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FORUMS General Gear Talk Flash and Studio Lighting 
Thread started 26 Apr 2011 (Tuesday) 09:40
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It's Time To Dispell A Myth About Speedlight's And Lightboxes

 
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PhotographersWorldWide
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Apr 04, 2012 17:01 |  #91

Wilt wrote in post #14208826 (external link)
As for measuring the intensity of subject illumination (what TMR Design's original post was about) neither of the above techniques was really necessary; for measuring subject illumination he measured 6 feet from the face of the modifier.


So in other words it doesn't matter that a larger modifier is chosen to increase the penumbra (external link).. what is important is that you lose no output, and don't change the characteristics of the light? What IS the object of using a larger modifier then? Is it to lose no output.. and not change the characteristics of the light???

The last sample cited isn't even into the realms where a sensible reading can be taken.. that doesn't happen until over another 5ft. any sort of adjustment until then will give practically the same EV:

54" x 72" Softbox - silver interior - with inner and outer diffusion panels - f/8 + .2




  
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Wilt
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Apr 04, 2012 17:06 |  #92

PhotographersWorldWide wrote in post #14210216 (external link)
So in other words it doesn't matter that a larger modifier is chosen to increase the penumbra (external link).. what is important is that you lose no output, and don't change the characteristics of the light? What IS the object of using a larger modifier then? Is it to lose no output.. and not change the characteristics of the light???

The last sample cited isn't even into the realms where a sensible reading can be taken.. that doesn't happen until over another 5ft. any sort of adjustment until then will give practically the same EV:

You and I understand the reason for a larger softbox. Many other folks do too. But they were fearful in buying a larger softbox for use with their speedlights, because of urban legend that it could cause a loss in the light output intensity, due to size. So TMR Design sought to address that concern, about loss of intensity, in the OP.

:confused: Your posts seem to try to turn his efforts into more than merely answering the loss of intensity.
As for 'loss of apparent softness due to hot spot center and falloff toward the edges of the front panel', that issue was not the point of the OP. Subtopic was outside the scope of the discussion, even though that subtopic is very valid consideration. Leaving it out of that discussion is not wrong, just as discussion of aperture selection effect on the DOF is not wrong in not encompassing the aperture effect on the out-of-focus areas of the photo...simply beyond the scope of DOF discussion.


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PhotographersWorldWide
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Apr 04, 2012 17:12 |  #93

Wilt wrote in post #14210247 (external link)
You and I understand the reason for a larger softbox. Many other folks do too. But they were fearful in buying a larger softbox for use with their speedlights, because of urban legend that it could cause a loss in the light output intensity, due to size. So TMR Design sought to address that concern, about loss of intensity, in the OP.
:confused: Your posts seem to try to turn his efforts into more than merely answering the loss of intensity.

I simply fail to see the point in misleading people and the issue is more than just a decrease in intensity.

'Buy big softboxes you lose no output' is completely different from 'Buy big softboxes you get no more benefit from them'.

When a change in size results in NO change in characteristics - whats the point?




  
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Wilt
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Apr 04, 2012 17:19 |  #94

PhotographersWorldWide wrote in post #14210283 (external link)
I simply fail to see the point in misleading people and the issue is more than just a decrease in intensity.

'Buy big softboxes you lose no output' is completely different from 'Buy big softboxes you get no more benefit from them'.

When a change in size results in NO change in characteristics - whats the point?

OK, now I understand your motivation! You are voicing concern about the many additional considerations that enter into the selection of size and shape and other characteristics of light sources which may be used. Very valid. It would have been good to start of with that as a comment. Instead you seemed intent on poking holes in the original topic (intensity) with some invalid statements of your own, "Roberts post was regarding softboxes which included a single layer of diffusion ", when three of the softboxes had double diffusion.


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PhotographersWorldWide
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Apr 04, 2012 19:38 |  #95

Motivation?

Your quotation doesn't relate to my first post at all, and your advice to start by pointing out 'other considerations' was already made then!!!

