Since this is being taken out of context.
You should use OneShot for things that will not move.
You should use AIServo for things that are moving or may move.
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I thought the 70D AF System handled fluorescent better.....not....
- Thread starter pdqgp
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You should use OneShot for things that will not move.
You should use AIServo for things that are moving or may move.
Karl Gnter Wnsch
Forum Pro
The 1/500th - it's using only a small portion of the 30Hz light intensity cycle of fluorescent lights. You can see the same in ultra slow motion taken at indoor events... There is nothing anything can do to remedy that problem because it's a natural phenomenon when you are using much shorter shutter speeds in these lighting environments.
Karl Gnter Wnsch
Forum Pro
Doesn't the 70D have the AI Servo II algorithm that no longer requires this second tracking time? The 7D does...
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regards
Karl Günter Wünsch
Perhaps, but, even so, at 7 frames per second, the AF sensor doesn't get much time to see the subject between shots. The more time it has to establish tracking before the first shot the better, especially in lighting that is varying with the electrical frequency.
Karl Gnter Wnsch
Forum Pro
That doesn't matter. Phase detection AF does know where the subject is after the first measurement and the delta is clear after the second, that's nominally 1/15th of a second. After that a single measurement of about 1/30th of a second does suffice.
Karl Gnter Wnsch
Forum Pro
You didn't mess around with the micro focus adjustment by any chance?
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regards
Karl Günter Wünsch
My 24-70L is set at -1 for 24mm but otherwise it's fine. I've confirmed these settings with more than one test method too. In the end, that -1 isn't a factor as the images were OOF way more than just that one tweak. It's spot-on everyday otherwise. I definitely think it was lighting / shutter speed and fluctuation related.
R2D2
Forum Pro
Gotta agree with Karl on this one. Darn! ;-)
With the 70D in AI Servo, tracking is established immediately upon AF acquisition, and is maintained no matter the subsequent framerate. I often shoot immediately upon achieving AF. I've also noticed that the 70D's tracking is considerably better than previous models when shooting at long distances (far beyond Canon's spec).
I've also been quite surprised that the AF performance has been so good in low light under fluorescents, though I'm often shooting at 1/200 or slower (often much slower).
R2
Used to recommend Tim Jackson's focus chart, but, now I'd recommend using the DotTune method instead as it is easier to do the focus distance you'll actually be using the lens at.
DotTune: Autofocus fine tuning in under 5 minutes
I had no luck with DotTune. Another thing I don't like about the method is that it picks a mid-point, which in theory, I get it. However, the adjustments that came back never showed as being the sharpest on my lenses. Using Tim's method, I tested my lenses near and far and all shots have come back spot-on. No real major adjustments needed for any of them except my 50mm f/1.8 which required a setting of +13. Now it's spot on near or far and in even in vary low light indoors.
Whatever works is fine.
This whole thread is about you having focus issues, and your response is that Tim Jackson's chart worked and DotTune doesn't?
DotTune can adjust your lens for the actual distance you'll be using the lens, Tim Jackson's chart doesn't.
Again, I used Tim Jackson's chart in the past, but, now I use DotTune, it is a better way of doing it.
This whole thread is about struggling with lighting and it's impact on the AF System based on flicker rate and shutter speed and how shutter speeds and lights interact. It's not about AFMA.
However, that said, DotTune for me didn't work. The resulting numbers didn't return images that were sharp at both distances or various focal lengths. Tim's method does and seems to work great for me. If not for you then stick with DotTune. I just spend the past week jerking around with various methods and my own extensive testing and finally found the results that work using his system. You're entitled to an opinion just as I am.
Like I said, you're entitled to your opinion and results. Feel free to stick with DotTune for your gear. It's unreliable for me and mine producing results that return less than perfect results compared to Tim's method.
tko
Forum Pro
Ive shot national and world level Taekwondo with the 7d and 5dIII. Back focus and continuous servo is an awesome combination. No problem with fluorescent lights, or any other type.
I do use AF expansion point, which might help. Don't know if the 70d has this.
I do use AF expansion point, which might help. Don't know if the 70d has this.
WilbaW
Forum Pro
That's way too simplistic. Here's a silly example that shows how it doesn't work - on a train, you would use One-Shot to shoot a billboard passing the window at 100MPH, and AI-Servo to shoot a portrait of your companion in the opposite seat.
The crucial factor is not whether the subject is moving but whether the camera to subject distance is changing. That happens due to photographer movement with static subjects, so a correct formulation is more like -
You should use One-Shot when you want to lock focus (e.g. to be able to recompose after focus acquisition, or for consistency among a series of shots).
You should use AI-Servo when the camera to subject distance might change for any reason, and you can keep an AF point where you want it on the subject.
R2D2
Forum Pro
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