canberrabirds

Using video to capture 'bird behaviour' - comments of note by Steve Wall

To: David Rees <>
Subject: Using video to capture 'bird behaviour' - comments of note by Steve Wallace in CBN 42(3) 295-296
From: Adam Spence <>
Date: Wed, 14 Feb 2018 13:47:03 +0000
Just a couple of quick notes.

Keep in mind different cameras sample their sensors differently. Canons for example use selective line sampling, so it will sample the image from every few lines of the CMOS. This can cause more artefacts on textured surfaces, which are better ironed out on higher end models. Think 5, Dx. I understand some models from Panasonic and Sony use full sensor sampling that has made them popular for wildlife filming in the past, but they generally deliver a more ENG look that I don’t like compared to the less detailed smoothness of Canon.

Also there is a lot of scope for time-remapping using frame interpolation. Film a bird taking off? As long as you use a high enough shutter speed (I think min 1/640) at the highest frame rate (I use 60p because in the internet age the old 25/29.4 is a bit redundant and the 24p mode cameras offer is marketing), you can then use software to approximate the effect of a proper high speed camera. I’ve yet to experiment much with this though.




On Wed, 14 Feb 2018 at 11:02 pm David Rees <> wrote:

I read the note by Steve Wallace in CBN 42(3) pp 295-296 with interest. As someone with more than a passing interest in filming birds and other wildlife I agree with Steve that video is a great way of capturing the life of birds and other wildlife. Personally I much prefer it as a medium over stills.

However, I’d like to make a few comments with regards picture resolution and image quality and related matters where I beg to differ in opinion to Steve.  Actually I think the ‘situation’ is much better than Steve made it out to be in his note. 

When you shoot video with a fully manual camera you face multiple choices as to what settings to use.  An important question to consider is are you shooting for the extraction of clean sharp frames or are you shooting to depict smooth motion?  The settings required for either are very different.  This very important point was not noted or discussed by Steve.

Video which records of a lot of motion, shoot with a fast shutter speed with each frame in sharp focus is often unwatchable as a motion image.  It is jerky/shuddery and will give you a headache if you watch it for long.  I can pull out many examples of this issue in my own work.  

There is however an old rule for filming smooth motion in video/film which is to shoot with a shutter speed of about double your frame rate.  Currently when I shoot video at 50 frames a second  I would  try a shutter speed of 1/100th of a second as a good starting point to record smooth motion.  Getting this right for optimum smoothness in any given situation is a 'black art' and I am still learning.  Obviously at such shutter speeds you will not get sharp individual frames – the problem Steve alludes to.  As you can see though, this can be fixed with utilization of different settings, if you had something else in mind in the first place.

Steve mentions image resolution.  As Steve states full HD (1080p) is a stream of 2 megapixel images – this is the resolution of most computer screens.  Almost all DSLRs shoot video at this resolution, not great relative to what they can do for stills.   However, you can shoot slo mo 1080p video at 180 frames a second. This could give you interesting images that you would not get with a still camera, regardless of resolution.

4K video is a steam of 8 megapixel images.  When I shoot this at 50 or 60 frames a second I know I can get interesting stills with the right settings. 

Actually, current reality is much better than Steve suggests –  cameras are now available that will shoot 6K video, a steam of 18 megapixel images at 30 a second in up to 10 min lengths – kills memory cards though!   No DSLR I’m aware of can currently do this but several mirrorless interchangeable lens cameras can.   At this image resolution I know decent images of frozen  animal behaviour can be obtained.

It gets better, out there now in ‘video pro land’ there are 8K ‘cinema’ cameras, e.g. those made by the likes of RED.  These can capture 35 megapixel images in raw at 50-60 frames a second for however long you want – resolution up there with the very best DSLRs, at a frame rate they can never match.  They use DSLR or mirrorless lenses, so no issues with the quality of ‘glassware’.  It’s not going to be long before this technology finds its way into a product ‘affordable’ by the keen photographer in a familiar portable form. I know of one manufacturer who has expressed an interest in doing this by 2020.  I wonder, when this happens what then will be the 'weapon of choice' to capture fast moving bird behaviour?

Oh, and another thing, video cameras record sound, and with a decent external powered mic (all internal mics on all cameras, regardless of price, are a waste of space when used outside) the sound quality captured can be very good.  Sound can be separated easily from vision and used and edited separately if required, don't get that taking stills.


David




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