I need help!

chris82 · I need help!

Ok so Ive been spending the last couple of weeks trying to learn how to create better images by achieving the correct setting,So Ive been reading magazines and looking at various web sites and all I see is words and numbers that I cant get my head round.I decided to buy a cdrom called digital camera know how.On the back of the box it reads "Confused by technical jargon?Help is at hand with digital camera know how."Then further on down the page in the tips covered section it shows you 8 topics.Number 2 reads "Help with understanding lens aperture,shutter speed and ISO settings,So I install the disk and click topic nunber 2(as topic no 1 is about which camera to buy)and once again all I hear is f stop this,dof that and I quote "Lets supose that the camera is equiped with a 1 3rd inch sensor,this coresponds to a 4.8 mm width and a 3.6 mm hight.The diagnal is equal to 6 mm.Thus a 6 mm focal lenth will corespond to a normal lens"(If thats not technical jargon what is)Now you all probably understand what this is referring to and I dont doubt that the cdrom is good software but I think the smart people at gsp.ee didnt realise that most the people who would buy this rom would be people like me who need to here things in laymens terms.So if anybody knows where I can find some good tutorials about e.g.F-stops(as on the canon display I dont know where the f stop numbers are because it dosent show you where)could you please tell me?

digitalkiwi

Hi Chris,

I make heaps of money out of this subject, lol, due to techno people confusing the hell out of every one with jargon, i run a digital photography course for beginners here in New Zealand.

F stop numbers refers to the Aperture which governs how big or small you make the aperture, which controls your depth of field.

Could you tell me what camera make and model you are using and i should be able to tell you which is which.

creators

Hi Chris, this is my idiots guide to f-stop, ISO and Shutter speed because I can't understand a word of the jargon either, so this is what I base all my picture taking on.

f-stop: Dictates how much light is available to the camera no matter the other settings. The lower the f-stop, the more light us available. Less is more. night shooting keep the f-stop low, bright sunlight, increase the f-stop.

ISO: Film speed. ISO relates to film speed. The higher the ISO the faster the film/sensor will record the image. At very high ISO settings you will get graininess, but you can take pictures at night without flash at faster shutter speeds.

Shutter speed: The duration of time that light is allowed to enter the camera. The shutter is a physical door in your camera that you open to let light in.

Evolution104

I understand where you're coming from. But where to start?

A face-to-face would help immensely, but I don't see that happening unless you're planning a trip to the states any time soon.

I'm not real sure how to approach this, so stop me if I'm covering ground you already understand.

Let's start with f-stop. It's a setting that controls the lens aperture. Think of aperture as a valve for light - it lets more or less light in, like a faucet for water. For now, don't worry about the details of what f-stop means or where the term came from.

The hardest thing to wrap your mind around is that the smaller the F number, the more light will enter the camera. So something like f2.8 means the valve is fully open and you're getting as much light as the lens can give you. Conversely, f22 means the valve is closed down to a trickle and not much light is getting in.

There are two ways to control how much exposure the sensor (or film if it's a 35mm) gets. Aperture (defined by that f-stop) and shutter speed. Shutter speed is how long that valve is left open. The longer the shutter speed, the more light gets to flow through the aperture. Think of a faucet - whether it's fully open, or almost closed, you can still turn it off. How long you leave it on determines how much water you get. If it's only open a crack, it takes a lot longer to get the same amount of water through it.

Now why in the world do we need both? If your subject is moving and you don't want blur, you need a fast shutter time. But if you don't have enough light available for that chosen shutter time, then the picture will be dark and underexposed. Being able to open the light valve by adjusting the aperture to a small number (like f2.8 ) lets in as much light as you can get and might be enough for your shutter setting. But like that faucet, if the valve is open too much for too long, you'll get a flood. Same thing for the light - that flood means you'll over-expose the image.

So the shutter speed used together with the aperture (f-stop) in balance will provide just the right amount of light.

Another thing aperture can give you is depth of field (dof). Depth of field simply means over what distance are things in focus? With a "short" depth of field, only a short distance is in focus. This might be as little as a few cm - mm even. The smaller the f-stop number (bigger aperture - the valve is wide open) the shorter (shallower) the area that will be in focus. This allows you to get that blurred background while keeping the subject in focus. A smaller f-stop number (i.e. f22 - smaller aperture - the valve is almost closed) creates a much larger (deeper) area which will be in focus. This is a great thing when shooting landscapes or far away objects (the moon) because nearly everything will be in focus.

I don't know if this helps or just confuses things more. I hope it helps a little.

creators

Just to show the difference you can capture using ISO, I was zoomed in trying to capture these characters, so couldn't achieve an f-stop lower than 4.5. I took one shot at ISO 200 on my D70 and it was blurred so whacked the ISO up to 1600 and got a sharper shot but graininess as well.

Brilliant walk through John!

Evolution104

Evolution104

One big issue you may be facing is information over-load.

Take one thing at a time until you understand it. Don't try to get it all at once. The same goes for any help from us - we can swamp you with too much stuff too quickly.

Ask us one question at a time. If we start to bury you, tell us to back up and slow down.

It's easy for us to get carried away Very Happy

creators

creators

Confucius say, 'too much food in mouth, hard to swallow, not swallowing leads to lack of nourishment.'

Confucius also say, 'better a large lump of food spat on table and a small morsel swallowed, than large lump of food stuck in throat'.

Confucius also say, 'Shut up Keith, go to bed'. Laughing

Evolution104

hil26

LOL - and a great walk through.

Chris - if you can buy

Understanding Exposure by Bryan Peterson - still need to realize what F stop (AV) is but it is very easy reading, and great tips

creators

A bit more on f-stop. It is the same as aperture. It controls the amount of light that can enter the camera. The bigger the hole the more light can get in. The smaller the hole the less light and smaller apatures use the best part of the lens, the middle part where there is less likely to be any distortion.

Diagram taken from Wikpedia.

jonH

http://www.shortcourses.com/using/index.htm

fantastic read for those making the jump from full auto photography

hil26

Chris

that diagram above should be agreat help
need to remember treat f stops as fractions

f22 = 1/22
f4 = 1/4

1/4 is bigger than 1/22

f22 big DOF f4 small DOF

It comes together in the end, or should do

Venom · Re: I need help!

chris82

Wow,great info and feedback people.Thanks.I think im going to have to print this out as I suspect I will be spending a lot of time reading this.Thanks guys. Very Happy

creators

Dunno how you're getting on digesting all this Chris. As an exercise may I suggest setting up with a tripod and taking exactly the same picture using different f-stops for each one, which will mean for low f-numbers you'll need faster shutter speeds and slower the higher the f-number. Try it on a distant shot and then try it on a close up. Speaking personally, I wouldn't worry about ISO at the moment, keep it on 100 or 200 which ever you have available. I can't remember what camera you're using.

chris82

Ok so I had a quick muddle around this thread and the weather predictions are good for today.So I think ill set off up yhat mountain again.I supose I better bring me tripod then.

jonH

You're probably already too late - try to get up stupidly early and get there for sunrise, or leave it till later and get there for sunset.

I need help!

Re: I need help!