Shop Mobile More Submit  Join Login
The basics of exposure by FallisPhoto The basics of exposure by FallisPhoto
The basics of exposure -- shutter speeds, apertures and f/stops.

A camera is pretty much a light tight box with a hole in it. Light enters the hole and exposes the film. In its simplest form, the pinhole camera, this is pretty much all there is to it. However, in most cameras, there is a film transport mechanism added and some provision has been made to add a shutter and lens to that aforementioned hole.

The advantages of this arrangement are that the lens can focus the light on the film more precisely, so you get a sharper image, and the shutter can more precisely regulate how much light gets in.

The shutter regulates the light entering the camera in two ways: shutter speed (or how long the hole stays open) and aperture (how big the hole is); both are adjustable, and each step of adjustment lets in exactly half as much light as the previous one (or twice as much, if you go in the other direction with your adjustments). So … how do you use these?

Well, let's examine a hypothetical situation. You have set up your camera next to a road and you are trying to photograph your brother’s newly restored red 1967 Barracuda as it drives by at 15 miles per hour. On the opposite side of the road is a nude hitchhiker who is sitting on a rock holding up a sign. You are using a 35mm camera with a 50mm lens.

Shutter speed (how long the hole stays open) is used to freeze or blur motion. If you have your shutter speed set for one second, then when the car drives past, it will have completely passed the camera between the time the shutter opened and the time it closed. All you will get is a red blur across the film. The nude hitchhiker and the background, on the other hand, will be in pretty sharp focus, since the nude hasn't moved much and the background hasn’t moved at all. If your shutter speed is set for 1/5000 second, on the other hand, the car will have only moved a fraction of an inch. You'll probably be able to read the label on your brother’s beer bottle, and the car may appear to be parked in front of the camera. If you hit the button at the right time, you may be able to catch the driver's expression as he first notices the hitchhiker, sprays beer all over his freshly polished dashboard and spills his bottle in his lap. A fast shutter speed is not always desirable though. You may want to set your shutter speed at 1/125 second so as to slightly blur the car and let the viewer know that it is moving.

Aperture controls something called "depth of field." When you focus a camera on a subject, it is only that subject, and other things that are the same distance from the film, that are in truly sharp focus. "Depth of field" refers to the amount of space in front of and behind the subject that is in acceptably sharp focus. Large apertures (big holes) will give you less depth of field than small apertures (little holes).

Apertures are measured in units called f/stops. Think of the "f" in f/stop as standing for "field." Big numbers (as they appear on your camera), like 22, will give you more depth of field and small numbers, like 2.8, will give you less.

Something that tends to confuse beginners is that the big numbers stand for small apertures and the small numbers stand for big apertures. This is because the f/stops actually are fractions -- although it most likely says nothing about this on your camera or in your owner's manual. The camera manufacturers must just assume that you know this. On your camera's aperture ring all you'll most likely see is the aforementioned 2, 2.8, 4, 5.6, 8, 11, and so on. You are meant to just ASSUME that there is an "f/" in front of those numbers.

The “f” really stands for focal length. The focal length is divided by a set of standard numbers (2, 2.8, 4, 5.6, 8, 11, 16, 22 and etcetera) to give you the size of the hole (which, as we now know, is called an aperture or stop) in millimeters. Well, let's assume that the lens is a 50mm one. A hole that is 50/22 millimeters in diameter is going to be a lot smaller than one that is 50/2 (the sum of pretty much any number divided by 22 will be smaller than it will be if it is divided by 2). This is really pretty simple, once you understand what it means.

In our hypothetical scenario, Remember that big numbers give you big depth of field. You will probably want to use a small aperture, like f/22 or f/16, so as to capture the nude and the background in fairly sharp focus. However, if the background is a trailer park, and your drunken father is urinating out the door of your double-wide, then you may not want to do this, and so you'd use f/11 or f/8. This will still capture the nude and the car in acceptably sharp focus, but will blur the background, and make it less noticeable.

However, let's say that the hitchhiker lowers her sign, so you can see her face. You suddenly notice that the nude hitchhiker is your mother. Well, now you know why your brother lost his beer. If you don’t die of embarrassment right on the spot, and if you are so hardcore that you still want to take the photo, then you may decide to use f/5.6 or f/4, so the car is still in focus but nothing else is and the nude is no longer identifiable.

Anyway, as mentioned previously, both the f/stops and shutter speeds are set up in such a way that each adjustment lets in exactly half, or twice, as much light as the previous one (depending on which way you go with the adjustments). This means you can adjust either the aperture or the shutter speed without changing the exposure, by adjusting the other to compensate. This is called using an “equivalent exposure.” Thus, a shutter speed of 1/60 second at f/8 will allow the same amount of light to enter your camera as a shutter speed of 1/125 second (the next faster shutter speed) if you adjust the aperture to f/5.6 (the next bigger aperture).

