FEC ?

[CorruptedPhotographer]

hey everybody,

I am pretty much done tryin to figure whats on what on my 20D. Except for the Flash Exposure Compensation? Is it Canon's fancy way of saying, strong flash or light flash?

any comment? suggestions ? tips ?

thanks!

[scottbergerphoto]

In ETTL/II, the camera determines flash output via analyzing the preflash. FEC allows you to override the camera program to give more (+FEC) or less (-FEC)flash then the program calls for.

[Al Nakib]

When using the flash, the photographer can change the amount of light produced by using the Flash Exposure Compensation. Alternatively, the photographer can compensate the amount of light entering the camera (by changing the aperature and/or the shutter speed).

Therefore, using the Flash Exposure Compensation does give you stronger/lighter flash. However, I don't think "Flash Exposure Compensation" is Canon lingo for flash output but an industry standard.

[CorruptedPhotographer]

Scott, so if I want the camera to determine proper flash exposure, do I set it to 0? Meaning set it to the middle mark in FEC?

al nakib thanks for the info!

[scottbergerphoto]

Yes. Leaving FEC at zero, tells the camera to go with what it thinks is right. It will only apply to Flash output and is independent of EC (Exposure Compensation) which does the same thing for ambient light exposure.

[wilflee]

I use FEC to compensate the camera's exposure computer because it isn't infallable.

For example, when shooting people in a very dark room and the subject doesn't fill up a majority of the frame, the flash exposure computer will often overexpose the subject because the dark background tricks the computer into trying to light up the background (esp. true if the flash exposure metering area points at the background instead of subject). In this case, dialing the FEC down a stop or two will help to properly expose the subject.

[Hellashot]

hey everybody,

I am pretty much done tryin to figure whats on what on my 20D. Except for the Flash Exposure Compensation? Is it Canon's fancy way of saying, strong flash or light flash?

any comment? suggestions ? tips ?

thanks!

No, in compact P&S digital cameras, strong flash, weak flash is their way of describing FEC. :)

[CorruptedPhotographer]

No, in compact P&S digital cameras, strong flash, weak flash is their way of describing FEC. :)


This is my first DSLR, so I was trying to understand if they were the same in the sense you control the flash's strength.

[martook]

This is my first DSLR, so I was trying to understand if they were the same in the sense you control the flash's strength.

Well, as you've understood by now - no, not really... :)
The camera does that all by itself with some fancy schmancy computer. With FEC, you tell the camera it's doing a crappy job and override what it's decided is best for you. ;)

I'm new to the DSLR club as well (welcome to both of us!), and the only thing I've learnt about the flash system is that it's a black art. The more I read about it, the less I understand. Bah.
Do get an external flash though, it's a world of difference between the built in one, and my 550EX.

Cheers!

[martook]

... and I'm pretty sure it applies to other 550 (and 420/580) flashes as well. Not only mine. :P

[CorruptedPhotographer]

Really martook? Ive been hesatating to pick one up. I find myself asking this question over and over again : "when will I use it?"

Sure I know I can use it at night :P

But I guess I need more scenarios and isntances where I will use it. Basically im saying, help me understand the need for a flash. Other than if I were a studio/glamour or so photographer.

[Bob_A]

With FEC, you tell the camera it's doing a crappy job and override what it's decided is best for you. ;)



FEC doesn't override what ETTL-II comes up with, it adds some +/- compensation in the event your images are under or overexposed. For example, with my 20D I typically always have FEC set at +2/3. This is my starting point, and I watch the histogram to see if I have to make any adjustments up or down.

Canon has made a decision (according to their tech support) to purposely underexpose a bit with ETTL-II in order to make it more difficult to blow the highlights. In post processing you can usually correct for a slight underexposure, but if something is overexposed it's a different story.

[scottbergerphoto]

FEC doesn't override what ETTL-II comes up with, it adds some +/- compensation in the event your images are under or overexposed.
Since you are the sole arbiter of what is under or over exposed and you are dialing in FEC, you are in effect overriding what ETTL/II would give you. By setting your camera at +2/3 FEC, you have overridden the internal program to give +2/3 stops more flash then it is programmed to do.

[Bob_A]

Since you are the sole arbiter of what is under or over exposed and you are dialing in FEC, you are in effect overriding what ETTL/II would give you. By setting your camera at +2/3 FEC, you have overridden the internal program to give +2/3 stops more flash then it is programmed to do.

