BMPC active MFT lens push focus and IS best practices

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Mike K. Kroesen

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BMPC active MFT lens push focus and IS best practices

PostWed Aug 07, 2013 1:14 am

What is the best practice for using the focus by pushing the focus button when using an active MFT lens. I have always been taught that you do not use auto focus tools when doing professional cinema/motion work. I can understand the purpose when taking a still photo but not sure the advantage or best practice rational is for using the push focus button. Perhaps I do not fully understand it's purpose or how it is best used in digital cinema.
Secondary question how much of a difference does IS lenses make? Is using a mono pod for short takes and then stabilizing in post a realistic workflow or is a lens with IS a must?
Thank you for your taking the time to read this post.
Cheers,
Mike Kroesen
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rick.lang

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Re: BMPC active MFT lens push focus and IS best practices

PostWed Aug 07, 2013 4:47 am

Kroesen wrote:What is the best practice for using the focus by pushing the focus button when using an active MFT lens. I have always been taught that you do not use auto focus tools when doing professional cinema/motion work. I can understand the purpose when taking a still photo but not sure the advantage or best practice rational is for using the push focus button. Perhaps I do not fully understand it's purpose or how it is best used in digital cinema.
Secondary question how much of a difference does IS lenses make? Is using a mono pod for short takes and then stabilizing in post a realistic workflow or is a lens with IS a must?
Thank you for your taking the time to read this post.
Cheers,
Mike Kroesen


Before you 'roll film' the one-time focus may be an aid to you but you may never use that feature but rely on focus peaking and the focus assist showing you the 1:1 image magnification. At least at initial release, it is only in the very centre of the frame and that may not be where you want to focus if your camera is locked down.

If you are using a stabilizer, then most image stabilization should be turned off. Some lenses can distinguish between handheld shaking and a camera panning or tilting so if that is a feature you have, it may not be necessary for you to manually turn off the IS or set it to recognize you are on a tripod for example. If you leave IS on while you are in motion on your stabilizer, your image is likely to look bad as the IS attempts to correct your intended motion.

You may not want to perform IS in post using the BMPCC in particular if your deliverables are HD video since stabilization in post will cost you lost pixels and you may not have pixels to throw away if you want the sharpest output. If the correction is small, it may not be a problem.

Rick Lang
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Last edited by rick.lang on Wed Aug 07, 2013 7:06 pm, edited 1 time in total.
Rick Lang
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Mike K. Kroesen

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Re: BMPC active MFT lens push focus and IS best practices

PostWed Aug 07, 2013 6:37 pm

Rick Lang, thank you for the reply. I found that information very helpful and armed with said information I will be able to head down the right path for tests prior to rolling when it counts. Cheers

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