Learning Lesson #2: ISO

Soooo I know I was supposed to be doing my learning Lessons upon learning them myself but it started to get a little more complicated and I thought I'd have a hard time explaining the next step in using your camera to take good exposed pictures. BUT I am finally here willing to give it a try.

SOOOO shall we begin:

ISO: Film Sensitivity.

So far we have discussed how Aperture and Shutter speed make up the exposure using the amount of light they allow into the camera. ISO is the next function that can affect light as well. Not in a way in which it allows more or less light in but how sensitive the light being let in shows. ISO ranges usually from 100 to 3200 on most digital cameras. Each one doubled from the previous. The lower ISO is used for lighter setting while the higher ISO is used for darker settings. (Example: You will use a lower ISO outside on a sunny day then you would inside a dim lit room.) This is because the higher the ISO makes the light more sensitive thus creating almost a delusion as if more light is being let into the camera., when in fact the light just looks brighter.

If you are taking pictures outside and its nice lighting then usually you'll keep your camera on 100 or 200 ISO. When shooting inside or in darker settings then you'll start to change your ISO around depending on what works best for your situation.

If you remember in the previous post we talked about STOPS and changing the aperature and/or shutter speed in order to keep an equilvilent exposure but change either the depth of field or motion blur. Depending on what you wanted to do creatively, you had to change BOTH teh same number of stops in order to keep a good exposure. When you throw ISO into the mix it is a little bit different. If you are going to change the ISO by one stop then you will change ONE of the other two functions by one stop as well. Either the shutter speed OR the aperture. Changing both shuttter speed and aperture with ISO just keeps everything equivilant and you dont want to do that considering changing the ISO doesnt really do anything to the picture creatively. You usually only change it to affect your lighting somehow which means you want to see the specific change.

ISO is one of those functions you where you can decide before shooting which would probably work best and you'd most likely leave it at that setting throughout your shoot because you can ideally use just aperture and shutter speed to create a good exposure. When people use film they have to buy the film already ISO specific which means they have no choice to change the ISO or not. If they buy ISO 100 film then that is what their ISO will be until they are done with that film.

There are cases though in which you will changed your ISO during the shoot and it is when you can not change your aperture AND shutter speed in order to create a good exposure. These cases is because you have reached your minimum or maximum setting and/or cant change them depending on the creative look you're going for.

EX: Most lenses that comes with the camera have a maximum aperture of F3.5 which means that is the widest the lens opens and the lowest F-stop it can reach. Well lets say you want a picture with a blurry background (wide aperture) and you are at F3.5 and a shutter speed of 60 (1/60th of a second), ISO 100 and your picture is still too dark. You need MORE light in to get a good exposure. Well you could lower your shutter speed one stop to 30 but usually around this stop is when its almost impossible to hold your hand still enough so your picture doesnt come out blurry. Remember, When your shutter is open for that long, if you move your hand then the picture will come out blurry because you moved while the picture was still taking. SO anyways, you want to keep your shutter speed at 60 and you cant open your aperture anymore....what could you do to get a lighter picture?

You could change your ISO one stop up. If you change just your ISO to 200 then that makes the light more sensitve otherwise making it seem like more light is coming in and can give you the exposure you were looking for. This is example is one reason you;d change the ISO because both other functions were at their max or min and your exposure was still off.

Now let's say you already have a good exposure but you just dont want to change one of of the functions of shutter speed or aperture bc of what you are trying to do creatively. Let's say you are trying to capture a picture someone running and you want the action frozen, so not blurry. Well you found a good exposure at F8, shutter speed 250, ISO 100. Well 250 doesnt seem to be fast enough to freeze the action so you need to move it up 3 stops to 2000. Since it's faster this is letting in less light. Well remember when you move one stop UP the other must go DOWN to balance out the light. Well your camera aperture can only go down 2 stops to F3.5...what do you do now?

You can leave your Aperture at F8 and change the shutter speed still to 2000 but now change your ISO from 100 UP 2 stops to 400. This compensates for not moving the Fstop and allows more light in.

ISO takes the place of one or the other

PHOTOGRAPHIC EXAMPLE: TREE

This is bracketing the ISO...meaning just changing the ISO and leaving everything else the same in order to see the effect the ISO makes.

