What is "Bracketing"? - Homework Help!

Masq

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Hey guys, I'm going to miss my class today because I can't commute to school, but I know what we're doing for class. However a section of the work I do not understand, if you can inform me what the following means, I'd be grateful.

"[FONT=Arial, Helvetica, sans-serif]two examples of "bracketing" - determine the exposure for the subject which is the 0 exposure and take the photo. Photograph the subject a total of four more times at +1, +2, -1, -2."

Does anyone have a clue what that means? Thanks for any help you can provide.
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Chris of Arabia

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At its simplest, bracketing is just a case of taking a series of photographs at exposure settings either side of what your light meter recommends.

So for example, if your meter recommends f8 at 1/125s and call that your 0 exposure, the others would be as follows:

+2 = f8 at 1/30s or f4 at 1/125s or f5.6 at 1/60s
+1 = f8 at 1/60s or f5.6 at 1/125s
0 = f8 at 1/125s
-1 = f8 at 1/250s or f11 at 1/125s
-2 = f8 at 1/500s or f11 at 1/250s or f16 at 1/125s

somebody check that lot for me would you, my tea's ready...

There are other combinations by the way.
 

Sideburns

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It just means
Take an exposure based on the meter. Then, you take an exposure 1 stop under, 2 stops under, 1 stop over, and 2 stops over.

If that's not simple enough..or you're still confused...let us know.
 

HighLife

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Stupid question from me here, what's "Then, you take an exposure 1 stop under, 2 stops under, 1 stop over, and 2 stops over"
I mean to ask what's a stop? is it the Ev ( exposure compensation ) or the Shutter keeping the aperture Constant ? CAn ouy please expand on that.


Im very new to this but a "stop" refers to opening and closing the aperture and the shutter (thanks for correcting that Chris)..

When he refers to the "take an exposure, 1 stop under etc etc " your camera will take 3 shots (dont believe it snaps off 3 shots, however it will take your 1 shot and apply the bracket afterwards, really not sure of how its actually done in the camera), each shot it will have a different Ev setting...the idea behind it is that 1 of the 3 shots will have the correct exposure.

Notice the relation to the numbers that Chris of Arabia posted....if your meter asks for a f8 and 1/125 for correct exposure, this isnt the only way to get that same exposure...say you want more DoF, if you move your aperture up 1 stop (closing the hole) you will have to move the shutter to 1/250 to get the same exposure...

So (+2 = f8 at 1/30s or f4 at 1/125s or f5.6 at 1/60s) what does this mean? for a +2 exposure f8 at 1/30 is equal to f4 at 1/125 is equal to f5.6 at 1/60.

Pls correct me if im wrong...im very new to this, but have read alot about it.
 

Chris of Arabia

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A stop does not refer to just the aperture, it can equally mean the duration the shutter is open.

Each stop is double the amount of light of the one before it or half the one after. Typically the following settings are available on a camera (or at least ones you have a measure of control over).

Aperture: f22, f16, f11, f8, f5.6, f4, f2.8, f2

Shutter: 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8

In the order presented (and assuming the other remains constant), each lets in twice as much light as its predecessor. The difference between each is what's known as a stop. At it's simplest, it should be apparent that a setting of f22 at 1/1000s needs one hell of a lot more available light than using f2 at 1/8s.

Most cameras also offer the ability to access intermediary settings, generally in 1/3rd stop increments, so that you have finer level of control over the exposure.
 

(Ghastly) Krueger

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Expanding a bit, if you bracket (automatically) in aperture priority mode, the aperture will remain fixed and the bracket will be made by varying the shutter speed, and vice versa. In practical terms, if you want to keep your DoF, bracket using aperture priority.

*Edit: Thanks to Chris of Arabia for the correction ;)
 

Chris of Arabia

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Expanding a bit, if you bracket (automatically) in aperture priority mode, the aperture will remain fixed and the bracket will be made by varying the shutter speed, and vice versa. In practical terms, if you want to keep your DoF, bracket using aperture priority.

:blushing: slight correction for clarity's sake...
 

mrodgers

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.....(dont believe it snaps off 3 shots, however it will take your 1 shot and apply the bracket afterwards, really not sure of how its actually done in the camera)........
I don't have a dSLR. My camera has both the image on the back display as well as a display inside the viewfinder (meaning the viewfinder is not optical). When I use the bracketing setting on my camera and have the preview enabled, I can see (and hear) the camera taking 3 seperate shots. It would be impossible not to because bracketing within your camera uses 3 seperate shutter speeds. It can't take one shot at 3 different settings, no matter if it uses shutter, aperture, or ISO. So, it has to take 3 seperate pictures.
 

HighLife

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I don't have a dSLR. My camera has both the image on the back display as well as a display inside the viewfinder (meaning the viewfinder is not optical). When I use the bracketing setting on my camera and have the preview enabled, I can see (and hear) the camera taking 3 seperate shots. It would be impossible not to because bracketing within your camera uses 3 seperate shutter speeds. It can't take one shot at 3 different settings, no matter if it uses shutter, aperture, or ISO. So, it has to take 3 seperate pictures.

Yes, testing for myself its actually 3 different shots taken...i just didnt want to speak about something i had NO idea on how it really worked. I understand the concept of it, but how its actually done i was stumped =)
 
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Masq

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out of curiosity, what does the autobracketting symbol look like?

On my dial (i've only used manual at the moment) I have the following symbols:

A circle:
Music Picture:
SF:
DEP:
Av:
Tv:
P:
L(Red Block):
Green Rectangle:
Face:
Mountain/Cloud:
Flower:
Running Person:

Are these common settings? Also, if anyone has any extra time, feel free to enlighten me. I'm assuming the last few settings are for landscape/etc/etc.
 

JerryPH

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It is different on different cameras. Don't be afraid to open up your manual and look. Its not very fair to ask everyone to rewrite the manual here for you or explain things that would be easier to search for here or your manufacturer's manual.
 

Chris of Arabia

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out of curiosity, what does the autobracketting symbol look like?

On my dial (i've only used manual at the moment) I have the following symbols:

A circle:
Music Picture:
SF:
DEP:
Av:
Tv:
P:
L(Red Block):
Green Rectangle:
Face:
Mountain/Cloud:
Flower:
Running Person:

Are these common settings? Also, if anyone has any extra time, feel free to enlighten me. I'm assuming the last few settings are for landscape/etc/etc.

The chances are that it'll be accessed via the menu structure, not from the dial on top. It certainly is on my 350D. As Jerry suggests, try the manual.
 

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