# TTL, iTTL, & ETTL?



## AaronLLockhart

Alright, first of all, I know my camera is TTL compatible. I also know that TTL stands for "Through The Lens." However, I do not know what the heck that's supposed to mean, how it works, or what the difference between iTTL, TTL, & ETTL are?

Could someone explain this to me please?

Also, is this a TTL flash?

Amazon.com: Yongnuo YN-560 II Speedlight Flash for Canon and Nikon. GN58.: Electronics


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## KmH

iTTL is Nikon, eTTL is Canon. TTL is universal.

TTL lacks *a lot* of the communication lingo that iTTL or eTTL use.

But yes, TTL means the camera uses pre-flashes seen _Through The Lens_ that are used by various camera systems to make changes to the camera settings and to the speedlight settings. iTTL ands eTTL are used in camera semi-auto or auto modes.

Learning to use TTL flash is fairly complicated and involved because the camera is making decisions based on assumptions made by a camera engineer 18 months before your camera was released for sale.

In other words, the camera has no clue why you are shooting what you are shooting, no clue exactly what you are shooting, nor what artistic goals you have in mind for the shot.

So, TTL flash is often inconsistent, because the camera has no real intelligence.


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## unpopular

If any technical people want to work on an open source solution to this with me, let me know. This proprietary TTL communication madness needs to stop.


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## Terenas1986

ETTL means Evaluative TTL .. which stands for the Evaluative metering mode used by the cameras. It breaks the scene you "show" the camera into many parts, evaluates the amount of light coming through each of them, and calculates a "proper" exposure from those. This by far is the best metering mode, but still can be fooled if you show it a white wall or a black dress. It goes way down and way up in exposure level. ... For Flashes, I never had a problem with TTL (in fact my flash is TTL-only), but I can still use FEC (Flash Exposure Compensation [CANON ONLY!]) to raise or lower the flash output level.


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## AaronLLockhart

Terenas1986 said:
			
		

> ETTL means Evaluative TTL .. which stands for the Evaluative metering mode used by the cameras. It breaks the scene you "show" the camera into many parts, evaluates the amount of light coming through each of them, and calculates a "proper" exposure from those. This by far is the best metering mode, but still can be fooled if you show it a white wall or a black dress. It goes way down and way up in exposure level. ... For Flashes, I never had a problem with TTL (in fact my flash is TTL-only), but I can still use FEC (Flash Exposure Compensation [CANON ONLY!]) to raise or lower the flash output level.



Nikon has flash compensation as well.


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## cgipson1

The Yonguo 560 is manual only.. No TTL....


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## KmH

cgipson1 said:


> The Yonguo 560 is manual only.. No TTL....


So, if you want TTL -

YongNuo YN-468 II E-TTL Speedlite With LCD Display, for Canon 50D 40D T1i Xsi XS 

Yongnuo YN-468 II i-TTL Speedlite Flash With LCD Display, for Nikon


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## sovietdoc

Nikon has flash compensation as well but he if referring to the name "flash exposure compensation" that's how its called on canon systems.  On nikon it's probably called something else...

like barbie horsie adventures or something..


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## AaronLLockhart

sovietdoc said:
			
		

> Nikon has flash compensation as well but he if referring to the name "flash exposure compensation" that's how its called on canon systems.  On nikon it's probably called something else...
> 
> like barbie horsie adventures or something..



Yep, completely different.

Let me see if I can even spell what Nikon calls it:

"Flash compensation." yep, I can spell it


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