Speedlite difuser

Feel stupid, but how do you use the pull out diffuser on the 430EX??

The manual does not say much about it and I cant really find any other useful information

Just pull on it.

pull it out till it stops and let it drop down over the flash. the only time i've used it was for close up stuff where the barrel of the lens would cause shadows from the direct flash. since then i've bought a stofen diffuser and i always bounce the flash off something. works much better than using the built in diffuser.

BTW that is not a 'diffuser', it merely widens the coverage angle of the flash to a wider FL coverage. A 'diffuser' makes the apparent size of the light source to be larger, and might have no effect on the coverage area size!

For example, with a studio flash head, I might have a 5" reflector, a 11" reflector, or a 24" beauty dish, and all of them might only cover a 100 degree angle of coverage! The SIZE is different, the coverage angle is identical.

The best "diffuser" is a wall or the ceiling. As Wilt said it's the size of the apparent light source that's important.

Wilt wrote in post #6158232
BTW that is not a 'diffuser', it merely widens the coverage angle of the flash to a wider FL coverage. A 'diffuser' makes the apparent size of the light source to be larger, and might have no effect on the coverage area size!

For example, with a studio flash head, I might have a 5" reflector, a 11" reflector, or a 24" beauty dish, and all of them might only cover a 100 degree angle of coverage! The SIZE is different, the coverage angle is identical.

I've always wondered where people came up with the idea that the wide panel or the catchlight panel is called a diffuser because I don't think that term is used anywhere in the flash manual.

PacAce wrote in post #6162348
I've always wondered where people came up with the idea that the wide panel or the catchlight panel is called a diffuser because I don't think that term is used anywhere in the flash manual.

You'd be amazed at how many people think that. I've had my friends tell me to pull out my diffuser on my flash to help soften the light. I usually have to correct them, and they're usually adamant that they're in the right.

Nowhere in the flash's manual does it say that it's a diffuser of any sort. I wouldn't want to use a diffuser on my 580 EX II anyway, it's either a bounce card or bouncing it off a wall or ceiling.

lol no i realize you just pull it out... i know how to pull it out but I didn't realize what it was for...

I'm not really sure where I got the word "diffuser" from... someone said it so I went with it...

So it widens the flash coverage?? So when you're bouncing off the wall or somesuch it just expands the coverage of the flash?

Wilt wrote in post #6158232
BTW that is not a 'diffuser', it merely widens the coverage angle of the flash to a wider FL coverage. A 'diffuser' makes the apparent size of the light source to be larger, and might have no effect on the coverage area size!

For example, with a studio flash head, I might have a 5" reflector, a 11" reflector, or a 24" beauty dish, and all of them might only cover a 100 degree angle of coverage! The SIZE is different, the coverage angle is identical.

I don't think that's totally accurate - if something is designed to scatter light waves, sound waves, e.t.c. it is a diffuser.

Creating a large light source is the key to softer lighting. It is not inherently necessary to 'diffuse' light in order to do so, using diffusion material just happens to be the best/easiest way of generating a large effective light source when using small strobes. Something like the Lumiquest Big Bounce is your best bet if you want to soften a speedlight with any real effectiveness.

Hermes wrote in post #6170728
I don't think that's totally accurate - if something is designed to scatter light waves, sound waves, e.t.c. it is a diffuser.

Creating a large light source is the key to softer lighting. It is not inherently necessary to 'diffuse' light in order to do so, using diffusion material just happens to be the best/easiest way of generating a large effective light source when using small strobes. Something like the Lumiquest Big Bounce is your best bet if you want to soften a speedlight with any real effectiveness.

By your definition, perhaps, but not by convention of the photographic world.
A 'diffuse' source, vs. a 'specular' or 'point' source of light in photography pertains to the relative size of the source. Clear sky sunlight is a specular source, overcast is a diffuse source.

Webster simply defines verb 'diffuse' as "To spread over or through as in air, water, or other matter, especially by fluid motion or passive means. " adjective is "Everywhere or throughout everything; not focused or concentrated. " The 'not focused' is the key.

Wilt wrote in post #6174426
By your definition, perhaps, but not by convention of the photographic world.
A 'diffuse' source, vs. a 'specular' or 'point' source of light in photography pertains to the relative size of the source. Clear sky sunlight is a specular source, overcast is a diffuse source.

Webster simply defines verb 'diffuse' as "To spread over or through as in air, water, or other matter, especially by fluid motion or passive means. " adjective is "Everywhere or throughout everything; not focused or concentrated. " The 'not focused' is the key.

By convention of the photographic world and by proper definition, 'diffuse' means to spread - In a lighting context, it has nothing to do with the size of a light source. Even if in your experience, photographers have mistakenly confused the concept of diffusing a light source with enlarging it, this doesn't make it a convention (none of the photographers and lighting directors I've worked with, assistants I've had, books I've read, e.t.c. have ever confused the two, and the only place I've ever seen any ambiguity on this matter is on internet forums). I can't see any good reason to pass on misinformation or misapplication of simple terminology to new or inexperienced photographers - diffusion has everything to do with coverage and little to do with size.

