What's your Focus point 'strategy'?

[GrillMouster]

...What do you guys mean by "focus and recompose"?

...most people lock focus with a half press of the shutter.

Most cameras (even point-and-shoots and camera phones) are set up to work as ukcatfan and disneyboy2003 explained. On many DSLRs you can disable that function and assign it to other buttons.

 

[SrisonS]

I also use the center point, using the focus/recompose method. The only time I can't get away with that is when I'm using my Sigma 30mm f/1.4. The dof is just too shallow. Any small movement can throw my focus area off. So I've become very accustomed to changing the focus point on-the-fly; so I can never just recompose.

 

[Wadecool]

I think I'm getting the focus/recompose theory but my Nikon D3100 has 11 focus points, are you saying I can enable only one of them?

 

[Anewman]

I think I'm getting the focus/recompose theory but my Nikon D3100 has 11 focus points, are you saying I can enable only one of them?

I have never shot that camera but I am confident you can enable only one.

Many cameras have a more sensitive/accurate center focus point, and on some cameras it is the only one always visible.

 

[ukcatfan]

I have to say, this is one of the better threads we have had here in a while!

 

[handicap18]

I think I'm getting the focus/recompose theory but my Nikon D3100 has 11 focus points, are you saying I can enable only one of them?

Yes you can. And you can then move from one focus point to the other using the the little thumb wheel on the back.

I don't know where in the menu it is, but you want to select Single-Point AF. I believe the default is Auto-area AF. Your other options are Dynamic-area AF (You select the focus point and the D3100 will use surrounding focus points if the subject moves after locking focus) and 3D-tracking: You select the focus point and the D3100 tracks the subject as it moves through the frame.

With my Nikon dSLR's I've always only used Single-point AF.

 

[Marlton Mom]

It's funny that this topic would come up because I am spending a ton of time reading up on my Nikon D90 focusing system and trying to understand it.

I know I HATED my old Nikon D60 and it's 3 puny focusing points and I was thinking that that was the cause of my focusing problems. Now I'm wondering if it wasn't because I was letting the camera pick the focus points.

I'll summarize what I've learned so far for the Nikon D90 in hopes that others can benefit from the info.

The D90 has 2 focusing control systems. (I'm not talking about Manual focus at all here.)

The first one AUTO FOCUS MODE - AFM tells the camera WHEN to focus.

The second focus control AUTO FOCUS AREA - AFA tells the camera WHERE to FOCUS.

AFM WHEN to FOCUS has:

AFS = auto focus single = when focus is set it stays that way and the camera will not auto refocus if YOU or the SUBJECT moves.

AFC = auto focus CONTINUOUS = camera keeps focusing until shutter release button depressed fully and picture is taken.

AFA = combo of above, 1st the camera uses AFS to lock focus but if the camera senses movement of SUBJECT OR PHOTOGRAPHER the focus control defaults to AFC.

AFA WHERE to FOCUS has:

Single point- you choose one of 11 D90 focusing points and the camera sticks with that focus bracket no matter what.
Dynamic Area- you select focus point BUT....
if Camera set to AFA or AFC AND subject moves, camera defaults to choosing focus. If camera set to AFS and Dynamic area then it will stay with your original focusing spot even though there is movement (subject or photographer)
Auto Area - Camera chooses focus point NOT YOU.
3D Tracking - When in AFA or AFC focus mode you can select the focus point but movement will cause the camera to refocus based on new measurements. When using AFS the camera will stick with the first focus area and not correct for movement.


I can think of 2 primary shooting situations that I will need to adjust my focus parameters between.

Stationary subject = camera set to AFS-single point (slows shutter release because camera will only take picture when subject is in focus and this could take small amt of time)

Moving subject = camera set to AFA-Dynamic area ( I can select focus point but if Subject/Photographer moves camera overides my focus selection and calculates new focus point.

My only question is how well the focusing system will work snapping pictures of the Disney parades at night utilizing my Moving Subject scenario especially in such potentially tough lighting and movement situations. I guess it's just one of those things I will have to experience and see for myself.

