p.67 #1 · ['NEW Fix' UPDATE!] - MkIII AF still broken
Sure, In AI-SERVO you can't really MF a lens (that is FTM) as it will constantly readjust (unless you have a dedicated focus button which many don't like including myself). So there you need to flip over to MF or ONE-SHOT to override the focus.
For me, every time that shutter snaps i want the latest, best, most accurate focus (unless i choose to manually override). AI-SERVEO tracks the AF point which i manually choose for EVERY shot. the 1D models can (or could) handle this. it has two processors to track the focus.
20/30D... not so much.
that said, i can see using "one shot" or "whatever shot" to get a 1DmkIII to focus like a 1DmkII if needed -- whatever it takes.
But AI SERVO should be the best choice for almost everything except tripod photography of still objects. If anyone has some reference reading to educate me further i'm all game.
Colin Key wrote:
I do not understand this statement - can you explain?
Nor do I understand the various other references to the fact that "anything moving should be shot in AI Servo" - e.g. dance shots.
The Artificial Intelligence focusing system is intended to predict where a subject, which is moving towards or away from you, will be when you press the shutter button. The excellent Swan shots by Necip are a good example of where AI Servo is useful, if not necessary.
Most BIF shots have the subject moving across the frame at more or less constant range. When this is the case I shoot in One Shot mode. Why people shoot static subjects in AI Servo just defeats me; they are asking the camera to do something which is not required and can be counter-productive.
p.67 #2 · ['NEW Fix' UPDATE!] - MkIII AF still broken
stan_g wrote:
I even "borrowed" my old 1d2 for two days and tested extensively and compared. That proved to me that what I suspected was true for me. I could mash focus a fleeting subject with the mk2 and it would either not take the picture at all, or take it with a high probability of my subject being in focus.
FYI - as most reading are probably aware, this is a personal function (to allow shutter release before AF is locked or not) on both cameras.
p.67 #3 · ['NEW Fix' UPDATE!] - MkIII AF still broken
Glen_C wrote:
AI-SERVO tracks the AF point which i manually choose for EVERY shot. the 1D models can (or could) handle this. it has two processors to track the focus.
Glen,
I have a different impression of the facts you state above.
1. There are two processors, but only one is dedicated to focus. The other handles "the rest" of the camera stuff. The xxD and xxxD series pack all the functions into a single processor, which is why they have lower performance focus systems.
2. AI Servo does not (strictly speaking) "track" the subject to keep it in focus. It is attempting (via software) to predict where the focus point will be in real time based on historical information. Thats why you hear users saying they need to "lock on" for a couple seconds before firing off a burst.
In fact, the manual states:
If the subject approaches or retreats from the camera at a constant rate, the
camera tracks the subject and predicts the focusing distance immediately before the picture is taken. This is for obtaining correct focus at the moment of exposure.
So there is an internal assumption of "constant rate" by the focusing mechanism, and the actual focus distance is a guess (prediction).
That could actually explain my less than stellar results. I'm shooting my dog in short runs (30-40 feet max), its doubtful she maintains anything close to a constant speed. Time to take her to the park for some longer runs.
p.67 #4 · ['NEW Fix' UPDATE!] - MkIII AF still broken
Glen_C wrote:
But AI SERVO should be the best choice for almost everything except tripod photography of still objects. If anyone has some reference reading to educate me further i'm all game.
Glen,
Thanks for your reply. I responded to your earlier post because I thought (and could be mistaken) that you were dismissing "One Shot Mode" on a 1D series camera.
There is a HUGE misconception that if the subject is moving, you should be in AI Servo mode -- simply not the case for reasons I stated above. And, I cannot agree with your quote above either: AI Servo is NOT the best choice for almost everything except tripod photography of static subjects.
AI Servo has a job to do (calculate focal distance for a subject moving towards or away from you in a predictive way) and if it is not needed (a static subject, or one moving but at a constant distance from the camera) it will still sometimes (not always) come into play and, finding itself "redundant" cause some focus problems. I have proven experience of this with the Mk III.
p.67 #5 · ['NEW Fix' UPDATE!] - MkIII AF still broken
Hi, i totally can NOT speak for the III
but if i purchased one and AI-SERVO (ie. continual focus) did not seriously outperform "One shot mode" routinely on moving objects i'd probably return the camera very shortly.
