so let's say I want to take a shot of these rocks and the sea and the waves
crashing against them and all the rest of it
let's construct that image it's going to be a landscape type shot so I want
lots of depth of field
so therefore i'm going to use a very small aperture i'm going to send after
f-22 now very small aperture is going to cut away a lot of light
the next thing I need to do is to choose choose manly voice choose my shutter
speed to go with that capture and they must do this looking through the
viewfinder of your camera looking at the light meter in the bottom so if i point it
down there and set it up on the back
I'm taking a light meter reading from here not of the scene that I want to
photograph so looking through the viewfinder and i'm going to show you
this in the back of the camera in a minute
looking through the viewfinder and get myself in position and set up the shot
that I want
ok f-22 that's telling me i can only have a tenth of a second shutter speed
I am in danger of getting camera shake at the moment i'm using an 18
millimeter lens so it's best to have at least 20th of a second shutter speed
otherwise the movements i make could cause the picture to blur my iso is
currently set on 200 which is the finest grain the best colors the best image
quality but i'm going to lift it up a bit
- 400 iso and that is now going to allow me to adjust my shutter speed all the
way up to
twentieth of a second I know I'm safe and I can take the picture that I want
to take the waves crashing on the rocks
let's just wait for a wave hopefully ones coming any minutes here we go
excellent and there we go
I've got the shot that I wanted without boosting the ISO i could not have
made my shutter speed fast enough
the only way I could have done it would be to introduce more like well that's
not really doable out here is it or use a wider aperture but I don't
want to do that
let's take a look at the different scenario
ok so the new scenario is I've got rid of the shorter lens and put on the long
one
why don't want the long lines well this kind of diffused light that we've been
we actually had a rain shower back in the shelter in the car but now we've got some a few sunlight
coming in and that's beautiful light from portrait long lens is a brilliant
for portraits and what could make a more dramatic backdrop for portraits
than that sea I'm lucky enough to have my favorite model back with us
we got lorna, hello lorna, so lorna if you can stand just about .
here and just kind of gaze that way sort of thing
ok brilliant thank you bear with me while I get a camera set up so let's see
what we can do
ok the sun's coming out a little bit so you're probably thinking there's enough
light
well there is kind enough life with a long lens is suffering from
camera shake that's not mention with the short one go watch the camera shake film
if you don't understand what I'm on about
so with the long lens to avoid camera shake
we need to use a shutter speed at least as fast
as the lens is long i'm using my this is a two 10 millimeter lens on a full-frame
sensor so that means that
where are we were up around 250 275 millimeters so i need to get my shutter
speed and up
well above the 250 for the second mark to ensure i don't get camera shake on a
windy day like this is even worse with a long lens because not only is the wind
buffeting the strap is buffetting the lanes everything's on the move and I don't
want a blured picture of the best model
so let's construct the image first off long lens because that's going to give
me the look that I want the shallow depth of field and the blurred
background of the sea
so I can move around and get my composition and I think it's about here
yeah that is fantastic it really does
chose my aperture I want a wide aperture to blur the background wide aperture this
lens the widest I'm gonna get is 5.6 again looking through the camera set up the
exposure with the shutter speed
just
wine that up a bit what do i got i can get a hundred sixtieth of a second
even at the widest aperture that really isn't going to be fast enough to ensure
the camera's not moving
well I can't introduce more light and I obviously can't open the aperture any
wider because it's already on the widest aperture the only place I can go
is my old mate the iso, so 200 I so I'm going to pump that up to 400 that should
double my shutter speed
assuming the light hasn't changed in the moment i did it
don't forget you've got to chase the light all the time
things are changing as you were so let's have another little look
ok so now i can manually increase my shutter speed
I can get a 320th which i think will be enough and it shouldn't blur the image i
am going to put this strap round my neck because it's blown about all over the place, Lorna do your kind
of gazing over there thing for me
her face is beautiful at the moment
put that right that's all i can see the movement through the viewfinder of this
jumping about over the place of the lights change I've had to go to 250th now
now hopefully that is good enough
yeah that's nice i like that I'm just going to check the sharpness it's always
worth checking sharpness while your on location
you know what I think that's a bit soft I'm going to increase the iso some more
it's probably camera shake and going up to 640 ISO this is going to introduce a
little bit of grain but it shouldn't be too bad and will still be a nice picture
do you stare again Lorna
she really is a great model
right let's get that focused and
and or popping up
let's have a look that's better that's much sharper thanks Lorna you can go in
the warm if you want while i wrap up where you going now
this is dropping things everywhere no she's even got a very patient Joe her
boyfriend here as well god you can give Joe and cuddle he will keep you warm so
there's a couple of ways you can use your ISO practical ways which will help
you achieve the images that you want when you're choosing an iso or even
indeed sorting out what you're gonna do with any image you need to think through
what you're going to do with it before you take it
for example are you going to make the image really big
you're going to blow it up large if you are then using a high iso which will
introduce some noise some grain that could be a problem because when you
increase the size of the image that grain becomes noticeable
so what can you do about that if you can't increase the I so you only have
really two options one is to wait until the light is brighter
so you can get the shot that you want a third option would be you could use a
faster professional lens with a wider aperture or and this is the most simple
one
my eye Thank You Joe use one of these
provided your subject isn't on the move you can stick your camera on the tripod
and you can use a slower shutter speed
if your subject is on the move that's another one you're going to need a
faster shutter speed if your subject is moving
if you've got something was on running around kids tearing about they're going
to blur in the picture because you're probably gonna be moving too
so you're going to need a fast shutter speed again your ISO can help you are
you going to crop into the image if you're using a high iso when you're
shooting
i strongly recommend you compose the shot in the camera rather than shoot a
shot and then crop away the bits you don't want because when you crop away
the bit you don't want you losing megapixels you actually enlarging a
small portion of the image which is then going to mean you're going to get more
and more grain into it
hopefully that's given you an insight into ways in which you can use your ISO
practically to help you use those fundamental building blocks to assemble the
image you want
ISO is a brilliant brilliant really really useful tool
I suggest you go and have a go with it in the meantime I'm going in the warm
come on in guys Joe is freezing look who's all hands up