I will be purchasing a 18-105mm f/3.5-5.6G ED VR AF-S DX Nikkor Autofocus Lens for my next trip to the parks in June. I chose this lens primarily for it's tested sharpness across all ranges as opposed to it's bigger sister the AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VR II Zoom Lens. I wanted a lens that would cover my range (18 -105) so I wouldn't have to keep swapping out between my 18-55 and 55 to 200 Nikon kit lenses.

My # 1 thing when taking pictures is that I want them to be SHARPLY focused...... so hopefully between understanding the D90's focusing system and using the proper lens I will achieve my goal!

I hope all this helps (somebody)

Marlton Mom

 

[WilsonFlyer]

Hey Marlton Mom! Got one of those handy-dandy references for my Canon rebel? LOL

 

[WilsonFlyer]

Yeah, this concept is a bit difficult to understand, and it's even more difficult to explain.

You are correct that the camera itself is not 0.2 feet closer to the bird. I think I might have to use some geometry and x- and y-coordinates to try to explain this. Sorry for the upcoming nerdy math...

Let's say that we've got a circle with a radius of 5 feet. My camera and I are at the center of the circle. The bird is located on the circle itself 5 feet away. In fact, the bird can be anywhere ON this circle and it will be in-focus. Since my camera is pre-focused at 5 feet, anything that's 5 feet away from me will be in-focus.

Here's where the nerdy math comes in. Let's imagine that this 5-foot circle is on a graph with x- and y-coordinates. My camera and I are located at (0,0). The bird in part (A) is located at coordinates (-1.4, 4.8).

As an aside: How did I come up with these coordinates? I used Pythagorean Theorem, where c2 = a2 + b2. Let c be the radius of 5 feet. Let b be the distance of 4.8 feet that we made up in part (B). Solving for a, we get 1.4 feet.

So even though this bird in part (A) is 5 feet away from me, it's actually 1.4 feet to my "west", and it is 4.8 feet to my "north".


When I "recompose" by moving my camera, my pre-focus distance is still 5 feet. If there was an object located at coordinates (0, 5) (ie. 5 feet directly "north" of me), then it would be in focus.

However, as we determined earlier, the bird's "y-coordinate" is 4.8 feet. It is 4.8 feet "north" of me. If my camera is pre-focused at 5 feet, this bird runs the risk of being out-of-focus in my photo because I recomposed by moving my camera. Even though the bird didn't change its position and I didn't change my position, the bird is now no longer in my camera's plane-of-focus.
​

In the end, this all is supposed to illustrate why focus-and-recomposing can sometimes not give you the sharpest image.

Hope I didn't make things even more confusing with all this extra math. I'm sure others can explain this concept better than I did.

Great post. Great explanation too. I get it. I majored in applied mathematics. LOL

So... How do we fix it?

I gotta play dumb here (Because I am!). How do you guys deal with these floating focus points when crap's happnin' at a hundred MPH? I don't get it. Maybe I just need to practice?

 

[Marlton Mom]

Hey Marlton Mom! Got one of those handy-dandy references for my Canon rebel? LOL

KILL me NOW!! I have SUCH a HEADACHE from the "if this, then NOT that" nature of the settings and it took me hours to parcel it all out using different sources of info. One source would mention something important but then fail to explain the other half! Aye yi yi!!

I think the rest of the camera will be relatively simple compared to all the permutations of the focusing system.

What happened to the good old days of manual focus, one ISO and shutter OR Aperture priority??? Um ok, never mind!

~MM

 

[WilsonFlyer]

I have to say, this is one of the better threads we have had here in a while!

This is a great thread. I just wish I would have had the nerve to start it but my ego gets in the way sometimes. I bet more of us have this problem than we hear about or than we're willing to admit.

This could easily become on of the forum's most valuable threads. Bring on more information. All help appreciated.

Thanks to the OP for starting it!

 

[ukcatfan]

This is a great thread. I just wish I would have had the nerve to start it but my ego gets in the way sometimes. I bet more of us have this problem than we hear about or than we're willing to admit.

This could easily become on of the forum's most valuable threads. Bring on more information. All help appreciated.

