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Pulling Focus Tips


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#1 weiming

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Posted 19 June 2006 - 11:27 AM

Hi all,

just like to find out if any of u more experienced ACs' have any tips or guidelines as to pull focus successfully.

recently tried to pull focus on a P+S mini35 / XL2 with an 85mm, aperture wide open, and it was damn hard to get the subject sharp. the shot was a MCU of a person sitting down talking, and she was moving her head back and forth as she spoke.

other than using a smaller aperture, are there any other tips which i can follow?

thank u : )
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#2 Bob Hayes

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Posted 19 June 2006 - 02:18 PM

Practice at home with a tape measure. Place something next to you to represent the camera then start guessing distances. On the set measure other items in the room that are fixed close to you actor, edge of table for instance. This helps give you a reference. Run your tape right before the take. If it is a tough shot ask the actor to freeze, they won?t but they might learn, and run a tape to where they were. Try to do this with confidence rather then insecurity. More like a gunslinger then Barney Feif.
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#3 Chris Keth

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Posted 19 June 2006 - 11:33 PM

Practice at home with a tape measure. Place something next to you to represent the camera then start guessing distances. On the set measure other items in the room that are fixed close to you actor, edge of table for instance. This helps give you a reference. Run your tape right before the take. If it is a tough shot ask the actor to freeze, they won?t but they might learn, and run a tape to where they were. Try to do this with confidence rather then insecurity. More like a gunslinger then Barney Feif.



One of the best things I have found that you can do is to get very, very good at eyeballing distances accurately. That will let you take those tape measurements and from those know the distance to any point on the set. Also, get in the habit of being very close to the camera when ou do it so you can see the lens barrel and the subject without turning your head. This makes it much easier to watch both things at once and not be late to your marks because of head-turning and reaction time.
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#4 Jamie Metzger

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Posted 20 June 2006 - 10:27 PM

Hi all,

just like to find out if any of u more experienced ACs' have any tips or guidelines as to pull focus successfully.

recently tried to pull focus on a P+S mini35 / XL2 with an 85mm, aperture wide open, and it was damn hard to get the subject sharp. the shot was a MCU of a person sitting down talking, and she was moving her head back and forth as she spoke.

other than using a smaller aperture, are there any other tips which i can follow?

thank u : )



Let the subject go in and out of acceptable focus??

Remember the 1/3 2/3rd's rule, use that 2/3's behind the focus point you set to bring it a little forward, giving the actor some more room to move. If they are moving tons, switch lenses or close down.

Edited by Jmetzger, 20 June 2006 - 10:27 PM.

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#5 Stephen Williams

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Posted 21 June 2006 - 02:29 AM

Let the subject go in and out of acceptable focus??

Remember the 1/3 2/3rd's rule, use that 2/3's behind the focus point you set to bring it a little forward, giving the actor some more room to move. If they are moving tons, switch lenses or close down.


Hi,

It's actually more of a misconception than a rule.

In Macro photography the DOF is distributed 1:1.

Shooting a landscape at the hyperfocus the DOF will be distributed 1: infinity.

Stephen
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#6 Chris Keth

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Posted 21 June 2006 - 07:44 PM

Hi all,

just like to find out if any of u more experienced ACs' have any tips or guidelines as to pull focus successfully.

recently tried to pull focus on a P+S mini35 / XL2 with an 85mm, aperture wide open, and it was damn hard to get the subject sharp. the shot was a MCU of a person sitting down talking, and she was moving her head back and forth as she spoke.

other than using a smaller aperture, are there any other tips which i can follow?

thank u : )


I forgot a useful trick that Doug Hart taught me: at a given stop and focus distance, if you mark the limits of the depth of field on the barrel of the lens (as in, a mark on either side of the witness mark for focus), it will tell you the depth of field at all other focus distances at that same stop. It will help you know your DoF so you can tell whether or not you nailed the shot.
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#7 Annie Wengenroth

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Posted 21 June 2006 - 09:00 PM

Practice the pull until you have physically "memorized" the motion of your hand. If you want you can even point your thumb at a certain orientation (12 o' clock, 3 o' clock, etc) on the follow focus wheel to help give yourself a reference point. Many times if your body knows something well enough, your mind will hardly have to consider it. It sounds like a stupid hippie trick and next I'm gonna tell you to do yoga, but it does help!
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#8 Chris Keth

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Posted 21 June 2006 - 09:39 PM

Practice the pull until you have physically "memorized" the motion of your hand. If you want you can even point your thumb at a certain orientation (12 o' clock, 3 o' clock, etc) on the follow focus wheel to help give yourself a reference point. Many times if your body knows something well enough, your mind will hardly have to consider it. It sounds like a stupid hippie trick and next I'm gonna tell you to do yoga, but it does help!



