7D Mark II - Focus Discussions

tonyxcom wrote in post #17579429
Funny you mention this. I was just telling a friend the other day how on my 1D4 my tracking sensitivity was at -1 and I had to set my 7D2 to +1 to match it.

I've only done any serious shooting with 1.04 so I can't comment on the before and after. As a little background to my statement above.....

I shoot karts and one of the shots I take is karts head on in a turn or right before turning. I generally just hold AF-ON and click off on the shutter when the karts are framed the way I want. The camera is nearly stationary. So it was during this scenario in which -1 on the 1D4 was sufficient for snapping the focus to the next kart; which could be 1-3 kart lengths behind the one leaving the frame.

I mistaking assumed that -1 on the 7D2 would be equal. Boy was I wrong. I watched out of focus karts enter and leave the frame. I didn't have much of a problem if I stopped and restarted focus but I'd rather avoid the finger cha-cha so I ended up at +1 on the 7D2 before it equaled the 1D4.

That does not surprise me at all. Quite contrary, given all the different hardware between just those two cameras it would be near darn impossible to come up with some objective measure for such setting. Some models, for example, use more voltage for lens drive making the lens focus faster (and better)...so that alone would have big impact on it. Heck, I would be surprised if the settings in those two cameras have much in common beyond the visual representation of the scale. If I tell you that my room is 5 arm-lengths wide and you tell me that yours is 5 arm-length wide as well, are we to conclude that our rooms are of same width? All things considered, very unlikely. I would wager the same about the sensitivity scale in those two cameras. But it is nice to actually take the speculation out of things whenever possible and you did just that. Thank you.

Michael132 wrote in post #17582072
Indeed, that was the first thing I thought of but, as mentioned before, I do not have adequate knowledge of canon AF system and how it exactly works...nor am I aware of canon fully disclosing it. Indeed, if the AF has full feed-back loop then this should not be an issue but I suspect that it does not, which is why contrast AF is arguably more accurate then phase detection for stationary subjects.

There's a series of articles over at LensRentals that says that yes, the EOS system has a closed-loop feedback system for AF... when both the body and lens are new enough to support it. When supported (and AFMA is set correctly, and the body and lens are healthy) they found that phase-detect was only a sliver worse than contrast. Without the closed-loop system, even when everything is set correctly phase isn't as accurate or consistent.

This one too.

http://www.dpreview.co​m …phase-detection-autofocus

wisv1k wrote in post #17578567
Round trip? Or they have it for 10 days?

Another update for you. They received my lens last Friday, I got the email on Monday and I checked the status this morning. Not bad for a non CPS member.

Thanks for that. I'm expecting it to be delivered to them today.

wisv1k wrote in post #17582420
Thanks for that. I'm expecting it to be delivered to them today.

Keep us posted.

digital paradise wrote in post #17582433
Keep us posted.

You usually get the email the next day.

Much to my surprise, it was delivered to them and a few hours later I got an email confirmation that it has been examined and being sent to begin necessary repairs, no mention of what they might be. Not sure, but seemed like just a form email. The process has been quick though. Less than 48 hours from FedEx in wi to examination.

wisv1k wrote in post #17582995
Much to my surprise, it was delivered to them and a few hours later I got an email confirmation that it has been examined and being sent for repair. Not sure, but seemed like a form email. The process has been quick though. Less than 48 hours from FedEx in wi to examination.

I have had the email on the same day before but it is typically the next day. Did you get an RN number or is just an email confirming they got it?

I got a repair number. Hopefully that means something is actually going to be repaired and not just part of the process.

wisv1k wrote in post #17583024
I got a repair number. Hopefully that means something is actually going to be repaired and not just part of the process.

Hopefully they will determine what is wrong and fix it, but acquiring a repair number means nothing. It's just a case identifier.

That was my impression of the email

wisv1k wrote in post #17583024
I got a repair number. Hopefully that means something is actually going to be repaired and not just part of the process.

They will examine it to make sure it is functioning correctly and if not make whatever adjustments that are required or replace parts if necessary. When they inform you that it is ready to be shipped back you won't know what they did until it comes back. There will be an explanation of what they did. If you wan to to know sooner you can call them when you get the shipping notice.

Could it be my imagination ? Wishful thinking ? Maybe I'm just nutz.....
For those who still aren't thrilled, would someone please experiment and verify ?

Today I shut off the BB focus and went back to the old fashioned way of doing things using the front shutter release button. Am I getting a faster and more accurate AF lock ? I'll play more tomorrow weather permitting.

CyberDyneSystems wrote in post #17579720
...For birds in flight this not what we want most of the time.

and again, I am and have been one of "those people" that use back button and AI SERVO all the time, but At the same time I have always had my AI Servo sensitivity toned way down.

Though I would never "Insist" that anyone else follow suit, And more importantly I would NEVER even suggest anyone use AI SERVO all the time unless that had decoupled the AF from the shutter release so they control when AI Servo is twitching with their thumb

I use Ai Servo and BB AF all the time because before the 7D2 it gave the best of both worlds; one shot and ai servo. Like you stated for stationary birds, once focus is achieve I let go of the * button (one shot now) and take the photo. Also, as you stated, for BIF my AF sensitivity is at the lowest setting, so that focus does not easily slip off the subject. I always suggest the lowest sensitivity when I see folks having issues with BIF.