Thanks to the OP for starting it!

My problem is not knowing how to do it, but actually making myself actually do it! I usually have a wife and kids staring at me saying "HURRY UP!" and I then try to do my best to get away with the fast way instead of the right way The kids are starting to get older now though, so hopefully my shooting time is getting longer.

 

[mom2rtk]

My problem is not knowing how to do it, but actually making myself actually do it! I usually have a wife and kids staring at me saying "HURRY UP!" and I then try to do my best to get away with the fast way instead of the right way The kids are starting to get older now though, so hopefully my shooting time is getting longer.

That's the same reason I come back from every trip with a series or 2 of photos completely overexposed. I go into a dark ride, crank up the ISO then stop for some photos outdoors with everyone hurrying me along, so I don't notice the flashing shutter speed in the viewfinder.......

 

[Wadecool]

It's funny that this topic would come up because I am spending a ton of time reading up on my Nikon D90 focusing system and trying to understand it.

I know I HATED my old Nikon D60 and it's 3 puny focusing points and I was thinking that that was the cause of my focusing problems. Now I'm wondering if it wasn't because I was letting the camera pick the focus points.

I'll summarize what I've learned so far for the Nikon D90 in hopes that others can benefit from the info.

The D90 has 2 focusing control systems. (I'm not talking about Manual focus at all here.)

The first one AUTO FOCUS MODE -
AFM tells the camera WHEN to focus.

The second focus control AUTO FOCUS AREA
- AFA tells the camera WHERE to FOCUS.

AFM WHEN to FOCUS has:

AFS = auto focus single = when focus is
set it stays that way and the camera will not auto refocus if YOU or the
SUBJECT moves.

AFC = auto focus CONTINUOUS =
camera keeps focusing until shutter release button depressed fully and picture
is taken.

AFA = combo of above, 1st the camera
uses AFS to lock focus but if the camera senses movement of SUBJECT OR PHOTOGRAPHER the focus control defaults to AFC.

AFA WHERE to FOCUS has:

Single point- you choose one of 11 D90 focusing points and the camera sticks with that focus bracket no matter what.
Dynamic Area- you select focus point BUT.... if Camera set to AFA or AFC AND subject moves, camera defaults to choosing focus. If camera set to AFS and Dynamic
area then it will stay with your original focusing spot even though there is
movement (subject or photographer)
Auto Area - Camera chooses focus point NOT YOU.
3D Tracking - When in AFA or AFC
focus mode you can select the focus point but movement will cause the camera to refocus based on new measurements. When using
AFS the camera will stick with the first focus area and
not correct for movement.


I can think of 2 primary shooting situations that I will need to adjust my focus parameters between.

Stationary subject = camera set to
AFS-single point (slows shutter release because camera will only take
picture when subject is in focus and this could take small amt of time)

Moving subject = camera set to AFA-
Dynamic area ( I can select focus point but if Subject/Photographer moves
camera overides my focus selection and calculates new focus point.

My only question is how well the focusing system will work snapping pictures of
the Disney parades at night utilizing my Moving
Subject scenario especially in such potentially tough lighting and
movement situations. I guess it's just one of those things I will have to
experience and see for myself.

I will be purchasing a 18-105mm f/3.5-5.6G ED VR AF-S DX Nikkor Autofocus
Lens for my next trip to the parks in June. I chose this lens primarily for it's
tested sharpness across all ranges as opposed to it's bigger sister the AF-S DX
NIKKOR 18-200mm f/3.5-5.6G ED VR II Zoom Lens. I wanted a lens that
would cover my range (18 -105) so I wouldn't have to keep swapping out between my 18-55 and 55 to 200 Nikon kit lenses.

My # 1 thing when taking pictures is that I want them to be SHARPLY
focused...... so hopefully between understanding the D90's focusing system
and using the proper lens I will achieve my goal!

I hope all this helps (somebody)

Marlton Mom

Thanks for the description. I'm still having trouble understanding "dynamic area" and "3D tracking". It seems like these two modes do the same thing. I am determined to figure this out.

