Honeycomb / Grid - Cell size = which angles ?

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MidnightUK

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Anyone know if there is a comparison list anywhere that shows

Cell size in mm
Cell size in inches (imperial)
Degree of coverage


I have 7 inch diameter honeycombs labelled with cells in mm :
2 mm
3 mm
4 mm
6 mm

but lots of discussions/shops etc difine honeycombs in terms of angles of degree or in imperial measurements (1/4 inch, 1/8 inch etc).
I would find it very helpful to be able to compare all these sizes directly, particularly to know what cell sizes the degree terms refer to.

I have done an internet search but not found a comparison table. Guess I am the only one to get confused by the different sizing methods!

Thanks for any info on this.
 
If there is a comparison list, I don't know of it, sorry.

And a statement of the size of the cells is pretty useless in itself, because there is another measurement that is just as important - the thickness/depth.
A few forum members who have been to either my own studio or to the Lencarta studio may have seen my 5 degree honeycomb, which I use a lot - it's probably twice as deep as any others, with the possible exception of the Elinchrom 8 degree one (I think) that I used many years ago, but that one although deep was fairly coarse.

My 5 degree honeycomb seems to be sold only in the USA and although various people list it on their websites for at least US$ 200, it seems to be permanently out of stock. Some years ago I tried to get some 5 degree ones made in China but without success (too small and specialised a market for China) and found that the only workaround would be to get a deeper/thicker one with the same cell structure as the 10 degree. Or, if you do something really clever, such as buying the Lencarta Honeycomb reflector, you'll find that another clever bugger has thought it through and made the lip deep enough to stack two honeycombs, which of course can also be rotated....
:)
 
Garry Edwards said:
Lencarta Honeycomb reflector, you'll find that another clever bugger has thought it through and made the lip deep enough to stack two honeycombs, which of course can also be rotated....
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Garry strikes with really useful info and design skill yet again!

I can see why depth of cell has an effect. Its a shame there is no consistent standard as its difficult to tell what people have really used or indeed what is available to buy. I have not seen anywhere yet that quotes cell depth on the sales page, which would be a help too. Product comparison with this stuff is not easy.

When you retire, its a great shame you cant work from home just one day a week to go on giving such useful answers about stock and techniques. I understand your desire to do other things in life though!

Just measured, the grids I have are 10mm deep cells.

I did find this thread which may be useful working out angles, but I will have to get someone who can do maths (not me!) to look at it and see if it can be applied to what I wish to know
http://photo.stackexchange.com/questions/9413/how-does-grid-depth-determine-beam-angle

My maths is dire, so finding a table would have been so handy. Thanks for the help you have given though as its useful in itself.
 
I'm not retiring for ages yet - 4 weeks:)
It's my day off today, but tomorrow I'll try to take some depth measurements and post them here.
This is the honeycomb reflector (or one of them)
mod046_angle-650x530.jpg

and it gives you an indication of the depth of the rim. You'll also see that there is no stippling effect near the front, which improves the efficiency of the honeycomb towards the edges - you'll find it hard to believe this, but it took nearly two years to get this reflector made
 
Garry Edwards said:
you'll find it hard to believe this, but it took nearly two years to get this reflector made
Click to expand...

No, I trust you on that. Sometimes projects are like pushing boulders up hill.

Does that fit the SuperFasts as well? - I see its listed for the other range.

Are you having a leaving party?
 
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Garry, on your pack of honeycombs page, does this need updating? "A set of 4 honeycombs for use with our new Standard Reflector only" as it does not seem to match with statements on the reflector pages, or I could be misreading.
 
MidnightUK said:
No, I trust you on that. Sometimes projects are like pushing boulders up hill.

Does that fit the SuperFasts as well? - I see its listed for the other range.
There are two flavours, one for the SmartFlash and another for the ElitePro and the SuperFast, they are basically the same, the only difference is that the SmartFlash has to have the umbrella in a different place to the one for the ElitePro and the SuperFast.

