November 28, 2014, 05:15:49 PM

Author Topic: Speedlite zoom setting in flash modifiers and camera ISO (with test results!)  (Read 1773 times)

IMG_0001

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Hello dear fellows,

In the last few months, I've been eager to start artificial lighting more seriously and I've been looking around for general knowledge on how to light my subjects correctly. Now, I think the cosmetic part of lighting I can deal with. However, now that I've acquired a pair of light stands and flash modifiers for my speedlites (nothing fancy really, just a pair of small 33'' umbrellas and two brolly boxes, 1 is 33'' and the other 40'') I'm a bit underwhelmed by the light intensity I'm able to achieve. Admittedly, I was expecting those modifiers to be a bit big for a single speedlite. Yet, the 33'' brolly needs to be at about 1m max to have somewhat decent exposure and this seems close to my untrained eye, not much room for composition if I want to avoid seeing the box in the image.

I've mainly tried to shoot in a dark room (light colored walls so stray light is bouncing all over) at ISO 100 and apertures from 2.8 and up. The flash unit is a Sigma EF610DG Super. Supposed to output GN61m at 105mm zoom, but I've mostly tried with the head at the 24mm setting to reduce the hotspot in the brolly. Now my questions are, as the title says:

1 - What zoom setting is best to maximize brightness in a light diffuser?
2 - Is it reasonable to shoot ISO 100 for a single off-camera speedlite?

I've tried some guesswork in playing with the various settings at hand, but since I've not been systematic enough, I did not come to any valid conclusions. Researching the web on those topics also provided me with all and the opposite as an answer. Possibly this post by Neuro was the most helpful I've found, but I'm not sure how this relates to big modifiers (http://www.canonrumors.com/forum/index.php?topic=18529.msg346022#msg346022 ). Therefore, I'd be interested in hearing how people around here set-up.



« Last Edit: August 05, 2014, 04:03:10 PM by IMG_0001 »
What a mess, my camera's sensor is full of massless particules that keep on trying to behave like waves!

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privatebydesign

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #1 on: August 04, 2014, 03:57:49 PM »
1: You need to do your own test with your own gear. Set up the flash and modifier and point the camera directly at it, then take your shot, close down until you see the pattern of the flash in the mod and adjust your zoom to suit.
2: Only for narrow dof images in general. ISO 200 gives your flash, effectively, twice as much power, why not use it? With well exposed subjects iso can easily be used at 400 and 800 even in older cameras, just not for low key stuff. But I already demonstrated that for you http://www.canonrumors.com/forum/index.php?topic=20523.msg388422#msg388422

Hands on testing trumps all internet "opinions" don't forget at least half the posters on any subject don't have a clue what they are talking about.
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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #2 on: August 04, 2014, 04:15:12 PM »
+1 for testing.  However, your setup sounds like it ought to work, unless your flashes are too weak.

In the following shot you'll see a (super-messy) setup I used to do some shots last weekend.  The softbox is about 40''. It was a good 2m away from the subject and the flash (a crappy, old sunpak) was at 1/16 power.

In the first shot the window seems to be casting a lot of light, but as you'll see in the following two (one with the flash on and one with the flash off) the window only provided fill.

The settings I used were: ISO 200, f/1.4, 1/160


Skirball

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #3 on: August 04, 2014, 04:24:14 PM »
I shoot ISO 100 with speedlights in modifiers all the time.  They're plenty powerful enough.  The only time I come anywhere close not having enough power is if I'm painting a background a color and/or I'm shooting at really small apertures (f/18+).

As to the question 'why not use higher ISO', because I usually don't want any ambient 'noise' and I prefer to work with the lights on.  If I'm doing small aperture stuff then I'll bump it up a bit, but normally I'm below 1/4 power on my speedlights anyway so I figure why not minimize noise and ambient light.

OP:  Something is wrong with your setup.  At f/2.8 and ISO 100 I have had to put ND filters on my flashes because the minimum setting is sometimes still too powerful even through a modifier.

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #4 on: August 04, 2014, 04:33:55 PM »
1: You need to do your own test with your own gear. Set up the flash and modifier and point the camera directly at it, then take your shot, close down until you see the pattern of the flash in the mod and adjust your zoom to suit.
2: Only for narrow dof images in general. ISO 200 gives your flash, effectively, twice as much power, why not use it? With well exposed subjects iso can easily be used at 400 and 800 even in older cameras, just not for low key stuff. But I already demonstrated that for you http://www.canonrumors.com/forum/index.php?topic=20523.msg388422#msg388422

Hands on testing trumps all internet "opinions" don't forget at least half the posters on any subject don't have a clue what they are talking about.

