TTL Flash Technology

Photo Tip Friday April 3

Flash Photography can be very awarding when you know the techniques. Most of the newest digital cameras allow you to enjoy the ease of use of TTL Flash Technology, but your experience will benefit greatly by understanding some basics first.

Many photographers, including myself, generally don’t like the harsh affect of flash in their photos, but there are several different techniques to tame this harshness and create natural looking images. In this tutorial I am going to explain some basics of TTL Flash Technology. In my example image below I used TTL Flash to capture more detail of the figurine in dim light conditions and so I could maintain a faster shutter speed to avoid camera shake in macro photography.

So what is TTL Flash Technology?

TTL means “through the lens”. Flash metering is done through the lens, using the camera’s metering system, which looks through the lens and filters you are using.

How does TTL Flash Technology work?

Nikon first introduced TTL flash technology in 1980 and the basics of TTL operation is rather simple and applies to all camera systems. With TTL flash exposure, when the shutter is tripped the light from the flash fires, racing to hit the subject. Let’s look a little closer at how TTL flash technology determines the amount of flash required. When you press the shutter release, a TTL flash will fire a Pre-Flash before the actual shot, the camera then measures the Pre-Flash with the ambient light level to calculate the power needed by the actual flash for the shot. Don’t try looking for a Pre-Flash though: it happens very fast, only a mille- or micro-second before the main flash. You will only detect one flash, not two, because the human eye is too slow to be able to separate and see the two individual flashes. (Note of interest for portrait photographers: the Pre-Flash in TTL flash photography can cause blinking in some people.)

What is the main difference in TTL and Manual Flash?

In Manual flash photography, the flash fires a certain amount of light (chosen by you) and you will need to set your camera (Shutter speed, Aperture, and ISO) according to the power of the flash and the distance between flash to subject.

Thanks to TTL flash technology, the computer inside the camera controls the output light of the flash and turns the flash off when the exposure is correct.

Can TTL Flash Technology be used indoor and outdoors? What are its limitations?

Two very good questions!  For the first: Yes, absolutely. As a matter of fact when you learn how to use TTL flash technology, you can use flash almost everywhere to create amazing effects. With TTL Flash Technology your camera meters the ambient light as well as the flash and makes an almost perfect exposure.  The only limitation of TTL, if it can be said as such, is that your camera’s meter will always set exposures to achieve a balanced average scene.  If you want to create a low key (darker) or high key (brighter) image, you will need to compensate for your camera’s metering parameters.  Fortunately this is not difficult to do!

Is it difficult to learn Flash techniques? 

Although many things about TTL Flash Technology and Manual Flash Photography can seem technical and complicated, flash photography is quite easy to learn and the techniques are fun to apply. We have scheduled a flash photography workshop for May 13 and 14. This two part workshop has plenty of time for hands-on experience working with your flash as well as practical assignments. The class size is limited to nine students. For more information and to register for this fun, informative workshop please follow the link below.

That is all for this Friday and see you all next Friday with more photography tips.

Ted and the Omnilargess Team