Good Exposure: F4.5 SS 500 ISO 100

F4.5 SS 500 ISO 200

F4.5 SS 500 ISO 400

F4.5 SS 500 ISO 800

The light in the pictures gets more sensitive as the ISO goes up. In order to keep the good exposure in each picture you'd change eith the Fstop OR the Shutter Speed the same number of stops.

One important thing about ISO is that if you make it too high the picture starts to look more grainy. So be careful.

One more example to take it home:

Bert and Ernie are both using their cameras but Burt wants to keep his ISO at 100 while Ernie wants to keep his ISO at 200.

Well the perfect exposure for Bert is ISO 100 F5.6 and SS 500. What are two different ways Ernie can reach the same good exposure without changing his ISO?

Option 1: Keep the F stop the same but change the Shutter speed. Since ISO 200 is only 1 stop UP from ISO 100 (letting in more light) then he would only change the shutter speed 1 stop Down to let in less light to balance it.
ISO 200 F.5.6 SS 1000

Option 2: Keep the shutter speed the same and change the Fstop. Again since the ISO 200 is only 1 stop UP from ISO 100 (letting in more light) then he would change the Fstop DOWN letting in less light to balance it out.
ISO 200 F.8 SS500

It's always like math. You want the balance of light. Not too under or over exposed. If you change one funtion of how light comes in you must change another to keep the balance.

Basically to keep it simple try top choose your ISO before shooting and ONLY change it when you have no other options.

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Learning Lesson #1 : Shutter Speed & Aperture

As promised I said I would share my photos from photography class with you. Well I have a few friends that got SLR cameras and like me, have no idea how to use them [manually that is] and reading the book doesnt help. Well unlike me, they are unable to take the class like I am right now. SO i figure I'd give little lessons on here. The cool thing is I get to use MY work to teach. yay!

I am taking my class at Los Angeles Valley College and the lessons are taught by Mrs. Nancy Kaye. So everything I learned I learned from her. She deserves the credit. I will try to be as basic as possible yet understandable. hopefully ;)

So the very first thing we talked about in class was EXPOSURE: The Amount of Light Coming Through

Exposure = Shutter Speed + Aperture

Both Shutter Speed and Aperature [aka F-Stop] are what controls the amount of exposure that is coming through the camera.

Shutter Speed: How Long the Shutter Stays OpenWhen you press the button down on the camera the shutter is the "window" that opens to capture your picture. This has to do with light because obviously the longer the shutter stays on the more light is able to pass through the window. The less time the shutter stays open the less light.

Shutter speeds are measured in fractions of a second.
ex: 4000 = 1/4000th of 1 second just as 4 = 1/4th of 1 second.
Now using simple math here 1/4000th of a second is obviously faster then 1/4th of a second so by setting your shutter speed to 4000, the shutter will only stay open for a very short time.

Now creatively the shutter speed controls the Motion of Speed. When I say creatively it means, it all depends on how the photographer wants the picture to come out. If you think about it, if your subject is moving fast and your shutter is opening and closing faster or close to speed then your subject will look clear and frozen. On the other hand if your shutter is opening and closing much slower then the subject is moving then the subject will looked blurred in the photo due to the movement.

The first set of pictures were displaying the use of Shutter Speed. To see this in effect to how shutter speed controls exposure we kept all variables on the camera the same and changed ONLY the shutter speed. The

SUBJECT: MOVING SWING

The swing will becoming more blurred as will the picture become lighter due to the shutter staying open longer in each picture.

Shutter Speed: 250 [1/250th of a second]

Shutter Speed: 125 [1/125th of a second]

Shutter Speed: 60 [1/60th of a second]


Shutter Speed: 30 [1/30th of a second]

The very next thing that effects your exposure is the Aperture (aka F-STOP): Depth of Field [in lamens terms, the size of the hole in the lens].

This smaller the FStop number the Bigger the "hole". Now you can see why this controls the amount of light coming in as well because if the aperture is wide then more light will be able to pass through the lens compared to if it were small.

