Last Updated on March 21, 2021

If you are looking to understand the difference between ETTL vs TTL then you are at the right article.

There are tons of acronyms used in photography and beginners tend to feel a bit overwhelmed getting a solid understanding of what they all mean.

No worries, TTL and ETTL are easy to understand so let’s get to it.

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What Does TTL Mean?

Note: Canon refers to their flashes as Speedlites while Nikon calls theirs Speedlights

TTL means Through The Lens

This acronym is associated with numerous camera features but is primarily used to note what you see when looking through your lens via your viewfinder as well as the light that is metered through your lens.

This feature is found in DSLR, SLR, and digital mirrorless cameras. TTL is not available with rangefinder cameras.

Before TTL technology a photographer had to use a handheld light meter but TTL has light metering built in to the camera.

What is a TTL Flash?

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A TTL flash is capable of receiving light information from your scene through the camera’s light meter. A TTL flash receives information through the camera’s hot shoe contacts.

The TTL uses this information to to automatically set the appropriate power output. Modern TTL systems are able to take incredibly accurate measurements for exceptional image quality.

It is important to note that there are many TTL systems available and there are differences in performance. For example; Canon offers TTL and A-TTL systems which handle ambient light information differently.

These different TTL systems utilize different protocols for communicating between the flash and the camera which can lead to poor performance when the appropriate TTL system is not used with a compatible camera.

This means that older TTL designs will not work efficiently with newer cameras. If an older TTL flash is used with a new camera then the flash will likely only work at full power, which can lead to poor image exposure.

For this reason, it is important to utilize a modern TTL flash to achieve optimal image exposure.

What Does ETTL Mean?

E-TTL means Evaluation Through The Lens

An E-TTL flash system utilizes a preflash before the image is captured. This preflash creates a better image lighting and exposure by allowing the built in light meter to intake the ambient light.

TTL and A-TTL systems are not able to meter tricky ambient light and therefore does not achieve the same exposure quality that an ETTL system will.

E-TTL systems also work better with light modifiers than TTL systems. When using a TTL flash with modifiers photographers often encounter exposure issues. Underexposed images is rarely an issue when utilizing an ETTL flash.

What is the Difference Between ETTL and ETTL II?

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ETTL II systems are designed with the controls for the image exposure in the firmware in the camera’s body. This allows the system to make more metering calculations which means firmware updates for the external flash are not required.

ETTL was first used in the Canon EOS 1D Mark II back in 2004. This system improved the ability to account for the distance between the lens and the subject. This allows the lighting to be adjusted to better eliminate hotspots in areas of your shot.

Manual Flash Advantages

It is important to understand the benefits of utilizing manual flash. Manual flashes offer the ability to achieve control and repeatability in addition to the lower cost generally found in manual vs TTL flashes.

Manual flashes also are offered by numerous third party producers further lowering the cost of great flashes.

Check out these article for the best Yongnuo flashes for Canon and the best Yongnuo flashes for Nikon

Manual flashes are also ideal for when creating specific image effects such as underexposed images. This is often used in portrait and surreal portrait photography.

Manual flashes are also excellent for creating fill lighting.

When setting your manual flash remember that power output is generally set as max power, 1/2 power, 1/4 power, and on down. Higher end manual flashes even allow for steps in between these settings for maximum power control.

TTL and ETTL Output Duration

The output duration of your flash is a very important factor to consider.

The lower the power output of your flash the shorter the duration of light output you will get.

A short flash duration is particularly desirable when shooting action shots. This will allow you to remove ambient light and use a small aperture setting. When shooting like this the flash duration is effectively the speed of your shutter.


When metering with a manual flash it is expected to take more time than when using a TTL or ETTL flash system.

This is because the light must be manually viewed after each shot and adjustments made as you go. This means that each scene will require adjustments to ensure proper exposure as you will not have the automatic adjustments made by TTL and E-TTL systems.

Manual flashes can also be metered with an external light meter. This is another cost you will incur but it will drastically speed up the process.

A light meter will allow you to quickly achieve lighting ratios and setups. Those who shoot with a flash frequently should invest in an external light meter when not shooting with a TTL or ETTL flash.


TTL and ETTL flashes both offer built in light metering that will help you achieve properly exposed images. The TTL system is the older of the two and does not offer the same advanced metering ability of the ETTL. If possible it is best to use an ETTL system as it will process ambient light leading to better image exposure and more consistent image quality than a TTL system will.