See? This stuff really isn’t rocket science. Well, not until you get into the darkroom with it anyway. It is a little simplified though. You see there are a couple of other factors to consider. The farther from the lens the subject is that you have focused on, the deeper the depth of field will be. Also, longer lenses have shallower depth of field. That is about it though.
Add a Comment:
 
:iconcynferdd:
cynferdd Featured By Owner Apr 7, 2009  Hobbyist Photographer
awesome tutorial :)
I was searching for things to help a friend understanding basics of photography, this will be really helpful =)
Reply
:iconmwppxkonciawa:
MWPPxkonciawa Featured By Owner Mar 15, 2009  Hobbyist Photographer
"If you hit the button at the right time, you may be able to catch the driver's expression as he first notices the hitchhiker, sprays beer all over his freshly polished dashboard and spills his bottle in his lap."

Hahaha priceless.

Thanks for the tutorial! it really helped.
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Mar 16, 2009
You're welcome. I used to teach this stuff in college. I tried to make my lessons simple and easy to understand while making them entertaining at the same time, so people could remember them long enough to use whatever it was I was teaching that day. Once they had actually used it, and it wasn't just dry info anymore, then they owned it forever.
Reply
:iconmwppxkonciawa:
MWPPxkonciawa Featured By Owner Mar 16, 2009  Hobbyist Photographer
well with how you wrote out that one, i'm sure it worked:D
Reply
:icondispach:
dispach Featured By Owner Oct 10, 2008
i love you dude, ive been looking for the name and the way to do this technique since i saw the cover of placebos meds cover.

[link]
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Oct 11, 2008
Just have your model start shaking her head no, set your shutter speed for 1 second, mount your camera on a tripod, and take the shot. Her body can't move at all, so it may take a few tries. I'd devote one whole roll of film to this, so as to be fairly certain to get it. If you are shooting digital, just keep shooting until you have half a dozen good shots, because as good as they may look on the preview screen, you won't really know for sure until you have seen it on the computer. The banner across her chest, if you want to reproduce that, is photoshopped, in the photo you linked to.It sould be done with a thin piece of doubled over "invisible" tape across the negative (or dodged in) if you wanted to do it with a print made with an enlarger though.
Reply
:icondispach:
dispach Featured By Owner Oct 11, 2008
i do digital, and I'm starting of by scratch with a fujifilm J10 and a tripod that's barely a foot high (for desks and such)
but behind that i have the great arsenal of imagination!
&
thanks a lot for the tips.
they're gonna be of great use.
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Oct 11, 2008
Next thing on your list should be a decent tripod. It is pretty much indispensable for serious photography.
Reply
:icondispach:
dispach Featured By Owner Oct 11, 2008
yea, its really hard without one.
for the moment using this one i'm going to have to stick to rats eye view pictures or a really big boulder lol.
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Oct 11, 2008
If budget is a problem, a good used tripod can be had cheap.

For example, this is a Davidson Star-D: [link]=p3286.c0.m14 ONe of the best ever made, the Tiltall, was based very closely on the Star-D. It is very heavy duty, very strong, and will support even a steel-framed large format camera.

Here is another one: [link]=p3286.c0.m14

Here is one of mine, restored, with a restored vintage medium format metal fim camera installed on it: [link]
Reply
:icondispach:
dispach Featured By Owner Oct 11, 2008
budgets the biggest problem,
I have little to nothing until Va answers my request for aid.
and this camera pretty much was the best i could afford at $115
now i cant even afford the tripods you showed me.

it will be a few months until i do.
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Oct 11, 2008
Oh well.
Reply
:icond3r-spitzel:
D3R-Spitzel Featured By Owner Mar 8, 2008
thanks a lot for the tut ^^

worth to Fav it = )
Reply
:iconanimationfan320:
animationfan320 Featured By Owner Feb 23, 2008  Student Traditional Artist
Your explanation does help me better than reading a large complex book but I got lost about half way. I'm a complete noob when it comes to photography. =(
I wanted to know what I would need to do on my camera if I wanted a to get a picture of a waterfall but the water looks really smooth, or to get a picture of a highway where there's streaks of red and yellow. Would I just adjust the shutter speed and aperture?
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Feb 24, 2008
"Would I just adjust the shutter speed and aperture?"

Yes. Shutter speed freezes or blurs motion. Aperture regulates depth of field. If you used a neutral density (neutral gray) filter, which would reduce the light and allow you to take a long exposure of the water, it would look whispy, like cotton candy, because of all the blurred droplets flying through the air. If you use a very fast shutter speed, it will look like glass, with every flying droplet frozen in place.