F2.8 is a wider aperture than F16 and it also lets in more light. Depth of field measures anything in the foreground or background of your subject. Creatively this is important due to what you want to be more In Focus. The wider the aperture the less depth of field you capture which means the more blurred the foreground and background of your subject will be. The smaller aperture means the more depth of field you have means the more clear anything in the foreground or background will be.

The second set of pictures were displaying the use of Aperture and F-stop. To see this in effect to how Fstop controls exposure we kept all variables on the camera the same and changed ONLY the Fstop. The Shutter Speed was kept at 200

SUBJECT: PLANT AND BACKGROUND

In this picture the background (depth of field) will become more clear as will the picture become darker as the aperture gets more narrow. The amount of background blurred in the background also depends on how close you are the subject and how far away the background is. The closer you are to the subject the better difference you will notice.

F5.6

F8

F11


F16

F22

So now after noticing how increasing the length of time of shutter speed makes the picture lighter and increasing the fstop makes the picture darker you can understand better how they work together to balance each other out in order to make a perfectly exposed picture. You have to use both in order to get a good picture. Depending on what you want the picture to look like creatively depends on what the two will be set on.

EX: Let's say you are taking a picture of a flower and you are testing the different exposures to see what looks good to you. Now according to this lighting around your subject, Let say you find a good exposure at 200/F11. Now as far as lighting is concerned this is a good picture BUT you want the background a little more blurred then F11 is giving you. Well since you want to change the depth of field we now know you have to work with the aperture. You want to make it wider which means you want the fstop to go DOWN. Well by the example pictures above you can see that by making the Fstop go down it will make your pictures lighter (b/c the aperture is getting wider thus letting in more light). Well now this will mess up your exposure. SOOOOO since the shutter speed will balance it out you have to change that as well.

LIKE MATH, you want to change the shutter speed the SAME number of "STOPS" as you change the fstop in the opposite direction.
STOP: A FORM OF MEASUREMENT USED IN PHOTOGRAPHY TO DESCRIBE THE CHANGING OF A SHUTTER SPEED OR APERTURE
ex: going from f3.5 to f5.6 is 1 stop. Going from shutter speed 400 to 200 is 1 stop. no matter which direction.

As one lets in more light you want the other to stop more light from coming in. If you change the aperture 2 stops down to F5.6 then you must change the shutter speed 2 stops up to 800 in order to keep the same perfect exposure. The only difference is now your background will be more blurred as you wanted. And you dont have to worry about the shutter speed changing anything because nothing is moving in your picture.

Now what if the subject was a kid swinging on a swing instead of a flower and the perfect exposure was again 250/F11 except this time since he is moving you decide you want the actual subject a little less blurred. This time you want to find the best shutter speed to create the look you are going for. Lets say at shutter speed 1000 gives you a more clear picture. Well by making just the shutter open and close faster (1/1000th of a second compared to 1/250th of a second) then your picture will let in less light then before thus making it darker. Now again you must balance the fstop out to get your perfect exposure back. If you moved the shutter speed 2 stops up to 1000 then you must move the fstop 2 stops down. f5.6 And since the subject is moving and it is the one being blurred or not then you dont have to worry about the fstop changing anything but the exposure.

MORAL OF THE STORY:
SHUTTER SPEED makes the SUBJECT more blurred or not (as long as the subject is moving)
FSTOP makes the BACKGROUND more blurred or not (depending on how close you are)

TOGETHER they can give you the perfect exposure.

until next time, go practice!

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New Class

So i started this new photography class. on my way to becoming a professional. haha really i jsut want to know how to operate my SLR camera manually. I mean I thought my pictures on automatic were pretty good until I started seeing other more professional pictures that gave me motivation to learn my camera better. I mean automatic is suppose to do everything for you right? except we forget it can't read your imagination and creativity so if you want a picture to look a specific way..sucks but you gotta create it yourself.

I took a photography class back in 2001 but as I can remember I dont think my camera had many manual settings at the time, it was just a point and shoot, so I dont remember really paying too much attention on all the key points. I think back then too I just thought the dark room was cool and developing pictures. Now that I am older and wise I appreciate the art of photography at its fullest. I'm happy to be able to share my growth with you as well.

My first assignment is due on Tuesday night. I have to take 16 different pictures working with Shutter speed and Aperture. Of course I will post my work so don't beg. :)

Off to shoot.

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