What size soft box for full length

[pastyman]

Hi Guys, what do you think would be a sensible sized soft box to use for full length portraits outdoors?

 

[Phil V]

Not technically perfect but my Godox 80cm produces this...
Mount-Pleasant-Sneak-peek07 by Phil Vaughan,

I can show what I get from a 120cm Octa too if you want to compare.

 

[-Rob-]

I've used anything from a small 40cm softbox to a large 120cm softbox. There's no right or wrong answer.

The only way to think about it is the larger the softbox the softer the light you'll get. How soft do you want it?

 

[Phil V]

I've used anything from a small 40cm softbox to a large 120cm softbox. There's no right or wrong answer.

The only way to think about it is the larger the softbox the softer the light you'll get. How soft to you want it?

That and it's about 'relative size'; a 120cm softbox at 10ft away is a smaller light source than an 80cm one at 3ft.

And in case you hadn't guessed, the lightsource is shopped out of my image above. Which is as simple as sending the VAL away once you've got the shot so you can take the 'register' shot to copy the background back in

 

[juggler]

It depends

Is it windy? Do you have sandbags or an assistant? How close can you get the lights? How much time do you have to position lights? What effect are you after? What light source are you using - speedlights or strobes?

If you can link to an image you want to emulate then we can be more helpful.

 

[Garry Edwards]

There's no right or wrong answer to this, it depends on the style of shoot you're going for, the distance of light source to subject, the amount of power available (relative to the power of the ambient light), plus other factors such as wind - which is likely to be a problem with any size of modifier, but which obviously gets worse with every increase in size.

Bear in mind too that unless you have loads of power, and unless you use it to completely overwhelm the ambient light, changes to type/size of modifier produce less obvious changes than they do in the studio, where ambient light isn't a factor.

Having said all that, personally I often use strip softboxes to create rimlighting outdoors - effectively creating sunlight behind my subject. But that's just me.

 

[pastyman]

Thanks for the input peeps....

 

[sk66]

IMO, the bigger question is what light source do you have to fill the softbox with, and what type of look are you wanting? These aren't really "options." If you want a specific look it will require a modifier of a minimum size, which will require a strobe of a minimum power, to light the subject from the required distance.

 

[Phil V]

IMO, the bigger question is what light source do you have to fill the softbox with, and what type of look are you wanting? These aren't really "options." If you want a specific look it will require a modifier of a minimum size, which will require a strobe of a minimum power, to light the subject from the required distance.

Whilst technically correct, this is the interwebs and the OP has probably never given that much thought to lighting.

The question is as specific as they've been able to work out. 'Full length portrait outdoors', all we can add is experience, and guidance re the rules and how to use them.

My educated guess is that the OP doesn't have the flash power for use in daylight, only speedlights, and as such there's a limit to the size of softbox due to that.

 

[sk66]

My educated guess is that the OP doesn't have the flash power for use in daylight, only speedlights, and as such there's a limit to the size of softbox due to that.

And then the best answer is probably "the biggest softbox you can fill." Somewhere in the 3-4ft range. But I like the stripbox idea in order to minimize wind issues outdoors.

 

[Tulipone]

Hopefully the OP will not mind me chipping in with a couple of questions.

The power of the flash is not diminished by the use of the soft box, but presumably the light is less concentrated the larger the box? I have a 60cm Godox, should I consider other sizes as well? Is there a rule of sum that can be followed with boxes?

Phil. You image above. It looks to have been taken at twilight. How far from the couple was the soft box?

I'm still having problems with self guiding ocf techniques and I want to be able to confidently be able to reproduce lighting but seem to never get it the same. I have a feeling that I need a constant light to light behind the subject as well as a single ocf.

 

[Phil V]

.

Phil. You image above. It looks to have been taken at twilight. How far from the couple was the soft box?
.

It was in the shot! And then removed in post.

I feel like a broken record on this but the most common fundamental mistake with lighting is not getting it close enough (in fact I'd probably have liked that a little closer)

You don't say what type of flash you have with your 60cm softbox or what kind of power, but if it's a speedlight with a front facing mount, then 80cm is about it (you can calculate the angle your light leaves the flash to the front of the softbox panel) with rear facing you can get bigger but the power is likely to be not enough.

I don't understand your last sentence, can you explain what you want to achieve? (Mixing in your own constant source is unlikely to be the answer though).

 

[Garry Edwards]

The power of the flash is not diminished by the use of the soft box,

It is to a limited extent, but mainly the power is lost because, over distance, the light is spread out over a larger area, and much of it is 'wasted' in the sense that it doesn't fall on the subject.

I have a 60cm Godox, should I consider other sizes as well? Is there a rule of sum that can be followed with boxes?

60cm is probably about the limit, if all that you're using to power it is a hotshoe flashgun, and the absolute limit is probably 80cm, if you have a Stofen-type diffuser fitted to the flashgun. Power is a limiting factor, but even more important than this is the fact that hotshoe flashguns have a fixed reflector, and this prevents the light from bouncing around the softbox as intended - so, go too large and the uneven lighting will become even more uneven. I mentioned a strip softbox earlier, but then I think in terms of our powerful portable flash systems, which of course don't have a built in reflector.. The softbox I have in mind measures 140 x 27cm and no hotshoe flashgun can light one of those, although there are some people who just don't get it and who are convinced that they actually work with hotshoe flashguns... We're introducing an even larger strip softbox this week, that will be fun with hotshoe flashguns Yes, there are sites that will tell you that hotshoe flashguns can do literally everything, but these are product placement sites, don't believe everything that they say. If their statements were true, nobody would be using studio flash, portable flash or bare bulb flash...

