7D 19 point autofocus - what's the point?

[MarkChap]

Don't forget that the actual area of the sensor used for auto focus is NOT limited to that tiny red square that is on the screen, it's actually quite a bit larger, the camera will always focus on anything closest to the camera
In your first image I am actually inclined to believe that you have some amount of camera shake, that has blurred the image, hence why nothing looks in focus.
The exif data has been stripped from the images, what are the tech specs on the shot, and what tripod is the camera attached to ?

The camera can obviously focus, at least to a point, you say so your self, in single point AF, you seem to be happy.

I own and LOVE my 7D, do I ever use "auto select", as in let the camera select my focus point, not on your nelly, I can not think of 1 single time where it would be prudent, beneficial, practical or acceptable to allow my camera to choose a focus point.
In fact, in the custom functions, I had turned of the option to use 19 point auto select, just not going to happen. For this reason I cannot say if mine does have a problem with focus when using that feature or not.
IF I had time, which I won't have for at the least the next week, I would give it a try just to check.

So whilst owning and operating a 7D for a bit over 12 months and some 10 000 frames, I can honestly say, any out of focus images have been down to me and me alone.

[Art Vandelay]

Some good points already made.

As a side note, they look way more than 50% crops.
And the first set looks suspiciously like a bit of motion blur.

[pmack]

pmack, either the camera focussed or it didn't.
If, as you have said nothing is in focus then the camera failed to achieve focus.
You have said that the camera focussed "somewhere between the trees in the foreground (10 meters away), and the hill which is 500 meters away" so therefore something must be in focus.

oh dear... are we arguing semantics now?
The elements inside the lens must have been in a position that corresponded to a focal point of somewhere between 10-500meters. I can estimate this by observing the bokeh of the foreground, and the background. yes there is probably a bit of dust that is in focus, but no you cannot see this spec of dust...

How many attempts did you have at allowing the camera to achieve focus based on the camera body's guesstimation of a focus point?
How many attempts did you have at allowing the camera to accurately focus when you selected the point to focus on?

for each instance, i took about 5 photos, and results were consistant with the examples posted.

No, the lens does not select a focus point, the camera body is wholly and solely responsible for determining focus ( autofocus ) from the information about light, contrast and colour that is transmitted through the lens.

well you're just arguing semantics again which is hardly usefull.
when i said the camera tells the lens to select a point, i was simply meaning a position that corresponds to a point, or more accurately, a 2 dimensional plane of focus.

As a final comment on this issue, I urge you to set up a definitive and technical focus test under controlled conditions with repeated examples and then determine the outcome for your self, either that or send the camera to Canon for testing and repair / rectification so that it falls within their specified tolerance.
Of course, the repair / rectification will either be free if outside of tolerances and the camera is under a local warranty or you will have to expect to pay for adjustments if the camera is out of warranty period or is a grey imported body.

I did do my test under controlled conditions, and do have multiple examples. There's just no point in posting them all as I didn't think i needed to prove this to anyone, i came here for help, not for people to tell me that "it looks like it has focused a bit here". I'm no idiot, i've done all this testing to be assured the results are repeatable. And yep I do plan on sending my camera to canon anyway, even just for piece of mind. If they say it's fine, they will probably say something like "when trying to focus close to infinity, it is best to have only one or several focus points active as the camera gets confused in this situation"
In which case, i'm fine with that, it should just be published in the manual, or known as a common fact if it is also the case with other cameras.

[pmack]

<>

hey mark,
yes i know the actual area used for the focus is larger than the squares show, that shouldn't have affected the results though.
Here's a shot where it has misfocused to the front (i pressume) again. Nothing could have been close to the squares:


(it actually doesn't look too bad reduced for web, particularly down the bottom, but trust me it's not in focus)

I took this same shot with single point and it of course had no problems.

I can assure you that this is nothing to do with camera shake, i have done this multiple times and it only misses focus when i have it on auto select.

As i have already stated, I do usually only use a single point, but i'll give you an example of where you might want to have all of your focus points active. Just say you're trying to get a close up shot (with a wide angle) of a dog running around. he's constantly moving so you can't easily frame and predict where you want the focus point to be in the frame, however as you know you want the the closest part (i.e the dog) to be in focus, you put it in auto select, and bobs your uncle. ANd i just thought of this one now, so not sure if it is valid as i've not tried it, but another example would be where you are tracking a moving object that fills almost the entire frame, any points that fall off the subject will be the background, hence it should only ever use the focus points on your subject. This should give you much better tracking ability, in theory. however my testing proves that auto select is useless, at least for subjects close to infinity

[Max]

I think main the point of the 19 point system is to keep the closest subject in focus, particular when using it to track multiple moving objects in servo mode. Think a number of runners close together or cyclists in a bunch.

oops, I think you said all this while I was typing, beat me to it.