For example, if you're standing on earth, the sun will produce a harsh, directional light. If you were standing a few feet away from it (with sunglasses and a very good apron), it would produce an even, flattering light due to the relative increase in its size - in neither case would it be diffused. I've worked on film sets where there have been large numbers of lights set up in a tightly-packed bank to produce a soft, directional light - clearly not 'diffused' but still a large, effective light source. At a pinch I've used mirrors lying around the location I've been shooting in as mid-sized reflectors - again, the light they reflected was directional rather than diffused but they still constituted a bigger light source than the bare-bulb of the strobe they were reflecting.

You can diffuse a light source without enlarging it and you can enlarge a light source without diffusing it - the fact that diffusion and enlargement are often combined to make one large, diffused light source (softbox, diffusion panel, broad cloud cover, foamcore reflector, e.t.c.) doesn't make the two terms interchangeable.

Let me just throw this into the discussion. According to the authors of "Light Science & Magic", i.e. Fil Hunter and Paul Fuqua, direct transmission of light is described as light passing through a material in a predictable path. And diffuse transmission is described as light passing through a material, such as white glass or thin paper, where the light rays are scattered in many random and unpredictable directions. The wide panel of the EX flash does not scatter light in random directions. The panel is a clear plastic with micro prisms on the surface to direct light in one direction or another but not randomly. So, by the above definitions, although the wide panel does scatter light, it really cannot be called a diffuser. Now, if the white panel were thin enough to let light pass through it, then that could be considered as a diffuser.

Let me just throw this into the discussion. According to the authors of "Light Science & Magic", i.e. Fil Hunter and Paul Fuqua, direct transmission of light is described as light passing through a material in a predictable path. And diffuse transmission is described as light passing through a material, such as white glass or thin paper, where the light rays are scattered in many random and unpredictable directions. The wide panel of the EX flash does not scatter light in random directions. The panel is a clear plastic with micro prisms on the surface to direct light in one direction or another but not randomly. So, by the above definitions, although the wide panel does scatter light, it really cannot be called a diffuser. Now, if the white panel were thin enough to let light pass through it, then that could be considered as a diffuser.

PacAce wrote in post #6176341
Let me just throw this into the discussion. According to the authors of "Light Science & Magic", i.e. Fil Hunter and Paul Fuqua, direct transmission of light is described as light passing through a material in a predictable path. And diffuse transmission is described as light passing through a material, such as white glass or thin paper, where the light rays are scattered in many random and unpredictable directions. The wide panel of the EX flash does not scatter light in random directions. The panel is a clear plastic with micro prisms on the surface to direct light in one direction or another but not randomly. So, by the above definitions, although the wide panel does scatter light, it really cannot be called a diffuser. Now, if the white panel were thin enough to let light pass through it, then that could be considered as a diffuser.

It's a good book but I wouldn't put too much store in that particular definition - no diffuser, including paper and white glass, scatters light in an 'unpredictable' way as you can always calculate the likely spread and area of coverage based on the properties of the diffusion material. The wide panel of a flash doesn't seem unique in this sense.

Maybe the point they're trying to make is that if you were to fire a single light wave/particle through a pane of glass or into a mirror you'd be able to accurately predict where it would end up as it would have a straight trajectory, whereas if you fired it through a diffuser there are a number of directions in which it could end up travelling. You could predict the rough area it would end up in by averaging the results of millions upon millions of waves/particles emitted from a light source but practically speaking (i.e. without an electron microscope and a lot of time on your hands) there would be no way of predicting the path each one would take.

Either way, the main point is that diffusion refers to the direction of light, not the size of the light source. If the OP wants their speedlite to act as a larger and softer light source then one of the bigger accessory softboxes would be the most convenient solution (there is a good one other than the Lumiquest Big Bounce but for the life of me I can't remember what it's called atm). If all they want to do is diffuse it then a Stofen Omnibounce or similar will do so for very little cost but I'm guessing that this isn't what they're looking for.

Hermes wrote in post #6176854
It's a good book but I wouldn't put too much store in that particular definition - no diffuser, including paper and white glass, scatters light in an 'unpredictable' way as you can always calculate the likely spread and area of coverage based on the properties of the diffusion material. The wide panel of a flash doesn't seem unique in this sense.

Maybe the point they're trying to make is that if you were to fire a single light wave/particle through a pane of glass or into a mirror you'd be able to accurately predict where it would end up as it would have a straight trajectory, whereas if you fired it through a diffuser there are a number of directions in which it could end up travelling. You could predict the rough area it would end up in by averaging the results of millions upon millions of waves/particles emitted from a light source but practically speaking (i.e. without an electron microscope and a lot of time on your hands) there would be no way of predicting the path each one would take.

Either way, the main point is that diffusion refers to the direction of light, not the size of the light source. If the OP wants their speedlite to act as a larger and softer light source then one of the bigger accessory softboxes would be the most convenient solution (there is a good one other than the Lumiquest Big Bounce but for the life of me I can't remember what it's called atm). If all they want to do is diffuse it then a Stofen Omnibounce or similar will do so for very little cost but I'm guessing that this isn't what they're looking for.

That is exactly my point. Light path through a diffusing material would be unpredictable. However, light path through the wide panel of the flash would be just like it is through a lens and, hence, it's not technically a diffuser. That's the only point I was trying to make. I do agree with your other points, though.