Annie has a very good point. Take advantage of muscle memory. It's your friend.

Annie, wanna go do yoga now? ;) :P
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#9 Joe Anderson

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Posted 22 June 2006 - 12:34 AM

These are all great tips, but no amount of muscle memory or barrel markings are going to help you in the situation described above. The depth of field on a wide open 80mm lens on a 35 adapter with its 1/2000th inch CofC is just not a reasonable amount to work with when shooting a moving human being. Even after taping out, there is no way to judge when an actor has leaned forward as little as 1". In this case it is best to inform the DP of this logistical nightmare rather than sit quietly and hope to get lucky. A professional DP will often plan ahead for these types of situations by lighting to a better stop. Unfortunately with the 35 lens adapters DP's feel they have free reign to stay wide open all the time. The best advice in this situation, is to make sure you have a really good view of the monitor and a 2nd AC who will listen to your complaints afterwords.
JANDY
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#10 Chris Keth

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Posted 22 June 2006 - 01:08 AM

These are all great tips, but no amount of muscle memory or barrel markings are going to help you in the situation described above. The depth of field on a wide open 80mm lens on a 35 adapter with its 1/2000th inch CofC is just not a reasonable amount to work with when shooting a moving human being. Even after taping out, there is no way to judge when an actor has leaned forward as little as 1". In this case it is best to inform the DP of this logistical nightmare rather than sit quietly and hope to get lucky. A professional DP will often plan ahead for these types of situations by lighting to a better stop. Unfortunately with the 35 lens adapters DP's feel they have free reign to stay wide open all the time. The best advice in this situation, is to make sure you have a really good view of the monitor and a 2nd AC who will listen to your complaints afterwords.
JANDY



Why the 1/2000th inch circle of confusion? The XL2 is a standard def camera, surely it doesn't need finer focus than 16mm film meant for projection...?
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#11 Hunter Sandison

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Posted 22 June 2006 - 10:35 PM

I forgot a useful trick that Doug Hart taught me: at a given stop and focus distance, if you mark the limits of the depth of field on the barrel of the lens (as in, a mark on either side of the witness mark for focus), it will tell you the depth of field at all other focus distances at that same stop. It will help you know your DoF so you can tell whether or not you nailed the shot.


This is a cool trick. But doesn't the depth of field grow with distance to subject?
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#12 Jon Kukla

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Posted 23 June 2006 - 02:59 AM

This is a cool trick. But doesn't the depth of field grow with distance to subject?


Yes, but remember that the focus marks are spaced logarithmically, not linearly.
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#13 Chris Keth

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Posted 23 June 2006 - 04:14 PM

Yes, but remember that the focus marks are spaced logarithmically, not linearly.



Exactly. It works exactly the same as the DoF markings on a still camera lens.


Does anyone know the answer to my question above? Why would the XL2, a standard def camera, require a 1/2000th inch circle of confusion? True, the sensor size is comparable to other formats that require such fine focusing but it can't resolve such fine detail anyway....right? :huh:

Edited by Christopher D. Keth, 23 June 2006 - 04:17 PM.

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#14 Stephen Williams

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Posted 23 June 2006 - 04:30 PM

Exactly. It works exactly the same as the DoF markings on a still camera lens.
Does anyone know the answer to my question above? Why would the XL2, a standard def camera, require a 1/2000th inch circle of confusion? True, the sensor size is comparable to other formats that require such fine focusing but it can't resolve such fine detail anyway....right? :huh:


Hi,

I would have thought 1/700 would be a good starting point, in reality maybe 1/500

Stephen
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#15 Chris Keth

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Posted 24 June 2006 - 01:02 AM

Hi,

I would have thought 1/700 would be a good starting point, in reality maybe 1/500

Stephen


Exactly. To have resolution to make a 1/2000th CoC matter, you would have to be in the pixel realm of 1080 HD.
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#16 Alec Jarnagin

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Posted 24 June 2006 - 02:09 AM

"These are all great tips, but no amount of muscle memory or barrel markings are going to help you in the situation described above. The depth of field on a wide open 80mm lens on a 35 adapter with its 1/2000th inch CofC is just not a reasonable amount to work with when shooting a moving human being. Even after taping out, there is no way to judge when an actor has leaned forward as little as 1". In this case it is best to inform the DP of this logistical nightmare rather than sit quietly and hope to get lucky. A professional DP will often plan ahead for these types of situations by lighting to a better stop. Unfortunately with the 35 lens adapters DP's feel they have free reign to stay wide open all the time. The best advice in this situation, is to make sure you have a really good view of the monitor and a 2nd AC who will listen to your complaints afterwords."