[pmack]

Some good points already made.

As a side note, they look way more than 50% crops.
And the first set looks suspiciously like a bit of motion blur.

nope they are 50, this is what a 100% crop of pic 1 looks like:


and as i said, definitely not motion blur, unless autoselect generates it's own internal vibrations...

[kiwi]

I always chuckle with these sort of focus tests where people use just ridiculous subjects such as this with so many different contrast points and items in different focal planes in the same rough focus zone, and miles away to boot!!! If you want to have a credible whine about the camera do some credible tests

[pmack]

I think main the point of the 19 point system is to keep the closest subject in focus, particular when using it to track multiple moving objects in servo mode. Think a number of runners close together or cyclists in a bunch.

oops, I think you said all this while I was typing, beat me to it.

exactly, see in theory, it has it's uses. it's only useless because it doesn't work as it should. (as least in my case)
It's a cop out to just say "select your own point, give up on 19 point auto select". the question is why doesn't the camera behave as you would expect it to.
people are so afraid to use Auto select, because that's the setting that "newbies" and amateurs use.
People need to get off their high horses once in a while and stop worrying about others judging them.
If you need to take a photo in a split second, and your camera is not ready, and all the settings are inappropriately set up for that night shoot you did last night, put it in "green" or P mode and snap that photo. You will not lose your soul if you commit this mortal sin.
Too much misguided elitism. what was that article on smh the other day about narcissism....

[MarkChap]

Tech Specs ??
Camera - 7D
Shutter Speed
ISO ?
Lens ?
Aperture ?
Exposure Mode ? (Av, Tv, M, Auto)
Tripod ?

Just asking ?

[Max]

I gather you took these with single shot focus?

[pmack]

I always chuckle with these sort of focus tests where people use just ridiculous subjects such as this with so many different contrast points and items in different focal planes in the same rough focus zone, and miles away to boot!!! If you want to have a credible whine about the camera do some credible tests

Glad you got a chuckle.

It's nice to know that if I print out a focus test chart, and in lab conditions, I can get my camera to focus properly on a test peice.

Now it's a pitty that in the real world, there is very little market for images of focus charts.
Heaven forbid a camera has to take an image as dramatic as this:

[pmack]

Tech Specs ??
Camera - 7D
Shutter Speed
ISO ?
Lens ?
Aperture ?
Exposure Mode ? (Av, Tv, M, Auto)
Tripod ?

Just asking ?

sorry i thought i left exif data on the images, must have selected save for web.

details of images 1 and 2 are:
f/4
1/800s
ISO200
24-105L (@105mm)
shot in Av
tripod, with shutter release
single shot, but shutter release carefully half depressed to ensure a focus lock.

[MarkChap]

exactly, see in theory, it has it's uses. it's only useless because it doesn't work as it should. (as least in my case)
It's a cop out to just say "select your own point, give up on 19 point auto select". the question is why doesn't the camera behave as you would expect it to.
people are so afraid to use Auto select, because that's the setting that "newbies" and amateurs use.
People need to get off their high horses once in a while and stop worrying about others judging them.
If you need to take a photo in a split second, and your camera is not ready, and all the settings are inappropriately set up for that night shoot you did last night, put it in "green" or P mode and snap that photo. You will not lose your soul if you commit this mortal sin.
Too much misguided elitism. what was that article on smh the other day about narcissism....

How can choosing, what I, am going to focus on be classed at "elitist"
And for the record, I don't believe I judged anybody for what settings they choose, I simply stated what I use and the reason I couldn't either confirm or deny if my 7D exhibited any thing similar.

Seriuosly, if you are convinced there is an issue with the AF system on your camera, pack it up and send it to Canon.

[zolaxi]

In the many years I've had a Canon 1D/5D type of camera, I've never used 19 point (and in the case of the 5D, 9 point) auto focus.

I can't see why anyone would want to?

And it's not a question of "why doesn't the camera behave as you would expect it to", but rather coming to an understanding of the functions of the camera. It's behaving quite normally. It can't read your mind.

