Tethering Equipment Setup
I shoot with my Nikon D750, which is equipped with Wi-Fi, which broadcasts a signal that my laptop can connect to. You can also connect via a cable and get the same functionality (potentially faster as well). Just make sure you get a long enough cable (5m is the usual), and be careful to avoid damage to camera and laptop ports (cable tethers are available, and a laptop stand with a lip will help).
Once connected I use some Open Source software called qDSLR Dashboard to control some camera settings, and to display the images I have just shot. Adobe Lightroom will manage your tethering if using a wired connection. Your camera manufacturer will probably provide appropriate software if you’d rather use that, or 3rd party developers make software such as digiCamControl. These programmes are also useful for time-lapse and focus stacking shooting.
Since our other option for viewing our photos is the tiny LCD which isn’t particularly well calibrated, tethering has a few advantages. Checking focus. Checking depth of field. Checking colours and exposure via histograms. Giving the sitter feedback on their posing, and hopefully relaxing them by showing how good they look.
While ththering I’ll shoot RAW to Card 1 and Small Jpeg Fine to Card 2. The jpeg is sent automatically via wireless to the laptop, and I’ll have the RAW files later to edit. Alter jpeg size to balance display delay time against quality of displayed image.
I have chosen the small fine jpeg to ensure the files sent are small but good quality. This means they will send quickly, but be of good enough quality to check for focus, depth of field and colour (LCD sometimes too bright on low key images).
Basics of Portraiture
The goal is to showcase the character and features of the sitter, using expressions and poses.
We should light the subject in a fashion to accentuate the sitter and the image we have in mind for them. Shoot using the most effective equipment and settings, e.g. low key would suit moody or dark, or high key would suit fun and friendly or elegant shots.
For non-environmental portraits, i.e. Studio shots or headshots/upper body shots, simple non-distracting backgrounds help to feature the sitter more prominently.
Eyes are almost always the most important feature since they are the part of a person’s face the viewer will settle on. Therefore catch-lights are important and add life to a portrait where you are trying to be complimentary to the sitter.
Backgrounds tend to be dark for low-key studio portraits, white for high-key portraits and are usually grey (or perhaps green) for shots intended to be extracted for composites.
Benchmark (Fundamental) Settings
Settings for studio flash photography pretty much choose themselves. You will use a small range for each setting for the majority of photographs you shoot.
Focal lengths - 85, 105, 135mm. These focal lengths offer the most complimentary results. Wider than this and the sitters features can be distorted (larger), and longer focal lengths seem to add weight to a sitter. Obviously these alternative focal lengths can be used to creative effect should they actually be desired in a particular image.
Shutter speeds - 1/125th, 1/160th, 1/200th, 1/250th for most cameras for non-HSS (High Speed Sync) shots. Shoot a frame at these settings without flash to see how much ambient light is captured. If your camera and flash support High Speed Sync you can create very interesting images outdoors in bright sun whilst still using flash. Very long shutter speeds should be avoided in case enough ambient is captured to potentially show in the image. At such a long shutter speeds ghosting and hand-shake may become evident. Again, this could be used to creative effect.
ISO - Base ISO + 1 stop, e.g. 100 base ISO, use 200 ISO. This require half as much light from flashes, which can save significant power when using battery powered speed-lights, and allows some wiggle room if ambient light needs to be adjusted further. Use base ISO for the cleanest images.
Aperture - This controls Iris size which limits light entering the camera, so governs exposure more than the other camera settings. However most photographers will set the aperture to the lens's sweet-spot, usually f5.6 - f8 to get the sharpest, least distorted image possible, and control exposure via the lights. Also, ensure you have enough Depth of Field that your shot requires. Shorter focal lengths and smaller apertures increase DoF at the expense of distortion and less light respectively.
Lights - Judge lighting power once camera settings are set. Lights have power settings or can be reduced by changing distance, or increased by moving closer to the subject. Speedlight flash duration is typically around 1/200th of a second at full power and 1/20,000th of a second at low power, making this your effective shutter speed. However, the wiggle room you have with shutter, ISO, and aperture will still allow you to control ambient light levels to a small extent on areas where your flash does not fall assuming you are not using very bright flash settings. However, it is usually easier to use other lights for controlling ambient levels. The inverse square law states that light power halves as distance from subject doubles. So moving a light twice as far away results in 1 stop less exposure for that light.
Modifiers - Light is basically either hard or soft, this refers to the edges on shadows. Small light sources create hard light, and large light sources create soft light. Size of light sources is also relative to distance from the sitter, e.g. The sun is the largest light source in the solar system, but due to being so far away it create a hard edge shadow. A soft-box 1 metre across, just a meter from the sitter will create a much softer light, whereas the sun is about the size of your thumbnail at arms-length. The material the light is bouncing off or travelling through will also affect the quality of light, e.g. Bouncing off a white wall will give a different light that bouncing of a metallic beauty dish.
Feathering - Light comes from a source and will be strongest in the direction the light source is facing. It falls off, or feathers as the angle to the subject changes, so lights do not always need to be pointed directly at the subject. This can be used to control shadows.
Spill - Light going to unwanted places. E.g., shoot through umbrellas suffer from spill much more than a soft-box which is more directional. A grid will cut down spill even more. Think about whether you want to control spill for the shot you want to get.