Not sure I agree with all of this. I DO agree that the DP is also responsible for focus by lighting to a stop that the focus puller stands a chance with. This stop is on a shot by shot basis and in part depends on the abilities of the 1st AC. I'll assume the stop in question here is a 1.3 because the original poster mentioned an 85 on the PRO 35 adapter and this is what the Zeiss Super speeds open to (I'm ruling out Cook S-4s, Primos, etc. since they are expensive and usually seem to end up on film jobs - big difference, in my book though, between a 1.3 and a 2 though). Was the camera moving or just the actor? It sounded to me like it was just the actor. If so, the 85 is a common lens for CUs and one needs to be prepared to get MOST of it in focus - I say most because it is indeed hard. More experienced film actors tone it down a tad for CUs, but not all, making it hard on the operator and AC alike. When faced with shots like this, you need to figure out a percentage of acceptability, which in a nutshell means how much do I need to nail?

As for it being impossible, I recently shot a bunch of Steadicam footage at a T2 on a 135mm in a boxing ring roaming about between the two boxers. Killer stuff, but I was keenly aware that only moments would be useable.
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#17 Matias Nicolas

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Posted 28 June 2006 - 05:26 PM

When you have this difficult shots , 85mm, T2, close to the camera , one thing you can do , is to ask for a little help . If you can , do a mechanic rehearsal with te actor. Tell the cameraman to tell you when you miss the focus. Do this with full aperture for 2 reasons : best definition for the cameraman and less DoF for you, to practice . Sometimes, that little out of focus, that generally happens when the actor moves forward or backward's , is compensated when you put the right T-stop ( unless you are working with full aperture!!!) . I always try this when I can. Also you will see the actor's movements , so when ready to shoot , you are more prepared cause you know when did you miss the focus.
Another thing you can do, is to put marks on the floor or the table , and ask your 2 assistant to follow the actor's eye with his finger.
And the most important thing, if you missed the focus, ask for another one !!!!! it's cheaper !!!!
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#18 Joe Anderson

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Posted 02 July 2006 - 09:16 AM

Christopher,
Regarding your question:
I do think Mini-35 adapters have a CofC of 1/2000 in. because of all the additional glass elements added behind the lens. Remember that there is a depth-of-field (in front of the lens) and a depth-of-focus (behind the lens). Once the image is projected onto a spinning ground glass, then bounced of three mirrors and then magnified by a diopter which is crudely attached to the front of a video lens, that focus tolerance is going to be greatly reduced, regardless of the definition of the CCD.
http://en.wikipedia..../Depth_of_focus
JANDY
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#19 Chris Keth

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Posted 02 July 2006 - 12:31 PM

Christopher,
Regarding your question:
I do think Mini-35 adapters have a CofC of 1/2000 in. because of all the additional glass elements added behind the lens. Remember that there is a depth-of-field (in front of the lens) and a depth-of-focus (behind the lens). Once the image is projected onto a spinning ground glass, then bounced of three mirrors and then magnified by a diopter which is crudely attached to the front of a video lens, that focus tolerance is going to be greatly reduced, regardless of the definition of the CCD.
http://en.wikipedia..../Depth_of_focus
JANDY



OK, so it's more to make up for the mechanics of the adapter, not so much that it can actually resolve a 1/2000th inch CoC?
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#20 Stephen Williams

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Posted 02 July 2006 - 01:07 PM

Christopher,
Regarding your question:
I do think Mini-35 adapters have a CofC of 1/2000 in. because of all the additional glass elements added behind the lens. Remember that there is a depth-of-field (in front of the lens) and a depth-of-focus (behind the lens). Once the image is projected onto a spinning ground glass, then bounced of three mirrors and then magnified by a diopter which is crudely attached to the front of a video lens, that focus tolerance is going to be greatly reduced, regardless of the definition of the CCD.
http://en.wikipedia..../Depth_of_focus
JANDY



Hi,

I don't understand why you are connectiong depth of focus and depth of field as they are inversely proportional.
With a macro shot the depth of field is tiny but the depth of focus is huge. If you don't believe me try a bellows on a 35mm still camera and see what I mean.

Stephen
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