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My lens is really sensitive to focus, any thoughts on how to do these shots?

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ryan elder
My lens is really sensitive to focus, any thoughts on how to do these shots?
on Nov 8, 2018 at 2:20:19 am

Basically I have a project where I want to shoot an actor running and I want to track the actor during from the side. I also have a shot where an actor is kneeling and I want to be on a close up of his face, at eye level, and rises and stands, the camera will keep eye level with him and rise with him.

So I thought I would use my 70-300mm lens zoomed in pretty far. The further zoomed in the more I can track and actor while running horizontally, or moving up and down vertically, such as from kneeling to standing.

But the lens is very sensitive to focus while zoomed in. According to my calcutations, on a close up from tracking the actors face as he goes from kneeling to standing, I have about 0.15 feet of depth of field to keep him within.

So I he is in focus when he is kneeling, but then when he stands, he goes out of focus in the practice shots I did.

And the aperture is already at f6.3 and I don't want to stop down too much more cause then I will more light. Any thoughts on this, or how to keep an actor in focus, with such a thin hair of focus in a lens like that, while zoomed in?


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Warren Eig
Re: My lens is really sensitive to focus, any thoughts on how to do these shots?
on Nov 8, 2018 at 3:24:31 pm

The easiest way to follow an actor and keep them in focus is to pull focus. I have a baseplate for my 5DMKIII that I attach a follow focus unit. I have geared all my Canon EF lenses. You turn the dial on the follow focus and it turns the lens. It's better to have a focus puller/ 1st A.C. doing this for you.

Otherwise the constrains of the depth of field of the lens will limit your creativity and your shot.

Warren Eig
O 310-470-0905


email: info@babyboompictures.com
website: http://www.BabyBoomPictures.com
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ryan elder
Re: My lens is really sensitive to focus, any thoughts on how to do these shots?
on Nov 8, 2018 at 10:21:14 pm

Okay thanks. It's very difficult to see what is in focus and what is not in this particular zoom lens, compared to other lenses where what is out of focus, is more obvious. I can get a focus puller, just wasn't sure if it was do-able. Thanks.


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Warren Eig
Re: My lens is really sensitive to focus, any thoughts on how to do these shots?
on Nov 9, 2018 at 3:52:04 pm

I do it with my EF-70-200. It just takes practice, because the throw or travel distance on a still lens is much shorter than a cine lens.

Good luck!

Warren Eig
O 310-470-0905


email: info@babyboompictures.com
website: http://www.BabyBoomPictures.com
Vimeo: https://vimeo.com/babyboompictures



For Camera Accessories - Monitors and Batteries
website: http://www.EigRig.com



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ryan elder
Re: My lens is really sensitive to focus, any thoughts on how to do these shots?
on Nov 9, 2018 at 10:23:30 pm

Okay sure. Do you think that 0.12 feet of focus is too little, or is there a limit as to how shallow the focus can be before it's just too shallow?


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ryan elder
Re: My lens is really sensitive to focus, any thoughts on how to do these shots?
on Nov 9, 2018 at 10:25:33 pm

Actually while I am practicing I discovered something else about the focus. What if you want multiple actors in a shot at the same time while zoomed in to 300mm at f5.6 around?

How do they do it in movies like when they are shooting on a telephoto and you see multiple people in the same shot?


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Blaise Douros
Re: My lens is really sensitive to focus, any thoughts on how to do these shots?
on Nov 9, 2018 at 11:44:18 pm

Sigh, I'm going to take the bait.

1. They have a dedicated focus puller.
2. DOF depends on more than just f-stop. Focal length and subject-to-camera distance also affect it.
3. When there are multiple people in-frame, subject-to-camera distance is much greater--the further from the camera, the deeper the DOF. Closeups like what you're talking about decrease the DOF because they're closer to the camera.
4. They may not be using lenses that are quite as long as 300mm, especially for shots where multiple people are in the frame.

And to answer your other question above: if your subject is likely to move more than 0.12 feet forward or back during the take, and you aren't able to pull focus well enough to follow that motion, then yes, it's too shallow. If you ARE able to pull focus on that move, then it's not too shallow. See how that works?

Regardless, maybe you should put on your thinking cap and figure out a different way to shoot it that doesn't place this requirement on your camera op. This would solve 93.6% of the problems you post on these boards.


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ryan elder
Re: My lens is really sensitive to focus, any thoughts on how to do these shots?
on Nov 9, 2018 at 11:50:41 pm

Okay thanks. Well getting deeper DOF does require more light, and the location is quite large and difficult to light that bright.

I can see about getting a better focus puller if that's best.


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ryan elder
Re: My lens is really sensitive to focus, any thoughts on how to do these shots?
on Nov 9, 2018 at 11:51:57 pm

I can get some more depth of field if the actors are further back but not enough to fit a group of actors in unless I pick and choose who is in focus, one at a time, which I'm not sure is the way to go. But I can see about getting separate focus puller.


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Bouke Vahl
and again, don't feed the trolls
on Nov 10, 2018 at 8:40:41 am

[Blaise Douros] "Sigh, I'm going to take the bait."

WHY?

[Blaise Douros] "This would solve 93.6% of the problems you post on these boards."

He has no problems other than being addicted to attention. Don't feed him, it's polluting the waters around here.

Bouke
http://www.videotoolshed.com


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ryan elder
Re: and again, don't feed the trolls
on Nov 10, 2018 at 8:42:35 am

Sorry, I was just asking for advice and do not mean to come off like I am addicted to attention. What would be a more proper way to ask for advice on this forum without coming off like an attention seeker?


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