Beauty Dish Size

JimResnikoff · Dec 7, 2018

Looking at another Glow EZ-Lock light modifier. Which size ? 25 or 34"? I typically don't work in areas with a lot of working room.

Thanks in advance.!

Glow EZ Lock

Ellis Vener · Dec 7, 2018

For a pan reflector (which is what they were called before some marketing genius found a way to sell more of them by changing the moniker) used for portraits , get the 24-inch model.

Part of the thing that makes a pan reflector a “beauty dish” is its size and proximity to the face.

Proximity determines falloff which helps contour the face and size determines the shape of the shadows. Too large and you do not get the transition from lit to shadowed areas, too far away and the falloff effect is lost.

--
Ellis Vener
To see my work please visit http://www.ellisvener.com
Or on instagram @therealellisv

jlafferty · Dec 7, 2018

Get the 34” silver! I just tested it and it’s great. Though TBH my preference goes to the 36” deep octa (also silver).

JimResnikoff · Dec 7, 2018

Thank you for the feedback Ellis, The falloff ratio is certainly something to consider.

Brooke Meyer · Dec 7, 2018

I'm a big fan of my Buff Omni which is only 18". Use it a lot with diffuser and grid. Not a fan of the beauty dish circle highlight.

But more importantly is position. Get it up on a grip arm or boom. If low ceilings, seat them.

Sailor Blue · Dec 7, 2018

Living in Thailand buying from Adorama is not really a viable option so I bought a Selens 26" foldable collapsible beauty dish. It is virtually identical to the same size Glow EZ Lock "beauty dish".

It does not even come close to being a beauty dish. It is an okay softbox and not too bad as a silver umbrella.

DPReview - Sailorblue - Review of Selens 65cm 26" Foldable Collapsible Beauty Dish Softbox & Honeycomb Grid Flash

A beauty dish is a very finicky thing. A beauty dish that works well on one light won't be worth a damn on a different light.

How a beauty works and produces their umbra and penumbra depends on the reflectivity, size, and shape of the dish as well as the type and position of the strobe tube and the position of the deflector plate.

If you want a beauty dish then you want a metal one that will work properly on your particular strobe. Very few, if any, collapsible "beauty dishes" will actual work like a real beauty dish.

Find others that have a real metal beauty dish that works on the same strobe as you have and borrow it for a test. If you can't borrow one ask for some test shots taken flat onto a white wall at distances of 1' intervals from one times the diameter to four times the diameter and you will get a good idea of how it works.

--
Living and loving it in Pattaya, Thailand. Canon 7D - See the gear list for the rest.

JimResnikoff · Dec 8, 2018

Sailor Blue - While I am new to this forum it did not take me long to see the wealth of information you post which has certainly not only helped myself out, but others as well. I will take your advice and see about getting a pan based one. I still have to master the 2x3 softbox as well. Many thanks.

Ellis Vener · Dec 8, 2018

Sailor Blue said:
If you want a beauty dish then you want a metal one that will work properly on your particular strobe. Very few, if any, collapsible "beauty dishes" will actual work like a real beauty dish.

In my experience t he exception that proves the rule in Sailor's advice is the Chimera Octa Beauty 24" Collapsible Beauty Dish. http://chimeralighting.com/shop/?item=29234

No it isn't cheap but i na world of cheap low cost light modifiers there are very good reasons why Chimera Lightng is still in business: Light Quality construction, and attention to detail.

I have nothing against low cost modifiers - I really like my pair of Adorama Glow 28" Deep Octas for example -

Sailor Blue said:
Find others that have a real metal beauty dish that works on the same strobe as you have and borrow it for a test. If you can't borrow one ask for some test shots taken flat onto a white wall at distances of 1' intervals from one times the diameter to four times the diameter and you will get a good idea of how it works.

But also get a person in there and the light o na boom so you can put over and slightly in front of their face.

JimResnikoff · Dec 8, 2018

Thank you for the information Ellis, if nothing else I see the value of going with a slightly smaller size modifier in this category.

Sailor Blue · Dec 9, 2018

JimResnikoff said:
Sailor Blue - While I am new to this forum it did not take me long to see the wealth of information you post which has certainly not only helped myself out, but others as well. I will take your advice and see about getting a pan based one. I still have to master the 2x3 softbox as well. Many thanks.

A 2'x3' softbox is a nice size for portraits. It is good for mid-thigh up to head shots for a single person and good for head shots of two persons side by side. Just use it between about 40" and 90" for nice soft light (roughly 1 to 2 diagonals).

You can probably light a full length portrait at 90". Aim it at the upper body and expect the exposure to drop off 1/2 to 1 stop at the feet. You can easily even out the exposure with a gradient filter in post.

Get something bigger in the future for a bit better lighting for full length. The cheapest is a 60" white reflection umbrella with a black backing if you can fit it into your space.

Selex · Dec 9, 2018

Could you clarify that point?

I thought a 24 inch pan at 24 inches from model would produce identical results to a 36 inch pan held 36 inches away, similar to 48 inches by 48 inches.

Are they not proportional? i.e. you get the same effect with scaling?

Dish twice as large can produce same effect at twice the distance?

(Ok, it might not be twice, since light falls off by square law, so a dish twice the size might have to be at square root of 2, which is about 1.4 distance).

