I used a strobe light, well after some trial and error on the intensity. I understand to quench the ambient light, I’m supposed to meter the subject right?
I tend to meter the ambient and set it at 1-2 stops under, then use flash to bring the exposure on the person up.
How do I achieve this? Will it be on manual mode?
Oh boy...there are multiple ways to shoot and meter flash + ambient lighting portraits. And part of the equation is the flash unit and the camera itself, but in general, my three-plus decades of flash experience leads me to the conclusion that, in most situations where one wants a specific result of flash + ambient, that the Manual exposure mode on the camera, and a manually-controlled amount of flash output is the _easiest_ way to get the desired result, consistently.
The issue is that when ambient lighting is the "main light" source, the brightness of the NON-flash portion of the exposure is determined by 1)the ISO in use 2)the lens aperture value and 3)the shutter's time duration. Now, when a "normal" flash burst is added, the shutter time MUST be at, or slower than, the maximum flash synchronization speed, which is usually 1/250 second, or 1/200 second, or somewhere in that area with a modern d-slr camera. So....the ambient light exposure MUST have a shutter time of 1/250 or slower. Say, 1/250 second at f/11 at ISO 100.
This type of scene is an ambient + flash shot, and there are in a manner of speaking, "two exposures" being made; one for the existing light, and a second exposure on the face, which is being lighted by both daylight AND by flash-lighting. The background areas, the far-away areas, are _not_ being lighted much, or at all, by the flash's output, in most cases.
If your camera can utilize a high-speed synchronization flash, and you own a high-speed synch capable speedlight or flash, then you could use a faster shutter speed, like say, 1/2000 second at f/4 and ISO 200, to "tame" the brightness of the background sun and highlight circles. Buuuuuut, only mid- to high-end cameras typically offer that feature.
I do not have time to explain the multiple ways one "might" shoot such a photo as this, but suffice it to say that YES, Manual exposure mode on the camera, and a manual, fractional power flash output level selection, made by you, at the time, is the fastest, easiest, most-consistent way to shoot this kind of a scene. The ISO, the f/stop used, and the flash-to-subject distance (
but NOT the shutter speed's actual time, as long as it is synchronized with the flash!) will control the brightness of the flash lighting on the subject. Typically, as this type of range, a flash output power level of 1/16 to 1/4 power is going to be more or less "normative" as far as providing some fill-in lighting on the face.
When you work in Manual mode on the camera and the flash, it's easy to make changes, and see the effects of the changes, immediately, and to then make adjustments with confidence. In auto-mode flash, or TTL flash, it's sometimes a bit trickier to make fine adjustments that will be consistent across, say, 50 frames.