Club Social with photo-booth and a bokeh table this week, the last of 2016. So we will talk a little bit about Bokeh before completing our examination of light modifiers, in particular the “hard” modifiers (that’s about the quality of the light not the difficulty of use), and wish you all the best till next year.
Bokeh is, I have a lingering suspicion, the best of , if not exactly a bad, then at least, an unavoidable, thing. It is points of light rendered by a lens in the area beyond the zone of acceptable focus. It has, by association, a certain dream like quality. Whether that association with bleary eyes is as the result of a blow to the head, strong liquor, watching too many ’60’s films, recently arising from a deep sleep or a biological need for spectacles I leave to the individual imagination and circumstances. That’s not the sort of explanation I am trying to provide. That’s between you, your conscience and the likelihood of your significant other cracking your alibi.
The shallower the depth of field the greater the area of view that will be out of focus. Bokeh occurs at the point where single light sources lose their shape and become mini suns or circular (sort of) shapes of light. The term is Japanese, meaning blurred or something that approximates to that. It is the product of lens design which in itself is limited by the laws of physics.
That blurred area, behind the subject in focus, is formed by circular pools of light where the light has spread out rather than been brought to focus. The patterns formed are diffraction patterns whose edges assume the shape of the lens aperture in the diaphragm through which they pass.
The shape (and number) of the diaphragm blades will impact in the shape of the blobs in the background. The size and smoothness are regulated by light source, focal length, aperture and the diaphragm and what constitutes “good” bokeh is purely a matter of personal taste.
We started last post to talk about light modifiers, specifically “soft” modifiers. So that leaves the “hard” modifiers. Probably the thing to note first is that hard light is the default with flash/strobes (I am going to use the terms interchangeably). Flash is probably the first port of call for additional and controllable light for most photographers progressing through the hobby. There are a number of pro’s and cons in using it. On camera and off camera flash provide some of the same problems but generally off camera flash, that which uses a separate flash gun, is by far the more flexible option and the one we will be talking about here.
More specifically on camera flash is more likely to deliver red-eye, demonising your subjects, the light is harsh and direct and can only come from the direction of the camera. Built in flash is less powerful than off camera, separate units and you can’t always control the intensity of light you do have manually. That isn’t to say that built in flash doesn’t have its uses, just that those uses are relatively limited compared to the more modifiable off camera varieties.
All flash lighting needs modifying most of the time, and there are four basic types of hard modifiers:
- Reflectors – your common or garden light modifying accessory, bowl shaped, they have a single but important purpose, to cut down light spill – light that spills to the sides of (a bare) bulb in a strobe (not exclusively) and when using umbrellas or grids. Also below.
- Grids – Does what it says on the tin. Black tubes formed in a lattice work they are very effective in stopping scattered light rays coming from the (strobe) bulb, creating a thin, relatively soft beam of light, which arguably puts it into the soft category I know, but I think sits better in this list. The quality of light is determined by the density of the grid (the number of tubes in the grid), while the size of the beam (expressed in degrees) is determined by the thickness of the grid. The grid is regulated by gates acting as barn doors, movable flaps on each side which allow for finer, narrower, beam control.
- Snoot – is a cone which focuses light to create a very harsh, small beam of light. Can be rigid or flexible, allowing for some control.
- Beauty dish – A small reflector, (usually gold, silver, or white) is placed in front of the strobe / flash, while a bowl-shaped reflector is placed around the light source. This creates a very even, hard light with an extremely sharp drop-off. Used almost exclusively in portraiture, it is very useful as a key light.
These are not mutually exclusive pieces of equipment. They can be and should be mixed and matched according to the creative need. They don’t all have to be shop bought, DIY is always an option, but for the bought stuff the guiding principle, generally, is, you get what you pay for, especially when talking about longevity. This in itself can be a function of the frequency and conditions of use, however when starting out, certainly a look round e-bay or other on line shops will throw up some “bargains”. The bargain is what you feel the value of what you have is.
There are three other essential elements, not, I would put forward, necessarily directly under the heading of light modifiers as they don’t work directly on the source. These are: flags, scrims and bounces (reflectors).
- Flags block light. Bought flags tend to be black material, some are paper, stretched over a frame with a small handle to make it easier to place on a stand accurately. Black paper and tape will get you a similar effect to stop a white or light coloured wall from reflecting or for shading specularity in shiny objects. Their primary use is to control light spill and keep down highlights.
- Scrims are panels covered in diffusing cloth, placed where light needs softened locally. You have probably seen them on film and TV sets, spreading tent like over the actors, in order to provide a soft and even light.
- Reflectors, other than the ones that wrap around your light source, a.k.a bounces, or bounce cards, can be anything that will reflect enough light to be useful, but are usually white, silver or gold material stretched out on a frame. You are probably aware of the five sided reflectors that also have a black surface and an opaque white that can be used as a scrim. Mirrors are frequently used, especially small ones on product shots. They are usually a way of lightening shadows created by the key and other lights. The type of material determines the light’s quality and, and intensity is a product of the distance from the subject and the reflectivity of the surface used. The black on a five sided reflector, for instance, is used to reduce the amount of light going into the subject.
And that, as they say in the World of Onions, is Shallot for 2016. Happy New Year.
N E X T M E E T I N G
5th Jan 2017 19:30 – Editing Images: Bring your laptops and challenge your editing skills.