Everyone has been asking me recently to run a photography course but I can’t see that happening for a long time so I’ve decided to write this to help all those of you who don’t understand the ‘maths behind the picture’.
So basically a good picture is one that is exposed correctly right but how do you do that without being in Full Auto Mode… this is where creativity comes into play! (by the way I never expose correctly but thats a way more advanced tutorial!)
There are 3 factors to a correct or balanced exposure
- Shutter Speed
- Aperture
- ISO
So if you don’t know what any of the above things are, here is a very simple way of understanding it.. Forget about your camera and think of the room you are in now with no windows or doors and you drill a hole in the wall and cover it with your hand so no light can get it – This is what a camera is! Years ago when cameras first came out they used very sensitive paper that once light hit it it changed colour… like if you left a newspaper out in the sun (newspaper isn’t very sensitive paper so it would need to be there for hours and maybe days in Irelands climate!). So what they would do is place this very sensitive paper behind the hole you drilled in your room and allow the light to shine in (in your case move your hand!) for a second or less depending on how bright it was on the other side of the room. So in that case the length of time you keep your hand away from the hole in the wall is the Shutter Speed, the width of the hole is the aperture and the ISO is how sensitive to light the paper was.
Now if that isn’t confusing enough there is more.. these are all governed by numbers, a Shutter Speed (usually indicated by Tv (canon) or S (nikon)) can range from around 1/8000 of a second to minutes or in most cameras 30 seconds, the Aperture ranges from around 1.2 to 32 (this number changes depending on what lens you have on – generally the lower the number the better the lens is), The ISO ranges from around 100 or 50 in some cameras to 16,400(which is ridiculously high and totally useless quality!). So how do we balance all these so that we get a properly exposed image? This is where it gets difficult to teach… the thing is you can’t ring me up and say I’m at a beach here what settings will I use as it depends on how bright it is but here are a few tips to help:
- Shutter Speed – as I was saying it ranges from about 1/8000 of a second to 30 seconds in a lot of cameras so if you think back to the room you are in, if it was bright and sunny outside you will not want the hole to be open for very long so you will go for less than a second, maybe somewhere between 1/100 to 1/1000 but if it was dark outside you will want the hole to be opened for as long as possible to allow the camera to pick up as much light as possible right? Simple to understand…
- Aperture – this is the width of the hole you drilled, and it is tricky to understand because whoever came up with it did it upside down if you ask me! An aperture of 1.2 is a huge hole in the wall whereas an aperture of 32 is a tiny whole so obviously if you had an aperture of 1.2 and its really sunny outside it will let more light into the room so you would not want the shutter to be open for long but if you had an aperture of 32, its tiny, you could let the shutter be opened for a lot longer to let more light in as its so small. Aperture depends on your lens, the smaller the number the more expensive the lens is generally but not in all cases.
- ISO – The ISO governs the other 2 above… it usually go’s up in doubles (eg. 100, 200, 400, 800). If we go back to the room you are in the paper at ISO100 can have light hit it for longer than ISO800 as it is not as sensitive. The higher the number the brighter you are making the place you are in. A good way of understanding this is to place the camera to 1/100 shutter speed, 5.6 Aperture in manual mode and then take the same picture 5 times with different ISO settings and go compare your results on a computer.
Now that you understand the concepts of whats what I can explain to you what each one does, they all have a purpose and control different things to allow you to get creative…
The Shutter Speed controls Motion in a picture and The Aperture controls the depth of field i.e if something had a nice blur in the background. Here are a few examples to help you understand…
Here is an example of shutter speed, this had to be taken as quick as possible to catch the water in the air like that because if I had of left the shutter speed open for 1 second there it would be blurry as the jeep would have moved a lot in 1 second. This one was taken at 1/400 of a second.
The one below is an example of a slow shutter speed. The shutter speed was open for 1.6 seconds here, just enough to show how the waves were moving up and down the beach.
This shows off aperture. This was taken with a ‘big aperture’ or a small number (see what I mean about being inside down!?) the smaller the number or the bigger the whole the more blur you will have in your image. This one for example was taken at 4.5 and as you can see the background is completely blurred which shows off the flower without any distractions.
The black and white shot above was taken on the opposite end of the scale, at an aperture of 22; notice how the rocks at the front of the picture are sharp while the Sea Stack is sharp too even though it is so far away.
Another thing to remember is that the Aperture is called “The F Stop” – why? I have no idea nor do I care to be perfectly honest!
Also if you are to use a very long shutter speed of any less than 1/80 of a second I would recommend using a tripod as the camera needs to be steady while the shutter is open otherwise every movement you make will be captured in the image – not nice!
There are other factors that can influence these things like distance and available light but I think that is enough to get you started. If anyone has any questions leave them in the comments or email me pdoherty5@gmail.com
Go get your camera, get out there and start experimenting. The only way to learn is to practice.
Until next time…
Paul
