Understanding Photography
Topic Outline
• The Triangle of Exposure
• Understanding Focal Point and How it Affects Your
Image.
• Guide to Aperture and Sunny 16 Rule • Depth of Field
• Shutter Speed
Triangle of Exposure
There are three main ingredients to good exposure: Aperture, Shutter Speed, and ISO.
Think of a perfect exposure as a perfect triangle – all the angles are equal, all the sides are equal. Now if you change just one part of that exposure or triangle, it is no longer perfect so you will need to change another point of the exposure or triangle an equal but opposite amount to make that triangle andthereforethe exposure perfect again
All the elements of exposure have an effect on the others – so
with that in mind we need to know the how’s and why’s of all the
different elements to best understand how to get both a good
exposure and the desired results in our photographs.
Aperture
Aperture is a circular opening (somewhat) in our lens that is adjustable from a very small circle to almost as large as the lens itself. We adjust it to let more or less light
The opening of our lens or Aperture is expressed in f stops and here is a very typicalrange of f stops:
Depth of Field
When we look at an image, there is a part that is in perfect focus and then there are parts that begin to be out of the range of focus. You can have a small Depth of Field (DOF) where only your subject is in focus, or you can have a deep Depth of Field where practically everything is in focus – or really anywherein between.
Depth of field is determined by three things; aperture (f stop), distance to your subject, and lens focal length (50mm, 200mm etc), with Aperture having a profound effectonDOF
Photographers that shoot portraits usually use larger apertures (low numbers) for a shallow DOF to highlight and isolate their subjects. Landscape photographers usually use small apertures to have a very deep DOF, all the way from the foreground to thebackground.
As usual, there are exceptions to these rules and that is ruled by the photographer’sartisticideas and vision.
Shutter Speed
Shutter speed controls how long the light comes through our aperture to our digital sensor or film. The longer the time, the more light will hit their surface. That is technically whatshutter speed does.
Artistically, shutter speed controls motion. Whether we want to freeze motion or show motion, shutter speed is the portionof exposure that willcontrolthat aspect.
Shutter speeds are expressed in fraction of a second 1/8, 1/125, 1/1000 etc.
Beyond that we can now make an artistic judgment – do we want to stop action, or show movement? And this is a judgment you need to make. Sometimes we may want to freeze our subject andkeep it sharp and clear. Other times we want some blur on the subject to give the viewer the impression that the object is moving or is at speed.
ISO (International Standards Organization
We use ISO to help us achieve what we want to do with the other two sides of exposure; Aperture and Shutter Speed. You may ask; Why don’t we just use the most sensitive one and forget about it? Well because the downside of higher ISO is that it increases the noise or grain in our images. This can sometimes make the image lookso bad that it becomes unusable
So our objective is to use the lowest ISO possible, but balancing that towhat we wantto achieve.
Shooting outdoors on sunny or even slightly overcast days we can use ISO 100 or 200 with ease. On heavy overcast days we may need to change our ISO to 400. Especially if we use a small aperture (letting in less light) for shooting a deep depth of field landscape shot, while still being able to maintain a shutter speed that we can safelyhandholdwithouta tripod.
As we move indoors to a brightly lit room we may need to move up to ISO 800 – 1600 to take natural light photos without the need for using our flash. As we move to dimly lit rooms or street scenes, we may need to move up to ISO 3200 or higher (remembering again that not all cameras can shootat thesehigher ISOwithoutexcessive noise).
Focal Length
Selecting different focal lengths can really reshape the aesthetics of your scene. Zooming in and out on the same subject area greatly changes the way that a subject relates to the background and the perceived distance betweenthe two.
However, there is never one best lens or focal length choice. If you’re wanting to show how a subject relates to the background, using lenses of different focal lengths can change the way the background appears in relation to thesubject.
Experimenting with these various focal lengths is a powerful part of the creative process. Focal length choice is a huge part of the composition process of an image. You can use a wide lens to lead into a background or create distance, or choose a longer focal length to compress your subject against the background. A focal length of any choice can be a good one dependingon theway you envisionthe scene.
70 MM from 55-200
35 mm
Rule of Thirds
• The basic principle behind the rule of thirds is to imagine
breaking an image down into thirds (both horizontally and vertically) so that you have 9 parts. As follows.
The theory is that if you place points of interest in the intersections or along the lines that your photo becomes more balanced and will enable a viewer of the image to interact with it more naturally.
Point of Focus
When a photographer uses the term "point of focus", he is referring to that object in a photograph at which he wants to draw the most attention. "Focus" itself refers to the amount of the image that is sharp. Both the point of focus and the amount of focus affect the resulting image. In short, altering each one changes the look of the finalphotograph.
Specific, Single, Off-Centre Auto Focus Point
• If your camera has this function, then you are able to select just one
of any of thefocus pointsas reference.
• For example, you are doing a commercial or stock shoot of some bottles
or glasses of wine all in a row. You want them fading into the distance using shallow depth of field and want just the first glass, on the left of the frame in focus whilst the remaining bottles fade and blur intothebackground.
All Focus Points
• As we touched on briefly before, there are only a few situations
where I personally would use all points, being mainly sports or
nature photography with subjects that move independently and
erratically.
• These would be particularly useful for fast moving objects where
it is virtually impossible to keep them over any single point. By
selecting all points, the smart chip in the camera decides which
point the moving subject is closest to and switches back and
forth instantly to keep the subject well in focus.
Ideas to Kick Start Photography
1) Fixed Focal Length Shoots - shooting with a prime lens (fixed
focal length) that makes you think about the composition of
your shots a little more.
2) The 1 Roll Rule - limit yourself to 36 shots (the number in a roll
of film). In doing so you’ll find yourself really thinking about
your shots. You’ll time them better and make sure each shot
3) Compositional Rules
4) Explore other techniques
5) Lighting Technique - similarly set yourself the challenge
to practice your skills with a particular lighting.
Photography Projects
1) 365 Days Project -take a picture of anything every day for a year.
2) 52 Photowalks- you should get out of the house once a week with your camera.
3) 100 Strangers - The idea is to approach someone you’ve never met before, ask if you can take their picture, and talk to them a bit to get some kind of backstory
4) A-Z - You can pick a place and try to get a picture of objects that start with or represent each letter of the alphabet.
5) Pick-A-Something - For instance, pick a color and try to go all day photographing only red things, or try only getting pictures of things that are square when you’re on a walk.
6) Go Mono – Your goal is to get better at converting photos to black and white, to see things differently, and figure out what photos would look better in mono, and which ones wouldn’t.
RESOURCES
• http://digital-photography-school.com • photo.tutsplus.com/
