Now LIVE - Podcast Suggestion: Exposure Compensation

[Iguanasan]

Forgive me if you've already covered this. I've listened to all the podcasts and did a search of the site but I cannot find it anywhere. I'm going to delve back into my camera manual but I thought this would be a good topic for a podcast. Just what the heck is exposure compensation and why do I want to use it? Would it make sense to simply bump up (or down) the ISO, aperture, or shutter speed to make an exposure adjustment - that is the exposure trinity. Why do I want to use exposure compensation?

[Marko]

I could easily do a podcast on this but it's really simple.

All exposure compensation does is easily add exposure or reduce exposure from Program modes like aperture priority or shutter priority. Let's say camera meter exposure reads 1/125 at F8 and you took the shot and it's still dark. Rather than change film speed, aperture, or shutter speed (which may take a few extra seconds) exposure compensation does the job faster. I believe that the exposure compensation works on most cameras on the shutter speed alone (meaning it does the compensating by making the shutter speed faster or slower).

If time is not an issue, don't use it as you have better control when you decide exactly what you want. But when speed is of the essence, it's gold.

If you shoot on manual, it's fairly useless imo. But it's amazing for program modes and I use it often. Hope that helps - Marko

[kat]

I can't use it in Manual mode. It won't do a thing. But it is great for quick shots! Specially sunset time.

[Marko]

There's no reason to use it in manual mode (since you are already fiddling) and that's why it's likely unavailable on your camera.

[Iguanasan]

I just find it interesting that on program modes, aperture priority, where I play once in a while, though I almost always shoot in manual, it almost always adds +2/3 this or -1/3 that. Rarely does it seem to just set the correct exposure without compensation. Maybe I just need to read my manual a little closer. It's waiting at home for me tonight!

[kat]

I've noticed that as well. Highlights are my biggest enemy! I find that most times if I'm in aperture priority (which I would use more often than shutter) I have to use that exposure compensation. I'm not that great with manual yet..I try to use it when I can but sometimes I jsut can't get it figured out the way I want it to go..lol..specially now that I've added some filters on!

If you find anything for why..fill me in!

[Marko]

...it almost always adds +2/3 this or -1/3 that. Rarely does it seem to just set the correct exposure without compensation.

I'm confused. IF you add exposure compensation, yes it often works in increments/decrements of 1/3 of a stop. BUT if you are on a program mode and exposure comp. is NOT on, you should see no such numbers. The photographer activates E.C. when needed.

IF on a program mode, normal scenes (scenes with a myriad of tonal values without 1 dominant tone like a bright shaft of light) are consistently showing up either dark or light, then check to make sure E.C. is indeed off.

[Marko]

This podcast just went live here http://www.photography.ca/blog/?p=558

Thanks again for the suggestion Iggy!

[flat]

hi, this is my first post here, although i've lurked for a while now. i'm very new to photography but..

when i'm in shutter priority mode, and change my exposure compensation it changes my aperture size. when i'm in aperture priority mode, changing exposure compensation changes the shutter speed.

i just think of it was a way to stay in a priority mode, but change the other part of the "trinity" quickly. instead of shooting in full manual... i can shoot in a priority mode to get close to the right exposure quicker and adjust if needed.
i have another button set to allow me to quickly change ISO if necessary. so, the exposure compensation button just becomes the "opposite of whatever priority mode i'm in" button.

i'm pretty confused by "flash compensation" though. like i said, i'm very new to this, and only use the built in pop up flash on my d40... but, does flash compensation simply alter the power of the flash? i'm also confused how to make my flash look good artistically, but i am trying to figure out the technicals first. can you help me out marko?

love the podcast, i plan to stick around the forum. thanks

[Marko]

i'm pretty confused by "flash compensation" though. like i said, i'm very new to this, and only use the built in pop up flash on my d40... but, does flash compensation simply alter the power of the flash? i'm also confused how to make my flash look good artistically, but i am trying to figure out the technicals first. can you help me out marko?


Hey Flat first off welcome to the forum !!

In terms of yr question, Yup flash exposure compensation alters the power of the flash. If the main subject being lit by the flash is too dark, up the flash's power - the reverse holds true as well.

To use flash artistically, you need to get an external flash and bounce it or even better, take it off camera with a sync cord or remote trigger. Your built in flash is almost useless for creative flash.

You probably listened to podcast 71 on portable flash (http://www.photography.ca/blog/?p=525), but if not - it's a good place to start. Strobist.com (http://www.strobist.com)is a fantastic site that also teaches you how to light with flash. Hope that helps - Marko

[kentw]

I posted the following as a comment on the podcast, but this seems tobe the proper place to have commented. Sorry about that.

Hi Marko –

I just listened to the Exposure Compensation podcast, and I have to say you (uncharacteristically) left me a bit confused. I shoot with Canon 50D (but have had 20D and 40D — they work the same, as far as I recall).

Suppose I am shooting in Aperture Priority Mode using Evaluative metering, and my exposure at ISO 200 is f/4 at 1/30 seconds. Now if I change the ISO to 400, thinking to lighten the image, it will not do so; instead, I will get f/4 at 1/60 seconds. If I look at the histograms for the two shots, they look the same. The meter has just given the same EV. So that is no way to achieve Exp Comp. If, however, I use the Quick Control Dial, and dial +1, I will get f/4 at 1/15 seconds. So my thinking is that the Exp Comp function overrides the meter.

On the Canons, I don’t think you can change the shutter speed in Av Mode without using the Quick Control Dial, ie, other than using Exp Comp. You can change the Aperture or the ISO, but if you let the meter determine the exposure, no compensation will be achieved.

In Manual Mode, Exp Comp is achieved by moving Exposure indicator needle (I don’t know what else to call it) either to the plus or minus side of the meter’s recommended exposure.

Ok, that’s the way I have understood Exp Comp. Is that what you were saying, or am I totally confused (it wouldn’t be the first time)?

[Marko]

I see your confusion Kent. You are saying that you CAN'T ONLY change the ISO to control exposure in either shutter priority and aperture priority, the second you do - the shutter speed changes so there is NO compensation. That's how it works on my camera as well.

Now that I think about it......I should have thought it through, Instead I just answered the question at hand assuming that that's what the photographer was doing. Instead he was theorizing.



So my thinking is that the Exp Comp function overrides the meter.

On the Canons, I don’t think you can change the shutter speed in Av Mode without using the Quick Control Dial, ie, other than using Exp Comp. You can change the Aperture or the ISO, but if you let the meter determine the exposure, no compensation will be achieved.

In Manual Mode, Exp Comp is achieved by moving Exposure indicator needle (I don’t know what else to call it) either to the plus or minus side of the meter’s recommended exposure.

Ok, that’s the way I have understood Exp Comp. Is that what you were saying, or am I totally confused (it wouldn’t be the first time)?This is correct, it (meaning you the photographer) overrides the meter in increments or decrements of 1/3 of a stop. On the Canon, yes this is done through the quickdial in aperture and shutter modes (as well as other modes that i never use). In manual mode, you just move the 'needle' right or left as you mentioned.

Hope that clears it up - sorry for the confusion,

Marko

[kentw]

Thanks for the clarification,Marko.

I look forward to your podcasts, but those other aspects of life that should never be allowed to get inthe way of photography have been monopolizing my attention lately.

best,
kent