Same thing with the lights on the highway. You use a long shutter speed. Since you will be shooting that at night, you may not need a neutral density filter (depends on ambient light).
Reply
:iconanimationfan320:
animationfan320 Featured By Owner Feb 24, 2008  Student Traditional Artist
If you don't use the neutral grey filter would it still work? I could just alter the color in photoshop, right?
Thanks for the help! =D
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Feb 24, 2008
"If you don't use the neutral grey filter would it still work? I could just alter the color in photoshop, right?"

Sorry, I assumed you knew how a neutral density filter works. It probably won't work unless you are shooting at night, and I doubt that is going to be the kind of photo you want. I'm going to analyze the problem for you in simplest possible terms:

For the whispy effect you need to leave the shutter open long enough to capture the light trails left behind by the sun reflecting from many droplets of water passing through the air. This takes time.

Presumably you will be shooting in daylight. I'd suggest late afternoon/evening, preferably on a cloudy day. Even late on a cloudy day, if there is any sunlight on your subject at all, and with your aperture stopped all the way down to f/22, this will probably still leave you in a situation where your slowest possible shutter speed is going to be somewhere around 1/15 second, even at ISO 50. If you use b&w film, there are some that go to ISO 25 and you might be able to go one speed slower. Well, this still isn't going to be slow enough. You are going to need something around a LEAST a two second shutter speed; ten seconds would be better, but two will work. Since it is going to be too bright for even two, you need to reduce the amount of light entering the camera. This is what the neutral density filter does. It has no effect on color at all. It has no effect on contrast. That is why they call it neutral. All it does is cut the amount of light that is getting to your film/sensor, so you can leave the shutter open long enough to get your photo. I'd say the one you want is a "two stop filter," which will cut the amount of light entering your camera to 1/4 what it would be without it.
Reply
:iconanimationfan320:
animationfan320 Featured By Owner Feb 24, 2008  Student Traditional Artist
okay. so I would need a neutral grey filter if I wanted to get the whispy waterfall effect, what about clouds and such?
Sorry for bothering you with so many questions, your answers really help though. =)
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Feb 24, 2008
"... what about clouds and such?"

Your best bet there, if you are shooting in color, would be a polarizer. If you were shooting in b&w though, it would be an orange filter. ornage emphasizes blue, so the sky would be bluer and the clouds would stay white.

In b&w photography, red filters enhance foliage and hide pimples and reddened scars in portraits. A dark red filter will give a smallpox victim creamy smooth skin with infrared film.

Orange is for enhancing clouds, and for hiding freckles.

Green makes male models look swarthy-skinned and rugged. Don't ever use a green filter with a female model. She will not forgive you. Never use it with guys who have acne either. It will make red roses pop right out of the photo at you.

Dark yellow is good for hiding mildly discolored skin and emphasizing thunder clouds.

Medium and light yellow are good for smoothing the skin of people whose only problem is a dry or coarse skin texture.

Graduated filters are good for emphasizing clouds in landscapes, where the sky and horizon meet in a relatively straight line. If they don't, use a polarizer instead. With lens filters, the color of the filter emphaisizes the color opposite it on the color wheel. To make a blue sky look bluer then, you'd use an orange filter. The clouds are not blue, so the orange filter won't have an effect on them.

Starlight filters give lights and highlights "rays" that come to points.

Enhancing filters give you warmer colors (reds, browns and oranges).

Twillight filters (blue and purple) are used to make color photos taken in the day look as if they were shot at night.
Reply
:iconanimationfan320:
animationfan320 Featured By Owner Feb 24, 2008  Student Traditional Artist
thanks =)
Reply
:iconangelyrica:
angelyrica Featured By Owner Nov 24, 2007
this is a lot of help.. thanks! =]
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Nov 25, 2007
Anytime
Reply
:iconczavelle:
czavelle Featured By Owner Sep 9, 2007  Professional Traditional Artist
this was just what i needed. thanks!
Reply
:iconleahconnor:
LeahConnor Featured By Owner Jul 4, 2007  Professional Interface Designer
Finally an excellent explanation in simple words! Thank you. I think I need to memorize this.

...I also might have confused myself a bit, originally, because I couldn't decide in which language I should learn this in order to understand. Oops. But, your explanation is by far the clearest and as newbie-friendly as it can get.

