GH2 -auto focus not always consistent (aerial video examples)

[photothrottle]

Hello community,

Have had great results with EOS Vanilla 44 hack. Using exclusively for Aerial video and focus has been fine almost every time I have shot with settings per below. Using Kit lens to be consistant.

Shooting in [u]720p at 80% slow setting[/u] in [u]smooth with -2-2-2-2[/u]; however not sure what I am doing incorrectly, but occasionally the AF begins to hunt. Again, using kit lens and same settings. S priority

Is there something wrong that I am doing causing the hunting for focus? AF set to CF but dont think it matters in video mode anyway.


Any settingd info greatly appreciated. Appologies in advance for the verbose posting.

[Julian]

Why do you use autofocus at all? Wouldn't this work out fine with f/5.6 or f/8 manually focussed at (or almost at) infinity?

[photothrottle]

We actually fly close to objects and at times we capture shallow DOF in low light/late evening shots. We also use EX Tele mode and need AF on for these type of shots.

I've just had great results with the way it is set almost all of the time. So just stayed with it. Somewhat of a noob but have watched almost all the videos on set up and purchased the EOSHD GH shooters guide; not confident in making too many changes while doing client work etc...

[Michael64]

Have been doing aerial photo and video for many years and one thing you must learn about aerial is first and foremost the machine needs to tuned like a sewing machine. In the video its all over the place and not very smooth. Second without the first one taking care of you will always fight with video, and three you never use auto-focus at all because that will always lead to focus being off most of the time and always doing the part you really wanted. In bright sun light you may get away with it some anything less and the odds go way down using auto-focus its the nature of the beast.

[photothrottle]

[quote name='Michael64' timestamp='1344987302' post='15735']
Have been doing aerial photo and video for many years and one thing you must learn about aerial is first and foremost the machine needs to tuned like a sewing machine. In the video its all over the place and not very smooth. Second without the first one taking care of you will always fight with video, and three you never use auto-focus at all because that will always lead to focus being off most of the time and always doing the part you really wanted. In bright sun light you may get away with it some anything less and the odds go way down using auto-focus its the nature of the beast.
[/quote]

Appreciate the info. Need to clarify- this set up is with a 3 axis gimbal. (eg. seperate camera operator) In addition,
we had faced wind gusts (a least 25 mph) and thus I was fighting the octo just to keep it from getting blown from the hanger while the camera operator was trying to frame shots from the fpv. We only had one oppty to get the shots and I made the "call" to go for the shots. Typically I wouldn't have taken this risk but after much thought i made the call to green light the copter shots.

Re Copter: My Octo is completely balanced. Carbon Props, Cam Gimbal, Airframe, and CG'd everywhere.

I've tested with the GH2 over 50 flights. All settings the same as per above. and have only had two issues where focus was hunting. My question to the forum is for wisdom around settings for moving objects.

Not sure of the odds of "getting away with it" but in doing the math it doesnt add up 48 out of 50 tests had focus without fail.

@ Michael64 - can you post some links to/of your AP platform and associated video's. Would love to see your footage.

Again thanks for the information.

[Michael64]

Sorry for trying to help. All I was stating was does not work. As far as 50 flight I do a day so this is not my first rodeo. I have helicopters as well as multicopters and carry various different cameras for Canon to Red Epic. As far as settings pre-set modes will not deliver the quality needed or at least not for my work. Manual mode and learning lighting and settings is what it takes to get quality video.

Michael64

[photothrottle]

Thanks for all the advice. WIll try to turn AF off and set all manually and see what it yields.

[galenb]

Oh you guys. I think if he wants to use AF and it's been working for him for the most part, just let him use AF. What's the big deal? Anyway, I have no idea what might be causing the issues off hand. Are there any common circumstances between the shots where it fails? Like, Low-light situations, moving at higher speed then usual, or low contrast in the shot etc?

[Julian]

[quote name='galenb' timestamp='1345054280' post='15771']
Oh you guys. I think if he wants to use AF and it's been working for him for the most part, just let him use AF. What's the big deal? Anyway, I have no idea what might be causing the issues off hand. Are there any common circumstances between the shots where it fails? Like, Low-light situations, moving at higher speed then usual, or low contrast in the shot etc?
[/quote]

Nobody is forcing him to stop using AF, but I'm pretty sure it's just a fact that AF is never going to be perfect in a situation like this.

So if you want to use AF you have to accept the fact that sometimes it will hunt, no setting is going to change that.

It's just the way autofocus works. It needs contrast, there might be a moment when there is not enough contrast on the AF points, the camera will lose focus, it has to start searching and the hunting starts.

[galenb]

[quote name='Julian' timestamp='1345056886' post='15775']
Nobody is forcing him to stop using AF, but I'm pretty sure it's just a fact that AF is never going to be perfect in a situation like this.

So if you want to use AF you have to accept the fact that sometimes it will hunt, no setting is going to change that.

It's just the way autofocus works. It needs contrast, there might be a moment when there is not enough contrast on the AF points, the camera will lose focus, it has to start searching and the hunting starts.
[/quote]
Agreed, but you see, this is a much more helpful answer then asking why he's using AF or just telling him he shouldn't. Right? I like when this community is helpful is all.

[dreams2movies]

I can't see it you have the video on private

[photothrottle]

Hello everyone, I took some of the collective advice and did some testing with new settings. It appears that if I raise the shutter speed much higher in full M movie mode based on the fps im am shooting the AF doesnt hunt. Oddly shooting at 60P at roughly 160ss the AF works pretty darn good. Of course I will use a combo of full manual focus and some AF but I think AF is now more predictable and I have more confidence when I need to use it. thanks to all who replied. Great community and great camera! Here is the result of my last shoot. All manual 60p 720p AF on. Used the kit lens in this video. Thanks again!

[url="http://vimeo.com/48159523"]http://vimeo.com/48159523[/url]