Through-the-lens flash metering, or as we call it TTL flashlight feature, is just like the automatic mode of your Canon, Nikon or Sony DSLR camera. If you are a beginner in photography or shoot in variable light conditions, then a TTL flash is an ideal choice for you over the manual flash.
How TTL Flash Metering Works?
When you use the flash in TTL mode, the output of the flashlight is determined on the basis of the light entering the camera through the lens. It means that the camera tells your flash to throw particular intensity of light on the subject after it has calculated the exposure reading of the frame.
It all happens in fractions of a second when you half-press the shutter release button and tell the camera to record the exposure reading of the scene. As the exposure reading is being taken by the camera on the basis of the light entering through the lens, thus this technology is known as though-the-lens or TTL flash metering.
You can use a TTL-enabled flash on-camera a well as off-camera with the use of a flash trigger and a receiver (if your flashlight does not have a built-in receiver).
How to Adjust Flash Output in TTL Mode?
There might be situations when you experience overexposed or underexposed photos while shooting with your flash on TTL mode. This could be because of way too dark or way too bright elements in your frame, as your camera takes the exposure reading as per 18% gray.
In case you want to manually adjust the intensity of the flashlight, you can do so by using the Flash Exposure Compensation (FEC) feature on your flash. FEC allows you to tell the flash to increase or decrease the intensity of the flash of a specific value usually ranging between -3 and +3. It means that your flash is still in TTL mode but you can command flash to throw the light which is more or less by the FEC that you set. This is just like using the exposure compensation feature in your DSLR camera while shooting in automatic mode.
Advantages of Using TTL Flash Mode?
If you have no or very less experience with a flashlight or have recently started practicing photography with the use flash, using TTL mode is the ideal way to start. Like I mentioned earlier, the TTL mode on a flash is just like the automatic mode of the DSLR camera.
- If you are shooting at an event or wedding where the lighting conditions are changing drastically, using the flashlight in TTL mode will ensure that you get correctly exposed photos. Whereas I you are using the flash in the manual mode, you will have to manually change the intensity every time the available light changes.
- If you have to click photos instantly and you can not afford to waste time in manually setting the flashlight intensity, simply switch to TTL mode and let the camera and flash work together to determine the flash light intensity.
TTL or through-the-lens flash metering is a functionality in which the camera determines the flash intensity based on the light entering through the lens and then communicates the same to the flash.
If you have recently purchased a flash or if you shoot in frequently changing light conditions, then clicking photos by setting your flash on TTL mode is the ideal way. But do not expect the photo to be correctly exposed every time you are shooting at TTL mode, as there are changes of your photos getting slight over or underexposed if a dark or bright colored subject dominates the frame.
If you ask for my suggestion, I would suggest you buy the Godox TT685 flash which is TTL enabled and performs perfectly during the shoots.