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Exposure


JawD
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I thought I'd put this together as I thought it might help anyone just getting in to photography.

 

First understand that every time you take a photo, what the camera is doing is trying to achieve a mid grey tone. It does this by controlling the amount of light that it lets in (through your aperture) and to the sensor (for digital cameras).

 

There are two ways the aperture is controlled. Size and speed of opening/closing. Your size is represented as a fraction F/5.6 for example. Its important to know these are fractions as F22 is a bigger number normally but know it as 1/22 and you will see it is smaller than 1/5.6. So the aperture is smaller and f/22.

 

The second way is simply the speed of the shutter told in seconds. So it could be 1/200 or a 200th of a second right up to 30" or thirty seconds. As you can imagine, longer shutter speeds need a tripod. If you hand hold for a length of time your hand is likely to move and you get a blurry picture. This is why when you take a picture in a dark or dull area your picture is blurry and you dont know why. Its because the camera needed a longer time to get the right amount of light in and you moved.

 

Longer shutter is fine for landscapes and is often used. Want that water to look all silky or those clouds smooth, maybe show movement in the trees etc? A longer shutter speed will capture that movement. I took a photo this week to give an example of this. I set my tripod up in Durham at a fixed object. A building isnt going to move, but people are. I added filters to the front of the lens making things much darker. this meant the camera needed more time to get the light in to reach mid-grey (tone). More time meant people walking past were blurry.

 

8330183093_c139c25625_z.jpg

 

Of course as I used my tripod, the brickwork etc is not blurry as it doesnt move and neither does my tripod. Only the people. This can be a good effect though to show movement as I wanted to achieve here.

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  • 1 month later...

I thought I'd put this together as I thought it might help anyone just getting in to photography.

 

First understand that every time you take a photo, what the camera is doing is trying to achieve a mid grey tone. It does this by controlling the amount of light that it lets in (through your aperture) and to the sensor (for digital cameras).

 

There are two ways the aperture is controlled. Size and speed of opening/closing. Your size is represented as a fraction F/5.6 for example. Its important to know these are fractions as F22 is a bigger number normally but know it as 1/22 and you will see it is smaller than 1/5.6. So the aperture is smaller and f/22.

 

The second way is simply the speed of the shutter told in seconds. So it could be 1/200 or a 200th of a second right up to 30" or thirty seconds. As you can imagine, longer shutter speeds need a tripod. If you hand hold for a length of time your hand is likely to move and you get a blurry picture. This is why when you take a picture in a dark or dull area your picture is blurry and you dont know why. Its because the camera needed a longer time to get the right amount of light in and you moved.

 

Longer shutter is fine for landscapes and is often used. Want that water to look all silky or those clouds smooth, maybe show movement in the trees etc? A longer shutter speed will capture that movement. I took a photo this week to give an example of this. I set my tripod up in Durham at a fixed object. A building isnt going to move, but people are. I added filters to the front of the lens making things much darker. this meant the camera needed more time to get the light in to reach mid-grey (tone). More time meant people walking past were blurry.

 

pic removed....

 

Of course as I used my tripod, the brickwork etc is not blurry as it doesnt move and neither does my tripod. Only the people. This can be a good effect though to show movement as I wanted to achieve here.

 

What type of filter did you use ?

This is the type of picture I'd love to take - but my previous exp. were all white outs - and now i know the reason why.

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Yeah with no filter you will be letting more and more light on to your sensor, hence getting a white out. The filter you would use is a ND filter (natural density) and you have different thickness or darkness. Things like 1 stop or 2 stop etc that let less and less light through.

 

Without a filter the best you can so is make sure the ISO is as low as possible (100 for example) and the shutter as small as possible (f28 for example) so to let as little light in. Really need a filter though.

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