused on. Much more noticeable with a DSLR than a fixed lens camera.

Jim

I have never used my 10d or 20d on anything but center-point
focusing. I mean, I guess I did when I first got my 10D but I
found it a real pain. You cannot switch if ast enough to react to
situations. Then there's the auto setting which selects the
"right" point for you. Well, you and I don't always shoot what the
camera might think is "right".

Basically, I think it's a marketing gimmick for than anything. I'd
just as soon manually focus that switch my focusing points around.

As far as your diagram questions, I have no idea. lol

Jim

Coming from the Sony 707 I am VERY used-to the focus-recompose
technique. I would use it all the time.

In reading around here, and on the web, "focus-recompose" doesn't
appear to be the best method with the 20D (or other dSLRs),
especially at wider apertures. I've been reading about the 9-point
focusing, and how to select the best point.

So I have some questions

First -- do a lot of you still use center-point focus and then do
focus-recompose, and how are your results?

Second -- for those of you using the 9-point focus... do you find
you can do so quickly? Was it just a matter of getting used to
doing it?

I illustrated more of my questions about 9-point focus below...

Look at the drawings below... tell me if I have the right focus
point selected...



and



Those are pretty straight forward (assuming I have it right...)

But what happens when the object you want to focus on is somewhere
in between? Like...



Any input on this would be helpful!

Thanks

Amy
--
Creativity is allowing yourself to make mistakes. Art is knowing
which ones to keep.
http://www.something-fishy.com/photography

--
Jim Fuglestad
http://www.fuglestadphotography.com
http://www.pbase.com/jfuglestad/galleries
http://www.pbase.com/jfuglestad/366

• You're not in third grade anymore. Take as many recesses as you

want!

• Why simply live and let live? Live and help live.

--
Jim Fuglestad
http://www.fuglestadphotography.com
http://www.pbase.com/jfuglestad/galleries
http://www.pbase.com/jfuglestad/366

• You're not in third grade anymore. Take as many recesses as you want!
• Why simply live and let live? Live and help live.

 

[pdqgp]

there's an artical by Chuck Westfall of Canon that recommends using the focus points not Focus Lock and Recompose. Especially at wide open apertures under a distance of 15'.

the reasoning is that they focus plain is then moved and as a result increases the chance of Front or Back Focus.

folks here will debate the issue to death, but I'm on the side of Chuck and believe him as an engineer for the Cameras. I've had absolutely no focus issues with the 20D and I have switched techniques to using the focus points as a result of his artical. The artical is based on the 45pt AF system of the 1D bodies, but the same is going to apply to the rest of the EOS systems too.

Here's the link. Page 11 talks about the technique more.
http://www.photoworkshop.com/canon/EOS_Digital.pdf

Coming from the Sony 707 I am VERY used-to the focus-recompose
technique. I would use it all the time.

In reading around here, and on the web, "focus-recompose" doesn't
appear to be the best method with the 20D (or other dSLRs),
especially at wider apertures. I've been reading about the 9-point
focusing, and how to select the best point.

So I have some questions

First -- do a lot of you still use center-point focus and then do
focus-recompose, and how are your results?

Second -- for those of you using the 9-point focus... do you find
you can do so quickly? Was it just a matter of getting used to
doing it?

I illustrated more of my questions about 9-point focus below...

Look at the drawings below... tell me if I have the right focus
point selected...



and



Those are pretty straight forward (assuming I have it right...)

But what happens when the object you want to focus on is somewhere
in between? Like...



Any input on this would be helpful!

Thanks

Amy
--
Creativity is allowing yourself to make mistakes. Art is knowing
which ones to keep.
http://www.something-fishy.com/photography

--
-tim
http://www.pbase.com/pdqgp

 

[James Fry]

I have never used my 10d or 20d on anything but center-point
focusing. I mean, I guess I did when I first got my 10D but I
found it a real pain. You cannot switch if ast enough to react to
situations. Then there's the auto setting which selects the
"right" point for you. Well, you and I don't always shoot what the
camera might think is "right".

