[Music] Welcome back DPReviewTV viewers
it's Chris Nichols here from dpreview.com and I'm trying annunciation this time
so no more 'Christicles.' I think
this week I'm gonna call you guys 'Deepers' that's what we're gonna go with,
that's your name this week. Let us know what you think and you know what we're
gonna do today is something that you've asked for on the forums, people are
saying we want some instructional videos on videography: techniques, exposure
handling, Log files all that kind of stuff so today we've got a fun and easy
entry level video we're we talking about video graphic exposure today. Now for
today's video we're gonna keep it simple so we're gonna assume that we're not
doing Raw recording or Log recording yet just that you're starting out and using
standard color profiles and if all that stuff that I just said makes no sense
don't worry we're probably gonna address that in future instructional videos for
you but we're gonna be talking about today is the four basic aspects of video
exposure so I know you guys are all familiar with your exposure triangle in
photography so this is simply an exposure triangle with four aspects
[Jordan] That would be a square Chris It's [sigh] we're going to go with trapezoid. It's a trapezoid
an exposure trapezoid because those are kind of triangular but with an extra
thing. Alright so I want to start off talking about aperture and how that
plays a part in videography you know essentially depth of field is identical
between photo and video but you can use depth of field in very creative ways for
video like you just saw now: a person walking from out-of-focus to the plane of
focus. Now of course very thin depth the fields a popular look in photography
because it very much draws the viewers eye to the focal point you want them to
look at and that does work in videography as well but some of the
challenges you're gonna face with ultra thin depth-of-field are, for example
looking at somebody talking just like I am if you're moving your hands a lot or
bobbing your head in and out you can very easily have that subject go in and
out of focus it could be quite distracting so you know one thing that
Jordan really recommends even though you bought those really expensive wide
aperture lenses he'll often suggest stop down a bit give yourself a little bit of
leeway so you have that coverage just in case in the end though it's all up to
you how you want use it creatively and don't forget you
can manually focus and use that depth of field in a very interesting way to draw
the eye visually through your frame. The last thing I want to touch on is f-stops
versus t-stops you're gonna hear that quite a bit in the video world now I'm
not going to get too technical but just remember that an f-stop value as part of
a mathematical equation, it's your focal length of your lens divided by the
actual diameter of the aperture blades in millimeters but it doesn't
necessarily mean that that's the exact amount of light coming through the lens
there's lots of other factors involved where you might lose some light
transmission what this all means is that if you buy a really fancy lens and it
says it's an F 1.4 it might not actually give you '1.4 amount' of light
you might be getting something more like 1.7 or 1.8 it really depends on the lens
so t-stops are very simply this rather than go with the f-stop value the
manufacturers actually figured out the true light transmission and they're
giving you a t-stop to represent the actual light going through to the camera
Now in photography f- stops aren't a big deal our cameras are often doing
automatic exposure so they compensate for this little issue here any sort of
post-processing can take care of it from photo to photo to photo we're talking
about you know in most cases a third stop but in videography this can be an
issue I mean imagine if you're doing multicam work for example on a live show
where you've got two different lenses at 2.8 and they're not giving you the exact
same amount of light that could be a problem and even if you can fix it in
post afterwards if you've got a multi-day shoot we're talking about a
lot of work from scene to scene as you switch lenses it's expensive and this is
why you might want to invest in t-stopped lenses. Hey everyone it's Jordan to
talk about shutter speed and this is definitely the exposure variable that
photographers struggle with the most because in photography we're primarily
using it to freeze action but in video it determines the sense of motion in the
shot and let's just wave our hands around in front of our faces right now
especially if you're on public transit right now and you can see we see a
natural blur when we do that same thing that you're seeing in the video right
now that's because we're using a shutter speed that's double our frame rate we're
shooting 24 frames per second right now we're shooting at a forty eighth of a
second and if your camera can go close 50th of a second but whatever frame rate
you're shooting at, double your shutter speed will give you nice
natural looking movement okay so for a perfect demonstration of shutter speed
I'm bringing in my friend, local legend Adam Mudry. Ad..[trails off] No you're supposed
to come from... you know we don't have time or enough fog, let's just, let's just
do this [Music]
so while Adam's playing right now I've shot this at a 50th of a second
which is going to give us natural-looking movement and a 500th of
a second which is a shutter speed I would use if I was photographing live
music to freeze action and you can see the 500th of a second looks
