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Friday, 23 January 2015

photography at Bristol Folk House {Pt 2}

Last week was all about the apertures, so we popped down to College Green to practice with Graham on hand if we needed any advice.  With Bristol Cathedral in spitting distance I focused on ... a feather and some bike gears.  See how I concentrated on keeping this magnificent piece of architecture at the preferred level of blurry-ness in the background?



Here's the feather taken in aperture priority mode (A on my dial) with a low f number on the left (small f number = small area in focus) and a higher one on the right.  A chained up bike caught my attention too - all the oil and spokes remind me of the cranes outside M-Shed.  


A few other random shots that I liked the look of when I went through them this afternoon...


 ...and on to the next brain twister - shutter speed!

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Shutter speed


The shutter blocks the light coming through the aperture from landing on the sensor

The shutter speed is the length of time that the shutter is out of the way, allowing the light to hit the sensor

Shutter priority mode on a camera is semi automatic - you choose the shutter speed and the camera controls the aperture (S on my camera)

A slow shutter speed may be measured in seconds, minutes or even hours (but typically seconds)

A fast shutter speed can open the shutter for as little as 1/4000 of a second

On my camera lcd screen settings over one second are indicated with the number then quotation marks - 2" for example, means the shutter will open, letting light reach the sensor, for two seconds

The slower the shutter speed is, the longer the shutter allows light to reach the sensor.  Generally the slower the shutter speed, the smaller the aperture - so the smaller the f number

Why control shutter speed?


By controlling shutter speed you can eliminate (or minimise) blur in pictures by using a fast shutter speed (say 1/ 500) - the light only reaches the sensor for a very very short period of time, so even if your subject is moving, there won't be blur

The other main reason to control shutter speed is to create blur,  for creative purposes.  By using a slow shutter speed but panning the camera to the side to follow a cyclist for example (trying to keep the same speed/rhythm) the cyclist will remain in focus, but the background will be blurred

Similarly, using a slow shutter speed but keeping the camera in the same position any movement of pedestrians walking past will be blurred, but the background will remain sharp

*I don't have examples of these to share yet, but will try to take some this weekend.

Points to keep in mind


The slower the shutter speed, the longer the length of time that light is on the sensor, so if the camera is going to be static consider using a tripod to minimise unintentional movement

Walls, floors, tables, trees - these can all be used to support you or the camera while the shutter is open

Consider using the self timer, as this will prevent possible movement of the camera as you press the shutter release affecting the picture

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White Balance


We only covered this in passing, in relation to taking pics in the cathedral, and I found it confusing, so I'm not in a position to explain it right now.  In the meantime, this is a corner of the Chapter House in the cathedral.  They are all taken with the same shutter speed and f number, the difference is the white balance setting (which I've always had on auto!).  


My vague understanding is that it has something to do with the type (or source) of light that's present - for example fluorescent or incadescent, or whether it's shady or fine.  We also briefly discussed iso, which is (I think) about setting the sensitivity of the sensor, so that if it's a darker day you increase the sensitivity so that the desired combination of shutter speed and aperture can be used.  I think.  Watch this space!

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Monochromatic photography


Taking pictures in black and white (and every shade of grey in between)

This has the advantage of preventing colours from distracting from your subject

Most cameras can be set to take photos in black and white, but they can also be manipulated later if taken in colour

The advantage to taking them in black and white is that you will line up shots differently when you're paying attention to contrast and texture as opposed to colour






...and Graham commented on how effective portraits can be in black and white,  so here's one of him ;-)

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