Another "win2 for the 20d and the joystick

Only kidding - I'd be more than happy to have a 10d

James

 

[Steven Sterne]

First -- do a lot of you still use center-point focus and then do
focus-recompose, and how are your results?

I know I shouldn't, but I usually DO use center-point-focus-recompose. And often, if the recompose moves the camera significantly, I do get a softer image. Usually sharpening makes it printable, but certainly it's not ideal. I do this because it's fast, and I'm normally taking pictures of fast-moving young children.

Second -- for those of you using the 9-point focus... do you find
you can do so quickly? Was it just a matter of getting used to
doing it?

I'm still working on that.

I illustrated more of my questions about 9-point focus below...

Look at the drawings below... tell me if I have the right focus
point selected...

I would use the point you have indicated, but do a little focus-recompose so the sensor locks onto the right subject. A small amount of recomposition is better than a large amount.

and

Yes.

Those are pretty straight forward (assuming I have it right...)

But what happens when the object you want to focus on is somewhere
in between? Like...

With this one, you would think that any point overlapping the focus area would be fine. But pay attention to the contrast, and be aware that all 9 focus sensors are 3x larger than the red square indicates - they all extend horizontally except the ones at 12 o'clock and 6 o'clock, which extend vertically, and the center point, which extends vertically AND horizontally so long as you are using a lens that is f/2.8 or wider.

So pick a focus point that will see more contrast in the part of the frame you want in focus. A very contrasty area to the immediate left or right of the red square could draw the sensor's attention if the area the red square touches is less contrasty! Immense potenial for misfocus there.

This is an important point to keep in mind no matter what sensor or focus method you are using. The tradeoff Canon made in this system was to increase sensitivity (focus speed) at the expense of precision (focus accuracy).

I hope this helps.

Steven

 

[DoctorG1]

Theoretical best and usability best are 2 diff things. I find it more difficult to set af points when shooting anything moving and still get the shot.

Depends what you shooting , static stuff use the correct method. For me , when I'm shooting moving stuff I use CF no 4 to transfer focusing to the FEL button away from the shutter . You can quickly use multiple presses of the FEL button which falls easily to hand to ensure focus is spot on , you can select any af point either and still do this.

Either you can meter for the subject with a half press of the shutter when focussing and keeping it down , or leave the shutter button entirely and meter for the new recomposed scene when shooting it while still having the subject in focus.

I would have liked to have been able to select multiple AF points instead of all or just one. I think your focussing technique depends on what you most comfortable with in the situation. One can always MF too, I often use MF if I dont trust the AF to do it right.

--
Rodney Gold

The nicest thing about smacking your head against the the wall is.......The feeling you get when you stop

 

[SFishy]

Steven,

Thanks for your answers!

So basically, the 9-points refer to the rule of thirds???

Like this:



Would that be fair to say?

Amy

With this one, you would think that any point overlapping the focus
area would be fine. But pay attention to the contrast, and be aware
that all 9 focus sensors are 3x larger than the red square
indicates - they all extend horizontally except the ones at 12
o'clock and 6 o'clock, which extend vertically, and the center
point, which extends vertically AND horizontally so long as you are
using a lens that is f/2.8 or wider.

 

[SFishy]

Yeah, I realize I may have to bounce between the different methods... with static object still-lifes, well it's probably easier to use the 9-point feature and focus using the proper point. I just wondered how "out in the real world" people are shooting, and if necessary, compensating if using focus-recompose. I became very dependent on the FR method with the Sony, but I don't want to end up with things out of focus, especially at wider apertures.

I"ll have to read more about the method you refered to... can you explain it more yourself (the FEL button?)?