Are you having a leaving party?
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I don't know about a leaving party, but my guess is that the rest of them will have a party when I've gone:) I've never claimed to be easy to work with, or easy going, and I'm 50 years older than most of the people there, and different generations have different approaches.
MidnightUK said:
Garry, on your pack of honeycombs page, does this need updating? "A set of 4 honeycombs for use with our new Standard Reflector only" as it does not seem to match with statements on the reflector pages, or I could be misreading.
Click to expand...
It probably does, there's a lot of info on the new website that needs to be updated.
 
Garry Edwards said:
I don't know about a leaving party, but my guess is that the rest of them will have a party when I've gone:) I've never claimed to be easy to work with, or easy going, and I'm 50 years older than most of the people there, and different generations have different approaches.
.
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What will I do for a coffee and a natter when I'm next working in Bradford?
 
OK, an update on this....

My super duper and totally unavailable 5 degree honeycomb as a depth of 25mm,
The ones that are available from us (10, 20, 30, 40 degree) have a depth of 10mm
Our new honeycomb reflectors have a lip for the honeycombs that accepts up to 18mm, which allows 2 honeycombs to be stacked.

Obviously, it's virtually impossible to line up two honeycombs exactly, so the back one will inevitably block some of the light from the front one, which means that not only will two together make a deeper honeycomb that will restrict the light much more, it will also be tighter since they cannot be lined up accurately.

I haven't got time to play, but it's clear that with experimentation, two together can create a VERY tight honeycomb, if required.
Phil V said:
What will I do for a coffee and a natter when I'm next working in Bradford?
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The coffee machine will still be there:)
I'm thinking of wandering off to Australia for a while, I have a daughter and her family there.
I may also move to Scarborough and live on my farm, nothing is yet carved in stone. But the people who will still be at Lencarta know how to operate the coffee machine and are much more chatty and accommodating than me...
 
The smaller the spacing, or the deeper the grid, the smaller the angle of the light leaving. There is no conversion possible w/ only the spacing given, but the spec doesn't really matter. What matters is the result you want, and distance also plays a part in the choice.
 
sk66 said:
The smaller the spacing, or the deeper the grid, the smaller the angle of the light leaving. There is no conversion possible w/ only the spacing given, but the spec doesn't really matter. What matters is the result you want, and distance also plays a part in the choice.
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In other words, the stated angle of coverage is the thing.

On a more general note, the angle of light modifiers is sometimes given, but I've often wondered how this is measured. Given that there's never a sharp cut-off at the edges, at what point is coverage said to end? Is there an industry standard like when brightness drops more than one or two stops or something?
 
HoppyUK said:
In other words, the stated angle of coverage is the thing.

On a more general note, the angle of light modifiers is sometimes given, but I've often wondered how this is measured. Given that there's never a sharp cut-off at the edges, at what point is coverage said to end? Is there an industry standard like when brightness drops more than one or two stops or something?
Click to expand...
I *think* it is typically a physical measurement of the exit opening back to the source at design distance... that wouldn't apply to specialized designs like focusing reflectors, but I don't recall having seen an angular spec for one (I have a focusing reflector, no idea what the spec is).

Edit: my telephoto reflector is 18*... I guess they must have measured the result. Since falloff at the edges is never part of the specs I have to assume "total coverage" to the "black edge" and probably a bit subjective if there is a very gradual edge.
 
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HoppyUK said:
In other words, the stated angle of coverage is the thing.

On a more general note, the angle of light modifiers is sometimes given, but I've often wondered how this is measured. Given that there's never a sharp cut-off at the edges, at what point is coverage said to end? Is there an industry standard like when brightness drops more than one or two stops or something?
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I think that the industry standard is to lie:)
I measure them to the point where the brightness has faded to what I consider to be a reasonable point, about 1 stop, it then falls off pretty quickly.
But I've seen figures quoted that I know must be false. For example, our softbox honeycombs measure 4x4x4cm and I state the angle to be 40 degrees, it's usually between 39 and 41 degrees, depending on how tightly it fits to the softbox, but I've seen websites that sell those useless very wide-spaced honeycombs (usually bundled free with the softbox because they don't work and aren't worth anything) that are also very shallow, and they often claim 40 degrees, which cannot be true - a bit like claims that the colour temperature is whatever, -+ 100K - which in reality only Bron can achieve
 
