Does size matter??

[onform]

No I'm not referring to the size of my manhood...

Now I know the larger the softbox you use the softer the light but Do you lose more light the larger the soft-box you use?? or is it just down to the diffusion materials..

I expect lots of views to this thread but very little answers..

 

[Garry Edwards]

No I'm not referring to the size of my manhood...

Now I know the larger the softbox you use the softer the light

Yes and no to that part of your question. It isn't size, it's relative size, e.g. it's the size of the light source compared to the size of the subject - so, all things being equal you're right, but a large softbox at a distance will produce HARDER light than a smaller softbox at a closer distance if the smaller one is larger relative to the subject.

2nd part of the question - it depends. I've just done some tests on both 60cm and 150cm softboxes and the 60cm version 'lost' more light than the 150cm version, simply because of the differences in diffusion materials and the design. All things being equal though, the larger softbox would 'lose' more light. Actually it doesn't lose light so much as spread it around

 

[onform]

Ah, Gary I was hoping you would spot this thread...

I want to light a model outside using strobes and a soft box during the day. I will probably use the fong lightsphere on camera for fill, but was unsure what size soft box to get for the key light.

If I go large will it have to be very close to the model to make any impact as well as reduce the shooting styles and options?

on the same note will a smaller soft box be more directional so i would have to move it back to get full coverage thus losing the power that way?

And i suppose the real question is what size soft box on a strobe would you say is the ideal/middle ground between light loss and coverage at say two-three metres distance from the model?

 

[fraggle101]

I was always under the impression that a softbox light will become hard(er) at distances longer the the diagonal measurement of the softbox, I.E if the softbox was 20inches from corner to corner, then you would need it no more then 20inches from the model before the light becomes harder.. so, the larger the softbox, the further away you can place it..

Im probably wrong, but its something like that..

 

[Garry Edwards]

Ah, Gary I was hoping you would spot this thread...

I want to light a model outside using strobes and a soft box during the day. I will probably use the fong lightsphere on camera for fill, but was unsure what size soft box to get for the key light.

If I go large will it have to be very close to the model to make any impact as well as reduce the shooting styles and options?

on the same note will a smaller soft box be more directional so i would have to move it back to get full coverage thus losing the power that way?

And i suppose the real question is what size soft box on a strobe would you say is the ideal/middle ground between light loss and coverage at say two-three metres distance from the model?

So you're shooting outside - in daylight or at night? And if in daylight, do you want the studio flash to overwhelm the daylight or just provide some fill?

If you want to overwhelm the daylight then you'll need a fair bit of power and your light will need to be close because of that, also it will need to be close if you want the light to be soft. If your studio light is the only or main light then you may or may not want the light to be soft. Using a smaller softbox and moving it further back will increase the area it covers but will also make the light harder.

I was always under the impression that a softbox light will become hard(er) at distances longer the the diagonal measurement of the softbox, I.E if the softbox was 20inches from corner to corner, then you would need it no more then 20inches from the model before the light becomes harder.. so, the larger the softbox, the further away you can place it..

Im probably wrong, but its something like that..

You're a bit wrong. ANY increase in distance will make the light harder, simply because the softbox will be further away and therefore smaller in relative terms.
The guide about having the softbox not further away than the diagonal of its front diffuser refers to the wraparound quality of softboxes only, i.e. to the fact that the light is coming from multiple directions if placed closer than the diagonal of the front diffuser

 

[onform]

Sorry Gary was gently persuaded to do the washing up!!!:razz:

I would like to be able to shoot during the day, I understand that I would be limited to early morning or evening as I will be using canon flashes on and off camera for all the light sources, (cant afford portable mono-heads and power packs just yet);

I would more often than not want to balance the daylight rather than overpower it which i'm not even sure is possible with the small strobes.