I am fairly new to photography, and I'm primarily interested in landscapes. Having looked through a lot of images, I've noticed that some people shoot a scene at, for example, one-thirtieth of a second, whilst others will expose a similar shot for ten minutes. I realise that part of this is dependent on apperture, however, I was wondering what the reason for the longer exposure times was. Any help would be appreciated.
Exposure question from beginner
- Thread starter JonathanH
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Firstly 
to TP forums Jonathan ... will we see an intro in the 'Welcome' forum soon ... 
The reasons for longer exposures may be many and dependent on so many factors ... I assume you are not talking about two exposures of the same scene taken at the same time ... :shrug:
That being the case one would generally expect to see longer exposures ... in any given set of circumstances ... to provide a greater DoF ... i.e. a smaller aperture setting to get as much of the scene in focus ... pretty much an absolute for landscape pics ...
But exposure time will depend on all the other variables including available light ...
HTH ... but please ask if it doesn't as I am sure others on the forum may explain it better than me ...
to TP forums Jonathan ... will we see an intro in the 'Welcome' forum soon ... The reasons for longer exposures may be many and dependent on so many factors ... I assume you are not talking about two exposures of the same scene taken at the same time ... :shrug:
That being the case one would generally expect to see longer exposures ... in any given set of circumstances ... to provide a greater DoF ... i.e. a smaller aperture setting to get as much of the scene in focus ... pretty much an absolute for landscape pics ...
But exposure time will depend on all the other variables including available light ...
HTH ... but please ask if it doesn't as I am sure others on the forum may explain it better than me ...
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Ignoring ISO for a moment...the two main things that determine the right exposure on a photo are aperture and exposure time.
What you use here is firstly dependant on the amount of light in a scene,
A wider aperture, lets in more light, and a longer exposure time, lets in more light.
If I was to take a landscape shot at dusk, there is less light, so I would have to either....open up the aperture nice and wide, OR, lengthen the exposure time.
Now doing either of these has a consequence on the shot. If I want sharp focus throughout the shot...Using a wide open aperture, of, say, f4 means that depth of field will be short, and not all my shot would be infocus. Normally if its a scenic landscape, I would require it ALL to be in focus.
That would mean I have to 'stop down' the aperture...to, say, f11 or f16 maybe.
The knockon effect of that means, smaller aperture, which means less light...As it's dusk, I still need more light in the photo, to expose it correctly.
Therefore the only other option available to me, is to increase the shutter time. So if 1/30s is too slow, I may use a 2 seconds or so, to get the correct exposure.
However, this can have an effect on anything moving in the scene. So if there are people in the scene, they will be shown as blurs over a 2 second exposure, but less so over 1/30s. The same with water, if I want blurry water, I would use a long exposure, but if I wanted 'frozen' water, I would need a quick exposure.
So the whole thing is a trade off. All photos require a certain amount of light, some more than others. How much light you require is determined by your camera meter. But depending on the effect you want...you need to determine how that light gets into your shot, and it's a trade off between aperture and shutter speed.
Some people require a long shutter speed if they want to blur water.....some people may want to freeze the water, so will need to open up the aperture instead.....
This is a very simple explanation of it, which doesnt take into account ISO (film speed / sensor sensitivity), which you can increase when you need both a small aperture AND a fast shutter speed.
So again, it's all a trade off.
Hope this helps.
What you use here is firstly dependant on the amount of light in a scene,
A wider aperture, lets in more light, and a longer exposure time, lets in more light.
If I was to take a landscape shot at dusk, there is less light, so I would have to either....open up the aperture nice and wide, OR, lengthen the exposure time.
Now doing either of these has a consequence on the shot. If I want sharp focus throughout the shot...Using a wide open aperture, of, say, f4 means that depth of field will be short, and not all my shot would be infocus. Normally if its a scenic landscape, I would require it ALL to be in focus.
That would mean I have to 'stop down' the aperture...to, say, f11 or f16 maybe.
The knockon effect of that means, smaller aperture, which means less light...As it's dusk, I still need more light in the photo, to expose it correctly.
Therefore the only other option available to me, is to increase the shutter time. So if 1/30s is too slow, I may use a 2 seconds or so, to get the correct exposure.
However, this can have an effect on anything moving in the scene. So if there are people in the scene, they will be shown as blurs over a 2 second exposure, but less so over 1/30s. The same with water, if I want blurry water, I would use a long exposure, but if I wanted 'frozen' water, I would need a quick exposure.
So the whole thing is a trade off. All photos require a certain amount of light, some more than others. How much light you require is determined by your camera meter. But depending on the effect you want...you need to determine how that light gets into your shot, and it's a trade off between aperture and shutter speed.
Some people require a long shutter speed if they want to blur water.....some people may want to freeze the water, so will need to open up the aperture instead.....
This is a very simple explanation of it, which doesnt take into account ISO (film speed / sensor sensitivity), which you can increase when you need both a small aperture AND a fast shutter speed.
So again, it's all a trade off.
Hope this helps.
I knew someone would be able to explain it a little better ...
If it helps you can find many useful resources on the web to help you understand better too such as this one ...
Exposure
And this one ...
Shutter Speeds
And there is a whole host of other useful stuff both on these sites and elsewhere ...
But if you are still 'in the dark' just add to this thread and we'll see what we can come up with ... :shrug:
HTH ...
If it helps you can find many useful resources on the web to help you understand better too such as this one ...
Exposure
And this one ...
Shutter Speeds
And there is a whole host of other useful stuff both on these sites and elsewhere ...
But if you are still 'in the dark' just add to this thread and we'll see what we can come up with ... :shrug:
HTH ...
