Back focus when changing canon al mount to Pl ti mount

[William Graydon]

Hi all, kinda need to some advice asap. I have a gig on Wednesday that requires a PL mount on my scarlet. I am renting one and swapping my al canon mount for the day. Technically* should I have to re-calibrate (not sure if that is the right word) the back focus? Or should it remain constant?

If* I have to adjust the back focus what is the standard protocol?

I really appreciate all of your assistance on this.

 

[Keith Putnam]

In my opinion, it's always a smart idea to double-check your back focus after changing a lens mount.
My quick-and-dirty method (which a good AC would probably never sign off on but which is close enough for me 90% of the time) involves putting on the widest lens from the set you're going to use, framing up on something far enough away to focus at infinity, setting your lens to focus at infinity, and then adjusting the back focus screw until the image at infinity is as sharp as possible.
If you have time, put on more lenses and check more focus marks at different distances. Assuming there's nothing wrong with your lenses, all measured focus distances should come up sharp at that mark on the lens. If they don't, work on your back focus adjustment.

 

[Daniel Grosseman]

Anyone else? Im interested in information about this as well...

 

[Ruff]

You need to set the flange depth.

If you have no experience with it, the technician at the rental house will do it for you. They use one of these: http://www.denz-deniz.com/index.php?page=7&productgroup=3&product=18 or similar.

If you are renting PL mount glass, the rental house should have the experience and the equipment.

 

[Jacek Zakowicz]

Another option

Another option

Optimator is the only device with interchangeable mount adapters
PL, PV, BNCR , Canon, Nikon available

 

[William Graydon]

I did some manual tests at 5 and 10 feet and honestly it was on point. May have been off a smidgen but overall everything was as it should be. But what I learned was if you're going to adjust your back focus, best leave to a technician who really knows what he/she is doing.

 

[Mike Lary]

Optimator is the only device with interchangeable mount adapters
PL, PV, BNCR , Canon, Nikon available

Hi Jacek,

Has the Optimator with Canon mount been tested extensively on Scarlet and/or EPIC with RED's Canon mount?

 

[Jacek Zakowicz]

Hi Jacek,

Has the Optimator with Canon mount been tested extensively on Scarlet and/or EPIC with RED's Canon mount?

Yes it's been tested and used. Come and see yourself at the Cine Gear this week!!!!

 

[Mike Lary]

Yes it's been tested and used. Come and see yourself at the Cine Gear this week!!!!

It would be better if you could bring it to KOBA.

 

[Benjamin Zimbric]

The info below is good except I would put it to a know distance on the lens. Back in my AC days we'd always do it at 5 feet. Set the object 5 feet from the camera, set the lens to 5 feet, then adjust the back focus. Also using a focus chart for this is invaluable. Print on off the interwebs if you don't want to buy one or own one already. You can also do it with cash (fine detail). For luck you're supposed to do it with $100 bill. Those are pretty scarce these days with producers being as cheap as they are getting though!

In my opinion, it's always a smart idea to double-check your back focus after changing a lens mount.
My quick-and-dirty method (which a good AC would probably never sign off on but which is close enough for me 90% of the time) involves putting on the widest lens from the set you're going to use, framing up on something far enough away to focus at infinity, setting your lens to focus at infinity, and then adjusting the back focus screw until the image at infinity is as sharp as possible.
If you have time, put on more lenses and check more focus marks at different distances. Assuming there's nothing wrong with your lenses, all measured focus distances should come up sharp at that mark on the lens. If they don't, work on your back focus adjustment.

 

[Jacek Zakowicz]

The info below is good except I would put it to a know distance on the lens. Back in my AC days we'd always do it at 5 feet. Set the object 5 feet from the camera, set the lens to 5 feet, then adjust the back focus. Also using a focus chart for this is invaluable. Print on off the interwebs if you don't want to buy one or own one already. You can also do it with cash (fine detail). For luck you're supposed to do it with $100 bill. Those are pretty scarce these days with producers being as cheap as they are getting though!

Of course it will not work on a still prime since the marks are not precisely calibrated.
It does work well with a zoom however since you don't need precise marks just zoom in and out and adjust the back focus at the wide end so it matches the long end.Simple!!!
Just remember to have your hero lens adjusted properly.. preferably by a pro....