Although I imagine with increasing distance one would need to keep increasing the power output of the flash, since the light falls off due to distance, but its modeling effect i.e. how hard/soft it is should be constant?)

Thank you

Ellis Vener · Dec 9, 2018

Eliot Kramer said:
Could you clarify that point?

I thought a 24 inch pan at 24 inches from model would produce identical results to a 36 inch pan held 36 inches away, similar to 48 inches by 48 inches.

That's the theory - but notthe reality, also the farther a light source is from a tthree dimensional subject the smaller the difference is between the light impininging o nthe part of the object that is closest to the light source - let's say that is a person's forehead iof the light is where most people palce abeauty dish which is front and above the person - and a point that is further away - the ears, chin and neck i nthis example.

Selex said:
Are they not proportional? i.e. you get the same effect with scaling?

As I said - that is the theory but not the full real world reality.

Selex said:
Dish twice as large can produce same effect at twice the distance?

Sort of but not entirely.

Selex said:
(Ok, it might not be twice, since light falls off by square law, so a dish twice the size might have to be at square root of 2, which is about 1.4 distance).

Although I imagine with increasing distance one would need to keep increasing the power output of the flash, since the light falls off due to distance, but its modeling effect i.e. how hard/soft it is should be constant?)

There is that too.

Selex said:
Thank you.

You are welcome. How big a difference do these differences make make? It is up to your eyes to make a decision about that. There is science here, but there is the subjective part as well, and how you use the science to achieve your vision is where the art of what each of us do is found.

Selex · Dec 10, 2018

Thanks, appreciate it.

Nothing in photography is "real". The more I learn the more I realize that everything is not how it is supposed to be.

Ellis Vener · Dec 10, 2018

At some point in the very early stages of my still ongoing education as a photographer I met a man who was able n the middle of a very successful career as a commercial photographer. He was talking to a group of us aspiring photographers and one of the bits of wisdom that he imparted, at length, was why making a photograph was a logically impossible given all the possible ways things that could go wrong from materials to equipment to subject to the photographer’s mistakes.

A briefer part of his imparted wisdom was that you have to know the basic physics of what light is (a form of energy, duh) and how to make it work for you through placement and modification but that once you are working what counts is the way it looks.

--

Ellis Vener
To see my work please visit http://www.ellisvener.com
Or on instagram @therealellisv

Sailor Blue · Dec 10, 2018

Eliot Kramer said:
Could you clarify that point?

I thought a 24 inch pan at 24 inches from model would produce identical results to a 36 inch pan held 36 inches away, similar to 48 inches by 48 inches.

Are they not proportional? i.e. you get the same effect with scaling?

Dish twice as large can produce same effect at twice the distance?

(Ok, it might not be twice, since light falls off by square law, so a dish twice the size might have to be at square root of 2, which is about 1.4 distance).

Although I imagine with increasing distance one would need to keep increasing the power output of the flash, since the light falls off due to distance, but its modeling effect i.e. how hard/soft it is should be constant?)

Thank you

One of the most important things about a beauty dish is the umbra and penumbra they can produce. The umbra is produced by the deflector plate.

Umbra, penumbra and antumbra - Wikipedia

It is because of the umbra and penumbra that you can get a properly exposed face with a "glow" surrounding the face IF your beauty dish works properly with your strobe and IF it is at the right distance.

Change the diameter of the dish without changing the size of the deflector plate and more light will be sent from the edges of the larger dish to the center of the projected disk of light, reducing the difference in intensity between the umbra and the penumbra.

Moving the dish further away also reduces the difference in brightness between the umbra and penumbra.

The inverse square law only works properly for point light sources, or light sources that are very small with respect to the size of the subject. The inverse square law is only approximate for beauty dishes or diffuse light sources a distances where they are used.

A hot-shoe flash that zooms to match the focal length of your lens uses a Fresnel lens to beam light at the subject so that the area illuminated matches the area of the image. The inverse square law simply does not apply in this case.

A beauty dish can also beam light to some extent, meaning the area illuminated increases with distance but less than it would from other light sources, thus the inverse square law doesn't apply.

Krav Maga · Dec 14, 2018

Sailor Blue said:
Living in Thailand buying from Adorama is not really a viable option so I bought a Selens 26" foldable collapsible beauty dish. It is virtually identical to the same size Glow EZ Lock "beauty dish".

It does not even come close to being a beauty dish. It is an okay softbox and not too bad as a silver umbrella.

DPReview - Sailorblue - Review of Selens 65cm 26" Foldable Collapsible Beauty Dish Softbox & Honeycomb Grid Flash

A beauty dish is a very finicky thing. A beauty dish that works well on one light won't be worth a damn on a different light.

How a beauty works and produces their umbra and penumbra depends on the reflectivity, size, and shape of the dish as well as the type and position of the strobe tube and the position of the deflector plate.

If you want a beauty dish then you want a metal one that will work properly on your particular strobe. Very few, if any, collapsible "beauty dishes" will actual work like a real beauty dish.

Find others that have a real metal beauty dish that works on the same strobe as you have and borrow it for a test. If you can't borrow one ask for some test shots taken flat onto a white wall at distances of 1' intervals from one times the diameter to four times the diameter and you will get a good idea of how it works.

Ellis Vener · Dec 14, 2018

Simple: Does the combination of lighting instrument and modifier produce the quality of light you desire.

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Beauty Dish Size

JimResnikoff

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