Yongnuo TTL flashes and wireless triggers

In photography, through-the-lens (TTL) metering is a feature of cameras whereby light levels are measured through the lens that captures the picture, as opposed to a separate metering window. This information can then be used to set the correct exposure, and control the amount of light emitted by a flash connected to the camera. TTL Flash Metering is the standard metering mode that your camera employs where you’re using the camera’s built-it or pop-up flash. You can also use this metering mode with some of the dedicated flash units available for your camera. TTL flash metering measures the burst of flash output light reflecting back from the subject and takes its reading through the lens. TTL manipulates the flash exposure with a dedicated sensor that measures the flash output reflected from the surface of the image sensor during active exposure.

TTL flashes and triggers are usually much easier to use than manual ones, especially for beginners. If you are using TTL flash like Yongnuo YN600EX-RT or YN565EX, YN568EX, YN685 and other, you can simply take photos in camera auto mode, the camera and speedlite will choose the correct settings. If you prefer to shoot in manual mode, then everything you need is to set ISO, aperture and shutter speed, and the flash will calculate the amount of light needed for correct exposure. If you own manual speedlite then you will have to set flash power also, which requires a little practice and experience.

TTL flashes have one big advantage over manual ones and that is AF assist lamp. Built in AF Assist lamp helps camera to focus in low light situations. Manual flashes do not have auto focus assist lamp so please take that in mind when choosing the flash for your needs. In my opinion, manual flashes like Yongnuo YN560 IV or Yongnuo YN660 are great, but I prefer to use them off-camera for 2nd or 3rd light, not for my 1st on-camera flash.

When it comes to TTL radio triggers then Yongnuo YN622C for Canon or Yongnuo YN622N for Nikon are my 1st choice for off-camera setup. These triggers will give you much more versatility than any other non-TTL triggers. Manual triggers do not allow you to remote control your flash from Camera like TTL triggers do. Imagine putting a flash speedlite into a soft-box and controlling it from your camera directly.