In this video
I take a closer look at focal length and background compressions.
Adorama TV presents Take and Make Great Photography with Gavin Hoey.
Hello I’m Gavin Hoey and your watching
AdoramaTV. Brought to you by Adorama, the camera store that has
everything for us photographers, including a
really great choice of lenses. In this video I’m going to look at two specific
aspects
of focal length, and that is the angle of view that you get from a particular lens,
and also how a lens choice can affect the compression
from your subject to the background or the expansion a bit as well.
So let's start with probably the easiest to grasp and that is the
angle of view. So to help me demonstrate this I’ve enlisted the help of Fern
and she’s going to be my model today, although we're not really here to take great
pictures of Fern it’s really about
understanding how all these things work and affect your photography.
Now today I bought with me a range of lenses from 24mm
to 200mm. The focal length
is the number part. So it works like this. If you have a small number
your going to get a wide field of view and your going to end up with things
looking pretty small in your photographs. If have a big number
you have a very narrow field of view and things seem really big
in new images. So let's put that into practice and to go back a little bit and
take some shots.
So let’s start with a wide end 24mm.
Here I go, great. So at 24 millimetres
as you would expect, it's a wide field of view. I can see all sorts of stuff around the
outside of the picture
and Fern looks teeny tiny in the center and that's exactly what you want with
that type of lens.
It's great for landscapes and great for portrait shoots when you want to show
your subject
in their environment. So now I’ve swapped to my 200mm lens.
I'm gonna take essentially the same shot and by that I mean
I'm not gonna move, Ferns not gonna move. The distance between us
is going to be exactly the same and that
is really important. Okay here we go.
So as you might expect, it’s a much
closer shot because it’s a much narrower field of view
and the two picture’s, well they look completely different. But are they
as different
as they first appear. Well to show you something that might surprise you I need
to jump from here
into my office and have a quick look at photoshop.
You’ll often hear photographers talk about background expansion
or compression and that simply where the background appears to be further away
or closer towards
your subject. They also talking about focal length.
But is it just about focal length? Let's have a look. So here I have the
200mm shot
and also I have the 24mm shot.
Now if I just go and get a little bit out the centre, I reckon that's about the
same area as the 200mm.
So just going to paste that in. Now obviously it’s a lot lot smaller
because it's a tiny crop from the picture, but if I go and expand it and
well just kinda bring the opacity down a little bit, and we’re going to make this a little bit
bigger.
Something like that. That looks probably.. yeah that looks about right and so we can just line
everything up.
Okay there we go. Pop the opacity back up and commit to that.
Now the first thing you see when you look at these two pictures one after
another
is there is a difference in the depth of field. Ignore that for today.
That is a whole other video topic. What I'm interested in
is the background. Does it appear further away on the 24mm
and closer on the 200mm? Or is it the same?
So this is the 24mm and if I flick onto the 200mm
it is exactly the same. Yeah there is a difference in the depth of field of
course.
Essentially the compression and the perspective distortion
are exactly the same on both the 24mm shot
and the 200mm shot. So if it isn't
the focal length that affects background compression and expansion,
what is it? Well the answer is it's you
and
your subject. Specifically how far apart you are
when you taking your shot and of course therefore what focal length you're
going to need to
frame-up your shot. Let's have a look. So I've got an idea in my head of how I
want to frame up a shot of Fern.
Let's start at the 24mm end of the lens.
That means I’m going to go really close. In fact
I've got to keep coming all the way to here. Now at 24mm
I have to be really close to Fern to get the shot that I want.
Ferns fairly close to me and relatively a long way away from the background.
End result is the background appears to be miles away from us.
In fact much further away than it appears with my eyes. So
thats the 24mm, but what if I double it to 50mm?
If I still stand here. I’d only see half the picture I had before.
So if I want the same framing at 50 millimetres
I need to step backwards.
There we go. We get the same shot again. Now at 50mm that background
has come a little bit closer to fern.
In fact that's pretty much how it looks to my eyes more or less.
By the time I get to 100 millimetres the distance between me and Fern is now
greatly increased.
When I take the shot is going to look really different. So now the background
is coming much closer
into the shot it looks like the distance between Fern and background has decreased.
When of corse in reality it's exactly the same. Okay let's go all the way to the
top, 200mm.
200mm. I’m going to have to go back.
Brilliant.
So there you go, at 200mm all I can see is background. The background
has come right out
behind Fern and completely fills the frame. So it breaks down like this.
if you got a distracting background that you want to push way, way back.
You can use a wide angle lens and go close. If you want to bring the
background
into your shot, you can use a telephoto lens but step back.
But of course is not just those two things we've looked at with focal
length.
There are other reasons for choosing one focal length over another
and if you want more information head over to the Adorama Learning Centre.
Alternatively of course you can click on the subscribe button
and see more videos from myself and the other amazing presenters
here on AdoramaTV. I'm Gavin Hoey, thanks for watching.
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