Softbox sizes.

[bass_junkie83]

I think i am pretty much settled on the studio lighting kit i am going to go for now, but i am thinking about going for a second soft box.
The kit itself comes with a 90cm octagonal soft box and a couple couple of umbrellas.

With so many variations of soft boxes available it's hard to decide what to go for, i'm sure each have their purpose so how do i determine what would be suitable.

Ie for,

• single head shots
• single full body portrait
• group portraits

What sort of sizes are suitable for each and what effect does the shape have?
Does the size of the room you have to work in play a part? If so i will primarily be using a double garage, but with the possibility of using smaller areas.

Thanks.

 

[Garry Edwards]

See this article

Basically, if you want the light to be soft then the softbox needs to be big relative to the size of the subject and close. So, no geat problem with a head shot but if you want reasonably soft lighting with a group portrait then you'll need a massive softbox because you can't get it close.

As for shape, the shape primarily determines the shape of the catchlight e.g. round = round, square = square.

Square and rectangular softboxes can also be used to 'feather' the light - either lighting the subject with just the edge of the softbox or graduating a background from light to dark, again using just the edge. If buying a 'bargain' price kit be wary about any softboxes supplied, not all softboxes are equal (come to that nor are the lights) and cheap softboxes often don't have the deeply recessed front panel that they need for creative lighting effects.

Both the size of the room and the distance from softbox to subject are very relevant. If a smallish softbox is placed very close to the subject it not only produces softer light, it also causes the intensity of the light to fall off much more rapidly. Using a larger softbox at a greater distance can produce a very similar level of softness but because it's physically bigger it may be difficult to put it as close, so the light will not fall off anywhere near as rapidly, which can be a real problem in a small space with the subject close to the background - and anyway, you may not have enough physical space for a large softbox.
For definition, 3' x 4' is medium, anything larger is large.

 

[bass_junkie83]

Thank you Gary, very helpful as always.