7D MK II BIF Question

CyberDyneSystems wrote in post #17716332
You need to go back and read that article I posted again.

They are not the same, Zone behaves differently in many ways.

Also, Expansion predates Zone by like 20 years. It was available on film bodies before there was a 1D.

I was not saying the article said that. I read other people said that. I understand the difference between expansion and zone. I use both all the time. The article did not have zone but with the AF points moving and turning red just I just looked like the birth of zone in the next camera series. Not zone itself.

CyberDyneSystems wrote in post #17716333
I've not read that here.

With Zone, I have no control over the starting AF point. That is a HUGE difference as compared to expansion.

It was not from here.

CyberDyneSystems wrote in post #17716327
That can only happen wioth the 1D4 in CF 8-3, ie: with the 45 point expansion on.

No zones, they were introduced with 5D3 and 1Dx

Based on what that article says about the ways expansion can be used/works, the fact that that article is as "straight from the mouth of Canon" as it gets, do you not see it contradicting some aspects of how you interpreted Artie's statement in the video?

No I don't. He wrote it that way as well. Can you explain it to me.

digital paradise wrote in post #17716456
No I don't. He wrote it that way as well. Can you explain it to me.

Jake. You would not know how much I regret getting into expansion vs zone or how expansion works. All I ever wanted to know was does AF switching adjustments effect the outer points in expansion AF, not zone AF. I know it does in Zone. Obviously I missed something in that article. I'll read it again. It was written before zone AF.

No, I think I misunderstood what you were taking away from the Arthur Morris video based on some of your earlier posts. (the whole Assist vs. switching debate had me convinced you were more lost than you actually were. It certainly had me lost!)

I honestly think i got lost in this thread trying to understand what the confusion was.

Your brief, concise post above makes it much clearer.

digital paradise wrote in post #17716494
... All I ever wanted to know was does AF switching adjustments effect the outer points in expansion AF, ....

To this I can say "I don't know either"

And I just realized my own error in all this.

With the 1D series I am fully confident that the "AI Servo tracking Sensitivity" Custom function does effect the speed with which the hand off to an expansion point will take place. this setting would be most similar top the 7D2, 5D3, and 1Dx "Tracking Sensitivity"

The adjustment available on 7D2, 5D3, and 1Dx for "AF Point Auto switching" was not available on the older 1D bodies. This is where I got confused in this discussion, because I misunderstood the reference you and Arthur made, to be a reference to a setting I have been adjusting since 2002. When in fact, it is a new adjustment. With the newer bodies, Canon broke up the adjustments for AI servo from just that one setting, into 3 different aspects of the AI Servo behavior.

My old timer mind was reading "AI Servo adjustments have no effect on expansion" when in fact Arthur was saying, THIS ONE aspect of AI servo adjustment only comes into play with Zone or 61 point..

Mea Culpa.

Sorry for getting frustrated. This got more complex but oh well. I must carry on. I went through it line by line and I did not spot anything new.

With C.Fn III -8 and a manually-selected AF point, A manually-selected AF point, AF can be expanded by using the AF points adjacent to the selected AF point.

My camera does this.

If the manually-selected AF point cannot achieve focus, focus can be achieved with one of the adjacent (expanded) AF points.

Yes. Bang on.

These settings can be effective for shooting a moving subject that is difficult to track with just one AF point.

Yes. Bang on again.

The [1: Left/right AF point] and [2:Surrounding AF points] options are the same as the EOS-1D Mark III.

I guess so. I did not have either.

It effectively allows the photographer to manually select the starting point for focus detection while gaining the ability to track the subject anywhere it moves within the 45-point Area AF ellipse indicated on the focusing screen.

My camera does not do this in expansion. It does have a centre point and 4 or 8 assist point clusters. I can move those 2 clusters anywhere I want to for my starting point. When tracking the system will try to maintain AF within a cluster. If I can’t keep up there aren’t 45 points to track it. I just lose it.

By comparison, when automatic focusing point selection is combined with AI Servo AF, the subject must be initially detected with the center AF point.)

Yes.

Moreover, C.Fn III-8-3 allows the camera to display the active focusing point in the viewfinder as it follows the subject during a burst shooting sequence.

My camera does not do this. I can only ever see the centre point and the outer points but they aren't doing anything visibly but they are working. They all flash simultaneously when the VF illumination is on.

Here’s how it works: When C.Fn III-8-3 is combined with AI Servo AF, up to 18 AF points adjacent to the manually-selected AF point will become active.

Mine does not have 18 but the 4 or 8 are doing it. I still can’t see them can’t see them doing anything but Canon says they are and I believe it.

