TTL Flashes and strobes only have so much power–if you’re fortunate enough to have one like the Phottix Indra or Profoto B1 Air TTL 500, then you generally will have no problems with lighting. But hot shoe flashes are very limited in the light output that they can deliver. This leads to being a very big technological limitation at times but more often than not if the flash is in the hot shoe.
But there are ways around it due to digital cameras having so many options on how exposures can be taken.
Raise the ISO of Your Camera
Years ago, photographers would never want to shoot over ISO 400 when it came to using a flash. The reason for this is because ISO 400 is the most sensitive that you can get to without seeing image noise–for film and older digital cameras. Modern digital cameras and even those that have come out a couple of years ago have developed really incredible high ISO output and you should generally have no problem shooting at up to ISO 1600 when it comes to using a flash.
This is great when shooting really dark events like wedding receptions and parties. Of course, it also means that your shutter speed (which lets in more ambient light) and your aperture will both be affected. So you’ll probably want to vary up your settings accordingly.
Open The Aperture Up
When you stop your aperture down, a TTL flash adds more power to get the scene to be properly exposed according to its light meter and based on factors like your ISO, aperture and distance away from the subject translated by the zoom head. If you open your aperture up, the flash uses less power per shot. If you open up the aperture, you’ll save power.
Use the Wide Angle Adapter
Everyone knows that the larger the light source is in relation to your subject, the softer the light will be. To create softer light in an image, you can use the wide angle adapter of your flash and depending on the settings you can even use the flash bare without bouncing it or adding in a light modifier. The Wide Angle adapter naturally spreads the light out in a wider and larger area than it will if it were zoomed all the way in to 105mm or even 85mm. The further out the flash is zoomed, the narrower the beam generally becomes.
Find a Way to Make the Light Output More Directional
Lots of photographers who use the flash in their hot shoe bounce it off of a wall or ceiling of some sort to soften the light and because it turns that area into a soft light source. The problem with this is that the light isn’t very directional and needs to travel a further way to properly illuminate the subject. In this case, the light needs to be stronger in output and you’ll therefore use more power. If you can find a way to make the light soft and also cut down on how much distance it needs to travel then do that. Part of this has to do with your exposure settings like the ISO.
Make Use of Exposure Compensation
Your flash has exposure compensation in its settings that let you tell it to output a stop more or less of light (or even more.) You can use this to easily get around needing to set it to manual mode if you’re in a bit of a tight bind and also depending on your exposure settings. Though in general, we’d tell you to raise the ISO first unless the work that you’re doing requires all the details you can possibly get.