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Lens/Device for practicing to pull focus?


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#1 Salil Sundresh

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Posted 06 January 2009 - 10:48 PM

Is there any sort of lens (I own a Pentax K100D Super and a Panasonic DVX100B) or device I could purchase for a couple hundred bucks or less that would allow me to practice focus pulling? The the SLR lenses I own, while they have distance markings on the barrel, they are very inprecise because just a small nudge may change the focus by a couple inches or feet. Any suggestions would be greatly appreciated.
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#2 Chris Keth

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Posted 07 January 2009 - 12:14 AM

Only way is to do it, my friend.
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#3 Salil Sundresh

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Posted 07 January 2009 - 12:17 AM

I guess the word (or words I guess.. ;) ) I was looking for was that my SLR lenses have a short barrel throw so this is of course a problem for practicing to pull focus.

Chris, I appreciate your responses, and agree that's the best way to learn, but I don't always have the opportunity of working with 35mm, usually prosumer or professional video cameras that tend to have a very deep depth of field. So I'd like to be prepared as much as possible for those few instances where I may be asked to pull focus on a camera with a shallower DOF.

Edited by Salil Sundresh, 07 January 2009 - 12:19 AM.

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#4 Chris Keth

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Posted 07 January 2009 - 12:52 AM

Sorry to say there is no easy way to learn it but to 2nd for someone that, with some time and trust, will let you pull some easy shots. Then, at some point, you'll have the terrifying experience to be thrown headlong into pulling focus all by yourself. You'll probably suck at it but learn a lot and be better at it next time.

Even if there was a device to simulate the motion, you just can't practice for every situation that will be thrown at you.
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#5 David Auner aac

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Posted 07 January 2009 - 02:53 AM

Hi Salil,

what about practicing distance guessing? I don't pull focus a lot but I think that might be helpful.

Cheers, Dave
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#6 Salil Sundresh

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Posted 07 January 2009 - 03:19 AM

Hi Salil,

what about practicing distance guessing? I don't pull focus a lot but I think that might be helpful.

Cheers, Dave

Thanks David, I've been working on doing lots of distance guessing and was hoping to get some practice with moving subjects. (maybe some rc car then a friend tells me when my focus goes soft, etc)

Edited by Salil Sundresh, 07 January 2009 - 03:22 AM.

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#7 Satsuki Murashige

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Posted 07 January 2009 - 03:21 AM

Good call David. It's really all about how accurately you can estimate distances without thought. When the distance is constantly changing, like with steadicam, then you really get to see what you're made of. All you really need to practice this is a tape measure (50' cloth or fiberglas tape and a 16' steel tape) and a lot of patience. There are other things you have to learn of course, but that's the big one and the reason it takes a long time and lots of practice to do well. Think of pulling focus as a dance between the camera's focal plane and the subject(s) and also between you and the lens. Your movements have to be precise, graceful, organic, and on tempo. How long does it take to train a dancer? How about a world class dancer? Right, now get to work! :)

One tip I can give you is that the closer you focus the lens, the further you have to turn the lens barrel to keep up. So when a subject is walking toward the camera, start very slow and gradually speed up the rotation of the lens barrel as they approach. It's not a linear speed increase but more of an exponential increase, if that makes sense. When they get to about 5' away or so (still walking at the same pace), you'll need to really crank the focus wheel hard in order to keep up.

I had to pull on a shot once where the camera started about 3'6" above an actor laying in bed and then quickly boomed down to a few inches away from his mouth. We had a diopter on the lens, so the focus marks were useless. That's where I picked up on this tip. Luckily I had a wireless follow focus and an HD monitor to pull from so we got the shot, but it took me a few takes to get the speed right. Sometimes you have to pull by feel, and that's when little tricks like this come in handy.
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#8 Ryan Thomas

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Posted 29 January 2009 - 12:24 AM

I might also recommend not even attempting to practice with your still photo lenses, on your 35mm still camera, or with an adapter and follow focus. This is just because the direction the lens has to turn to go to infinite or close focus, is the opposite of that of cine lenses. So normally when you pull you'll find that your thumb will go in the direction of the action, but since it's reversed with still lenses you'll find your gut instinct getting all funked up. I've just had a few blunders where I've been pulling on these adapters for a while and someone throws an actual lens at me and I feel like I have to totally change my brain over to get things going.

I think just getting really good at guessing distances is a good way to start. Then...just do it! (Easier said than done...I know...:))

Edited by Ryan Thomas, 29 January 2009 - 12:26 AM.

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#9 Dan Diaconu M

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Posted 29 January 2009 - 11:59 AM

I might also recommend not even attempting to practice with your still photo lenses, on your 35mm still camera, or with an adapter and follow focus. This is just because the direction the lens has to turn to go to infinite or close focus, is the opposite of that of cine lenses. So normally when you pull you'll find that your thumb will go in the direction of the action, but since it's reversed with still lenses you'll find your gut instinct getting all funked up.