Thanks

Amy

Theoretical best and usability best are 2 diff things. I find it
more difficult to set af points when shooting anything moving and
still get the shot.
Depends what you shooting , static stuff use the correct method.
For me , when I'm shooting moving stuff I use CF no 4 to transfer
focusing to the FEL button away from the shutter . You can quickly
use multiple presses of the FEL button which falls easily to hand
to ensure focus is spot on , you can select any af point either and
still do this.
Either you can meter for the subject with a half press of the
shutter when focussing and keeping it down , or leave the shutter
button entirely and meter for the new recomposed scene when
shooting it while still having the subject in focus.
I would have liked to have been able to select multiple AF points
instead of all or just one. I think your focussing technique
depends on what you most comfortable with in the situation. One can
always MF too, I often use MF if I dont trust the AF to do it right.

--
Rodney Gold
The nicest thing about smacking your head against the the wall
is.......The feeling you get when you stop

 

[Steven Sterne]

So basically, the 9-points refer to the rule of thirds???

Well, I think that's a leap, but not a bad one.

Here is a chart developed by a DP Review forum participant, Olaf DK, showing the sensor sizes compared with the focus squares:



You will see that there are more "vertical" sensors than I had said there were in my first post - my incipient senility, no doubt.

I urge you to read the entire thread from whence this came:

http://forums.dpreview.com/forums/read.asp?forum=1019&message=10526152

But for shooting purposes, you could use your "rule-of-thirds" guide to determine which point to activate, allowing for greatest focus accuracy and least degree of recomposition. I do believe that the 9-point array was developed by Canon to facilitate use of the rule of thirds - I read that somewhere.

Again, thanks for your questions - very thought provoking and helpful.

Steven

 

[andycarnall]

I use a mix of both - for anything fast moving I usually use the center point only and recompose if necessary (or manual focus)

For stationary subjects I normally leave all the focus points enabled and just flick to manul if I don't like the one it's chosen

Be aware though, that one of the big reasons Canon advise against focus-recompose is flash photography - ETTL uses the active focus point to judge the exposure, if you focus and then recompose then your focus point isn't in the right place adn this can lead to odd flash exposures (way under because your active point happened to end up on a light bulb when you recompose or way over because it was metering off the background)

Andy

Coming from the Sony 707 I am VERY used-to the focus-recompose
technique. I would use it all the time.

In reading around here, and on the web, "focus-recompose" doesn't
appear to be the best method with the 20D (or other dSLRs),
especially at wider apertures. I've been reading about the 9-point
focusing, and how to select the best point.

So I have some questions

First -- do a lot of you still use center-point focus and then do
focus-recompose, and how are your results?

Second -- for those of you using the 9-point focus... do you find
you can do so quickly? Was it just a matter of getting used to
doing it?

I illustrated more of my questions about 9-point focus below...

Look at the drawings below... tell me if I have the right focus
point selected...



and



Those are pretty straight forward (assuming I have it right...)

But what happens when the object you want to focus on is somewhere
in between? Like...



Any input on this would be helpful!

Thanks

Amy
--
Creativity is allowing yourself to make mistakes. Art is knowing
which ones to keep.
http://www.something-fishy.com/photography

 

[Steven Sterne]

Be aware though, that one of the big reasons Canon advise against
focus-recompose is flash photography - ETTL uses the active focus
point to judge the exposure, if you focus and then recompose then
your focus point isn't in the right place adn this can lead to odd
flash exposures (way under because your active point happened to
end up on a light bulb when you recompose or way over because it
was metering off the background)

Absolutely correct - use FEL (the * button) to lock flash exposure before recomposing.

Steven

 

[Wild-Mike]

First -- do a lot of you still use center-point focus and then do
focus-recompose, and how are your results?

Can't answer for everyone else, but I do and my results are fine.
Mike
--
Gallery: http://tkis.com/mike/

 

[DoctorG1]

I"ll have to read more about the method you refered to... can you
explain it more yourself (the FEL button?)?

Bascially you have one button for focussing and another for shooting. There is a button on the back of the camera thats used for Flash exposure lock , all you do is assign focussing to that button away from the shutter button by setting a custom dunction. Try it.

There are other options using the custom function no 4 in regard to focussing that make the way you want to handle the camera in he situation quite flexible.

--
Rodney Gold

The nicest thing about smacking your head against the the wall is.......The feeling you get when you stop

 

[SFishy]

I'll definitely check out the thread you point to... but let me see if I understand what it means...

