Photography: ISO, aperture and speed
This isn’t a great photo. I took it out of the window, trying to get my settings right before taking photos in wet cloudy weather. This was taken with my Nikon D3200 DSLR. It has a larger sensor than a bridge camera or compact camera and so is better in low light. Bridge cameras have a good zoom, but if you double click this picture to make it larger you can see that the definition is such that I can zoom in and read the number plates on those cars easily.
This photo was taken at the same time, but it’s not so good:
The camera had the wrong white balance setting for this photo. I had been taking photos indoors and it was set for fluorescent lighting. In the first photo I had it set for cloudy. The blue tinge to the picture is also partly caused by the wet weather. The camera was set on aperture priority for these shots.
The sensitivity of the sensor in the camera that captures the image can be adjusted by setting the ISO level. On a dark and dull day, you need a higher level, but a high level can also make the image ‘noisy’ which shows up as tiny white spots especially in night photography.
Photographers talk about the photography exposure triangle which consists of ISO, aperture and speed. I set the ISO for this shot and I had the camera on aperture priority. That means I set the aperture for each shot and the camera selects a suitable speed. The aperture is in F stops. Think of the shutter as being like a door that opens and lets in the light. The bigger the stop behind the door the less it opens. A small stop will allow it to open a lot and let in a lot of light. The aperture affects focus and for this shot I needed a narrow aperture to make the whole shot in focus (depth of field), but not too narrow or the tram would be blurred because the speed would be too slow. Getting it right is just practice and a little luck! If you are a regular reader you might remember me featuring a picture of Fei wearing traditional Chinese dress at her university in China. I took this photograph of her and her boyfriend Damien from France arriving here to visit me on Monday at the Midland Metro Station..
That photo isn’t too bad considering the weather was very cold and damp. The photographs we took later indoors were OK, but had a slight yellow tinge. I forgot to change the white balance from ‘cloudy’ to incandescent light.
I hope you found today’s information useful. White balance is quite important, but you can set it on auto and cameras have different setting for ‘snapshots’. I took good shots at a Christmas party with it set on auto because the light was constantly changing with different shots. If the light is reasonable, the sports setting is quite useful. The camera adjusts for best speed for the conditions.
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