focus scales on lenses

[85hal9000]

i´m moving my first steps as focus puller on student films.
and i was wondering what´s the best way to know how a measured distance corresponds on the focus scale on the lens (according to the logaritmic progression of focus scales...).
thanks.

 

[Kevin_Zanit]

What? :lol:

I don't quite get the question.

Measure the distance to the subject from the marked focal plane of the camera. Assuming your lens's barrel markings are calibrated (check during the camera prep), set the lens at the desired distance.

Now split focuses and stuff like that can be more complex if thats what your asking about.

 

[85hal9000]

i mean:
if i measure an actor who is 3.5 meters far from the focal plane and i have just 3meters and 4 meters marks on the lens, do i just set my focus in the middle or what?
and what do i do with those lenses where you have some focus mark at 5 meters and then infinite?

 

[sk]

If nobody can answer your question, you should easily be able to find it in the ASC manual. If I can find my old copy, I'll look it up.

 

[henry1406]

Focus scales

Focus scales

To make certain that you have accurate and reliable distance marks on your lens barrel, you need to do focus tests for that particular lens during prep. It's simply a matter of getting a focus chart, setting it at a measured distance from the focal plane, eye balling the focus and then marking that point on the lens. You can do this using camera tape or by writing on the follow focus ring if you have one. Do this for any number of distances and you will then have a set of lens markings you can trust. There will always be "in between" distances and you are right that it's not a linear scale - this is where experience comes in, but if you work out your depth of field you should be OK. For more info check my website: http://www.eyefish.tv/dictionary/focus-puller