Back to Basics - Exposure, Part 1 - Understanding Aperture

[Chris Dodkin]

Slackers!

 

[Ahmad Bhai]

Is there any way to add tutorials (as this) as part of the main page.
I feel it adds value to RPF particularly for those who may not join yet visit,
or chance upon it in google.

 

[Hamish Gill]

I like the idea ... but really, if you want tutorials, http://www.cambridgeincolour.com/ is very hard to compete with for quality!

 

[Ahmad Bhai]

You, Pete, Chris and others have taken time to write tutorials it would be a valuable main feature of RPF.

(Im what is termed a "Kinesthetic" learner ... aka fumble)

 

[Raza Shaikh]

Thank you, Hamish. Great in-depth guide.

 

[Stephane Tougard]

The scene modes employ a combination of settings
Portrait mode will rely of face detection to find the face, adjust exposure on skin tone and focus on the eye (if it's good enough) it will then use a large aperture to help knock the background out of focus.
Some cameras will even soften skin tones! Madness putting that in the hands of a camera IMO but there we go...

Landscape mode will do the opposite, meter of the whole frame, set a small aperture to get as much from front to back in focus as it can. Some will adjust colours slightly too ...

There is nothing wrong with scene modes for those who have little interest in learning ... Photography is not for everyone, but everyone wants to be a photographer ... Of you get my meaning ...

Portrait mode can be emulated in the following way
Set the camera to aperture priority, and a large aperture
Set it to spot meter, or centre weighted
Set the camera to focus from the centre spot
Point that at the subjects eye, holding the button half way down, recompose the frameing to how it looks best and take the shot

I was banging on to Paul on the phone yesterday about how if somthing is easier it shouldn't nessasarily be dismissed ... portrait mode does make things easier, as it takes away the need to think!
Photography should be about thinking about what you are doing ... Especially as an ameture!
Technology that makes things easier is much better employed for speed by a pro who already knows how to do it the hard way ... I'm rambling again here ...

In fact, the width of the front glass of the lens is equal to the length of the lens divided by its max aperture. So a 300mm f2 (a very expensive lens) would have a frontal glass of 15 cm, at least. BTW, don't forget that those number are given for the focus at the infinite, if you focus closer, your 300mm has a longer length, it eats more light. So a 300mm f2 is not f2 at all if your subject is at 10 meter away. It's usually ignorable, except for macro photography, when a 50mm become a 100mm when you focus really close (and more), then 2.8 become 5.6.

I remember once, we were making photographs of a watch with a 4x5 inches camera. The focus was so close that we could not see any picture on the glass (too dark, even at the widest aperture). We had to make the focusing with Polaroids (the negative of B&W Polaroids is actually very good for this).

The aperture of a lens starts at 1, each following value is equal to the previous one times the square root of 2.