One-Shot AF: This mode is intended for use with stationary subjects. It locks focus upon completion of lens drive, allowing the photographer to recompose if desired. One-Shot AF is also recommended for maximum performance in extreme low-light situations.
AI Servo AF: This mode is intended for use with moving subjects. It operates continuously up to the instant of exposure, and it also operates between exposures in burst mode shooting. In AI Servo AF, you can tell whether the AF system is tracking the subject by observing the focus indicator in the viewfinder below the picture area. If the focus indicator does not light, the system is tracking. If it is blinking rapidly, the system is not tracking.
p.67 #6 · ['NEW Fix' UPDATE!] - MkIII AF still broken
mbellot wrote:
That could actually explain my less than stellar results. I'm shooting my dog in short runs (30-40 feet max), its doubtful she maintains anything close to a constant speed. Time to take her to the park for some longer runs.
Well, this was a helpful thread.
Instead of the dog I had my two four year old daughters start at the back of the yard and run towards me.
The lighting was bad (I was at ISO1600), so judging actual sharpness is iffy at best. But there is no doubt in my mind that the camera tracked accurately. Viewed at 50% magnification (to blend away some of the noise) with just a tad of sharpening (in Bibble) puts the focus dead on where it should have been.
The only time the camera lost it was when one of them came closer than MFD on my 70-200.
p.67 #7 · ['NEW Fix' UPDATE!] - MkIII AF still broken
Photon:
Thanks. I was hoping I was unaware of a function that could help but alas, not. Thanks for responding anyway. I can see setting C.Fn IV-13, set to 1 if using AI-SERVO thereby increasing the speed of starting a sequence even before focus lock but in oneshot that would be silly. I have re-thought everything again, and tried most options over again and now I'm not sure of some.
also:
for me, in one shot with side expansion assist, I have often been glad I had the assist on because it shows in the viewfinder (especially if using center spot AF) if AF is using the feature because both the center spot and the assist spot light on lock. Then I can decide if both are in the same plane and shoot, or if not in the same plane, re focusing, all quite quickly.
Glen:
Although, re-thinking a couple comments has made me more sure of how they work for me. I seldom use servo when:
1) shooting subjects in the distance through a very cluttered foreground ie. through trees, through fences, through windows with reflections, the reflections themselves, etc. and I need to be able to determine with confidence what the AF has chosen.
2) When I'm moving by a subject with a complex backgrouond and to the camera everything is moving at a similar speed.
3) the scene is of low contrast for subject, foreground, and background.
4) very dim lighting when the subject is also dim AND bright background spots near the subject ie. into shadows with nearby lights in the distance.
5) erratically moving subjects, ie. basketball, soccer.
6)I can go on. I just don't often shoot subjects that servo is useful. I do once in awhile realize too late that servo may have been better. alas.
p.67 #8 · ['NEW Fix' UPDATE!] - MkIII AF still broken
stan_g wrote:
for me, in one shot with side expansion assist, I have often been glad I had the assist on because it shows in the viewfinder (especially if using center spot AF) if AF is using the feature because both the center spot and the assist spot light on lock. Then I can decide if both are in the same plane and shoot, or if not in the same plane, re focusing, all quite quickly.
If that's the case you may need to check if your Mark III's center AF sensor works properply....otherwise i see no reason for using the expansion AF points at one shot mode, unless your subject is relatively quite big and you want more coverage with the AF points,,,,
p.67 #9 · ['NEW Fix' UPDATE!] - MkIII AF still broken
Glen_C wrote:
Hi, i totally can NOT speak for the III
but if i purchased one and AI-SERVO (ie. continual focus) did not seriously outperform "One shot mode" routinely on moving objects i'd probably return the camera very shortly.
Glen, that article was first published in June 1992 - things have moved on a bit since then!! I could not access the other link.