In my first post I pointed out that there were no examples of softbox illumination, Point 1: The very starting point of using varying sizes of softbox demands an even coverage of each softbox to start with and the inevitable consequence of increasing size in this condition being a loss of GN.(The 'Myth'). Compared to using a strobe, which these factors are present, using a speedlight doesn't perform the same, nor result the same and only exists as its own confirmation that it doesn't change for the reasons I gave. Roberts figures bears that up well, but covering point point 1: Even coverage.. Fails completely and makes the results pointless as softbox size was irrelevant.

I even mentioned these differences in direct comparison to a strobe use, which I've tested and already illustrated.

Heres my first post:

There's not a single example of a softbox cover shown here. So the 'myth' is far from proven as the purpose of the softbox is to provide even coverage across the whole face of the softbox. The larger the softbox, the more difficult it is to obtain an even coverage.

The reason that theres no difference in the results seen between a small and large softbox here is because a speedlight facing through a softbox cover will illuminate exactly the same area when placed at the same distance from the cover in each softbox, making THAT area the effective softbox (lightsource) size.

Unlike a strobe tube which illuminates the softbox walls AND cover, a speedlight projects its light forward AT the cover and is incapable of illuminating the cover evenly - especially with larger softboxes.

Rear facing speedlights in softboxes work well (as shown by Jannie https://photography-on-the.net/forum/...3&pos​tcount=55) as the illumination is totally indirect. The comparable light loss is also considerably greater. In THIS example the light loss of using the Octabox is nearly 3 stops. (Based on the GN of a 580EXII being 92 @ 24mm).

Factually, using a speedlight in a softbox loses less comparable output to its unmodified state than a strobe loses. However, the coverage by the strobe will be more even and more fitting to the choice of softbox size.

Instead you seemed intent on poking holes in the original topic (intensity) with some invalid statements of your own, "Roberts post was regarding softboxes which included a single layer of diffusion ", when three of the softboxes had double diffusion.

I illustrated the same single diffusion layer, and I'm still waiting to see any samples of any other size softbox covers with even coverage using a single speedlight - especially the 6 foot X 5 foot version.

If I wanted to 'poke holes' I could find them quite easily.

As I've tried to point out - 1. Is the intention to use increasing sizes of softbox with their inherent increase in 'softness' and reduction in GN, or do you just want to 2. Blast a speedlight through 2 pieces of nylon? If your answer is 2. Then where can the Myth exist when no change exists?




  
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FJ ­ LOVE
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Apr 04, 2012 22:15 |  #96

PhotographersWorldWide wrote in post #14210908 (external link)
Motivation?

I'm still waiting to see any samples of any other size softbox covers with even coverage using a single speedlight - especially the 6 foot X 5 foot version.

If I wanted to 'poke holes' I could find them quite easily.

just so i understand all this, you've been a member of this forum for 4 years and 90 posts

you have found a thread that is one year old that you don't quite agree with

the op is not even a member of the forum anymore and your waiting for samples to be given to you

others have tried to help you see what this thread was about but you continue to troll this thread looking what ? :confused:


DILLIGAF about your bicycle or your gear

  
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Apr 04, 2012 22:40 |  #97

FJ LOVE wrote in post #14211796 (external link)
just so i understand all this, you've been a member of this forum for 4 years and 90 posts

you have found a thread that is one year old that you don't quite agree with

the op is not even a member of the forum anymore and your waiting for samples to be given to you

others have tried to help you see what this thread was about but you continue to troll this thread looking what ? :confused:

yeah sorry I think this is partially my fault for bumping this thread asking about what happened to Robert.:oops:


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akfreak
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Apr 04, 2012 23:03 as a reply to  @ flowrider's post |  #98

Robert is doing well! That is all I have to say :) LOL


http://www.speedtest.n​et/result/1460485335.p​ng (external link)

  
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elv
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Apr 04, 2012 23:03 as a reply to  @ FJ LOVE's post |  #99

For what its worth we have done a lot of testing with speedlights and softboxes, and the flip down wide angle diffuser on Canon/Nikon flashes does a great job of providing very even light across the face of a large softbox up to 36" x 48". Some results were more even than a bare bulb Elinchrom monolight.

