Multipoint focussing

[Cyril7]

What is the point of using multipoint focussing? Or, to put it another way, when is it better to use any other point than the centre one? I find it confusing to see the focussing point changing - often to to an inconvenient part of the scene.

[24Peter]

I've had my XT for 1 1/2 yrs and taken nearly 40,000 photos with it and never used the multipoint AF. I could never figure out what the point of multipoint is. Maybe for action shots? :confused:

[cdifoto]

One of many reasons is action. It's easier to maintain tracking on 10 different points than just the center...especially with erratic movement like soccer, basketball, field hockey, etc.


That said, I still only use one point for sports...the center...since it's the most accurate.

[aparmley]

I believe the point of multi-point focus modes are so that when new comers use their first SLR with multi-point they can't figure out why their shots are OOF; This was set in place to maximize the amount of roles of film they used until they figured it out. :D Now, in the DSLR world its so the manuf. can hopefully get a few lens upgrades out of the new comers before they realize why their images are OOF. :p

Like Peter, I've never used multi-point focus mode. . . Even when tracking for action shots. . .I find that the AF system in at least the XT and 30D are not sophisticated enough to be useful. So, I only use single point selective focus - which is the reason for all the AF points - so you don't have to focus then recompose because with certain aperture settings, this can be the difference between a shot where your subjects is in focus and OOF.

[Rhys]

I believe it's so that you can put your camera on a tripod and select the area you want to be most in focus. Personally, I use centre-sport only. I did try that crazy mode that's supposed to ensure everything is in focus and found nothing to be in focus.

[ktixx]

I use center 90% of the time, it is the easiest to ensure that your shots will be accurately focused - Especially when shooting at large apertures. If you are taking a portrait shot and you use multi point, there is a chance that it will focus on the persons body instead of their head. If this happens and you are shooting at f/1.8 this could be the difference between a great shot and an awful shot.
I use multi point when I am shooting landscape or architecture type shots and am using a small aperture. With these types of shots usually all 9AF points will light up on my viewfinder telling me the shot is focsed completely. The difference between only using center and using multi point is probably minimal, if any at all, but it gives me a little more confidence to know that all my points (or most) are in focus.
Ken

[Sungrazer]

Good thread. I was going to ask the same question. I preferred my shots taken with center point only but was concerned I wasn't using the full capabilities of the camera or something.

What about you guys that have the 1DS Mark II? Does it have 45 autofocus points? How do you use them?

[adam75south]

i'm a center pointer as well.

[BonjiB]

I find myself constantly changing focus points. With the 4 way joystick thing on the 20d it makes it really easy to select which point you want to focus on. I find when i'm shooting vertical people shots i use the far right (or top if vertical) point the most because it's closest to the persons face which is what i want to be in focus. For group shots i find myself using all different focus points depending on what i want to draw attention to in the photo. To limit yourself to center point could potentially cause you problems especially at really low aperatures where the slightest camera move can cause something from going razor sharp to just sorta sharp if you're focusing then recomposing. I try to pick the focus point that will make me have to move the camera the least to recompose to the shot i want. Hitting that 4way to select the focus point is as much of a part of my technique as pushing the shutter button. Every picture needs a different focus point in my opinion. As for automatic or multipoint... i dont trust the camera to make any decisions for me beyond metering and even then i don't trust it sometimes. Just my input.

[ktixx]

I find myself constantly changing focus points. With the 4 way joystick thing on the 20d it makes it really easy to select which point you want to focus on. I find when i'm shooting vertical people shots i use the far right (or top if vertical) point the most because it's closest to the persons face which is what i want to be in focus. For group shots i find myself using all different focus points depending on what i want to draw attention to in the photo. To limit yourself to center point could potentially cause you problems especially at really low aperatures where the slightest camera move can cause something from going razor sharp to just sorta sharp if you're focusing then recomposing. I try to pick the focus point that will make me have to move the camera the least to recompose to the shot i want. Hitting that 4way to select the focus point is as much of a part of my technique as pushing the shutter button. Every picture needs a different focus point in my opinion. As for automatic or multipoint... i dont trust the camera to make any decisions for me beyond metering and even then i don't trust it sometimes. Just my input.

