Q: What's EC & FEC & "Stopping Down"

Scott_Quier

I received a PM from another DGrinner asking the following questions.

I want to ask some advice. Adjusting exposure settings and flash compensation.....both of these I'm sure are important but I know nothing about them and never use them in my work. However, I can't help but wonder if I am missing out on something that might help me. I keep seeing people mention stopping down the lighting on this or that, but I have no idea what they are talking about. Short of buying a bunch of books, what can I do to get a better grasp on these things?

Thinking this might be something that others are interested in knowing, I thought I would post the question here, take my best shot at it and let others with more knowledge/skill than me add the $.02 to the mix. So....

Adjusting exposure settings. It sounds like you've not yet explored the Tv, Av, OH BOY, M modes of your camera. It's when you start that exploration that the fun really begins! If, indeed, you haven't yet explored these modes, then yes - you are missing out on a big part of the fun. Let me be the first to recommend you pull out your camera owner's manual and play with at least the Tv and Av modes. Then you can start on the following.

EC - This is a way to over-ride the exposure set by the camera. For example, say you're in Av mode and shooting a backlit subject. There is a good chance the camera will be metering all of what it sees and will not sufficiently expose the "dark" side of your subject (the aspect of the subject that you can see) - so you get a dark face. Not good. What do you do? Well, you dial in some positive EC, thus telling the camera that it's close, but you need it to expose it just a bit more so you don't end up with a dark/shadowed face.

FEC - Take the same situation as above but we are going to further assume our subject is our SO and the backlight is supplied by a beautiful sunset - almost as beautiful as our SO. What we would like is to be able to see our SO's face and also get the colors of the sunset. If we just dialed in +EC, we get the face alright, but we would blow out the sunset - not our intent. But wait, we have a flash! So we turn it on. If we were to press the shutter, the flash would attempt to light the near objects (our SO's face) to "full exposure". But, this would look really, really fake - our SO's face is not being lite by the sun - remember. So, we set the FEC to -2/3 (or so) and let the camera meter for the sunset (no EC). Assuming the camera selected a shutter speed slower than or equal to our shutter sync speed, we should get a nicely expose sunset and our SO's face should be filled with just enough light that we can see it without it being so much that it looks really, really fake.

Other sources of information? Well, you can read this thread I started not so long ago to which Andy supplied some useful information. If you check the date on that thread, you will note that I started that thread less than a year ago. Almost all the "knowledge" I have gained since then has been from reading posts on a couple different forums. There is no substitute for reading and testing what you have read. It's not really your knowledge until you have actaully used it a couple (or more) times.

pathfinder

EC stands for Exposure Compensation. It refers to +/- adjustments made to the Exposure Values suggested by the cameras metering system.

FEC is Flash Adjustment Compensation and is a similar +/- adjustment to the recommended flash setting suggested by the camera.

'Stopping down' refers to changing the aperture values to adjust the amount of light hitting the film or the sensor. Stopping down means adjusting the Aperture numbers to higher numbers - from f4 to f8 or on to f16 - each step decreases the amount of light hitting the sensor by 50%. Stopping down from f5.6 to f8 results in cutting the amount of ligh to the sensor by 1/2 ( unless a corresoponding change in shutter speed is made)

Here is a post I made previously about the EOS system flashes and how to use them..............................

I have described the use of the EOS sytem flashes several times, ( google flash - Pathfinder ) so I am going to refer you to the best links on the web re: the EOS system flashes. You cannnot decipher the results UNLESS you know the philosophy behind the various modes - The exposures are different when you shoot in Av or Tv, P, or Manual and you need to understand what the sytem is doing or it will be very confusing - Lots of folks complain about the exppsure with the EOS system and it is because they do not understand the basic plan behind the results.

The EOS System flashes work great and are emminently flexible and controllable, but their manuals do a poor job of explaining how to get them to do your bidding. I use the EOS flashes frequently since I read these three links and figured out what the underlying philosphy re: expsoure is. Do a search here on dgrin using "pathfinder and flash" and you should find some of the threads I have posted here also.

There are three links

http://photonotes.org/articles/eos-flash

http://photonotes.org/articles/eos-flash/index2.html

http://photonotes.org/articles/eos-flash/index3.html

There is also a great video put out by Blue Crane and available from B&H that is very helpful

http://www.bhphotovideo.com/bnh/cont...goryNavigation

Read the links, and if you still are having problems, PM me and I'll help you sort it out.

Cason

Is it safe to say that if you are in AV mode and your meter is in the middle and you want to increase EC, then all it does is slow the shutter speed? Although AV is aperture priority, increasing or decreasing the EC is just overriding the shutter speed...

pathfinder

Yup.

In AV mode, altering Exposure Compensation, changes the shutter speed.

In TV mode, altering EC, alters the aperture.

In Program mode, something will probably change