Canon flash and umbrella question

[gooble]

For those using hot-shoe flashes with umbrellas and such where do you set the zoom on the flash? It seems like the default in slave mode is 24mm. Is that enough or should one pull out the wide angle diffuser that's 14mm?

Also when you're positioning off-camera flashes when they're not being used with an umbrella do you adjust the zooms or leave them set wide? How do you know where to set them if you do?

[wallybud]

For those using hot-shoe flashes with umbrellas and such where do you set the zoom on the flash? It seems like the default in slave mode is 24mm. Is that enough or should one pull out the wide angle diffuser that's 14mm?

Also when you're positioning off-camera flashes when they're not being used with an umbrella do you adjust the zooms or leave them set wide? How do you know where to set them if you do?

I am quite new to this but if you want your flash output to be spread wide after the umbrella bounce and a little softer than set it wider. If you want more of a "beam" (but not really a beam) of soft light coming back off the umbrella set it to 70/80mm etc. Also keep in mind the distance between subject and umbrella when changing the zoom....obviously lol

A tighter mm setting will get you more distance from your umbrella I assume (you can also use a "snoot" I think it's called on you flash when shooting into the umbrella to get a more direct shot of light.

Check over at strobist.com

[gooble]

I've spent a lot of time at the strobist site but I haven't seen this topic discussed; maybe I've just missed it.

I did a couple test shots aimed into the umbrella, one with the wide angle diffuser out and one at 24mm and I could definately tell the difference. The 24mm didn't seem to cover the umbrella like the diffuser did. This goes along with what wallybud said but what I don't know how to figure out now is how to know what zoom setting to pick based on flash distance from subject. Trial and error or are there some rules of thumb? Do you pretend the flash is a lens and envision which focal length would cover the subject?

[wallybud]

No I just go by how much area I want the umbrellas flash to cover...The diffuser (stofen I assume) it going to spread the light WAY out because some of it isn't even going into the umbrella lol its going straight sideways/up/down etc...It depends a lot on how much room you have to work with and how far the light will be from the model.

flash is SO much trial and error I wanna throw up sometimes...

for this shot the flash was set to 24mm but I was shooting with the 35. The umbrella was about 3 feet away so I wants nice wrap around light but with the 45" umbrella so close I didn't need a lot of power at all and at a low setting a lot of the wide light just gets feathered away...
http://i550.photobucket.com/albums/ii411/Lodzinskiw/Natalia_Attitude-Small.jpg

[gooble]

By diffuser I'm referring to the pullout wide-angle diffuser built into the flashes. When you pull it out the zoom is shown as 14mm on the screen.

My last question, in case it wasn't clear was what you do with the zoom when you're not using an umbrella, soft box etc.

[wallybud]

Don't really know? lol...outside Id most likely set it to a longer focal length in order to "get the light, there"? I usually keep between 24/35mm though...I like my light to feather away. If I wanted harsher light Id set it to 105 to concentrate the beam more...I havn't had that much experience on my own lol...at the wedding we use profoto lighting and use the cone to feather or concentrate the light + grids/umbrellas/boxes etc so the speedlite option seems a bit blah to me? why not just fire it at a white wall and see how the changes affect the output?

[gooble]

Ok, thanks for the help wally. I'll have to experiment.

[Wilt]

Fill the umbrella to its edges, without spill over past the edges. That maximizes the apparent size of the umbrella, softening the light to the greatest amount for that umbrella. Anything less defeats the purpose of using that size umbrella, and you might as well be using a smaller (and cheaper) one instead!

[Lithian]

Keep in mind if you do spill over the edges you can pull the umbrella in closer to the flash. The best way to check is to take a picture of the umbrella, you may have to power down the flash/stop down to see the light clearly.

[Jannie]

I experimented yesterday pulling out the diffuser on my 580EXII while using the Westcott double fold white shoot through umbrella and I think it's an improvement in that it not only spreads the width of the light but appears to do it more evenly with less concentration in the center of the umbrella. Not that that is a bad thing and sometimes desired but for overall softness I liked what I saw with the diffuser covering the lens.