I will stand my ground and maintain that AI Servo only provides any useful purpose when the distance between camera and subject is changing (i.e. the subject is moving towards or away from you), and to state that it is useful "on all moving subjects" is incorrect. If the distance between subject and camera sensor is constant (e.g. a jet plane flying across/perpendicular to your direction of shooting) then AI Servo serves no useful purpose and can in fact deteriorate the image quality and focus accuracy by making the camera attempt to do something it does not need to do, and results in "hunting" AF.
p.67 #10 · ['NEW Fix' UPDATE!] - MkIII AF still broken
how about 99% of moving subjects? ::
the PDF is the eos-digital 1D white paper most here already have. sure things have changed, including the improvements in constant focus ability. i think some people get hung up on the term "AI" and also the lesser models "ai focus" mode which is like auto-pilot where the system jumps between constant focus and one shot.
maybe we're just talking semantics. How can the "distance" not change when the photographer is standing still unless you're at infinity focus? These same principles apply as to why to never focus & recompose (if you want dead-on focus).
now if someone's technique adapts to the one-shot, or if one-shot obtains intial focus faster in some cases that is a different story but wit 8-10fps i also don't think that can improve photos (1 good photo then 9 followups OOF).
p.67 #11 · ['NEW Fix' UPDATE!] - MkIII AF still broken
Colin Key wrote:
Glen, that article was first published in June 1992 - things have moved on a bit since then!! I could not access the other link.
I will stand my ground and maintain that AI Servo only provides any useful purpose when the distance between camera and subject is changing (i.e. the subject is moving towards or away from you), and to state that it is useful "on all moving subjects" is incorrect. If the distance between subject and camera sensor is constant (e.g. a jet plane flying across/perpendicular to your direction of shooting) then AI Servo serves no useful purpose and can in fact deteriorate the image quality and focus accuracy by making the camera attempt to do something it does not need to do, and results in "hunting" AF.
By definition, isn't a plane flying "perpendicular" (I assume you mean something like from your right to your left) to the photographer changing the distance between the camera and plane? As it approaches from the right, it's relatively farther away, gets closest at some point, then moves farther away as it flies off to the left. I've experienced this when trying to shoot swimming ducks with a 400/5.6 where the DOF is very narrow. If I'm relatively close and not using Servo, the duck's movement will take it slighly out of focus.
p.67 #12 · ['NEW Fix' UPDATE!] - MkIII AF still broken
theoretically, the only two conditions that one-shot AF should work are:
1. subject is relatively still, within the DOF
2. subject is spherically moving around me, within the DOF, at a relatively constant (ego-centric) distance to me
otherwise ai-servo should be used if something is moving outside of the DOF. because from my perspective, it is moving toward/away from me. even if it's moving left, right, up or down.
p.67 #13 · ['NEW Fix' UPDATE!] - MkIII AF still broken
Paul B wrote:
By definition, isn't a plane flying "perpendicular" (I assume you mean something like from your right to your left) to the photographer changing the distance between the camera and plane? As it approaches from the right, it's relatively farther away, gets closest at some point, then moves farther away as it flies off to the left. I've experienced this when trying to shoot swimming ducks with a 400/5.6 where the DOF is very narrow. If I'm relatively close and not using Servo, the duck's movement will take it slighly out of focus.
Yes (and no); if you were shooting something like the Red Arrows display team at a distance of, say, 300-500 metres, you would not (or I would not!!) keep the button pressed for more than a few seconds. Within that time the change in range between the subject (a group of small jet planes) and yourself will be relatively small and with even a moderate DOF (i.e. not shooting at maximum aperture) the focus distance would be catered for.
I take the point that "cross flying" subjects are not attached to a piece of string of constant length, but my experience is that such subjects (which are not moving significantly further towards or away from you) can be captured better in One Shot than AI Servo mode.
There seems to me to be a mental block amongst many people that "anything moving" requires AI Servo - this is just not the case.
Take, for example a wind kite on a fixed line moving quickly and erratically in a strong wind - would you use One Shot or AI Servo to photograph it?
p.67 #15 · ['NEW Fix' UPDATE!] - MkIII AF still broken
Yakim Peled wrote:
Well, I confess I have that mental block as well. Regretfully, it works in the field…..
Happy shooting,
Yakim.
