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Wednesday, 4 May 2011

Measuring Brightness


Camera sensors are NOT as good as our eyes. There is a big difference in the range or more accurately described the Dynamic Range of light intensities. In essence it is the difference between the darkest to the brightest a camera sensor can capture.

As a the sensors in the cameras dynamic range is not as efficient as our eyes a well-exposed photography is often a compromise of what we see; with the ideal being that the highlights and shadows are not blown out and retain detail.

Most modern cameras have internal metering modes and depending on which metering patterns are used can effect the way an image will be exposed.

  • Centre-weighted – evaluates the entire view but gives more importance towards the centre of the frame
  • Evaluative – breaks the view into smaller zones and averages them across the frame
  • Partial – This takes the metering from a smaller area towards the centre (10-15%) of the frame
  • Spot – similar to partial but even smaller area of the centre 1-5%

There is a really nice explanation on this YouTube video

Metering Modes

With all of these metering modes the camera can set the exposure automatically or manually through the aperture, shutter speed and ISO sensitivity to gain the ‘correct exposure’ (or as at least to the average tone for the camera and conditions). With each mode having more or less usefulness under different lighting conditions. However this raises the question. Do we want ‘correct exposure’ (average tone) for the scene? There maybe times where we want more or less detail dependant on the subject; do I want more detail in the shadows being less concerned with the highlights? or vice versa.

So while the in camera metering modes work we can still override using manual metering or using exposure compensation controls.


Monday, 2 May 2011

The intensity of light


Some of this returns back to some of the basic concepts of exposure. To recap here are a few terms and links to fuller explanations

Shutter Speeds – The duration of light getting to the camera sensor

Aperture – The amount of light getting to the camera sensor

ISO – Measurement of light sensitivity

Histogram – A graphical representation of exposure and tone

 


Sunday, 1 May 2011

Taking a break


You may have noticed the extended break in blog updates since the last assignment; this was due to a conscious break from the course.

Well this is just a quick update to say that I’m back!

There have been 2 main reasons for the break, the first being on a personal level; my wife and I have just had a new baby which has been keeping everyone’s hands full. The second being business.

I wanted to concentrate a bit more time towards the business side of photography and while the intention was to run the course alongside my business, I was finding it difficult to keep up with the exercises and assignments over running a small business.

Anyway with all the above being considered and now having the business where I want it to be; with a steady and manageable flow of work I’m able to return to the coursework and continue my art and photographic journey.

For more information about my work please visit my new website and business blog


The raw material of photography

The next section to be covered is all about light; in much the same was as exploring other elements of design and learning to dissect them I will be doing the same with light and looking at it in isolation.