The best test will be when I get my remote cord or second flash so I can take a photo of the umbrella with the flash set either way, that and just how I like the look.

I imagine that if you put a piece of diffusion, like the rosco or even thin tupperware right over the lens it would spread the light in a more random or soft way, unlike the Sto-fen which sends a lot of that light off to the sides.

[homersapien]

I set my 430ex to 24 or 35mm, then take a few shots of the umbrella to make sure I'm right at the edges, with no spill and no hot spot. It's going to depend on the size of the umbrella and it's distance from the flash. Experiment :)

[Wilt]

TMR Design did a wonderful test which happens to show filling umbrellas vs. not filling them properly...

http://photography-on-the.net/forum/showpost.php?p=7271173&postcount=1


Look at the 4th column, with the shoot thru umbrella

[tkoutdoor]

I experimented yesterday pulling out the diffuser on my 580EXII while using the Westcott double fold white shoot through umbrella and I think it's an improvement in that it not only spreads the width of the light but appears to do it more evenly with less concentration in the center of the umbrella. Not that that is a bad thing and sometimes desired but for overall softness I liked what I saw with the diffuser covering the lens.

The best test will be when I get my remote cord or second flash so I can take a photo of the umbrella with the flash set either way, that and just how I like the look.

I imagine that if you put a piece of diffusion, like the rosco or even thin tupperware right over the lens it would spread the light in a more random or soft way, unlike the Sto-fen which sends a lot of that light off to the sides.

Soft light is created by the size of the light source and its relationship to the subject. I think many people have the idea that when light passes through a diffuser it automatically becomes soft. That's a misconception. Try a test with a constant light source so you can immediately see the results or shoot a flashed pic and observe the results on camera. Shine it into an umbrella and move it closer and further from the subject while keeping the subject a foot or two from the wall so that the shadows on the wall behind the subject may be observed. Compare this to shooting a flash straight at the subject with only a diffuser over the flash head. The diffuser will produce hard light when flashed directly on the subject. It's the size of the light source and relationship to the subject (distance and relative size) that produce the soft light, not the fact that it passed through some unique material that's about the same size as the flash.

The typical flash cover style diffuser is good at one thing though. It will cast light on the subject from more than one direction. So if one bounces the light off the ceiling there will also be a second light source created by the small transparent lip that sticks up 1/2" or so above the end of the flash. This can produce a catch light, but it can also make shadows (because it's still a small light source, therefore creating hard light). It might be better to just bounce of the ceiling without the diffuser (as it creates a small second light source) so as not to introduce hard edge shadows, but that's a judgment call. I've also found that my optical triggers are more responsive to the diffuser as it offers more than just straight on rays of light to be seen by the trigger.

A corn flakes bag rubber banded to the flash can produce softer light than the typical diffuser shot straight at the subject because it's a larger light source. Bouncing the flash (with or without a diffuser) makes for very soft lighting because the size of the light source has become gigantic (the light source became the whole ceiling where the light was applied), not because it was shot using a diffuser cap over the end of the flash head.

[gooble]

TMR Design did a wonderful test which happens to show filling umbrellas vs. not filling them properly...

http://photography-on-the.net/forum/showpost.php?p=7271173&postcount=1


Look at the 4th column, with the shoot thru umbrella

Looks informative. Thanks.

[Mister Cool]

the whole discussion makes only a sense if you consider the distance flash-umbrella and diameter of the umbrella! It is obvious that the setup will be different for 70cm umbrella and 120cm umbrella (with the same distance)

[tkoutdoor]

the whole discussion makes only a sense if you consider the distance flash-umbrella and diameter of the umbrella! It is obvious that the setup will be different for 70cm umbrella and 120cm umbrella (with the same distance)"Soft light is created by the size of the light source and its relationship (distance and relative size) to the subject."

Good! Glad to see that it's making sense to you. As they've been pointing out... Getting the umbrella as full as possible helps as it makes it as effective as possible at the largest size it can be.