light meter is a device used to measure the amount of light in a photography. It is to determine the proper exposure for a photograph, which allows the photographer to determine which shutter speed and F-number they need to set for the right exposure. For photography, it is ideal to use a handheld light meter so you can get closer to the object or scene you are taking a photo off (Just be careful, because if you hit it; you may lose it by it breaking or they might be annoyed that you hit them in the face and walking off while flipping off the bird)
a reflector is an improvised or specialised reflective surface used to redirect light towards a given subject or scene. This can help make the focus of the photo more clear by reflecting light onto them, but be careful if you have a model because it go straight into their eyes.
Barn doors are used in combination with fixed lights or strobes to focus the light and to avoid reflections. They are normally attached to lights seen around the stage at a theatre, to help focus on a part of a stage. They normally have 4 sides but there are some models with two, so check before you use.
A Soft box is a type of photographic lighting device, one of a number of photographic soft light devices. All the various soft light types create even and diffused light. This ‘bounces’ light off the second surface to diffuse the light. A “soft box” is an enclosure around a bulb comprising reflective side and back walls and a diffusing material at the front of the light. You could make one using aluminum foil
Gels are used to change the colour of the light source (AKA a lamp, it wouldn’t work very well if you’re light source is THE SUN)all you need to do it place a transparent sheet over the light and the light will shine through the light and be the colour of the sheet.
A colourama is a sheet used as a background to help keep focus on the object or model. This can help pull focus onto your subject, also the colour backdrop can help add to the subject. Just make sure the colourama is flat as it can be picked up in the photo. Also help your subject on, I remember tripping on it when I was young.
A diffuser spreads the light from the flash, to spread around the area and make the photograph clear to see. This will help get rid of harsh light and dark areas. There are ideal for portraits to make it look more 3D.