It doesn't matter if you use center point, then move the camera (to recompose) as you are focusing based on distance, as long as you don't move backward and foreward after you have locked focused you won't have a problem. There is nothing wrong with just using the center point only then recomposing the shot. If you don't believe me, I have about 10,000 examples to show you, or to make it easier on me and my bandwith...just try it yourself :)

[kjosker]

I use center point focusing all the time. When I bought my 24-105mm lens, I was disappointed with my results, soft focus. Trying to analyze what was wrong, I tried multi-point focusing, and the change in image sharpness was startling. The lens suddenly became what I had hoped it to be.

Further analyzing the problem, I came to realize that I was the problem; I had become lazy, and rushed in my composition and picture taking. Focusing and composing close enough was not close enough (thinking I could post process anything), and the results showed it. Once I understood this and focused more precisely on what I wanted to, the results became much better, and I returned to center point, where I continue with satisfying results.

In this life, I have observed that I have to learn the same thing over and over sometimes.

[sunnythepsychocat]

I use center point focusing all the time. When I bought my 24-105mm lens, I was disappointed with my results, soft focus. Trying to analyze what was wrong, I tried multi-point focusing, and the change in image sharpness was startling. The lens suddenly became what I had hoped it to be.

Further analyzing the problem, I came to realize that I was the problem; I had become lazy, and rushed in my composition and picture taking. Focusing and composing close enough was not close enough (thinking I could post process anything), and the results showed it. Once I understood this and focused more precisely on what I wanted to, the results became much better, and I returned to center point, where I continue with satisfying results.

In this life, I have observed that I have to learn the same thing over and over sometimes.
I actually had oppsite experience than you. I used multi-point on my 400D and the photo was somehow out of focus. Did not figure out why until I swtich to center focus and the got my money worth with the 24-105.
I think we all need to "learn the same thing over and over sometimes."

[24Peter]

I should add that I rarely use the center focus point b/c I don't want to focus and recompose my shot and I rarely place my subject in the middle of my frame. I often use the two right most points (top most in portrait orientation) for my portrait/people shots. There are varying opinions (an apparently experiences) on whether or not recomposing jepordizes your focusing. For me, it's not so much that as I like to compose my shot, focus and then shoot. But it's probably more a matter of taste than effectiveness. I should also add I'm the one who complains how poorly my XT focuses, so take my opinion with a grain of salt (or shot of vodka). :o

[cdifoto]

I should add that I rarely use the center focus point b/c I don't want to focus and recompose my shot and I rarely place my subject in the middle of my frame. I often use the two right most points (top most in portrait orientation) for my portrait/people shots. There are varying opinions (an apparently experiences) on whether or not recomposing jepordizes your focusing. For me, it's not so much that as I like to compose my shot, focus and then shoot. But it's probably more a matter of taste than effectiveness. I should also add I'm the one who complains how poorly my XT focuses, so take my opinion with a grain of salt (or shot of vodka). :o

I'm with you on this...to a point (pun very much intended). Challenging light, I go straight to center. Sports....center again. Portraits/good light/want optimal composition...I'll go with the AF point that lays over my subject.

[Honest Gaza]

Looking through the Manual for the Canon 400D (XTi), would this not be used during "Auto Depth of Field" feature ?

[cwphoto]

Good thread. I was going to ask the same question. I preferred my shots taken with center point only but was concerned I wasn't using the full capabilities of the camera or something.

What about you guys that have the 1DS Mark II? Does it have 45 autofocus points? How do you use them?

My cameras have 45 points but I never use all of them. I have them configured to only use the middle row of nine (or eleven, not sure), and then I just use the thumb-wheel to change them depending on my composition.

I avoid multi-point as it is too slow and too inaccurate (I prefer a scalpel to a broad-sword).

[cwphoto]

It doesn't matter if you use center point, then move the camera (to recompose) as you are focusing based on distance, as long as you don't move backward and foreward after you have locked focused you won't have a problem. There is nothing wrong with just using the center point only then recomposing the shot. If you don't believe me, I have about 10,000 examples to show you, or to make it easier on me and my bandwith...just try it yourself :)

I'm pretty sure that technically speaking the focused distance changes subtlely between those two examples (at least the maths says it does).

Any observations saying it doesn't matter is probably as a result of the focused distance changes lying within the DoF than anything else.

Try doing an extreme example with subject close at say f/1.2 and you'll see what I mean.

I agree that for most shots this will be moot as the DoF will cover any subtle change.

