Focusing with the Brevis MP.1 at DVinfo.net

Jason LeFrense · April 1st, 2009, 05:53 PM

Hey Folks, I'm still working out some bugs with my new Brevis. One issue I have is focusing. I have my back focus perfect and I can get some really sharp images but anything farther then 15ft is soft. I'm new to the 35mm adapters so excuse me if this is normal. If I'm 15ft away from say a podium there is no way I can get them in focus. I'm using Canon FD lenses and I have tried 3 different kinds. And I used a canon EF lens and I got the same results. Is it because the aperture is wide open ?Focusing on object from 15ft or closer is a piece of cake.I'm using the Brevis Mp.1 with Sony EX3.

David W. Jones · April 2nd, 2009, 03:36 AM

Quote:

Originally Posted by Jason LeFrense

One issue I have is focusing. I have my back focus perfect and I can get some really sharp images but anything farther then 15ft is soft.

Then I would say you incorrectly set the back focus.

Dennis Wood · April 2nd, 2009, 07:36 PM

Jason, definitely check out our video segment covering micro-collimation. The adjustment ring allows accuracy better then +- .01mm so you should be able to get it perfect with very little messing around.

You may wish to start with your lens set at infinity and then adjust the ring (leaving the lens mount "loose") until you have a sharp image. Then you can fine tune by using the tape measure technique we discuss in the video. What lens are we talking about here?

Cheers,
Dennis Wood
www.cinevate.com

Leonard Levy · April 4th, 2009, 10:08 PM

People use the word back focus on adapters to mean 2 different things. You may be referring to the video cameras focus on the surface of the adapter screen. That's an incorrect use of the word back focus though. It should reference the 35mm lenses being the proper distance from the screen on the adapter also called collimation. If this "back focus" is set correctly then you should be able to focus the 35mm lens on a distant image approximately at the lens barrel's infinity mark.

If you can't focus beyond 15' you obviously don't have it adjusted for infinity.

Brevis has a very good method of setting collimation. Follow Dennis's instructions above.

April 1st, 2009, 05:53 PM	#1
Jason LeFrense Regular Crew Join Date: Jun 2008 Location: Sydney Canada Posts: 126	Focusing with the Brevis MP.1 Hey Folks, I'm still working out some bugs with my new Brevis. One issue I have is focusing. I have my back focus perfect and I can get some really sharp images but anything farther then 15ft is soft. I'm new to the 35mm adapters so excuse me if this is normal. If I'm 15ft away from say a podium there is no way I can get them in focus. I'm using Canon FD lenses and I have tried 3 different kinds. And I used a canon EF lens and I got the same results. Is it because the aperture is wide open ?Focusing on object from 15ft or closer is a piece of cake.I'm using the Brevis Mp.1 with Sony EX3.

April 2nd, 2009, 07:36 PM	#3
Dennis Wood Major Player Join Date: Mar 2005 Location: Ontario, Canada Posts: 916	Jason, definitely check out our video segment covering micro-collimation. The adjustment ring allows accuracy better then +- .01mm so you should be able to get it perfect with very little messing around. You may wish to start with your lens set at infinity and then adjust the ring (leaving the lens mount "loose") until you have a sharp image. Then you can fine tune by using the tape measure technique we discuss in the video. What lens are we talking about here? Cheers, Dennis Wood www.cinevate.com

April 4th, 2009, 10:08 PM	#4
Leonard Levy Trustee Join Date: Feb 2006 Location: USA Posts: 1,684	People use the word back focus on adapters to mean 2 different things. You may be referring to the video cameras focus on the surface of the adapter screen. That's an incorrect use of the word back focus though. It should reference the 35mm lenses being the proper distance from the screen on the adapter also called collimation. If this "back focus" is set correctly then you should be able to focus the 35mm lens on a distant image approximately at the lens barrel's infinity mark. If you can't focus beyond 15' you obviously don't have it adjusted for infinity. Brevis has a very good method of setting collimation. Follow Dennis's instructions above.