really weird here where our 50th of a second we're seeing some blur we can
actually see where the drumsticks are going at a 500 they just appear and
disappear around the frame irregularly looks extremely weird it's not how our
eyes see motion you look at things like horror movies occasionally they'll use
fast shutter speeds for effect because it's disorienting but I don't want
everything that I shoot to look like a horror movie and it doesn't just apply
to fast action here you can see Chris talking and I guess doing some judo or
something and you can see even with this slower movement the fast shutter speed
looks weird when we're looking at it right now and that's why we want to try
to stick to that double your frame rate rule so what this really means is
shutter speed is just going to be a fixed exposure setting for the vast
majority of your shooting, if you really want to control light levels generally
you're going to be using your iris to do that [Chris] Jordan it's an aperture, they're the
same thing, stop using your video speak Iris or aperture to adjust exposure if
you're in lower light you're also going to be using your gaint to adjust exposure
[Chris] That's more video lingo now I'm gonna explain that later in the video
We'll get to that, or you can also use filters if you're in bright light again
we'll touch on all that stuff later you know what, Chris can talk about something
now I'm out. Alright deepers this is a quick and easy one I want to talk about
ISO and essentially when it comes to photo and video ISOs identical same
values same kind of light sensitivity but that being said I just want to keep
in mind Jordan just talked about how he often use relatively slow shutter speeds
to do video as compared to photo and because of this you don't often have to
crank your ISO that high. Also on top of that if you do need to raise it to get
your depth of field where you need it by all means do it but I find that in video
it's a little bit more forgiving because with the motion the noise patterns
always changing it's not as abrasive as in a photo. Last thing I want to mention
because videographers think that they're cooler than the rest of us they like to
call ISO 'gain' it's an acronym I believe it stands for gangsters and
industry ninjas because that's what they consider themselves
Alright so let's talk about the fourth leg of this exposure square I'm calling
it a square Chris. [Chris] it's a trapezoid and you know it. Regardless right now we're
shooting in a bright day we're at our lowest sensitivity, we're at a 50th of a
second so I get nice natural motion blur but you can see we've got this really
distracting background and Chris has already put a three-stop ND filter on it
just to be able to shoot at 5.6 but i still don't love this background so
we're gonna put some more ND on right now so now we've got 6 stops of neutral
density on there so we're able to shoot at f/2 and you can see we've knocked
that background out more effectively so I'm using my aperture choices creatively
and then I'm using neutral density when I'm in bright Sun to control the
exposure that's why you really want to have these in your bag now there's a
couple types of neutral density filters I like using these fixed ones because we
can swap them over and out and there's no issues with reflection anything like
that you'll also find variable neutral
density filters and these will let you smoothly move between different exposure
gradients the trouble with that is they're polarisers as well, so you'll see
weird things happening with your reflections when you change exposure and
even when you pan the camera so I prefer working with fixed ones but it is
certainly a bit less convenient. So now Chris is shooting me with a neutral
density filter and a polarizer and polarisers are great because you
probably already have one in your gear bag they'll cut down on average 2 stops
of light now right now Chris doesn't have the polarizing effect on but as he
swings it over here you can see that the reflections in the water lessen also the
exposure on my face shifts a little bit looks really great the problem is if I'm
using two angles one with the polarizer one without the polarizer my saturation
and exposure are going to shift between shots so I love using 'polls' for video
just don't mix and match shots with and without a polarizer. All right I hope you
enjoyed that useful little tutorial on the video exposure trapezoid you know
the video exposure square. It's a trapezoid and you can you can solve that
argument on the comments below and don't forget there's so much more we want to
talk about in terms of video exposure and techniques things like frame per
second things like Log file, Raw recording, camera movement audio lots of stuff that
we want to touch on let us know what you guys would like to see in the comments
below and also don't forget to check out our Twitter our Instagram feeds and
definitely subscribe if you want to see more content yeah I mean that's the way
to show us that you want to get more of this content so
That's how you show us love. Yeah show us up we're so insecure, all youtubers we need
the love and of course comment below anything else you want to talk about we
could do photography tutorials otherwise in the meantime if you looking for some
more information yeah if you really found this useful check out Richard
Butler wrote an 'Intro to video for photographers' you can see the link in
the description below great article to get you started as well but don't worry
more reviews coming soon so stay tuned [Music]