Advice on exposure


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MaGixShOe

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wat issit for?
i tried taking it with different exposure settings and the photos seems to be the same...
 

Tweek

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do you mean different combinations of exposure, or different exposure compensation, or just plainly different exposure? They all mean different things leh...
 

MaGixShOe

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i set it to the extreme lor
+1.5 and -1.5

wats the diff?
wat is it used for?
wat is exposure?!?!?
 

munfai

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it depends on what you're shooting with. with negative film you can barely see the difference. with slides you can.

don't know about digital, but you should be able to see the differences.

compare the darker or lighter areas for a set of photos taken with different exposure compensation, you should be able to see a difference in depth, detail and colour saturation
 

Paladin

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do a bracketing if your camera has the fuction or just take 3 shots manually at equally apart EV settings lor....
 

Flare

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Ok...

The +ev or -ev is known as exposure compensation. But firstly what's exposure?

Exposure is the act of exposing photographic film to light, and in digital photography, the CCD to light. The brightness of the image depends on the amount of light the CCD/film is exposed to. The amount of light that gets onto the film and CCD is controlled by the aperture and the shutter of the camera. A wider aperture is going to let in more light compared to a smaller aperture, a slow shutter speed is going to let in more light compared to a faster shutter speed.

Other than the shutter and aperture, the amount of light available is also very important, under the afternoon sun is going to be a lot brighter than in the evening. It is possible that the amount of light available indoor is a few hundred times dimmer than under the sun. A photographer thus has to know what is the amount of light available and this is measured using a light meter. Most modern cameras has a light meter built into the camera that measures the amount of light available and give an appropriate shutter speed and aperture value so that the correct amount of light is allowed onto the film or ccd, in other words achieve a "correct" exposure.

Correct is subjective, sometimes the photographer wants to intentionally underexpose or overexposure a picture, which is letting less or more light onto the film other than the "correct" amount. And sometimes the light meter may be fooled and give an inaccurate exposure. So to allow this, the photographer can of course take over the controll of the aperture and shutter speed and set them manually, or use exposure compensation.

Exposure compensation is a system which allows adjustment over the values given by the camera's light meter. say a ev-1 will mean an exposure compensation of -1 stop. That means the camera is going to set the apeture and/or shutter speed so that the amount of light is going to reach the CCD/film is going to be half of what that is reccomended by the light meter... a +1ev will mean double that of recommended and so on. When you set the exposure compensation, you will be able to notice the aperture and/or shutter speed values change.

Below are some examples:


This is shot at ev+0, which in other words, is the aperture and shutter speed value reccomended by the camera's light meter. Which is shutter speed of 1/4 seconds and aperture of f3.5


This is shot at ev+2. The amount of light allowed onto the CCD/film is 2 stops higher, which means 4 times more (1 stop is double, doubling 2 times = 4 times) light is getting onto the film or CCD. Here the shutter speed is 1 second, aperture is still at F3.5. The shutter is open for 4 times longer compared to ev+0. Notice the image is brighter? But due tothe brightness, details are lost as hot spots?


This is shot at ev-2. The amount of light allowed to ended is 1/4 (1/2 two times) of what the light meter recommends. The aperture is still F.3.5 but the shutter speed is 1/15, about 4 times shorter than 1/4. See, its darker than the first image and some details are not captured....
 

MaGixShOe

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thankx flare

so in simple terms it means that the more +EV u set the more light will enter the cam resulting in a brighter image and lesser EV means lesser light will enter the cam resulting in a darker image rite??
 

Flare

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correct. It allows the photographer to fine tune the exposure from the one the light meter gives. Remember to avoid over exposing or under exposing the image tho... unless you intentionally wants to achieve that.
 

R

rainyboy

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Flare,

That is a really clear explanation.
I finally understand wad EV is all about.
Thanx!

:p
 

O

Olympus2000

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Like to add one more point.

Do instruct your photo developer not to adjust the colour saturation/contrast/whatever settings too. Else, he/she might happily adjust the exposure settings while developing your pictures and BING, back to square one. get 2 identical pictures with diff EV setting.

my 2 frames worth...
 

Tweek

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Originally posted by Olympus2000
Like to add one more point.

Do instruct your photo developer not to adjust the colour saturation/contrast/whatever settings too. Else, he/she might happily adjust the exposure settings while developing your pictures and BING, back to square one. get 2 identical pictures with diff EV setting.

my 2 frames worth...
it's ok lah, cos he is using a DC. :D Btw, can we request for that even for negative prints? As in, ask not to do any adjustments. Never tried asking that before.
 

O

Olympus2000

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Hi Tweek,

That depends on which outlet you go to. Some outlet lets the minilab do the adjustments (DC or FC make no diff) automatically while others are done manually. I think you can forget about asking if its operated automatically. The darn machine will run a software that 'balances' the colour, brightness etc... It's supposed to produce consistently good pictures by some standards... but again, no software is better than an experience human developer. All they do is punch a few buttons to make minor corrections and it'll usually turn out superb.
 

Tweek

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Originally posted by Olympus2000
Hi Tweek,

That depends on which outlet you go to. Some outlet lets the minilab do the adjustments (DC or FC make no diff) automatically while others are done manually. I think you can forget about asking if its operated automatically. The darn machine will run a software that 'balances' the colour, brightness etc... It's supposed to produce consistently good pictures by some standards... but again, no software is better than an experience human developer. All they do is punch a few buttons to make minor corrections and it'll usually turn out superb.
I see..thanks for the info. So which outlet would you recommend?
 

O

Olympus2000

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Hi Tweek,

I'm a west guy. I find that one Kodak (who has a lady master doing the adjustment) outlet near where I live in Jurong. Can't remember the name of the shop. If you're interested, I'll make a note when i visite that area and post it here.

I think there are a couple more in the town whom some of my frens swear by. I've not tried them and therefore will not make any comments here.

cheero!
 

Tweek

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Originally posted by Olympus2000
Hi Tweek,

I'm a west guy. I find that one Kodak (who has a lady master doing the adjustment) outlet near where I live in Jurong. Can't remember the name of the shop. If you're interested, I'll make a note when i visite that area and post it here.

I think there are a couple more in the town whom some of my frens swear by. I've not tried them and therefore will not make any comments here.

cheero!
ok, it's alright lah, cos I'm a East guy and I seldom pass by Jurong. Thanks anyway! I'll try asking at the labs that I encounter.
 

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