[pmack]

How can choosing, what I, am going to focus on be classed at "elitist"
And for the record, I don't believe I judged anybody for what settings they choose, I simply stated what I use and the reason I couldn't either confirm or deny if my 7D exhibited any thing similar.

Seriuosly, if you are convinced there is an issue with the AF system on your camera, pack it up and send it to Canon.

I wasn't reffering to you or anyone specifically, just the general responses, and the general "fear" people seem have of the 19 point Auto Select.
(but in my testing, founded fear... go figure)
Oh and of course I'm not saying that choosing your own focus point is elitist. That's just common practice, i'm only referring to people who say you should NEVER use 19 point auto select. As long as it actually worked properly, there are definitely examples of where it would be the preferred setting.

[pmack]

In the many years I've had a Canon 1D/5D type of camera, I've never used 19 point (and in the case of the 5D, 9 point) auto focus.

I can't see why anyone would want to?

And it's not a question of "why doesn't the camera behave as you would expect it to", but rather coming to an understanding of the functions of the camera. It's behaving quite normally. It can't read your mind.

please see below:

I do usually only use a single point, but i'll give you an example of where you might want to have all of your focus points active. Just say you're trying to get a close up shot (with a wide angle) of a dog running around. he's constantly moving so you can't easily frame and predict where you want the focus point to be in the frame, however as you know you want the the closest part (i.e the dog) to be in focus, you put it in auto select, and bobs your uncle. ANd i just thought of this one now, so not sure if it is valid as i've not tried it, but another example would be where you are tracking a moving object that fills almost the entire frame, any points that fall off the subject will be the background, hence it should only ever use the focus points on your subject. This should give you much better tracking ability, in theory. however my testing proves that auto select is useless, at least for subjects close to infinity

I think main the point of the 19 point system is to keep the closest subject in focus, particular when using it to track multiple moving objects in servo mode. Think a number of runners close together or cyclists in a bunch.

oops, I think you said all this while I was typing, beat me to it.

exactly, see in theory, it has it's uses. it's only useless because it doesn't work as it should. (as least in my case)
It's a cop out to just say "select your own point, give up on 19 point auto select". the question is why doesn't the camera behave as you would expect it to.
people are so afraid to use Auto select, because that's the setting that "newbies" and amateurs use.
People need to get off their high horses once in a while and stop worrying about others judging them.
If you need to take a photo in a split second, and your camera is not ready, and all the settings are inappropriately set up for that night shoot you did last night, put it in "green" or P mode and snap that photo. You will not lose your soul if you commit this mortal sin.
Too much misguided elitism. what was that article on smh the other day about narcissism....

[pmack]

And it's not a question of "why doesn't the camera behave as you would expect it to", but rather coming to an understanding of the functions of the camera. It's behaving quite normally. It can't read your mind.

You have got to be kidding me. Clearly you're not paying attention to this topic.
The camera should not have to read the operators mind to focus in the image i've shown.
I don't care which square it chooses to select to focus on in this case.
It claims that it made focus on about 7 focus points, but in reality, the entire image is out of focus as it has focused on a plane in front of the photographed scene.
how hard is this to understand? If you honestly think that should be normal operation... i really don't know what to say then.

this is honestly the most frustrating topic i've even made on any forum, gah.

[MarkChap]

That would be as Darren replied, I think your testing methodology is flawed.

But that is just my humble opinion

[pmack]

That would be as Darren replied, I think your testing methodology is flawed.

but the only thing my testing was trying to test, was the ability to focus on a generic scene at great distance, whilst in 19 point Auto select mode.
and it failed that test.
which tells me that either 7D's cannot focus well in that situation, meaning you need to ensure a only a single focus point is used, OR, there is an issue with my camera.
Only way for me to know would be for someone to do a simillar test to mine, or i send it off to canon.

[zolaxi]

Hey, if the 19 point auto focus works for you, keep using it. Maybe I have a closed mind on this topic (I admit!) and should explore it further.

But in the the case of a pooch/cyclist/runner and even BIF, I always use single point focus. In the case of a cyclist, I don't want the camera deciding to focus on say the front wheel. So I use a single focus point aimed at the body or preferably head/face area.

For things like birds, if the eye/head is not in focus, the shot is not in focus to my way of thinking. So I aim there with a single focus point.

As for talk of "misguided elitism", how ridiculous. It's about applying your photographic technique and getting effective results from your camera, not what you do.

If the 19 point auto focus works for you? Hallelujah, and keep using it!! I won't be.