Explaining the Difference Between ETTL vs. TTL Flash

Many people know that ETTL and TTL have the ability to gauge the strength of the flash a camera requires when shooting, but they don’t know the technical differences between the two.

This guide explains the difference between ETTL vs. TTL flash.


Cameras come with an inbuilt exposure meter, and this is where the TTL flash obtains the reading. The TTL flash then produces a flash that corresponds to the reading.

The ETTL is much more advanced than the TTL. Instead of obtaining the reading from the camera exposure meter, the ETTL fires a pre-flash to obtain exposure from the subject.

In this guide, we will be explaining the technical and operational differences between ETTL vs. TTL flash. 

The History of TTL 

If you have ever heard of “through the lens” metering, it is all about TTL.

However, many camera manufacturers don’t use TTL as is but use it to develop advanced flashing systems. 

The TTL flashing technology has been there since the days of film cameras.

The only difference is that it was used to control the light entering into the film, but the modern cameras don’t have the films.

The flashing system nowadays works by firing the first flash, which helps the camera to calculate the amount of light required to properly light the subject.

Then the flashing system fires the second flash with the right amount of power. 

What Is The Meaning Of E-TTL/E-TTL II?

If you have heard of ETTL or ETTL II, you might be wondering what they mean.

E-TTL in full means ‘evaluative through the lens’, which is an advanced technology used in many Canon flashes. As you might be trying to guess, ETTL II is an advancement of ETTL. 

Diving down to years of introduction, ETTL came into being in 1995, and then ETTL II came into being 9 years later in 2004.

That means that every modern camera will be using the ETTL II flashing system.

If you are familiar with flash auto mode, you can tell how closely the TTL flash system relates to it.

It will make your shooting experience easier and straightforward but limit your ability to control the exposure.

Why Would A Speedlite Flash Set To TTL Not Work With A Camera?

People have been using the term TTL for years, and so they end up using TTL even when they mean ETTL or ETTL II flashes.

Although many people think they can use them interchangeably, they might be surprised to discover that their Canon cameras cannot use TTL mode if they are set to ETTL metering. 

How Do ETTL And ETTL II Function? 

Below is what happens when you capture images with the ETTL flash active:

  • The camera’s complex algorithm begins to read the scene ambient light 
  • The flashing system fires a pre-flash before firing the second flash when capturing the image 
  • The camera uses complex algorithms to analyze the pre-flash light with the ambient light readings
  • With the help of complex algorithms, the camera decides on the best amount of light and communicates to the flashing system the right amount of electric power required to fire.

When Should I Use E-TTL/E-TTL II Flash?

There is no need to use E-TTL Flash if you’re comfortable using manual flash settings and lighting.

In events such as parties and weddings, lighting changes abruptly, and changing your settings is impossible. In these situations, the ETTL can be helpful.

On the other hand, ETTL can hinder your creative skills when it comes to exposure control, as your camera gear will be deciding the correct exposure for you.

If you want to sharpen your photography skills, it is not advisable to always use the exposure the camera decides for you.

However, ETTL can be helpful to newbies who might not be familiar with exposure.

Although the camera algorithm might not get the ideal exposure, it might get better exposure than most first-timers.

Final Thoughts 

The ETTL flashes are newer and have some benefits over the old TTL flashes. ETTL flashes can adapt to varying shooting conditions, whether the subject is far away or close by. 

Following the above explanation of the difference between ETTL vs. TTL flashes, you will be able to make the right choice on the flash to purchase for your camera.

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