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Photography ConCrit Interested amateur photographers can post photos and receive constructive critiques from others. Please read the guidelines thread before posting any photos.

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Old Oct 27 2008, 07:48 AM   #1
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Default Aperture - crude basics

It seems to me that camera makers do a disservice to your average snapshooter. Even the basic basic Point-and-Shoot is loaded with dials, switches and options that do little but confuse and intimidate the user.

And the manuals are so badly written, apparently designed more to perplex than explain. And shoving it on a CD hardly makes it portable and readable once you're out the front door! OK, gripe over.

What people often forget is that, under all the sparklies and knobs, a camera is still just what it was 150 years ago - a lightproof box with a small hole at one end and a recordable medium at the other.

The lens is just a series of glass pieces that arrange the light so it arrives at the film or sensor in a coherent manner.

Of course, in modern cameras, you can let the camera decide everything. All you have to do is frame the picture and press the button. On Canons, it's called the Green Box setting. Other manufactuters will have a similar position on the main dial.

Beyond that, photography is simply a matter of juggling three factors which control the light -

shutter speed
ISO (the sensitivity of the recording medium).

It's useful to know that all settings in all three parameters above work on the simple arithmetical principle of halving or doubling.

But why three?

APERTURE is an assembly within the lens that acts like the iris of the human eye. In bright sunshine, your iris will contract to a pinpoint, restricting the amount of light entering the eye; in dim light it'll open wide. So it is in a camera. The ƒ numbers tend to put people off, but are just a way of expressing an optical formula.

Why is aperture useful? Because it gives you control of Depth of Field - basically what is in focus in front and behind your subject. At a wide aperture, DOF is narrow, thus isolating your subject and making it jump out of the picture.

To illustrate the point, here's a shot I just took at the widest aperture of ƒ1.4 on my 50 mm lens. Note the background - all blurry and indistinct. The subject should pop out of the frame.

And here's a shot from the same location, shot at the smallest aperture of ƒ22 - see how much more is in focus?

You can already see the possibilities, right?

On a landscape shot, you'd want the foreground object (a tree?) in sharp focus while also keeping the distant mountains sharp. So you'd set the camera to shot at a small aperture, somewhere around ƒ11.

But shooting a head-and-shoulders portrait, you don't want distracting elements in the background to intrude and detract from the subject. So you focus on the eyes and open wide to ƒ2 to blur the background.

Aperture is just a tool which allows you to tweak your image.

There is a direct link between aperture and shutter speed - ƒ2 at 1/100 sec will give exactly the same exposure as F2.8 at 1/50 sec - double one; half the other.

I'll explore that later, if people are interested, I can chuck a new subject into the pot every week. If you have questions, I'm guessing Hans and others will be happy to help out.

What do you think?
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Old Oct 27 2008, 08:52 AM   #2
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Default Re: Aperture - crude basics

As far as I'm concerned an interesting peoposal I think people might be interested and for myself it'll be a refresher course which I'll gladly take.

On the other hand... I thin the majority won't even have acces to SLR camera's, whether digital or not. Maybe we also need to take the modern, more simple digital camera's into the equasion and see what tricks we can come up for those...?
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Old Oct 27 2008, 09:26 AM   #3
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Default Re: Aperture - crude basics

You are right. I was indeed planning to integrate an average point and shoot, explain the differences, and how to get round the occasional limitations of the smaller format.

Was thinking of using my tote-everywhere Canon Powershot A700, which has features roughly in line with most decent P&Ss. It's around three years old, so pretty representative of a current middle-range camera.
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Old Oct 27 2008, 11:26 PM   #4
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Default Re: Aperture - crude basics

This was incredibly interesting...for me it was like making sence out of a foreign language...LOL.
BUT...yes, I would agree with Hans...can we P L E A S E have at least a few more, simple digital camera's instructions thrown into the mix. Your camera looks lovely...but I just got a small digital a couple of years ago, and would just enjoy to know how to better use it.

I will gladly stand back and admire/comment on your photos, along the way
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