Garry Edwards said:
I think that the industry standard is to lie:)
I measure them to the point where the brightness has faded to what I consider to be a reasonable point, about 1 stop, it then falls off pretty quickly.
But I've seen figures quoted that I know must be false. For example, our softbox honeycombs measure 4x4x4cm and I state the angle to be 40 degrees, it's usually between 39 and 41 degrees, depending on how tightly it fits to the softbox, but I've seen websites that sell those useless very wide-spaced honeycombs (usually bundled free with the softbox because they don't work and aren't worth anything) that are also very shallow, and they often claim 40 degrees, which cannot be true - a bit like claims that the colour temperature is whatever, -+ 100K - which in reality only Bron can achieve
Click to expand...

I meant modifiers in general, not just grids, but I think I've just answered my own question in about two minutes. Elinchrom 60 degrees small 18cm reflector drops by one stop, pretty much exactly at 30 degrees off centre, so that would seem to be a decent yardstick :)

BTW, even Bron can't do +/- 100K colour shift throughout the power range. Good colour control tends to go hand in hand with power range - the wider the range, the greater the shift. As you'd expect really.
 
HoppyUK said:
I meant modifiers in general, not just grids, but I think I've just answered my own question in about two minutes. Elinchrom 60 degrees small 18cm reflector drops by one stop, pretty much exactly at 30 degrees off centre, so that would seem to be a decent yardstick :)
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OK, got you now, I assumed that you were talkiing about honeycombs as that's the thread subject. With some modifiers, it's very easy because there is a sharp transition - think focussing spots, snoots, fresnel spots, beauty dishes. With others, same as my answer with honeycombs.
BTW, even Bron can't do +/- 100K colour shift throughout the power range. Good colour control tends to go hand in hand with power range - the wider the range, the greater the shift. As you'd expect really.[/QUOTE]
OK, got you now, I assumed that you were talkiing about honeycombs as that's the thread subject. With some modifiers, it's very easy because there is a sharp transition - think focussing spots, snoots, fresnel spots, beauty dishes. With others, same as my answer with honeycombs.
HoppyUK said:
Bron can just about do it on many of their flash heads, nobody else can. What you are saying is absolutely right re the wider the range, the greater the shift, and one of the outstanding examples of what not to do is Alien Bees, where with their non IGBT models that I've tested, the colour shift is unbelievably bad.
MidnightUK said:
Garry, on your pack of honeycombs page, does this need updating? "A set of 4 honeycombs for use with our new Standard Reflector only" as it does not seem to match with statements on the reflector pages, or I could be misreading.
Click to expand...
You're right and I've now updated that page.
What happened was that when the new website came online, a lot of the pages that it migrated from the previous site were out of date, in other words the previous website had many pages that were changed after the date on which the pages were migrated. We're still trying to pick up the last of these annoying faults.
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Paulo Rodrigues, one of our long-standing members at the Strobist group on Flickr, came up with a formula for the beam angle from a grid some years ago.

Essentially it is Length = Aperture/Tan(Angle/2) , or any other flavours of the same equation.

He even put an interactive calculator for it on his blog, accounting for the variables of cell width, grid length and beam angle.
I've never tried it myself so cannot vouch for its accuracy, but plenty of others have used it over the years and seem happy with the results. And Paulo's a great bloke so I'm more than prepared to give him the benefit of the doubt. :)

Here's the page with the formula and calculator on Paulo's blog: http://paulophotoblog.blogspot.com/2008/01/width-at-widest-point-mm-beam-angle.html
 
Garry Edwards said:
you'll find it hard to believe this, but it took nearly two years to get this reflector made
Click to expand...

But not so long for me to order one, as taking the modelling light out of the SuperFast is already annoying me, so have put in an order. Will be interesting once it arrives, to compare the edges.
 
Nionyn said:
sorry I didn't see the thread earlier.
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Nice you helped at all. It was not urgent information, just stuff I thought it would be really helpful to know. Thanks again - and to all others who have kindly posted here.
 
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