Hi, I'm Ollie Kensington.
And today, I thought I'd
give you some tips if you find yourself suddenly having to use a DSLR
of a mirrorless camera not for stills,
but to shoot video.
There are a few things to consider when you're shooting video and exposing based on your frame rate
and also gamma curves that you might be using in the camera.
So, I'm gonna cut to a live feed from my EOS R here
and show you the things that you'll need to bear in mind when exposing for video.
The first thing to consider is our exposure triangle. You can see
along the bottom on the EOSR interface:
we have our shutter speed,
we have our aperture and we have our ISO.
So the shutter speed here is currently at 1/20 but in my video that would be too low
based on my frame rate.
My frame rate is 25 frames per second,
so my shutter speed has to be twice as fast in order to maintain a
normal amount of motion blur.
So I need to have my shutter speed on 1/50 of a second.
If I very either direction,
I'm either gonna introduce to slow a shutter I'll end up with motion blur,
or I'll have to fast of a shutter.
And I'm gonna introduce a strobing effect which also looks artificial.
That's essentially taken away one of my three exposure points.
So I have my hand tied behind my back in many ways when I'm exposing,
which puts a lot more emphasis on lighting.
Now my aperture,
that's pretty much exactly the same as if we were shooting stills.
I want to think about what depth of field I'm trying to achieve and choose an aperture that matches that.
The last thing here is, of course, my ISO.
My ISO can be moved up and down.
But again,
whereas with stills we can shoot raw,
we have a lot less room for manoeuvre with video, unfortunately,
which means we can't just start changing the ISO after the event like
we can with a raw file.
So my ISO,
I'm going to adjust within a smallish range until the chip at the top.
So this is the 90% reflectance chip
is sitting at 90 on the histogram.
Those little lines you can see,
the vertical lines on the histogram,
those air at 20% increments.
So the furthest left is zero.
And then we have 20, 40, 60, 80 and 100%.
So you can see the spike is exactly halfway between my
80% on my 100%.
Now, I should point out you don't have to use a chart like I am here.
In order to use this technique for exposing you could, of course,
just use any white piece of paper.
And that should also fall at 90% on a histogram.
So at ISO 400 F4 1/50 shutter speed,
this image is perfectly exposed.
But what if we change our frames per second?
I've just said how the frames per second dictates the shutter speed based on the
normal amount of motion blur.
If I change my shutter speed from 25 frames per second to 50 frames per second,
the exposure is still correct currently,
but that's because I've left my shutter speed at 1/50.
If my frame rate is now 50 frames per second,
that means my shutter speed has to be 1/100 of a second in order to maintain
normal motion blur.
I now have to compensate by pushing up, in this case my ISO,
in order to get back to where I began.
The other thing that I need to bear in mind is if I want to change my gamma curve,
on the EOS R I have the option to use the Canon log curve.
And if I turn that on and come out,
you can see instantly that my exposure has changed.
Because my exposure was set correctly before I altered the gamma curve.
I actually don't need to change my exposure.
It doesn't matter that
I've changed into Canon log.
It is still correct. In fact,
what it reveals is that a 90% reflectance chip should sit at
exactly 60% or 60 IRE.
when you're exposing Canon log.
So there are a few things to consider there which you might not expect when moving from using your
camera for stills to video.
Even fundamental things like the exposure triangle suddenly become a little bit more tricky
when you're shooting video.
Hopefully, these tips will prepare you for that time when you come to the point where you're shooting
video with your DSLR or mirrorless Canon camera.