But, for subjects which are not moving significantly towards or away from you, how do you know that employing AI Servo is giving better results over One Shot mode?
p.67 #16 · ['NEW Fix' UPDATE!] - MkIII AF still broken
I don't as I never tried it.
My motto is very simple: Moving objects = AI servo. Static objects = One shot. It works so well that I never looked at a picture and said: "It's not my fault that the picture turned out bad, it's the camera's fault".
p.67 #17 · ['NEW Fix' UPDATE!] - MkIII AF still broken
1D Mk III Manual, page 83:
"AI Servo AF for Moving Subjects"
"This AF mode is for moving subjects when the focusing distance keeps changing. While you hold down the shutter button halfway, the subject will be focused continuously."
If you are using AI Servo in any other circumstances you are not only wasting your time but you are degrading your images. Full stop (pun intended).
p.67 #18 · ['NEW Fix' UPDATE!] - MkIII AF still broken
Colin Key wrote:
1D Mk III Manual, page 83:
"AI Servo AF for Moving Subjects"
"This AF mode is for moving subjects when the focusing distance keeps changing. While you hold down the shutter button halfway, the subject will be focused continuously."
If you are using AI Servo in any other circumstances you are not only wasting your time but you are degrading your images. Full stop (pun intended).
Colin
Your 1st statement is quite true. AI Servo is designed for where the distance from camera to subject is continually changing. Obvious.
I disagree with the statement that AI-Servo in other circumstances is degrading your images. That is simply taking the manual too literally. I have done multiple studio shoots with a static model in AI-Servo mode and the results have been no different had I had used One Shot AF mode. Indeed, I printed some of those shots today at A1 and they are perfectly in focus. Sure, your statement applies to xD and X0D bodies where AI-Servo mode (in my experience) has difficulty in maintaining focus on a static object but with a 1D series, in my experience, no problem.
p.67 #19 · ['NEW Fix' UPDATE!] - MkIII AF still broken
Colin Key wrote:
1D Mk III Manual, page 83:
"AI Servo AF for Moving Subjects"
"This AF mode is for moving subjects when the focusing distance keeps changing. While you hold down the shutter button halfway, the subject will be focused continuously."
If you are using AI Servo in any other circumstances you are not only wasting your time but you are degrading your images. Full stop (pun intended).
Colin
________________________________________________________________
Hey Colin in Portugal,
Maybe that's why all of us are/were having tracking problems with the 1d Mark III.
Though from reading any of the Canon manuals I have-(page 83 of 1d Mark III manual, page 66 of 1ds Mark II manual, page 77 of 40d manual, page 65 of 20d manual), I ALWAYS thought that when I am at the beach taking surfpix I should only use ONE SHOT Auto Focus for Still shots, like non-moving seaweed washed up on the beach, as per the same/previous pages in the above said manuals, while AI Servo was the best suited for moving action, such as surfers and BIF, etc...
I gotta tell you though, after getting my early model 1d Mark III-( bought June 2007 # 5253**) fixed again by Canon Irvine last week-(S/M fixed Dec. 2007, with 2 dots in battery compartment and 2 trips to Irvine in the last 3 weeks-the last to calibrate and mate my lens+tc's)-I am getting the MOST in-focus sequences of guys and gals surfing that I EVER had with my Mark III+600mm +/- my 1.4/2.0 tc. , ESPECIALLY AFTER I change my TRACKING preferences from CF 3-0 to CF3-1, from CF 4-1 to 0, and CF 8-1/2 to 0.
Sequence after sequence, I am getting the best in-focus shots I've ever gotten with the Mark III while shooting surfpix here in Los Angeles...
Maybe some day I'll try shooting surfpix in One Shot focus mode,
if the surf sucks!
Late, Randy Wright
LAsurfpix.com
p.67 #20 · ['NEW Fix' UPDATE!] - MkIII AF still broken
Colin Key wrote:
But, for subjects which are not moving significantly towards or away from you, how do you know that employing AI Servo is giving better results over One Shot mode?
Colin
But at least with the 1D II say, assigning the AF to the * button and using AI servo, you can keep the * pressed down to track or if the motion stops release it and lock focus (ie one shot) and get the best of both worlds. So it's very easy to compare both approaches in a split second. I assume youy can do a similar thing with the 1D III?
