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Sigma 30mm 1.4 - Canon 60 D - Noisy Autofocus

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Caleb Trevatt
Sigma 30mm 1.4 - Canon 60 D - Noisy Autofocus
on Mar 6, 2012 at 11:38:07 am

Hey Guys,
I just bought a Canon 60 D and a Sigma 30mm 1.4 lens to go with it.
In movie mode, the autofocus is quite slow, it is noisy and judders.
The sound is clearly audible in the background when playing-back clips.
It's brand new, is this a fault?

It doesn't judder so much in still modes.

-- Caleb


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Noah Kadner
Re: Sigma 30mm 1.4 - Canon 60 D - Noisy Autofocus
on Mar 6, 2012 at 5:08:47 pm

Are you using the built-in mic? If you're using a lav mic or a shotgun- chances are you won't pick up any camera noise.

Noah

Call Box Training.
Featuring the Panasonic GH2 and Panasonic AC160/130.


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Caleb Trevatt
Re: Sigma 30mm 1.4 - Canon 60 D - Noisy Autofocus
on Mar 6, 2012 at 9:30:52 pm

Yeah, I'm using the built in mic.
I've been experimenting a little more, it seems like it's only live mode and movie mode the autofocus struggles. It almost seems to overshoot the target, judder back and try again. Sometimes the aperture gets confused too and the diaphragm shrinks and grows rapidly in conjunction with the autofocus.

-- Caleb


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Peter Burger
Re: Sigma 30mm 1.4 - Canon 60 D - Noisy Autofocus
on Mar 7, 2012 at 8:21:36 am

[Caleb Trevatt] "In movie mode, the autofocus is quite slow, it is noisy and judders."

Don't know this exact lens, but experienced that problem with other glass too. From what I know, autofocus is not that fast and doesn't work that accurate in Live-View mode because of a different way the camera tries to set focus.

------------------------------------------
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Noah Kadner
Re: Sigma 30mm 1.4 - Canon 60 D - Noisy Autofocus
on Mar 7, 2012 at 5:06:22 pm

Step one- get better audio gear and use it. The onboard mic is useful for exactly one thing- a guide track to sync up your proper audio that you've recorded using a good mic, preferably a wireless mic or a shotgun mic on a boom pole and generally into a much higher quality outboard digital recorder (double-system sound).

The onboard mic is the absolute bare minimum quality there is and it's about as far away from the thing you want to hear (generally a person on camera speaking) as imaginable. So work on that part of your production and you'll achieve much better results.

Noah

Call Box Training.
Featuring the Panasonic GH2 and Panasonic AC160/130.


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John Young
Re: Sigma 30mm 1.4 - Canon 60 D - Noisy Autofocus
on Mar 7, 2012 at 7:23:30 pm

I haven't used that particular lens. But I have used a less-expensive non-Canon option (Tamron 17-55) and one of the things I notice is slower auto focus.
But, Caleb, as I said in your other post regarding this question, the video that you get while auto-focusing will be useless anyway (that is just how DSLRs do auto-focus). I am not sure why you are worried about the audio being useless as well.

Maybe I am missing something.

John

http://www.johnathanyoung.com


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Caleb Trevatt
Re: Sigma 30mm 1.4 - Canon 60 D - Noisy Autofocus
on Mar 8, 2012 at 6:51:11 am

Yeah sorry about the double post, I tried to post it on this thread and instead started a new one.
I'm new to DSLR video, (and Creative Cow) so my bad. I assumed autofocus was done this way, but I can see that it doesn't make much sense. I believe some Nikons autofocus during recording though?

So to focus in video mode, I'm guessing I either set the aperture to f22, so everything's in focus, or use the manual focus ring?

Really sorry to mess everyone around like this,
I thought my lens was faulty...

Thanks for helping.

-- Caleb


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John Young
Re: Sigma 30mm 1.4 - Canon 60 D - Noisy Autofocus
on Mar 8, 2012 at 3:13:31 pm

Don't worry Caleb. Much of this DSLR stuff is pretty new to a lot of people. Even people who have been doing video production for a long time. In many ways it is just a different way of going about things. It is a throwback to days of film in many ways.

You can focus a couple of different ways. You can use the 5x and 10x magnification button to get a real close look of what your trying to focus on. Then manually set your focus using the focus ring on the lens. Or if you need to move a little bit faster, you can move your on-screen selection box to the area of the frame you want in focus. Then press your shutter button halfway down until the camera auto-focuses. Then press record.
You should not have to mess with you aperture at all. If you do it will change your depth of field.

I know the Sony Alphas with the transparent mirror auto-focus while recording, but a few of the examples I have seen of it didn't look super smooth.

http://www.johnathanyoung.com


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