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Sony XDCAM EX Pro Handhelds
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Old May 14th, 2010, 09:46 PM   #1
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Back Focus ?

I have never experienced this but have to ask a stupid question.

Can you have back focus issues if you only use Manual focus.
I know dslr's have had issues before but seemed that it was always using auto focus.
I am hoping that what you are seeing in the viewfinder is what is being recorded. If not I want to do some test more often to make sure this is not an issue.

Sorry if this is really a stupid questions, just seeing lots on this topic and hard to believe so many use Auto Focus.
2 Canon XF305's
Kyser Photography
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Old May 14th, 2010, 11:14 PM   #2
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In all my years, I had never ever ever used Auto Focus.... UNTIL I got my EX1. It's really good. And it saved my buns a few times when the action was too fast for me to catch up or subject would change positions quickly without warning. Love this camera.
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Old May 15th, 2010, 12:57 AM   #3
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Back focus issues could occur while using manual or auto focus but would be more noticeable using manual focus depending on how quickly the auto focus adjusts. Since back focus is the inability of the lens to keep focus while changing focal lengths (zooming in or out) it really has nothing to do with manual vs. auto focus. You just may not notice it as much when using auto focus if you're not zooming too quickly and the auto focus can keep up with adjustments.
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Old May 15th, 2010, 11:12 AM   #4
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Its not a stupid question and the answer is absolutely yes you can have back focus issues on any camera mainly with zoom lenses, and more with manual focus . I'm afraid I don't have the energy to explain the entire issue here again, but if you research back posts and you do some web research googling back focus then you'll be able to educate yourself about this very basic optical issue . Every cameraman should understand it. It has been a problem with EX-1s and is a persistent problem with EX-3's everytime the lens is changed.
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Old May 15th, 2010, 12:10 PM   #5
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I thought the Ex3 "remembered" the settings of each lens ie standard and the Fuji wide angle. If I use an adaptor with Nikon Lenses will the EX3 forget settings when I put the standard lens back on?
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Old May 15th, 2010, 01:25 PM   #6
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Yes the EX3 is supposed to remember setting for serial number on lenses, only EX lenses though.

I once had my EX3 forget the setting, while shipped as carry on luggage on a bumpy ride. The lens never was taken off but something got bumped. And it was way off when I went to use it.

The moral of the story is, always carry a BF chart. I keep one on the back of my slate board, that is always with me. I have set it a few times in the field even with the talent holding the chart, amazing but it does work, You do have to be on a tripod though. And keep the BG as plain as possible. It is easy to do.
Olof Ekbergh
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Old May 16th, 2010, 10:58 AM   #7
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Yep, bumping a lens around in transit can cause the back focus to shift. Every time I fly and the camera goes in the hold I have to redo the back focus on arrival.
Alister Chapman, Film-Maker/Stormchaser My XDCAM site and blog.
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