[sunnythepsychocat]

Looking through the Manual for the Canon 400D (XTi), would this not be used during "Auto Depth of Field" feature ?
I think for A-DEP mode, it uses all 9 points.

[sunnythepsychocat]

My cameras have 45 points but I never use all of them. I have them configured to only use the middle row of nine (or eleven, not sure), and then I just use the thumb-wheel to change them depending on my composition.

I avoid multi-point as it is too slow and too inaccurate (I prefer a scalpel to a broad-sword).
Don't tell me you have either a 1Ds Mark II or a 1D Mark II or a 1D Mark II N :eek: Man, I will get my hands on new 1D Mark II N replacemenet someday:D

I wish 400D has the thumb-wheel:( However, I did find that I need to change my AF point when I take vertical shot or I have to raise my arms to get the center AF point to line up with my subject. Very uncomfortable:(

[cwphoto]

Don't tell me you have a 1Ds Mark II since you do a lot of protraits :eek:

I own the EOS-1D Mark II N and the EOS-1V HS, but I borrow the 's' from time to time when I need the width on digital.

[ktixx]

I'm pretty sure that technically speaking the focused distance changes subtlely between those two examples (at least the maths says it does).

Any observations saying it doesn't matter is probably as a result of the focused distance changes lying within the DoF than anything else.

Try doing an extreme example with subject close at say f/1.2 and you'll see what I mean.

I agree that for most shots this will be moot as the DoF will cover any subtle change.

I agree, for extreme situations (macro especially), focusing without moving the plane of field is important to get sharpness, but for your every day shot, I think center point works fine.

[JMWallace]

Just curious...it sounded like CW said he uses the wheel to choose the auto focus point on his Mark. I know on the 30D you can choose to use the wheel near the shutter button or the 4-way...are you talking about the thumb wheel or the other?

Is there a custom function that allows the use of the thumb wheel? That might seem to faster??

The DARN most FRUSTRATING part of the battery grip is that the 4-way is very awkward to use in portrait and I find the wheel next the shutter to be inefficient.

I too use center pertty much all the time unless I am in a same situation as cdi pointed out.

It was funny...when i first started using my camera in the default set up I kept pressing the shutter half way to set focus. I would do it again (beep), again (beep), *sh#t* again (beep), again (beep), again (beep) SH#T!!! It seemed to almost focus on something different every time! Funny now that I look back!!!

[cwphoto]

The wheel on the 1-series can be programmed to adjust the focus points - not sure about the other cameras.

There is also a programmable 'Assist' button which I use to pre-register a favourite focus point. If I hit and hold that button it instantly returns to said point - release and it goes back to the prior point.

[forno]

The wheel on the 1-series can be programmed to adjust the focus points - not sure about the other cameras.

There is also a programmable 'Assist' button which I use to pre-register a favourite focus point. If I hit and hold that button it instantly returns to said point - release and it goes back to the prior point.

I was going to ask you a similar q'

When I used to do a bit of film SLR stuff on a OM2 I would focus on a spot and then pan with the subjectto that spot and hit the shutter, I was wondfering if you did this with you PI and Bathurst shots

[cwphoto]

I was going to ask you a similar q'

When I used to do a bit of film SLR stuff on a OM2 I would focus on a spot and then pan with the subjectto that spot and hit the shutter, I was wondfering if you did this with you PI and Bathurst shots

I think it was mostly single-point AF with AI Servo.:)

[forno]

I think it was mostly single-point AF with AI Servo.:)

1 Series AF Servo though;)

[drew_viii]

It was funny...when i first started using my camera in the default set up I kept pressing the shutter half way to set focus. I would do it again (beep), again (beep), *sh#t* again (beep), again (beep), again (beep) SH#T!!! It seemed to almost focus on something different every time! Funny now that I look back!!!

should i laught at myself too? hehe im still doing the same thing... didnt know most people doing selective focusing... im kinda lazy to scroll the wheels, first, it takes time, second im still not use to it... maybe i should start doing it...

[Rhys]

A-dep failed miserably to get anything in focus when I tried it. The main subject was hopelessly out of focus.

As to points, I use centre-spot focussing and single focus. That way I can set focus and move the camera a bit without it deciding to refocus.

[Cyril7]

Thanks folks. Thought I was missing something but it seems that but for very rare occasions, the centre point is the majority choice.