Exposrure compensation

Hi all,


I am a newbie to photography. I have been using my 40d for 6 months now and have a fair amount of knowledge about various techniques. This one thing I could never figure out how to use though? I mostly shoot in manual mode, so i set the aperture ,white balance, shutter and iso. I also know and use the exposure settings on my 580exII flash.


How does the "exposure compensation" on the camera differ from that? How can I use "exposure compensation" to benefit in manual mode?





Cheers! and Thanks in advance,


Dev

Dev,





Expouser comp on the camera affects the amount of light that hits the sensor. Its a way to fine tune expouser in 1/3 stops rather than full stops through a change in shutter speed or arpeture. A positive expouser will let more light in, eg an overexposed pic. This is good for making whites white, blowing out backgrounds, dark/meek weather and lighting shadows.


A negative exposuer does the opposite: under exposes the photo, making blacks black, deeper/richer sunsets ect.


The 40D also has an incamera flash compenstation that works to offset and tweak exposuers with a flash.

Thanks for that info Ehcalum. Still wondering which parameter gets affected or rather is used by the camera to do the exposure compensation? does it use the iso such that it increases/decreases the light hitting the sensor? or shutter and or aperture or something else entirely?


Sorry about the million questions.


Dev

Quote:

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Originally Posted by devsalvi

Still wondering which parameter gets affected or rather is used by the camera to do the exposure compensation? does it use the iso such that it increases/decreases the light hitting the sensor? or shutter and or aperture or something else entirely?
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• M: There is no Exposure Compensation. You control both the shutter and the aperture.
• Av: Exposure Compensation changes the shutter speed (slower for EV+ and faster for EV-)
• Tv: Exposure Compensation changes the aperture (larger smaller number for EV+ and smaller larger number for EV-)
  

Thanks a lot Mark. That makes sense. So EC does not apply to me. Glad i didn't bother to look till now :D





Cheers!


Dev

Even though you shoot manual, it's still handy to play around with the exposure compensation feature once in a while. I shoot in manual mode most of the time, but in order to get my exposure right I might switch over to Av or Tv to get me close to the right exposure so I know where to start in Manual. If I know I'm going to want to underexpose the scene, I can find out what settings the camera believes will underexpose the shot, and go from there. It just cuts down on the time it takes to dial in the exposure while in Manual mode.

There is Exposure Compensation in manual mode. If you look at the meter bar and the icon blinks in the middle you have EV (0) if the bar blinks to the right you have EV + the value and if the icon blinks to the left you have EV - the value. If your camera is using the default settings each tick on the graph is a 1/3 value.


In manual mode you can affect the EV value by adjusting either the Shutter Speed or the Aperture.


In both EV and TV mode there is a camera function that allows you to dial in the exposure compensation +/- of what you want for the shot otherwise the camera will always adjust either the ISO, Shutter Speed or Aperature (depending upon the mode you are in to achieve and EV(0) Again, EV - values are to the left of the center line in the meter bar and EV + values are to the right of the meter bar.


Hope this helps.

Thanks Sean for that tip.


Thanks Don for that information. Since I shoot manual I always use the EV graph but I see the EV+- settings in the exif data for some pics everyone posts online and I was wondering if I was missing out on using the "Exposure compensation" technique. True, setting EC while shooting in AV/TV mode regulates the brightness/darkness of the picture. I can easily confuse myself !





Cheers!


Dev

I think we are dealing with semantics here. I would agree that usually exposure compensation is usually used in reference to Av or Tv mode. So if someone is giving their EXIF information for a shot taken in Av, for example, they would give aperture, ISO, EC and shutter speed. I don't think that the EXIF information includes EC for shots taken in Manual mode (am I wrong?) because it is not a controlled parameter (although I guess shutter speed is not controlled in Av mode). Anyway, you can obviously bias your exposure one way or the other in Manual mode, I just think the term "exposure compensation" is used most common when you actively set your EC and it doesn't float as it does in manual.

Sorry about the confusion. You are absolutely right Stephen. The EC adjsutment provided with the camera only applies in the Shutter/aperture priority modes. In manual mode you pretty much choose your own EC(by adjusting aperture,shutter,iso) and not the cameras EC control, for the desired effect.


Thanks for replying!


Dev

Exposure compensation in manual mode doesn't change anything about the image, but it might be useful as a "guideline." Say you're shooting pictures in a snowy environment. If you "match the needle"--i.e., set the manual exposure so that the blinking icon is at "0," the images will be too dark and the snow will look grey. That's because the camera is set to make a grey (about 18% grey) target look correct. When it sees a lot of white, it will tend to underexpose. You can deal with that in manual mode two ways. First, you can leave exposure compensation at 0 and ensure that the blinking icon is at about +2. Second, you can set exposure compensation to +2 and set the blinking icon at 0. The results would be the same, but one method might be more convenient for you. Setting the exposure compensation might be a good way to "remember" to push up the exposure. On the other hand, if you move to another scene, you should remember to reset the exposure compensation.

One cool thing with the Nikon's* exposure compensation (I wish Canon would do it, too), is that if you set the EC for , say, -2 stops, and then switch to manual mode, the light meter will be biased to underexpose by 2 stops, so if you set the exposure to what the meter dictates, the photo will be underexposed.


*My friend's Nikon D40 does this; I don't know about other Nikons, although I'd assume they are the same.

Quote:

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Originally Posted by ShutterbugJohan

One cool thing with the Nikon's* exposure compensation (I wish Canon would do it, too), is that if you set the EC for , say, -2 stops, and then switch to manual mode, the light meter will be biased to underexpose by 2 stops, so if you set the exposure to what the meter dictates, the photo will be underexposed.


*My friend's Nikon D40 does this; I don't know about other Nikons, although I'd assume they are the same.
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You mean it maintains the exposure setting from mode to mode? That's neat (I forgot to check if my 5D2 does so... probably it doesnt)

Thats what caused the confusion in the first place. Before i bought
my Canon 40d my friend lend me his nikon d200.


i set the EC to -2 at fixed aperture and iso and chcked shutter speed was required to get the properly exposed picture. The marker at 0 on the EV graph. Then i set it to +2 for the same subject with same aperture and iso and checked what shutter speed was required to get a properly exposed picture and it turned out to be exactly the same. So i gues for canon atleast 40d, the EC does not play part in manual mode. Please correct if I am wrong.


Cheers!


Dev