Softbox sizes

[Wayner]

Hi all, Is there a maximum size to a softbox that can be used with a studio flash in comparison to the power of the light. If so, how would you determine the size or is it not critical.

Hope that makes sense.

 

[Garry Edwards]

It isn't critical.
The theory gets a bit complicated, but in practical terms this is what happens:
Large softboxes 'lose' more light than small ones but the light loss from them falls off more slowly, so at anything other than a very close distance the exposure is likely to be similar.
An equipment comparison test I did for Lencarta a couple of weeks ago showed very little difference between a 60cm and a 150cm softbox of the same make.

 

[Wayner]

Cheers Garry, that's interesting reading

Whilst i've got your attention, what info can you give regarding differences in softbox quality. I've seen 95cm octagonal boxes on ebay for around £50, Lencarta's Octa 120cm softbox for around £80 and others up to whatever you want to pay for them. What is it that affects the overall performance?

 

[Garry Edwards]

What is it that affects the overall performance?

It's a mixture of ease of use, ease of assembly, quality of materials, choice of materials and design.

Ease of use - some are very fiddly to fit onto the lights and fiddly to rotate.
Ease of assembly - self explanatory
Quality of materials - some are made of very thin material that drops to bits
Choice of materials - the most important factor is the thickness/density of the diffusers. Better diffusers can't cost much more to produce but produce a much crisper light
Design - some leak light out of the back, don't have recessed fronts and often the inner diffuser is far too close to the outer one to be effective.

I did some comparison tests with a cheap one that you may find interesting and a short article on how to improve a cheap softbox The softbox used here was one of the cheap imported ones. it's generally a good idea to spend a bit more and get one with a name on it.

 

[Wayner]

Would the Lencarta boxes fit the bill? They're mid priced and I know Lencarta have a good reputation for their lights. Do the accessories also follow suit?

 

[Garry Edwards]

Would the Lencarta boxes fit the bill? They're mid priced and I know Lencarta have a good reputation for their lights. Do the accessories also follow suit?

The folding softboxes, which are more expensive, are excellent. The non folding ones are good value for money and IMO are at least as good as some that cost far more - but not top drawer.

 

[Wayner]

Thank you Garry, I will investigate.