I'm still having problems with self guiding ocf techniques and I want to be able to confidently be able to reproduce lighting but seem to never get it the same. .

Lighting is just simple applied physics. If you understand how light works then you can reproduce the same lighting (if that's what you want to do) every time, simply by placing lighting in the same position, at the same angle, at the same distance from the subject and at the same power.

I have a feeling that I need a constant light to light behind the subject as well as a single ocf.

Why on earth would you want to add a continous light - why not just add another flash, which is far easier, smaller, lighter, cheaper, more powerful and better? Continuous lighting is severely over-rated when it comes to still photography.

 

[Tulipone]

Wow thanks for your answers. Much appreciated.

Phil - I was I interested in how far your soft box was away from the subject. As the mans trousers are dark, they don't show on the picture so I am guessing the box must have been some distance away.

I have a Yougnuo 560EX only. Typically I am using indoors during the day and finding that the soft box doesn't really produce much light further than 1.25 metres away from the subject. So the setup has been window to the left at 45 degrees and soft box to the right at a similar angle. The window side is less lit. I was thinking that a light that illuminates behind the subject would help even the light cast but now thinking that a reflector may actually be the answer. Probably worth the investment rather than another flash and a trigger anyway!

Garry. Your wording is better than mine, the larger soft box wastes the light of it doesn't fall on the subject.

I get that if you can reproduce a similar environment, then light follows the same rules. The trouble is that environments change and my understanding of what needs to be changed is still failing. I get results but not always what I expected.

 

[Garry Edwards]

Wow thanks for your answers. Much appreciated.

Phil - I was I interested in how far your soft box was away from the subject. As the mans trousers are dark, they don't show on the picture so I am guessing the box must have been some distance away.

Phil has already told us that he used an 80cm softbox close to the subject, so it's easy to work out that it only lit the top half of the subject, which is why the lower half is darker

I have a Yougnuo 560EX only. Typically I am using indoors during the day and finding that the soft box doesn't really produce much light further than 1.25 metres away from the subject.

So get a more powerful light

I was thinking that a light that illuminates behind the subject would help even the light cast but now thinking that a reflector may actually be the answer. Probably worth the investment rather than another flash and a trigger anyway!

Yes, better to use light that's already there and reflect it to where you want it to be. Get a big reflector though.

I get that if you can reproduce a similar environment, then light follows the same rules. The trouble is that environments change and my understanding of what needs to be changed is still failing. I get results but not always what I expected.

Environments change very little in reality, or at least the changes to the environment make very little actual difference, at least out in the open.
Here's a simple physics example...
The Grand Canyon was formed by the flow of water, this is known to be a fact, and the water has caused huge amounts of wear to the landscape. Now, some very distant planets have almost identical types of wear on their surfaces, and it's obvious to the physicists who study these things that the wear could only be caused by huge volumes of water, ergo there is or at some point has been liquid water on those planets - so, hugely different environments, but exactly the same, predictable results cause by exactly the same predictable forces. It does take a bit of experience to calculate exactly how light behaves, but if you're struggling a flash meter will do all the calculations for you, at the speed of light

 

[Phil V]

Wow thanks for your answers. Much appreciated.

Phil - I was I interested in how far your soft box was away from the subject. As the mans trousers are dark, they don't show on the picture so I am guessing the box must have been some distance away...

Nope on 2 counts, firstly the grooms trousers are lit, they're just very dark, you can see the flash lighting the dress (though not as bright as the top due to falloff from a relatively small source), how would it bypass the trousers and hit the dress?

There are ways of guessing light distance, but it requires some knowledge, at this point we know it was an 80cm softbox (actually closer to 70cm) it was about 5ft away, slightly above the couple and pointing down, about 60 dog from camera right.

.

I have a Yougnuo 560EX only. Typically I am using indoors during the day and finding that the soft box doesn't really produce much light further than 1.25 metres away from the subject. So the setup has been window to the left at 45 degrees and soft box to the right at a similar angle. The window side is less lit. I was thinking that a light that illuminates behind the subject would help even the light cast but now thinkying that a reflector may actually be the answer. Probably worth the investment rather than another flash and a trigger anyway!

Garry. Your wording is better than mine, the larger soft box wastes the light of it doesn't fall on the subject.

I get that if you can reproduce a similar environment, then light follows the same rules. The trouble is that environments change and my understanding of what needs to be changed is still failing. I get results but not always what I expected.

Not impossible but you're making life difficult mixing with windowlight, it's more variable than it appears.

The other 'mistake' is using 2 light sources both at 45degrees. Why? What's the point? How many lights are usually illuminating people in the real world?

That windowlight at 45deg is your 'keylight' all that needs adding is fill, either from a flash behind the camera or a reflector bouncing back the windowlight.

There's lots of other lighting patterns you can use that windowlight for, you should read up on lighting patterns, the what and the why, it's 'illuminating' (pun intended).

 

[Kodiak Qc]

•


On location, specially as I have an assistant
to take care of the lighting, I very much like to
use the 1x4 strip box… often gridded!