Each time the subject moves to another AF point, the expanded AF points will also shift to surround the AF point covering the subject.

My camera definitely does not do this. They do not shift to surround the AF point covering the subject. There is only one layer of 8 active points surrounding the centre point so it is impossible.

In response to the subject's movement, the AF point lit in red also shifts continuously.

Not on mine.

Since the clump of active focusing points can shift automatically according to subject movement, all 45 focusing points are effectively available for burst mode shooting. As long as the subject is within the Area AF frame, autofocusing of the subject will continue.

Mine can’t shift automatically.

This is the same logic as with automatic AF point selection. However, since the focusing is concentrated over a smaller area than during automatic AF point selection, focusing a particular subject is easier.

Yes. Focusing is definitely over smaller area.

Also, if the main AF point loses the subject by a considerable amount during automatic AF point selection, all 45 AF points are used to search for the subject.

Not on mine but the 4 or 8 that surrounding the centre point do.

With C.Fn III-8-3, the 18 expanded AF points are instead used to search for the subject. For example, even if there is an object closer than the main subject, the camera can still quickly and securely track the main subject.

According to Canon in expansion the centre point is primary and they instruct to put it on the subject to start focusing which I do.

If One-Shot AF is set and focus cannot be achieved with the manually-selected AF point, focus is executed with an expanded area of up to 44 AF points.

Yes but only up to 8.

Subject detection is done in three instant steps, with 6, 18, then 44 AF points. Because the manually-selected AF point is where the subject is supposed to be, focusing is easier with the AF points closer to the main AF point.

I only have 4 or 8

Better yet, DPP 3.7.3 and higher can display the active focusing point for each image when C.Fn III-8-3 is used together with manual focusing point selection, even when the active focusing point differs from the manually selected focusing point. C.Fn III-8-1, III-8-2, or III-8-3 must be on for C.Fn III-4 [AI Servo AF tracking method] to become fully effective.

In one shot you can see the centre and "only" one other assist point. In AI Servo all you ever see is the centre point. Canon says it works exactly the same in AI Servo as it does in One Shot

The exception occurs when using Automatic Focusing Point Selection, in which case both settings for C.Fn III-4 are effective.

My camera does not have that

Regardless of which C.Fn III-4 setting is used, the C.Fn III-2 setting [AI Servo tracking sensitivity] generally takes priority. However, if a subject blocks the main subject when the C.Fn III-4 setting is 0, the camera refocuses on the new subject regardless of the C.Fn III-2 setting.

Yes. You can control that with parameter settings on the 7D2 and 5D3

CyberDyneSystems wrote in post #17716521
To this I can say "I don't know either"

That was why I said maybe AF switching does effect expansion speeds but because the area so small you would not see a significant difference so Art said don't bother. That is for smaller erratic objects. Larger slower targets where is it easier to track so faster speeds won't make a difference anyway. Or he knows something we don't and Canon just forgot to expand (haha) on it.

I still see keeping them at a fixed rate whether you are 0, 1 or 2 not completely off the wall. If they are not going to benefit much why use up resources? You defiantly benefit controlling switching speeds in zone.

I'd like to know why he said that.

Jake. So many things get lost over conversation so I have to tell you where this started. I can't finish it this way. Reading about the AF system Canon explains that Cases 5 and 6 are for erratic movement. That to me is smaller and faster than average steady targets that will switch directions quickly and go the outer areas of the viewfinder.

The instructions say single point is disabled but we know it will work, just not be very effective because most people will never keep up with one point. So that got me thinking. How much more helpful will a slightly larger AF area be to me. Not much because the expansion groupings are not that big.

digital paradise wrote in post #17713830
He pushes everything to the max I'l have to check it out as well. I don't use case either 3 so I'll try that out too. I can flip back and forth between it and case 2 and compare.

Well if anything it confirmed my suspicions that AF switching has nothing to do with the assist points in expansion. It was never a big deal but I was searching for an answer for a long time.

AF point auto switching operates in all modes except Single Point or Spot AF.

Joe52 wrote in post #17717031
AF point auto switching operates in all modes except Single Point or Spot AF.

I know it operates. I'm not sure how many times I have to say this. I must so hard to understand I'm surprised I can order a cup of coffer through the drive thru.

When you adjust AF from 0 to 1 or 2 do they assist faster in expanded? I use the term assist because that is what Canon refers to them in every document. I know they do in zone. If so can you prove it and why did Art Morris say adjusting AF switching didn't effect their switching rate?

I know I’m not the smartest person around and I can live with that. I just don’t people to think I’m completely inept stupid so I will make one more attempt to explain what I meant b switching and assisting.

