580EX II 14mm zoom more powerful w/ modifiers?

Hmm, nicely done graphs, subscribing to read later

Well I did another test, OUTDOORS this time. In the middle of my back yard, 40 feet from anything, in the dark.

Here the results are a bit more understandable. The bounce card behaved like I would predict. The softbox gets brighter at higher zoom settings because of the direct light sneeking through the plastic.

The plastic cover and the Promax w/ white cover still produce counterintuitive readings.

If you want to know where the light is going, do the test I suggested above and take pictures of a plain wall with the gun at different head-zoom settings. Measure the size, shape and brightness of the light pool, and see how it changes dramatically with the wide-panel flipped down.

Then armed with that knowledge, work it back to see how much light is hitting the diffuser attachment, how much is going directly forward, what proportion is going to the ceiling and the sides, and how that component is being further diffused, absorbed and dispersed by the surfaces and suroundings.

More importantly, what does the quality of the light look like when it hits the subject, what is the area of coverage, and how do different attachments work in different locations/surroundings​.

Lots of work...

Hoppy1 wrote in post #12687500
If you want to know where the light is going, do the test I suggested above and take pictures of a plain wall with the gun at different head-zoom settings. Measure the size, shape and brightness of the light pool, and see how it changes dramatically with the wide-panel flipped down.

Then armed with that knowledge, work it back to see how much light is hitting the diffuser attachment, how much is going directly forward, what proportion is going to the ceiling and the sides, and how that component is being further diffused, absorbed and dispersed by the surfaces and suroundings.

More importantly, what does the quality of the light look like when it hits the subject, what is the area of coverage, and how do different attachments work in different locations/surroundings​.

Lots of work...

That's some Homework, you left him with.. He'll be pleased.. Or maybe get a really well-paid job from Gary Fong...

I still think Lumiquest w/White would come tops if the LSoftbox wasn't direct, but used as a bounce...

Shoot me down in flames, but i think the light speeds up with the scoops from sides, on it... Mr Einstein might have agreed..

Well I started measuring this stuff for a whole different educational purpose and at the time, the zoom setting wasn't even part of the equation.

I'm probably done collecting data, at least with these modifiers. Stay tuned for more comparison and analysis.

The Shaheen wrote in post #12678546
Again, i can't scientifically prove it, but the scoop shape really helps to throw the light forward and around objects...

Can you clarify that. I don't think it is like a curve ball in baseball. Once it come out of the scoop light still travels in a strait line. It can only get around something when the light source is bigger than the subject. This is just based on everything I have learned.

The Shaheen wrote in post #12687546
Shoot me down in flames, but i think the light speeds up with the scoops from sides, on it... Mr Einstein might have agreed..

It may but light is extremely fast. It think it would take extremely expensive equipment and a lab with a bunch of guys with pocket protectors to figure that out. I think this test is all about intensity of or concentration of light.

The Shaheen wrote in post #12687546
That's some Homework, you left him with.. He'll be pleased.. Or maybe get a really well-paid job from Gary Fong...

I still think Lumiquest w/White would come tops if the LSoftbox wasn't direct, but used as a bounce...

Shoot me down in flames, but i think the light speeds up with the scoops from sides, on it... Mr Einstein might have agreed..

Mr Einstein might not... Speed of light is effectively instant - it can travel around the earth seven times in one second. Or it could if it didn't travel in a straight lines.

Curtis N wrote in post #12687566
Well I started measuring this stuff for a whole different educational purpose and at the time, the zoom setting wasn't even part of the equation.

I'm probably done collecting data, at least with these modifiers. Stay tuned for more comparison and analysis.

Good stuff

Forgot to say that when the lab guys got the results my guess is the difference would be very insignificant for real world applications.

digital paradise wrote in post #12687587
Can you clarify that. I don't think it is like a curve ball in baseball. Once it come out of the scoop light still travels in a strait line. It can only get around something when the light source is bigger than the subject. This is just based on everything I have learned.

Sorry for the bump. I don't think light follows the curve in the scoop. I think a photon is emitted from the flash and it hits a point in the scoop and just gets re-directed. Kinda like playing pool.

digital paradise wrote in post #12687587
Can you clarify that. I don't think it is like a curve ball in baseball. Once it come out of the scoop light still travels in a strait line. It can only get around something when the light source is bigger than the subject. This is just based on everything I have learned.

Yes, ordinarily, light would travel in a straight line until reflection and refraction come into play.

digital paradise wrote in post #12687646
Sorry for the bump. I don't think light follows the curve in the scoop. I think a photon is emitted from the flash and it hits a point in the scoop and just gets re-directed. Kinda like playing pool.

Exactly like playing pool - light bounces off a surface at the same angle it strikes it, pool ball style.

Hoppy1 wrote in post #12687682
Exactly like playing pool - light bounces off a surface at the same angle it strikes it, pool ball style.

This is true with direct reflections, not true with diffuse reflections. If the bounce card in these tests was replaced with a mirror, the results would be quite different.

I don't mean to pick nits here, I understand that the "surface" at the atomic level is different from the "surface" as we see it. But the distinction between light bouncing off a mirror and light bouncing off a white ceiling is critical for fledgling photographers to understand. Diffuse reflection allows us to use bounce cards, ceiling bounce, softboxes, cloudy skies and north-facing windows.

digital paradise wrote in post #12687646
Sorry for the bump. I don't think light follows the curve in the scoop. I think a photon is emitted from the flash and it hits a point in the scoop and just gets re-directed. Kinda like playing pool.

Sorry i missed that the first time..

We were having this discussion in another thread. Some photographer wrote an article about this... i'll have to try to find it...

All the time you are assuming it's ONE beam. Even a laser beam has thickness (which is another possible discussion)

Imagine the square area of a flashead, that's not one beam coming out of there, it's hundreds... Every single one of these beams are coming out at different rates (albeit really quickly), and they all bounce at different angles, as they hit the inside of the scoop and also bounce of the walls.. Again at different angles.

This article had a drawing of a flat table top and beams bouncing at completely different angles.. Now imagine, walls, furniture, lamps, curtains, picture frames.. The flashlight is coming at the subject from all over the place and wrapping around it.

It's like millions of tiny bullets ricocheing off the uneven walls or surfaces... They would be coming at you from everywhere, including from behind, depending on what they hit and bounced from..

That's the curve effect i am talking about.. Not that light curves itself..

That makes sense to me. I never think of as one beam but as an explosion of light with a huge number of photons going in all types of directions. Only used one beam to illustrate the reaction when it meets a curve.