Based on your graphic, it would be more like this???



than



???

Amy

So basically, the 9-points refer to the rule of thirds???

Well, I think that's a leap, but not a bad one.

Here is a chart developed by a DP Review forum participant, Olaf
DK, showing the sensor sizes compared with the focus squares:



You will see that there are more "vertical" sensors than I had said
there were in my first post - my incipient senility, no doubt.

 

[Juli Valley]

which assigns focus to the * button. I focus and recompose. It's not perfect but it works well enough for me. I shoot mainly static subjects.

 

[SFishy]

And is it Canon who says not to focus-recompose? When I looked in the manual, they actually have an example of how to focus then recompose (page 69 - One-Shot AF Mode Basic Zone or Creative Zone)

Amy

Be aware though, that one of the big reasons Canon advise against
focus-recompose is flash photography - ETTL uses the active focus
point to judge the exposure, if you focus and then recompose then
your focus point isn't in the right place adn this can lead to odd
flash exposures (way under because your active point happened to
end up on a light bulb when you recompose or way over because it
was metering off the background)

Absolutely correct - use FEL (the * button) to lock flash exposure
before recomposing.

Steven

--

Creativity is allowing yourself to make mistakes. Art is knowing which ones to keep.
http://www.something-fishy.com/photography

 

[Ben_Egbert]

I have three shooting modes, and the focus depends on what I am shooting. For indoor flash of family, I use all 9 and shoot at f8 usually with my 17-40. For landscapes, usually 17-40 I use at least f11 and then focus on something about 20 feet out (choosing the focus area that is closest). This usually gives me everything in acceptable focus, for critical photos, I may bracket the f-stop and the focus point. For birds, with a long lens, I use all points and AI-servo with continuous mode to get predictive focusing.

I note that this does not work as well on the 20D as it did on the 10D. I think it is because I usually have a 1.4X attached and the lack of light (f8) slows down the focusing to an extent that it cannot keep up with the faster burst rate.

I have little application for low light photos, and never use low f-stops except for wildlife. Well except wild life is often in poor light, so yesterday I needed an 800mm f1 lens and maybe a searchlight.

Ben

--
http://www.pbase.com/roserus

Ben

 

[Diane B]

I"ll have to read more about the method you refered to... can you
explain it more yourself (the FEL button?)?

Bascially you have one button for focussing and another for
shooting. There is a button on the back of the camera thats used
for Flash exposure lock , all you do is assign focussing to that
button away from the shutter button by setting a custom dunction.
Try it.
There are other options using the custom function no 4 in regard to
focussing that make the way you want to handle the camera in he
situation quite flexible.

--
Rodney Gold
The nicest thing about smacking your head against the the wall
is.......The feeling you get when you stop

I quickly checked to make sure the 20D works the same as 10D and it does---you can use the * button to set AE lock in partial and centerweighted metering to be different from the AF point--to a big degree, very similar to using C.Fn. 4/1 but with this C.Fn. you must keep the * button depressed while you shoot to lock the metering. YOu can AF, then choose where to meter--or vice versa. With the AEL button--it will actually lock that metering until you press the * button again--or take the picture. You can also hold down the * button if you are in default mode and lock the exposure from frame to frame.

Personally I use C.Fn. 4/1 and separate AF and AE (BTW, I note that PHil says that AF and AE are locked on the button with the 20D but states it as I wrote it with the 10D. Has that changed?? I suspect not and that he has made a mistake--see here http://www.dpreview.com/reviews/canoneos10d/page8.asp ). I do focus and recompose.

Where I use the 7 AF points of the 10D is when I am on tripod, having composed my shot and then making the decision as to where I want to focus for the DOF I need (this is for my commercial shooting). Otherwise I must AF, then compose--more of a pain. If I do it with the multi AF points I find it much easier to manually bracket the shot--and since I often blend RAW conversions for more dynamic range, this works to my advantage.

Diane
--
Diane B
black and white lover, but color is seducing me
http://www.pbase.com/picnic/galleries