Wednesday, March 19, 2008

Bokeh Blades

I have an admission to make.

I cannot make sense of aperature and,
worse,
I haven't tried very hard to learn
the science behind it.

However, when it comes to making
Good Bokeh,
an understanding of how a lens works
is essential.

The number of blades needed for Bokeh is much discussed these days.

Some posters have no time for obsessing over
the "How Many Blades Make the Best Bokeh"
question, but I think, if you don't know anything
at all about lens technology, it would not be
the worst place to start.

I have taken to following light trails with my
camera, wherever I find them.
It's trial and error, but especially
when we go out in the car, some good effects
can be made by slanting the camera in ways that
pick up bubbles of light reflected from the car
windows, or from droplet of rainwater on the
windscreen.

The film makers and cinematographers are the best
guides.

I came home from seeing "In Bruges" with a whole new
series of ideas. Just a "caveat", BTW, if you are of
a "sensitive nature". This is a very well made and
superbly acted film, with some very frightening imagery.
Best keep your eyes shut, as I did, through many of
the more grotesque parts.
But the Bokeh is extraordinarily good, as many of
the bistro scenes include Christmas lights.

3 comments:

DaviMack said...

You'll make sense of it if you do the following:

- Shift your camera over to Av.
- Half-press the button, to bring the scene into focus (a flower is good).
- Spin the wheel that's right next to the shutter-release button & you'll see some numbers change (through the viewfinder).
- Spin the wheel as far as it'll go in one direction without the 'not enough light' thing blinking and take a shot.
- Now, go through the same process, but spin it the other way until you get the warning blink, then take THAT shot.

What you'll have is a shot at the smallest aperture value you can get, which will bring out all the background, and you'll have a shot at the widest aperture value, which will blur out the background.

The narrow aperture is subject to your hands shaking, of course, where the wide aperture isn't so much, and is great for flowers & people. The narrow aperture is great for landscapes & if you want to get people in front of something.

It's my favorite thing, these days, to drop out the background, particularly when I'm shooting food or flowers.

I'm shooting most of the time using Av rather than P, on the little selector wheel, mostly because I can control things like this.

Tv is to control the time, which is helpful as well - it's just controlling the other side of the see-saw. Av lets you control aperture & the computer control Time, Tv lets you control time & the computer control Aperture.

Fully manual lets you control both, and I haven't gone there yet. :)

DaviMack said...

If you take a look at my long exposure shots and at my short exposure shots you'll see what I mean about the differences. It's not so dramatic in these, because I was using a 'slow' lens, and because I didn't have much light to work with (it being night, as you'll see if you look at the other shots I got around the same time).

Short exposure (wide aperture) is particularly evident, though, in shots like this, where the bread roll that's all of 2 inches behind is way out of focus, and also in this, where the entire background drops out to nothing, and even some of the basil leaves are fading away into blur.

It gives you a very shallow depth of field.

I know - way more than you wanted to have show up in your comments.

I still haven't managed to catch a bokeh.

Tales from the Birch Wood. said...

Many thanks for such detailed instructions.
One tip is to edit your photo with the software that comes with the Canon Digital Rebel. Bokehs are often hidden in the background and all it needs it a bit of exploration to find them. Irfanview can be useful as well. It's trial and error, but if I can see how I go about it, I'll post in about a fortnight's time.

I'm going to take a good, long rest from photography, as seed sowing time has hit Dublin.

In the meantime, have a
Great Easter.