 

[handicap18]

This is a great thread. I just wish I would have had the nerve to start it but my ego gets in the way sometimes. I bet more of us have this problem than we hear about or than we're willing to admit.

This could easily become on of the forum's most valuable threads. Bring on more information. All help appreciated.

Thanks to the OP for starting it!

I've been on this board for going on 6 years and this subject doesn't not come up very often, however I completely agree with your statement that I put in Bold.

The focusing system on dSLR's can be VERY confusing, not just for those new to using a dSLR, but even for those who have been using one for years.

I've found that it is VERY difficult to explain in written form because there are 2 aspects to it as Marlton Mom pointed out. when I got my first dSLR I noticed right away that there was something wrong with my focus and realized that it was the camera that was choosing where to focus. I did not like that. I used Nikon's ViewNX software (free with the camera) to figure out my focus issues. There is one part of the software with shows you on your image as you view it on the computer what focus point was used. I found that very helpful when it came to focus points. I could actually see what had happened.

This topic hasn't come up in a while and even so, this is by far the most in depth we've gone with it. I hope it helps a lot of people become for familiar with the camera's and makes taking pictures that much more enjoyable.

Todays camera's are great and can do a lot of things automatically very very well, however, IMO, focusing is not one of them.

 

[handicap18]

It's funny that this topic would come up because I am spending a ton of time reading up on my Nikon D90 focusing system and trying to understand it.

I know I HATED my old Nikon D60 and it's 3 puny focusing points and I was thinking that that was the cause of my focusing problems. Now I'm wondering if it wasn't because I was letting the camera pick the focus points.

I'll summarize what I've learned so far for the Nikon D90 in hopes that others can benefit from the info.

The D90 has 2 focusing control systems. (I'm not talking about Manual focus at all here.)

The first one AUTO FOCUS MODE - AFM tells the camera WHEN to focus.

The second focus control AUTO FOCUS AREA - AFA tells the camera WHERE to FOCUS.

AFM WHEN to FOCUS has:

AFS = auto focus single = when focus is set it stays that way and the camera will not auto refocus if YOU or the SUBJECT moves.

AFC = auto focus CONTINUOUS = camera keeps focusing until shutter release button depressed fully and picture is taken.

AFA = combo of above, 1st the camera uses AFS to lock focus but if the camera senses movement of SUBJECT OR PHOTOGRAPHER the focus control defaults to AFC.

AFA WHERE to FOCUS has:

Single point- you choose one of 11 D90 focusing points and the camera sticks with that focus bracket no matter what.
Dynamic Area- you select focus point BUT....
if Camera set to AFA or AFC AND subject moves, camera defaults to choosing focus. If camera set to AFS and Dynamic area then it will stay with your original focusing spot even though there is movement (subject or photographer)
Auto Area - Camera chooses focus point NOT YOU.
3D Tracking - When in AFA or AFC focus mode you can select the focus point but movement will cause the camera to refocus based on new measurements. When using AFS the camera will stick with the first focus area and not correct for movement.


I can think of 2 primary shooting situations that I will need to adjust my focus parameters between.

Stationary subject = camera set to AFS-single point (slows shutter release because camera will only take picture when subject is in focus and this could take small amt of time)

Moving subject = camera set to AFA-Dynamic area ( I can select focus point but if Subject/Photographer moves camera overides my focus selection and calculates new focus point.

My only question is how well the focusing system will work snapping pictures of the Disney parades at night utilizing my Moving Subject scenario especially in such potentially tough lighting and movement situations. I guess it's just one of those things I will have to experience and see for myself.

I will be purchasing a 18-105mm f/3.5-5.6G ED VR AF-S DX Nikkor Autofocus Lens for my next trip to the parks in June. I chose this lens primarily for it's tested sharpness across all ranges as opposed to it's bigger sister the AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VR II Zoom Lens. I wanted a lens that would cover my range (18 -105) so I wouldn't have to keep swapping out between my 18-55 and 55 to 200 Nikon kit lenses.

My # 1 thing when taking pictures is that I want them to be SHARPLY focused...... so hopefully between understanding the D90's focusing system and using the proper lens I will achieve my goal!