Scott ... I guess I don't think of this as "overriding" but just a fine tuning. I just wanted to point out that the program is the same, you are simply adding a +/- bias to the result. I wouldn't want anyone to think that by using FEC that ETTL-II is tossed aside.


p.s. The We're not Afraid site in your sig is pretty cool.

[martook]

Well, I guess we're splitting hairs here :)

My explanation was probably a bit too simple though, and it wasn't entirely correct... sorry about that! As you guys write, it still uses ETTL-II, it's more like one is fine tuning what the camera has decided is best for you, to your liking.

[martook]

Really martook? Ive been hesatating to pick one up. I find myself asking this question over and over again : "when will I use it?"

Sure I know I can use it at night :P

But I guess I need more scenarios and isntances where I will use it. Basically im saying, help me understand the need for a flash. Other than if I were a studio/glamour or so photographer.


It does of course depend a lot of what you are shooting. If I only did landscapes and/or birdhunting at 500mm, I wouldn't get one. But if you ever take portaits of people or animals, inside or outside, day or night - you should have one. Seriously.

If you take a look at my crappy pictures of my cousin here:
http://photography-on-the.net/forum/showthread.php?t=85154
You can see that the first shot is very dark... as I write there, I forgot my flash at home, otherwise that would have been a much better photo.

Fill flash makes a huge difference IMHO, helps remove ugly shadows and so on...


If you decide to get a flash, read this thread to get some understanding of how ETTL works:
http://photography-on-the.net/forum/showthread.php?t=80413
and of course the stickys in "Small flash..." section.

[I Simonius]

It does of course depend a lot of what you are shooting. If I only did landscapes and/or birdhunting at 500mm, I wouldn't get one. But if you ever take portaits of people or animals, inside or outside, day or night - you should have one. Seriously.

If you take a look at my crappy pictures of my cousin here:
You can see that the first shot is very dark... as I write there, I forgot my flash at home, otherwise that would have been a much better photo.

Fill flash makes a huge difference IMHO, helps remove ugly shadows and so on...


If you decide to get a flash, read this thread to get some understanding of how ETTL works:
and of course the stickys in "Small flash..." section.

Wow, your cousin is a dish! ;-)
anyway... do you think it is worth getting a Flash unit?
I would also ask when will you use it where the built in flash ona 20D won't suffice??
Won't it only be press type photographers who need it, i.e. for portrait and people flash further than the built in can reach??

[EOSAddict]

For what I have seen so far for the limited times I use flash (indoor family 'snaps' or small amount of outdoor fill-in) I would see little point in buying a dedicated flash unit. But I guess if you are into portraits, weddings etc it makes sense.

I think the built-in flash is actually pretty good for my purposes (especially as now I have hacked my 300D I can get FEC!)

[scottbergerphoto]

At f/8 ISO 100, the built in flash is only good for about 5 feet. At ISO 400 that only increases to 10 feet. If that's all you need and you don't care about the occasional red eye shot, then the in camera flash is fine.
Distance = GN/f stop at Iso 100. x1.4 at Iso 200, x2 at Iso 400

[ed2day]

Really martook? Ive been hesatating to pick one up. I find myself asking this question over and over again : "when will I use it?"

Sure I know I can use it at night :P

But I guess I need more scenarios and isntances where I will use it. Basically im saying, help me understand the need for a flash. Other than if I were a studio/glamour or so photographer.

Do you shoot indoors? You can't be happy with your 17-40 under available light, can you? I guess if you use your 50mm all the time indoors you can get by without a flash but that seems pretty limiting.

[ed2day]

When using the flash, the photographer can change the amount of light produced by using the Flash Exposure Compensation. Alternatively, the photographer can compensate the amount of light entering the camera (by changing the aperature and/or the shutter speed).

Therefore, using the Flash Exposure Compensation does give you stronger/lighter flash. However, I don't think "Flash Exposure Compensation" is Canon lingo for flash output but an industry standard.

While all this is true, I think it's important to note that FEC is more than just an alternative to exposure compensation. FEC allows you to control the mix of ambient(background) exposure vs. subject (foreground) exposure.

[CorruptedPhotographer]

ed2day, its been a while since I shot anything other than landscape. So honestly I could not tell you if my 17-40 f/4 L is sufficient or pleasing me. This is probably why I dont already own an external flash lol

[ed2day]

At f/8 ISO 100, the built in flash is only good for about 5 feet. At ISO 400 that only increases to 10 feet. If that's all you need and you don't care about the occasional red eye shot, then the in camera flash is fine.
Distance = GN/f stop at Iso 100. x1.4 at Iso 200, x2 at Iso 400

I would add "And if you don't mind a flash picture that screams 'I was taken with the onborard flash'". I personally think the onboard flash is terrible and consider the purchase of a flash unit the biggest upgrade I've made.

