Week 2

This evening we looked at some of last weeks photos. Many of you tried the rule of thirds and setting the camera to centre focus.  Well done.   We saw a host of photos from the Giants Odyssey which took place 20-22 April in Liverpool. Here's a link to the Liverpool Echo Flickr group .

http://www.flickr.com/groups/liverpoolecho/discuss/72157629434599724/

It's well worth a look.

Teacups in the Rain

We started with a little thought experiment. Imagine I have a normal teacup which I have marked with a line inside to show where half-full is. I have three lids for the cup each with a different sized hole cut in it. The the lids look like this.

From left to right they are labelled 22,  8  and  2.8.

Outside there is a torrential downpour of rain, during the experiment the rain falls at a constant rate. My aim is to fill the cup to the half way line.

If I fit lid 2.8 and put the cup out in the rain, the water will reach the line after 5 seconds.

If I fit the number 8 lid the the line is reached after 45 seconds. Fitting the 22 lid and leaving the cup out in the rain will mean 360 seconds will need to pass before the line is reached. (Did anyone notice that during the session I said this was 3 minutes? 360 seconds is of course 5 minutes, is that why I can never cook soft-boiled eggs?)

in our analogy, the half way line is equivalent to a correctly exposed photograph. If we leave the cup out in the rain too long, the rain level goes past the line and we have an overexposed photograph. If we don't leave the cup in the rain long enough, the water does not reach the line which is equivalent to an underexposed photograph. This is the case when I use any of the three lids.

Why move off Auto?

When enrolling for the course quite a few of you mentioned that you would like to begin to use the camera off the Auto setting. The Auto setting generally does a pretty good job. I posed the question tonight, why bother using any other setting? 

 

“The camera doesn't know what I'm trying to achieve.” was a really good answer

I would suggest some other reasons might be:

• I don't understand the other settings.
• I'm afraid I'll ruin the photos I take.
• I can't be bothered reading the manual
• I've paid this much for the camera, shouldn't I be getting the most out of it?

I forgot to say during the session that there is only one situation when I use Auto, that's when I hand the camera to someone else to take a photo.

What Does Auto Do?

In the Auto setting the camera will decide on Aperture, Shutter speed, ISO and whether or not to use the flash. For a given scene the camera will calculate the settings it thinks will give the correct exposure. One problem here is that the camera will probably look at the whole of the frame when deciding on an exposure setting. This will not always work, as I will try to illustrate in the next scenario.

Imagine sitting in a Mediterranean café having a drink with some friends or family on a beautiful sunny afternoon. You are all sitting beneath a canvas canopy, shaded from the heat of the sun. You want to take a photo of the group with the sea and land across the bay in the background. You point the camera at the group and shoot, the camera looks at the light in the frame and decides that it's a bright scene and exposes accordingly. The consequent photograph will show the sea sky and land across the bay perfectly, but the faces of your family or friends will be so dark that they are unrecognisable.

Here's a real-life example:

The above photo was taken by my wife of my Sister-in-law, my son and my mother-in-law, on the Liverpool Duck on Albert Dock.   As you can see the Maritime Museum in the background is perfectly exposed but the figures are too dark to see properly.

Another example of the camera not performing well in auto mode could be in the following situation.   It's summer, you're at a barbecue, it's early evening and it's starting to cloud over; rain threatens. There are some toddlers running around and you decide to capture the moment of fun they are having. They won't stand still, but you get your camera set on Auto and manage to capture a blur of faces and flowery dresses. The reason behind this is that the camera has looked at the scene and decided that the light is low, but not low enough to use a flash,  it has opened the shutter long enough to capture sufficient light, a slow shutter speed.

Portrait / Landscape Format

Just a quick note to clear up any confusion, Portrait and Landscape can be used in two different situations in photography. 

 

Portrait Format refers to presenting the photograph with the shortest sides on top and bottom. Landscape format refers to presenting the photograph with the longest sides top and bottom.

Semi-Auto modes

Portrait mode
is an auto setting that most cameras will have available. This will set a wide aperture and process for skin tones

Landscape Mode

The camera may automatically set the focus in the distance and will definitely use a small aperture.

Sports mode

Will set the camera to use a fast shutter, and may allow focus on a moving target.

Child Mode

This mode will also use a fast shutter and may add processing for skin tones and bright clothes

Macro Mode

Compacts and bridge cameras probably fair better than SLRs in this mode. The mode will allow the focusing on very close subjects. Something that you won't particularly be able to do on an SLR without a special lens or adaptors. Some processing will take place to enhance the image.

Night Mode

is for shooting in low light situations and sets usually adopts a slow shutter speed to help capture details of the background, and then fires off a flash to illuminate the foreground or subject.  this could be a person or people.  Keep the camera steady in this mode or you will end up with camera shake in the image.

No Flash Mode

Pretty obvious, the flash will not be used, but the shutter will slow down and aperture will open up. Keep the camera steady to avoid motion blur.

Depth of Field

Depth of field (DOF)  can be used to bring attention to your subject.

In a photograph it is the distance between the closest object in focus and the farthest object in focus. A shallow depth of field is when that distance is shorter it's ideal in a portrait when you wish to keep the background out of focus so that the viewer's eye is not distracted by objects behind your subject. 

A shallow DOF is achieved with a wide aperture.

Greater DOF is advantageous in photographs where you wish to keep the foreground and the objects in the distance in focus. Landscapes are an obvious example but another might be a photo taken in a huge cathedral. The cathedral scenario is a tricky one because you will want to use a smaller aperture, so the shutter speed will need to be longer so you will definitely need to support the camera on a solid object, tripods are sometimes not allowed in certain buildings.

F stops

These are the numbers assigned to the aperture. If you cast your mind back to the teacup in the rain experiment, the lids were numbered 22,  8 and 2.8. 22 having the smallest hole. F stop numbers are used by all cameras and have been picked so that we can understand the settings no matter what camera we use.

The range of f stops that you will normally see are.
2       2.8     4       5.6      8        11        16         22   
Remember the larger the number in an f-stop the smaller the aperture.

Shutter speeds

You'll see these numbers when referring to shutter speed, the time that the shutter remains open, don't forget you need to put a 1 over the number. So 500 is actually 1/500 this is fast enough to freeze action whether it's a fast moving animal or a moving vehicle.

2000      1000      500     250      125      60      30      15

It is well worth getting familiar with these numbers because it will help to understand how the camera works.

F-stops related to shutter speed

Remember the Cup in the rain scenario, if we make the hole smaller we have to leave the cup out in the rain longer to fill to halfway.  With the camera, if the aperture is smaller we need to keep the shutter open longer.  Suppose we measure the light from a particular scene and the camera suggests f8 at 1/125 shutter. If we take the two lists of numbers f-stops and shutter speeds and align f8 with 125 we can look along the scale and  2 aligns with 2000. This means that the same amount of light at  f2 1/2000 reaches the CCD or film.  

1.4       2       2.8      4      5.6       8      11      16      22

          2000  1000   500     250   125     60      30     15

To expose for the same amount we could set the aperture to 11 and shutter to 1/60.

The Task

Find the setting on your camera that will give a shallow depth of field and try and get some shots. To give you something to think about, pick a colour or colours and the number 5.
See if you can work those into a photograph or two.

Any questions,  please feel free to email me.  

Have  a good week 
Mark