Beyond 48" it will start to fall away at the edges unless you have a deeper softbox. But thats still not a big issue.

I agree that 24mm zoom is the most efficient power-softness, but the wide angle diffuser is noticeably softer if thats what your after (at the cost of a stop of light).

The Stofen cap was the least efficient and does much less to reduce a hotspot than the wide angle diffuser.


FLASHHAVOC.COM (external link)

  
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z-monster
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Apr 04, 2012 23:12 |  #100

FJ LOVE wrote in post #14211796 (external link)
just so i understand all this, you've been a member of this forum for 4 years and 90 posts

Alright! Finally, someone has made it clear that post counts are a measure of ones skill! ;)


Damn I'm doomed! I had better get my post count up fast. :razz:


My feedback

  
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FJ ­ LOVE
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Apr 04, 2012 23:38 |  #101

z-monster wrote in post #14212156 (external link)
Alright! Finally, someone has made it clear that post counts are a measure of ones skill! ;)


Damn I'm doomed! I had better get my post count up fast. :razz:

a post count may not indicate skill, but it sure does make someone wonder what has that member so fired up that he comes out of the woodwork after a 4 year absence to post 8 times in a thread that has been dead for a year, just sayin ;)


DILLIGAF about your bicycle or your gear

  
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PhotographersWorldWide
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Apr 05, 2012 02:15 |  #102

elv wrote in post #14212113 (external link)
I agree that 24mm zoom is the most efficient power-softness, but the wide angle diffuser is noticeably softer if thats what your after (at the cost of a stop of light).

1. The 24mm zoom is the most efficient power-softness,
OK, so thats the optimum...

2. but the wide angle diffuser is noticeably softer..
Therefore: The 24mm zoom is the most efficient power-softness.. is wrong.. the point of a softbox being..soft ?

3. (at the cost of a stop of light)
Isn't THAT the whole point of what this 'myth busting' is supposed to be all about?




  
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PhotographersWorldWide
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Apr 05, 2012 02:27 |  #103

FJ LOVE wrote in post #14211796 (external link)
others have tried to help you see what this thread was about but you continue to troll this thread looking what ? :confused:

see my previous post.. people are really helping.




  
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PhotographersWorldWide
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Apr 05, 2012 02:47 |  #104

FJ LOVE wrote in post #14212265 (external link)
a post count may not indicate skill, but it sure does make someone wonder what has that member so fired up that he comes out of the woodwork after a 4 year absence to post 8 times in a thread that has been dead for a year, just sayin ;)

Hello.. I'm still here by the way, but I haven't had a 4 year absence, and in another 2 years I won't have posted over 19,000 posts making the zero contribution you haven't made, particularly to you posting here. Just sayin ;)

If so many people didn't want to chip in and say that I'm wrong, I would have posted once. My first post (as plainly pointed out by Wilt) is all that needed to be said, (I said it !!!) but some people need convincing further it seems.

The offer to post samples showing any softbox face along with the EV is open to anybody, including you. Anybody. Theres plenty of heresay and circumstantial evidence, but nothing tangible. Even better would be if you were to compare the even covered softbox faces at various sizes and their GN value.

Accusing people of Trolling is a sure way to increase your post count though.. off topic.. wrong.. as well as irrelevant.




  
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PacAce
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Apr 05, 2012 07:26 |  #105

Discussions are good, folks, but let's not get into personal attacks, OK?

BTW, just for the record, I'm inclined to agree with the arguments presented by PhotographersWorldWide​. Logic says that if you use a smaller modifier (softbox), then you can zoom the flash head in to more efficiently cover the smaller frontal area of the softbox and still maintain an even distribution of light across the face of the front panel. Zooming in increases the relative brightness of the light from the modifier.

However, if the discussion of this thread is about using the flash at the widest zoom setting, then I also agree that the size of the modifier/softbox will not make much of a difference in terms of the light coming out the modifier. :)


...Leo

  
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