[ed2day]

ed2day, its been a while since I shot anything other than landscape. So honestly I could not tell you if my 17-40 f/4 L is sufficient or pleasing me. This is probably why I dont already own an external flash lol

Gotcha. The 17-40L is a beaut for landscapes, isn't it?

[CorruptedPhotographer]

ed2day, wow I did not think that one could distinguish easily between the built-in flash and an external one. I guess one of the main reasons im avoiding a flash is because of the complications of trying to learn how to properly use it. The last two years were hectic academically, they were my Junio and Senior year for a BAcherlors in Accounting. This coming semester will be my last one with easy electives. I will probably pick one up and see how it reacts to Chicaaaaaaaaaaago ;), since i study 40 miles away

and yes, the 17-40 f/4 L is fantastic landscape, I only wish the 20D did not eat up 10.2mm of my shot!!
damn 1.6x crop

[ed2day]

The big thing is an external flash lets you "bounce" the flash or otherwise diffuse it. You don't get the harsh off of faces etc. And it can be as simple as using the internal flash. Now get back to those balance sheets.

[CorruptedPhotographer]

ed2day, when you say bounce, do you mean aim the flash @ a wall or a relfector? If so, how do you do that with the 580EX? Is it flexible in the sense that you can point it away from infront of you?

Leave me and my lovely balance sheets alone, hahahha

[ed2day]

Yep. I have the 420EX, but it's similar in that it can pivot both horizontally and vertically.

[martook]

Wow, your cousin is a dish! ;-)
anyway... do you think it is worth getting a Flash unit?
I would also ask when will you use it where the built in flash ona 20D won't suffice??
Won't it only be press type photographers who need it, i.e. for portrait and people flash further than the built in can reach??


Oh you bloody brits... wtf do you mean? *don't understand*
If you mean that you could eat her, I'll have to punch you in the face, you pervert! ;D

Yeah, and only the press could possibly need L-lenses as well... ;)
Naw, seriously, I think an external flash is worth the money it costs, if you are indoors, you can bounce it off a wall or the ceiling which means you get a much softer light, it has much more power so it reaches longer and also a lot wider.

Try to borrow a flash from someone, that's probably the best way to find out if you want/need one or not.

[ed2day]

Another advantage of the external flash is for flash assisted focusing (can't remember the exact term) in low light. The internal flash puts out a heinous white strobe while the external unit puts out MUCH less noticeable red light.

[Roy NN7DX]

This might help...
Fill flash cheat sheet: http://www.popphoto.com/assets/download/821200311318.pdf
Note that there are two exposures, the background and the subject. Both are "tuneable".

[I Simonius]

Oh you bloody brits... wtf do you mean? *don't understand*
If you mean that you could eat her, I'll have to punch you in the face, you pervert! ;D

I hadn't thought of the origins of the term 'she's a dish'! Perhaps that IS what it meant in days of yore! Anyway normally it just means 'gorgeous' - Oh poo, perhaps that means you could gorge on her - oh blimey! Oh no that comes from 'God Blind me'!
Let's just say she's a feast for the eye, aaaagh... 'delectable' then..no that's worse..
You're right, all brit terms of female appreciation are gastrononmic!...there's no denying she is tasty though :lol:

snip
Try to borrow a flash from someone, that's probably the best way to find out if you want/need one or not.

I did that and decided I didn't really need one, not yet anyway

[martook]

I hadn't thought of the origins of the term 'she's a dish'! Perhaps that IS what it meant in days of yore! Anyway normally it just means 'gorgeous' - Oh poo, perhaps that means you could gorge on her - oh blimey! Oh no that comes from 'God Blind me'!
Let's just say she's a feast for the eye, aaaagh... 'delectable' then..no that's worse..
You're right, all brit terms of female appreciation are gastrononmic!...there's no denying she is tasty though :lol:


*lol*
I'm not sure I want to tell her what you think about her ;)

You've got a lot of weird expressions in the UK. Met quite a few of you people when I was travelling around the world and I had to learn a different language (let's just say that "I was pissed off my tits!" wasn't in my english textbooks in school) to be able to communicate with you :)


I did that and decided I didn't really need one, not yet anyway

Oh, you'll leave the dark side soon enough, trust me! (pun intended...)