There are two things Canon says about expansion

- The centre point is the primary and has to be on the subject

- In expansion AI Servo works the same way as One Shot.

In one shot, if an assist point is activated it illuminates first followed by the centre point. The centre point indicated it was the preferred AF point. Yes the assist point switched on to help but the centre point never switched off. There may a percentage or a complete contrast loss but the centre point was always active. There is always only one active assist point, no more. This makes more sense in AI Servo.

AI Servo works the same way according to Canon. Canon says that clearly. The primary point must be on the target. If the system cannot use the centre point one assist point which the system determines to be the best candidate to help switches on to assist until the centre point can require AF again. The centre points mission is still to be the primary point. So while the assist point switched on to help the centre point did not switch off. The two never switch on and off between each other. The centre point never stops working to be the primary AF point. When the centre point is good to go again the outer point switches off.

I’m going to use 65 point for my zone example. The target is on the right side of the viewfinder and the AF points are flickering off and on keeping it focus. Then the object takes off to the left so the AF points to the left switch on to track the bird and the ones on the right switch off because there is nothing to focus on.

There isn’t a point or a group points on the right trying to reacquire the object they lost. They are done. They remain idle until something shows up again. This to me is what Canon means by switching. One point turns on and another turns off. They switch on and off between each other.

If I’m wrong then that is fine. If people think that the assist points in expansion are flickering on that is OK. It is possible more than one assist point activates but that is not what Canon says and I'm OK with that. We can’t see it to confirm it anyway. Either way I still think the primary is the centre point and the system will always try to use it first and maintain focus using it. When on single point you have a choice of 65 points for precision focus. Assist points just that centre point maintain focus. That is why Canon says expansion is superior to zone because the focus point is precise, not random like zone.

It still doesn’t matter to me because I have to keep the expansion cluster on the object at all times. My query has always been focused specifically on the instructions regarding expansion in cases 5 and 6 "only" which are pre set at the factory for erratic movement. I know that if I'm using expansion on a swift and I set AF switching form 0 to 2 it will not slow the bird down or inject adrenalin in may arms so I can react faster. Once that bird takes off in another direction I will lose it.

This is how I thought my camera worked since getting it last fall. I hope at least one person understands what I’m trying to say and I don't care if I'm wrong because it does not matter on such a small cluster of points.

Just found this AF guide, perfect! Thanks!

javapop wrote in post #17717413
Just found this AF guide, perfect! Thanks!

It is a a very helpful document. After you are done answer my original question for me.

When in expansion and you set AF switching from 0 to 1 or 2 do they assist faster (every Canon document calls them assist points) and even if they do what are they going to do for me in Cases 5 or 6 when I'm trying to track a small fast erratic object.

Art Morris says nothing and I agree. Thanks in advance.

I do not own any of the cameras with this type of AF system. However given the language used through these posts this is my take on the "Asist" points. Firstly I would expect that the primary point, and the assist points will all be actively "powered up" If the primary point is able to achieve a focus lock at some distance it will do so, and in the case of Servo, maintain that lock as the system updated. If the primary point is initially unable to achieve a lock, or during Servo it loses lock the AF system will look at the output from the assist points, and using some algorithm based on the number of assist points producing a lockable signal use one of those to either grab lock, or maintain lock in Servo. Of course in servo part of the algorithm will be looking to ensure that any assist point used will produce a result that is close to the same, or the appropriate predicted, distance as the primary point was/should be at. In the case of Servo I would expect the system to always look first at the primary point, and then resort to the assist points for each update in the servo process.

I would also expect that if there were a sudden jump in focus distance, that was rejected by the tracking sensitivity setting, the one regarding the subject passing behind/in front of another object, that it may also then resort to looking at the assist points before just sitting and waiting.

In the case of zone tracking, which from the description is much like using the all points tracking in AIServo in my 50D, but with a choosable primary point, rather than just the center point I get. The AF system will first have to get a lock on the subject using the primary point, then if the system loses lock on the primary point, it will look for an appropriate new point to take over the tracking. The system will continue to track with this point, and if it again loses lock it will repeat the search for a new tacking point, just as it did when it initially lost track using the initial primary point. The tracking may end up back on the initial primary point at some time, if the subject tracks back over it. The only way to ensure that the AF will go back to the initial primary point is to stop the AF system, and start tracking all over again.

This is my perspective as an engineer reading the provided information on these systems. Now I haven't read up on any of the case settings etc for these cameras, as I do not own one, and the likelyhood of me acquiring one is quite low. I gather that these case settings are used to fine tune the algorithms that are used to control which assist points are used, or how the system determines which point to switch to in the case of zone focus. I hope this may be of some help.

Alan