Thanks again. :D
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Jul 4, 2007
You're welcome. I've always thought that most textbooks unnecessarily complicated this.
Reply
:iconviewtiful0:
viewtiful0 Featured By Owner Apr 4, 2007
Thanks, I assumed that bigger aperture numbers meant a bigger hole. It still strikes me as a bit odd that the smaller holes get more in focus. :confused: Your obviously very skilled in your discipline, your gallery is great, I'm just doing photography as a hobby but I'd like to know what I'm doing :D you helped out a lot thanks :thanks:.
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Apr 4, 2007
Well, I wanted to keep it simple, but it has to do with something called (believe it or not) "circles of confusion" and the size of the cone of light and where it intersects with the film plane.
Reply
:iconviewtiful0:
viewtiful0 Featured By Owner Apr 4, 2007
... I have no problems with you keeping it simple ;)
those circles do sound confusing... but I think I may nearly understand how that can work now... is it sort of like how the lens in your eye adjusts it's shape to focus the light from different distances on the back of your eye (I should of paid more attention in biology...) but instead of getting thicker and thinner, it gets bigger and smaller in terms of its circumference.... no now I've just confused myself :D. Great work anyway, and good tutorial :thanks:.
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Apr 4, 2007
Okay, the circles of confusion (no kidding, they really are called that) are cross-sections of that cone of light entering the camera. Only one thing out there in front of your camera is in truely sharp focus (the subject you have focused the lens upon). The cone of light entering the camera is focused on the film at a sharp point for that thing, whatever it is, and every point on the subject that is at the same distance, has a corresponding sharp point of that cone of light intersecting the film. Everything ELSE gets a broader section of that cone, which is why it appears out of focus.

Well, the angle of the cone itself can be modified by the aperture, becoming more acute at smaller apertures and more obtuse at wider apertures. So at a narrow aperture, like f/16, even if the cone is not focused really sharply on the film, the cross section of the cone that intersects the film will be much narrower than it would be at a wider aperture, like F/2, and so you get a wider range of ACCEPTABLY sharp focus.

In my college photography book we had about ten pages explaining this, but the previous two paragraphs are pretty much all of it in a nutshell.
Reply
:iconviewtiful0:
viewtiful0 Featured By Owner Apr 4, 2007
ahhh, that makes sense :D
smaller aperture number -> bigger hole -> bigger cross section hitting the sensors or film -> less light hitting the sensors or film in the range where it would appear sharp.
bigger aperture number -> smaller hole -> smaller cross section hitting the sensors or film -> more light hitting the sensors or film in the range where it would appear sharp.

I hope thats right, if so I'm going to confuse my friends with circles of confusion :D
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Apr 5, 2007
That's pretty much it.
Reply
:iconviewtiful0:
viewtiful0 Featured By Owner Apr 5, 2007
Great :D
Reply
:iconichwill:
IchWill Featured By Owner Apr 1, 2007
excellent overview =)
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Apr 1, 2007
Thank you.
Reply
:iconichwill:
IchWill Featured By Owner Apr 1, 2007
your very welcome, i went an a long trek through alot of stuff last night after reading your forum on "the best camera" i believe it was. heh, your like the uber oracle of camera's, thats awesome.
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Apr 1, 2007
Well, I just try to keep it short, simple, and memorable. Most people over-complicate things.
Reply
:iconichwill:
IchWill Featured By Owner Apr 1, 2007
yeah, at the same time though you are incredibly through in your thoughts and very down to earth. i really enjoyed how you made these as a deviation so it can be tracked for reference
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Apr 1, 2007
Well, you're welcome.
Reply
:iconmightystag:
mightystag Featured By Owner Mar 29, 2007  Hobbyist Photographer
Very thorough lesson.
Reply
:icon26deg:
26deg Featured By Owner Mar 26, 2007
interesting :)
Reply
:icondenisdoda:
denisdoda Featured By Owner Mar 25, 2007  Hobbyist Photographer
very nice tutorial thanks
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Mar 26, 2007
You're welcome
Reply
:iconeduardofrench:
eduardofrench Featured By Owner Mar 25, 2007   Photographer
As always something that is very complex and elaborated you have managed to do it easy to understand a must fav :)
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Mar 26, 2007
Well, thanks, but it isn't rocket science.
Reply
:iconeduardofrench:
eduardofrench Featured By Owner Mar 26, 2007   Photographer
but many people gets confused easily :) so it is a great guide :highfive:
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Mar 27, 2007
I think most people get confused because the person explaining it to them attempts to MAKE it into rocket science.
Reply
:iconeduardofrench:
eduardofrench Featured By Owner Mar 27, 2007   Photographer
you are right, many people try to do something simple very complex.
Reply
:iconebm-grrl:
EBM-Grrl Featured By Owner Mar 6, 2007
thats a great tutorial,
i know nothing and now i know a lil' something ;)

thanx



(\_/)
(O.o)
'(_ _)' What the hell is this bunny doing here??? :D
Reply
:iconfallisphoto:
FallisPhoto Featured By Owner Mar 6, 2007
Thanks!
Reply
:icondarkest-of-roses:
darkest-of-roses Featured By Owner Mar 5, 2007
Thanks for this, it really helped out and it made me chuckle a bit too.
Reply
Add a Comment:
 
×




Details

Submitted on
February 9, 2007
Image Size
23.2 KB
Resolution
329×327
Link
Thumb
Embed

Stats

Views
5,598
Favourites
70 (who?)
Comments
63
Downloads
596
×