Part 2 – Composition, Exposure, Aperture and ISO

Hey guys! It’s time for the next part. This will explain the basics of different camera functions, and briefly explain why each settings are used in different situations.

Again, I’d just like to say: Please fav this article and post links in your journals, as this will help more people to see it!


Composition:

Composition is absolutely key in creating a powerful image. Without proper composition a photo loses the potential it has to be spectacular. It is therefore essential to think before you shoot… I cannot stress enough how important this is!!!


Rule of Thirds

This rule is an essential rule for composition. It follows the basis that humans are naturally more inclined to like an image that follows this rule, than one that does not. As I don’t know how to put images into this article, I will try to explain it in words.

If, however words don’t quite work, then here’s a link: [link]

Imagine that your image is split into 6 pieces. 2 high and 3 wide, then draw imaginary lines along where they split… This forms the basis of your grid. All segments should be of equal size. Now placing objects/ people on either the left or the right hand line where they cross the horizontal lines will put the subject a third of the way into the image. Examples can be seen here:



And one portrait example:




As you can see, it can create some powerful imagery, and lead your eyes on to the rest of the scene. This composition works best if the scene is not too cluttered. Cameras such as the EOS 40D have focus points positioned a third of the way into the scene, so putting the object of interest on these focus points will help you to follow the rule.

In some instances, when composition is deliberately changed to focus the main subject in the centre of the image, symmetry can be key to producing a strong image.

Leading lines

Another powerful tool… Composing a shot with a path running through, or lines converging on a point give a photo good depth and direction. Some examples:




Foreground Interest: Will be explained in landscape specifics.

HOWEVER - These are simply guidelines. They don’t have to be followed down to the last detail. Once you get used to these rules and how they work for the scene presented before you then you can use and manipulate them as you will. For example, some people believe seascapes shouldn’t have the horizon in the centre… But if it works for a certain image, then it works.

Exposure:

A perfectly exposed photo will have minimal clipped highlights and lost detail in shadow. Normally your cameras metering system should take care of this but there are occasions where it falls short. This is particularly noticeable whilst shooting landscapes. The difference in light between ground and sky is often too large and has to be equalised by the use of graduated filters. This will be explained in detail in landscape specifics.

“Blown highlights” is a term used for referring to a section of a photo that has lost its detail in the highlight (bright) areas.



These show evidence of blown highlights in the sky, and do not give a nice effect… The use of filters in this situation would have been preferable…

With filters used:



As you can see, these photos show proper detail in the ground, and no blown highlights in the sky. Much better.

Advanced Exposure:

This section is slightly more advanced than the standard exposure section.

The exposure histogram is an essential tool for getting the perfect exposure. Your camera (without exposure compensation) is designed to give the “bell-shaped” histogram, with the peak in the centre. However, technically, the best exposure is one that has a histogram leaning towards to the right hand side. Whilst this will appear overexposed on your LCD, it should be aimed for. This is due to the fact that if this is done, then more detail will be captured by the sensor in the shadow areas, and when corrected in post-processing, will result in a more detailed shot. However, be careful not to blow any highlights!

Personally, I always shoot with +2/3 or +1/3 exposure comp and Canon’s Highlight Tone Priority on.

PS. Always shoot RAW!


Light:

Light, as you’d imagine, is very important for photography! I’ll go into the specifics for each style of photography in their own section, but if the light’s not right, the photo won’t be either…


Aperture:

Pretty much all of the time, my camera is set in Av mode (Aperture Priority). This controls how open the hole in your lens is. (to put it simply.)

Things to note:

1. A large aperture allows more light in. This increases shutter speed and reduces DOF.
2. A small aperture allows less light in. This decreases shutter speed and increases DOF.
3. The smaller the aperture, the higher the f number (eg. f22 is a small aperture).
4. “Stopping down” a lens refers to decreasing the aperture. (increasing the f number)
5. Stopping down a lens increases corner sharpness (to a certain point).

As you can see, by controlling the aperture, you can control a lot of aspects of your shot.

ISO:

As a general rule, a higher ISO gives more noise. This is due to the fact the sensors pixels become more sensitive to light. More noise is noticeable with a smaller image sensor, so compact cameras fair the worst for noise.


Whole ISO stops: 100, 200, 400, 800, 1600, 3200, 6400.
Whole aperture stops: 2.8, 4, 5.6, 8, 11, 16, 22.
Whole shutter speed light stops: double, or halve exposure time.

These ISO measurings show the changes in ISO required to generate a change of a whole stop of light. For example, shooting at ISO 100 compared to ISO 400.will reduce shutter speed by 4 times providing the aperture is kept constant. The whole aperture stops represent the change in the values of aperture needed for a whole stop of light change.

For example: 1/25s @ f11, ISO 100 is the same as 1/100s @f11, ISO 400.

1/25s @ f11, ISO 100 is the same as 1/100s @f5.6, ISO 100.

1/25s @ f11, ISO 100 is the same as 1/200s @f5.6, ISO 200.

1/100s @f16, ISO 800 is the same as 1/25s @ f11, ISO 100.

I hope that with these examples you can see what I mean. One light stop in shutter speed terms, either doubles, or halves the exposure time. This information is only really useful for using grad filters or neutral density filters. I’ll explain it in full in landscape specifics.

It is possible to manipulate your aperture and ISO to get longer or shorter shutter speeds. Alternatively you can use Tv (Shutter Priority).

One for the film SLR users:

Say your vintage SLR only goes up to ISO 1600. If you load it with 3200 film, then it’s metering system won’t work properly. However, using the rules above it’s easy to calculate what will give the correct exposure. Simply keep your camera set to ISO 1600, and adjust aperture and shutter speed till you get what the camera believes is the correct exposure. Now, all that has to be done is to halve the exposure time. Eg, If you’ve got 1/160s, then the correct exposure will be 1/320s.


Please note again, that these articles reflect my views and are not necessarily correct and everybody has their own opinions. If you do something differently to me, then feel free to comment below and say it. I would like to learn off you as well! Last article ^KevLewis pointed out that he’s a big fan of Live-view and made some excellent points as to its benefits. This sort of feedback is what I want to see down in the comments so don’t feel like you can’t write it!

Also note that I have no photographic qualifications, and have never done a photography or post-processing course. So if something here is wrong then sorry!