I hope all this helps (somebody)

Marlton Mom

Excellent information.

What I do is ALWAYS leave my camera in Single-Mode AF. With that I will switch between AF-S and AF-C. I mostly use AF-S (candid's, portraits, landscapes, etc...). With this I will either use just the middle focus point and then lock focus and recompose, or switch from one point to the other with the thumb wheel on the back of the camera. With this setting I get a "BEEP" when the point I've chosen is in focus. I use AF-C sometimes when I'm shooting sports or when the kids are running around or riding their bikes or some other type of action. With this I do not get the "BEEP" when the point is focused, however, when it is focused and the subject moves and I move the camera, so long as I keep my shutter half pressed, the camera will keep that subject point in focus.

For me with my camera its easier. The D300 has a switch on the body that easily allows me to switch between AF-S, AF-C and M (though I never use M). On the D90 it only switches between AF & M.

 

[WilsonFlyer]

I hate to ask but alas, I must.

Has anyone done a paralysis/analysis of the Canon focusing system akin to what Marlton's Mom has done for the Nikon system?

I know it's asking a lot, but if some kind soul could share this kind of information, with this kind of circle drawn around it for the Canon, I know it would certainly help me, and I bet it would help others as well.

TYIA.

 

[mom2rtk]

I hate to ask but alas, I must.

Has anyone done a paralysis/analysis of the Canon focusing system akin to what Marlton's Mom has done for the Nikon system?

I know it's asking a lot, but if some kind soul could share this kind of information, with this kind of circle drawn around it for the Canon, I know it would certainly help me, and I bet it would help others as well.

TYIA.

Hey, didn't you just get a new Canon? I say send the old one to Marlton Mom as a gift and maybe she'll do the research for all us Canon shooters. Come on over to the dark side MM!

 

[Marlton Mom]

Excellent information.

What I do is ALWAYS leave my camera in Single-Mode AF. With that I will switch between AF-S and AF-C. I mostly use AF-S (candid's, portraits, landscapes, etc...). With this I will either use just the middle focus point and then lock focus and recompose, or switch from one point to the other with the thumb wheel on the back of the camera. With this setting I get a "BEEP" when the point I've chosen is in focus. I use AF-C sometimes when I'm shooting sports or when the kids are running around or riding their bikes or some other type of action. With this I do not get the "BEEP" when the point is focused, however, when it is focused and the subject moves and I move the camera, so long as I keep my shutter half pressed, the camera will keep that subject point in focus.

For me with my camera its easier. The D300 has a switch on the body that easily allows me to switch between AF-S, AF-C and M (though I never use M). On the D90 it only switches between AF & M.

Thanks for the lovin!

On the D90 there is the AF button on the top of the camera next to the control panel window near the shutter release button.

This sets the Focusing Modes (When to focus) AFS, AFC, AFA

~ For Focus AREA (Single, Dynamic, Auto tracking and 3D) I believe you have to go to the menu and change it there. Now I'm wondering if you can assign a function button to the Focus area but since I know exactly where it is in the menu I think It'd be quicker for me to get there via the menu as opposed to any function assignment.

(Besides, I'm saving those function buttons for "Coffee making" and "bill paying" )

~ MM

 

[Marlton Mom]

Thanks for the description. I'm still having trouble understanding "dynamic area" and "3D tracking". It seems like these two modes do the same thing. I am determined to figure this out.

The Nikon Digitutor site has an excellent video that SHOWS you what the heck 3D tracking and dynamic area are.
As we all know, a picture is worth a thousand words and a video is a mind saver!

Here is the link for the D90 digitutor
http://www.nikondigitutor.com/eng/d90/index.shtml

Skip the intro to get to the menu. The menu is on a pull out tab on your left. Choose AF area mode and then watch the video for Dynamic area and 3D tracking which is listed in a progress bar on the bottom of the picture.

Keep in mind that if the camera is set to AFS and Dynamic area then it will stay with your original focusing spot even though there is movement (subject or photographer).

These kind of brain numbing permutations are what make digital photography and it's focusing systems SO FUN!!!

~ Marlton Mom