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Measuring Focus with Lens Adapter


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#1 Nicholas Jenkins

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Posted 20 September 2008 - 04:59 PM

Hey all,

I'm working with an XL-2 with the Canon EF Lens Adapter. I'm going to have a 50mm, 70-200mm, and a 17mm but I suppose that doesn't really matter. What REALLY matters is I'm not quite sure how to measure focus on this camera.

Am I measuring to the chip? Or to the end of the lens? Is there a mark on the camera and I'm just blind?

I searched and didn't find anything specific for THIS camera, but to be honest... I'm not the best search user on the planet.

Any info would be greatly appreciated.

Thanks,

Nick J.
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#2 Stephen Williams

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Posted 21 September 2008 - 02:32 AM

Hey all,

I'm working with an XL-2 with the Canon EF Lens Adapter. I'm going to have a 50mm, 70-200mm, and a 17mm but I suppose that doesn't really matter. What REALLY matters is I'm not quite sure how to measure focus on this camera.

Am I measuring to the chip? Or to the end of the lens? Is there a mark on the camera and I'm just blind?

I searched and didn't find anything specific for THIS camera, but to be honest... I'm not the best search user on the planet.

Any info would be greatly appreciated.

Thanks,

Nick J.


Hi Nick,

Those are still camera lenses, which aren't collimated, so you will probably have to make your own focus marks. The focus on the zoom probably won't hold as you zoom. A quick test will tell you.

Stephen
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#3 Jamie Metzger

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Posted 21 September 2008 - 10:44 AM

Just as stephen told you, you need to play with the lenses.

Depending on which lens adapter you are using, it's just like backfocus on an f900; it will shift. You cannot trust the focus markings on the lens, so you will need to eye focus, which is a pain for multiple focus point shots.

Keep the inside of the adapter clean as well.
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#4 Nicholas Jenkins

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Posted 22 September 2008 - 01:07 PM

Just as stephen told you, you need to play with the lenses.

Depending on which lens adapter you are using, it's just like backfocus on an f900; it will shift. You cannot trust the focus markings on the lens, so you will need to eye focus, which is a pain for multiple focus point shots.

Keep the inside of the adapter clean as well.


Ug... thanks for the input guys. That's what I was afraid of. :( You'd think they would have come up with some type of system.

Grrrrrr...
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#5 Albert Wood

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Posted 25 January 2009 - 02:54 PM

Hello All, Canon 'have come up with a system'! The FU1000 viewfinder. When using any black & white instead of colour viewfinder it is easier to see if the view is focussed. Professional viewfinders (including the FU1000) should be adjusted such that the details in view have a bright fringe when in focus. The amount of fringing can be set to suit the operator preference. The effect is similar to range finder focussing on still cameras.
Usually focussing on a straight vertical or horizontal line at the required distance makes it easier to see when focus is attained.
Cheers, Albert.
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#6 Stephen Williams

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Posted 25 January 2009 - 02:59 PM

Hello All, Canon 'have come up with a system'! The FU1000 viewfinder. When using any black & white instead of colour viewfinder it is easier to see if the view is focussed. Professional viewfinders (including the FU1000) should be adjusted such that the details in view have a bright fringe when in focus. The amount of fringing can be set to suit the operator preference. The effect is similar to range finder focussing on still cameras.
Usually focussing on a straight vertical or horizontal line at the required distance makes it easier to see when focus is attained.
Cheers, Albert.



Hi,

That's fine for a static image, but when camera & actor move it won't help you very much.
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#7 Freya Black

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Posted 25 January 2009 - 07:42 PM

Hey all,

I'm working with an XL-2 with the Canon EF Lens Adapter. I'm going to have a 50mm, 70-200mm, and a 17mm but I suppose that doesn't really matter. What REALLY matters is I'm not quite sure how to measure focus on this camera.

Am I measuring to the chip? Or to the end of the lens? Is there a mark on the camera and I'm just blind?

I searched and didn't find anything specific for THIS camera, but to be honest... I'm not the best search user on the planet.

Any info would be greatly appreciated.

Thanks,

Nick J.


To answer your original question tho, the focal plane would be where the chip is. I've never seen it marked on a video camera tho. Normally there would be like an o with a line through it on the body of the camera. Nice cameras have tape hooks for your tape measure even allegedly. :)

love

Freya

Edited by Freya Black, 25 January 2009 - 07:47 PM.

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#8 Albert Wood

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Posted 27 January 2009 - 06:57 AM

"Hi,

That's fine for a static image, but when camera & actor move it won't help you very much."

That's why focus pulling is such a skill.
Cheers, Albert.
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