.... just DO IT. Get an adapter and yes, use all SLR lenses you can get your hands on. Practice with aperture wide open and tape every take. Use a cheap dolly (skateboard) and keep something in focus as you get closer or further away from. Got a cat? or a dog? They'll teach you instant reactions (good for steadicam when the time comes). Some of the SLR lenses will coincide with cine lenses, others will be reversed. Some will move 2 degrees for a foot, others will take 30 degrees. It is good brain training (nothing will take you by surprise)
Some measuring devices could help too. Good luck.
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#10 Rob Featherstone

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Posted 29 January 2009 - 12:38 PM

Hi:

I always found focus pulling to be a combination of experience and intuition: tricks and and techniques.

On the job training and working with cine gear is obviously the best, but I found being able to judge distance to
within a quarter inch an invaluable tool.

So I would say using an slr and a tape measure and setting up objects and guessing their distance then checking
would be a great exercise.

I was always assisting a lot of hand held situations so guessing on the fly was really important.

I leaned the distance from my sternum to end my finger was exactly 3' and that was really useful if silly.

Another trick was to think of nothing but the distance between focal plane and subject.

Almost trance like I would chant the distance as it changed 1/4 inch by 1/4 inch (85 mm at t1.3 yikes)

Any how definitely practice any way you can even without a full on cine rig!

-Rob
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#11 Chris Keth

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Posted 29 January 2009 - 07:56 PM

I leaned the distance from my sternum to end my finger was exactly 3' and that was really useful if silly.


Not silly at all. I know the distance of my fingertip-to-fingertip wingspan is 5'7".

I have also learned a good trick for steadycam, where you're usually trying to pull from perpendicular to the distance you're judging. I measure the length of the camera from front of mattebox to the back of the body. Call that the 'camera length.' Then measure the distance from the film plane to the front of the mattebox. Call that the 'lens length.' I'll put a bigger hashmark on my followfocus at distances equal to 1 camera length + lens length and 2 camera length + lens length. I do this because it's very easy to judge visually when the camera is 1x or 2x its own length from talent. It's more complicated to explain than it is to do.
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#12 Steve McBride

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Posted 31 January 2009 - 12:05 AM

Try to dolly grip a bit when you can, even if its a digital shoot (on a higher non-prosumer camera) the dolly grip and focus puller have to be in good sync so that they hit their marks at the same time. Sure, it isn't the same as the focus puller (far from it actually) but with talking back and forth with the focus puller you'll probably pick up some good tips and hints along the way.
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#13 Bob Hayes

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Posted 31 January 2009 - 01:57 PM

Take a board and hammer a nail in the board. Place the board in your livingroon and guess the distance from the board to different objects in the room. Do it until it becomes obsessive. Take your steel tape messure and start guessing distances as you go about ton. It is important that you always guess the distance from an object near you to a far away object as this most reflects the real world. Take up a sport like darts will help hone your hand eye co-ordination and tain your torelax under pressure.
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#14 Jean Dodge

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Posted 16 April 2009 - 02:23 PM

Working as a carpenter, remodeling your own home is good distance training, too. With practice you can intuit the size of a floor rug, room, couch, tabletop etc. but experience measuring things in the real world teaches you to judge distances well. A dollar bill is six inches long... a piece of plywood is 4x8... a floor tile is 12 inches, etc. Parking spaces, theater seats, these things are standardized to a degree.

How far is it from your Mr Coffee pot to your favorite breakfast chair? From your couch to your telly, or the front door? Shouldn't you know this already? "Get to know your rabbit," as the magicians always say. Whatever mind/eye training system you invent for yourself is usually the best system, since it's yours. But don't just go around guessing - measure it!

As for practicing with cine lenses there is such a thing as practicing on an empty insert stage at the rental house, or in an owner/operator's living room, over a pizza and beer. It doesn't all happen on set. ANY method that puts you at ease is going to be a big help come crunch time. You just have to make it all second nature somehow. Why not play around - it can't hurt much, and it might help a lot.

Print out a bunch of focus targets and make your girlfriend or kid sister wear them on her hat as she walks around the house! Get creative, but with that method you could have a civilian-friend look thru the eyepiece and trust their opinion of whether you are doing a good job or not, even if you are using your Pentax. A homemade "pogocam" ( a cheap monopod with a weight on bottom) with a camcorder on it is just as good as a steadycam and a panaflex for learning the basics - assuming you aren't afraid of looking like a fool, with a fake remote in your hand. A tuna fish can on a clipboard seems stupid, but if you had two friends who would "freeze" on command and let you run your steel tape, at least you would see for yourself if you had the knack or not. There is no wrong answer except "not trying."

As for practicing by yourself (careful - it puts hair on your palms!) I've seen some pretty interesting footage on vimeo of people who use a camcorder in macro mode, duck taped to the viewfinder of an slr just to get a basic shallow focus look thru a fast 50mm. I suppose that would enable you to have a monitor to judge by - BARELY - but it might also train you to rely too heavily on on-board monitors to chimp in to the zone. Pull first, by eying the subject movement, then check the monitor. If you are wrong, start over, don't correct by looking at the monitor - VERY BAD HABIT to get into. It's not a fishing expedition!

But in general, I'd put more faith in you and a tape measure - no camera - as the best practice. Let us know how it goes.... everyone likes movies in focus!
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