Alice studies photography

 

Tuesday 12 May 2010

It was a beautiful day today, and a great surprise to see the sun come out.  Today was also the first day of my short photography course that will last for another month and half.  It was good to meet up with my other classmates, Ian, Aniko, Billy, Kelda, and our tutor Matt.  When we arrived in the morning we were all gathered together around a small round table in the canteen while Beckie passed around the paperwork for us to fill in our registration details an attendance forms.  I remarked that I was so happy to see the sun come out again, especially given that it was so cloudy yesterday and had been raining on and off all day.  Ian then said he wished the weather would warm up.  I must admit it has been a very cold day.  However, I explained that I was not too concerned about the cold, because too me, so long as it was sunny and it did not rain then I was very content. 

     

There were only four of us in the photography course, and we were very fortunate, because this small number meant that we received more attention from our tutor and it was very nearly like having one to one tuition.  This meant that there was time for us to ask questions during the lessons, and our tutor was able to come over to each of us at our desks, to help us individually, using our own personal cameras.  Given that I had difficulty locating vairous buttons on my camera, this extra help was particularly useful – there will be  more on that later!  Getting back to questions, one of the (many) questions I asked was relating to the use of filters for the cameras.  As we were on the topic of UV rays, I asked “what happens if you shoot directly into the sun?”  Well, the answer, I was told, was “… not to”.  I wanted to know why, and was I was informed that we could break our camera. Well that is a scary thought, especially when you invest so much money into purchasing the things!  So my lesson learnt today was to avoid pointing the camera into the sun.

Our tutor advised us to keep a reflective journal of the photos we take, so that we can see how we can do things, and how we can do them better.  We spent all day today learning about the theoretical aspects of photography, as follows:

A. Overview of camera types: i) full size sensor pros and cons; ii) vibration reduction lenses; iii) emphasis importance of lens quality & aperture.

B.  Overview on what effects the quality of captured image: i) sensor; exposure; ISO; file format; If JPEG must be used how to maximise quality; and ii) how sensor size relates to Mega pixel and print size; iii) exposure basics – metering modes on camera; histogram on camera; shutter speed & aperture on camera; depth of field; & ISO.

C. Lastly, we finished today with a practical application of the knowledge & skills covered above.

Here are some of the notes I took down during class today, and these are relating to the digital SLR.

Exposure is commonly measured in ‘stops’, also called F-stops.  Exposure is controlled by the shutter speed and the aperture.  You will be familiar with the terms ‘over exposed’ if there is too much light in the picture, or ‘under exposed’ when the picture is too dark and there is too much contrast.  You can use software like photoshop etcetera to try to fix these problems, that takes aways from the quality of the print of the photo and is called ‘destructive’.  Therefore it is best to use the buttons on the camera, when taking your photo to control the shutter speed and aperture to get a balanced exposure. 

SHUTTER SPEED:  1/15,  1/30,  1/60,  1/125,  1/250,  1/500

The shutter speed determines how long the light sensor is exposed to light.   “On many cameras the choice of shutter speed varies from 30 seconds to 1/4000 of a second.  To increase the exposure a slower shutter speed is selected.  If the shutter speed is set to 1/250, to increase the exposure by one stop a shutter speed of 1/125 of selected.  1/125 half as slow as 1/250, i.e. 1 stop.  To decrease the exposure by 1 stop a shutter speed of 1/500 is selected because this exposes the sensor for half the time of 1/250.

There are three settings on the camera – (1) Auto; (2) Priority: shutter speed & aperture (3) Manual.

CAMERA:  The camera, if it has a full frame sensor, similar to a 35mm film, will have a 3/4 chip, and this has a better depth of field, and better able to cope with low light, better noise characteristics and better tonality at extremes. 

LENS:  The quality of the glass relates to the sharpness of the picture.  The aperture in the lens.  Generally the more expensive the lens the better it is.  These can go up to a couple of thousand pounds for a decent one.

APERTURE:  determines the quantity or amount of light entering the camera.  The aperture is a variable size diaphragm in the lens. 

f=aperture.  Note that one stop is halving or doubling the light.  f1.4 is the largest aperture lens, the biggest, and not many lenses have these.  What is important is how it relates to the shutter speed.  If you want to increase to a higher aperture but your lens does not go that high, then you can compensate for this by increasing the shutter speed.

Standard apertures values are:  f/1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32.  Each one is 1 stop apart.

For example, moving from an aperture f8 to f5.6, is similar to moving from shutter speed 1/60 to 1/125.  Then moving from f5.6 up to f4 is similar to moving from 1/125 to 1/250.  Moving from f4 to f2.8 is similar to moving from shutter speed 1/250 to 1/500.

CHARACTERISTICS OF LENS:

  • Sharpness
  • Speed
  • Focus
  • Anti-shake
  • Build Quality

Nikon lenses are well built and tend to last longer.  Sigma lens are usually not built as well as a Nikon or Canon.  Nikon lenses are weather sealed so they don’t get moisture in them.  This benefit is particularly important for those spending hours, or all day long in the countryside, the Peaks district, the Lakes district, and so on. 

If you had a 1/60 (60th of a second) shutter speed you tend to get camera shake.  Anything that is lower than a 60th of a second will also normally get camera shake.  If your lens has an ‘image stabiliser’ that will allow you to shoot where you wouldn’t normally be able to shoot.

IMAGE SENSOR:

This relates to how large a print you can get from your photo.  The resolution is dots per inch.   A sensor size of a 12 mp camera will be 3,000 dots by 4,000 dots.  If your printer gives you 250 or 300 standard printer resolution per inch, then that is 3,000 divided by 300 = 10 inches.  Therefore the maximum size of your print can be 10 inches.

  • tonal adjustments
  • exposing
  • For previews, see D preview
  • For examples of smooth tonality, see the work of John Blakemore
  • RGB, red (256), green (256), blue (256) pixels = 16.7 million (256x256x256), gives the illusion of colour.

One way to gage the exposure of our photos is to use the histogram feature on the camera.

HISTOGRAM:

   

The first photo I took of the whiteboard wasn’t quite right, so I tried to adjust this.  You can see from my second photo above that I went in the wrong direction and it was too dark and under exposed.  The third photo was better, and here is the histogram for that last photo.

I have run out of time to complete these notes, so will post the rest of these notes here sometime over the next few days.  In the meantime, you may be interested to see the handouts we were given during class today:

  • Camera Histograms: Tones & Contrast – more
  • Raw File Format – more
  • Tutorials: Depth of Field – more

Published by Alice Letts

Online training for parents and children. Online piano and music tutoring. Online tutoring for English as a Second Language (ESOL) with an emphasis on pronunciation. Online meditation coaching for parents and how to incorporate meditation into daily family life.

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