Thanks Private,

I've taken a few pictures of the modifier, it provided a good insight on the light distribution, but I felt it was hard to judge on the intensity. Probably, by proceeding rigorously I will get to the point I want. I think I'll try to see if I can convert to B&W and posterize on a few levels to compare the contours and intensity of the light.

I was reluctant to use higher ISOs because, as you said, 1 ISO stop is like giving your flash twice the power, but it also effectively gives ambient light twice the power. Therefore, changing the ISO might also change the feeling of the image drastically. I'm not all that fussy about noise though, I can work around it.

I do intend to test for myself as there is no replacement for experience. Nonetheless, I felt that I could make use of others knowledge to guide those experiments. In my original post, I almost said that I was turning to CR to get some more info pointing in all directions, but I refrained thinking that may be some might not be amused and keep their answer for themselves. Honestly, I feel I've been around CR long enough to weight most answers, as opposed to info gathered from the internet in general.
What a mess, my camera's sensor is full of massless particules that keep on trying to behave like waves!

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #5 on: August 04, 2014, 04:40:42 PM »
+1 for testing.  However, your setup sounds like it ought to work, unless your flashes are too weak.

In the following shot you'll see a (super-messy) setup I used to do some shots last weekend.  The softbox is about 40''. It was a good 2m away from the subject and the flash (a crappy, old sunpak) was at 1/16 power.

In the first shot the window seems to be casting a lot of light, but as you'll see in the following two (one with the flash on and one with the flash off) the window only provided fill.

The settings I used were: ISO 200, f/1.4, 1/160

Thanks,

It is amazing how light can really shape the subject being photographed. You would never guess that the the subject in the first and last image is the same ;)
What a mess, my camera's sensor is full of massless particules that keep on trying to behave like waves!

IMG_0001

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #6 on: August 04, 2014, 04:45:28 PM »
I shoot ISO 100 with speedlights in modifiers all the time.  They're plenty powerful enough.  The only time I come anywhere close not having enough power is if I'm painting a background a color and/or I'm shooting at really small apertures (f/18+).

As to the question 'why not use higher ISO', because I usually don't want any ambient 'noise' and I prefer to work with the lights on.  If I'm doing small aperture stuff then I'll bump it up a bit, but normally I'm below 1/4 power on my speedlights anyway so I figure why not minimize noise and ambient light.

OP:  Something is wrong with your setup.  At f/2.8 and ISO 100 I have had to put ND filters on my flashes because the minimum setting is sometimes still too powerful even through a modifier.

Thanks,

This was the kind of info that I was looking for to benchmark my tests.

I think I need to check that my flash is behaving adequately. I'll have a go tonight with a fresh set of batteries and a static model and light setup. I did felt like ISO 100, F2.8 and the light at 1m and full power should just be plenty powerful.
What a mess, my camera's sensor is full of massless particules that keep on trying to behave like waves!

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #6 on: August 04, 2014, 04:45:28 PM »

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #7 on: August 04, 2014, 05:18:39 PM »
1 - What zoom setting is best to maximize brightness in a light diffuser?

StoFen:


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Click through for test descriptions, and there are images in the set for the Honl snoots and grids, too.
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IMG_0001

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #8 on: August 04, 2014, 05:39:54 PM »
1 - What zoom setting is best to maximize brightness in a light diffuser?

StoFen:


Honl Heavy Frost:


Click through for test descriptions, and there are images in the set for the Honl snoots and grids, too.

Thanks Neuro,

I had seen this thread already, but I was not sure on how to extrapolate those results to larger diffusers so I'll take the opportunity to ask you to help me think this out.

Basically, it looks to me like under 35mm, or even 50mm, the efficiency of the reflector is very low and there is a lot of power loss. As a result, for small diffusers that will get completely lit anyways, just going up to 50mm is likely to improve the general intensity of the output.

However, if the diffuser is bigger, it seems to me that concentrating the light is likely to bias the light towards the section directly lit by the flash while the rest of the diffuser will only be comparatively faintly lit. This would then translate to a uneven lighting of the subject if I'm correct.

As other have said, I guess I'll need to try this for my particular setup.
 
What a mess, my camera's sensor is full of massless particules that keep on trying to behave like waves!

Skirball

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #9 on: August 04, 2014, 06:02:20 PM »
The whole point of a diffuser is soften the light; use the widest setting you can (don't use the pulldown wide angle option) that doesn't shoot outside the umbrella.  With the brollys it doesn't matter.  And I don't know if your previous question was answered: a single speedlight can do just fine in a 43" umbrella.

But something is wrong, ISO 100, f/2.6 and flash at full power should be nuking your subject, even at a meter.  What are you using to trigger?  You don't happen to have any filters on your lens do you?  Do you just have the one flash?  I suggest trying another.

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #10 on: August 04, 2014, 10:35:55 PM »
The whole point of a diffuser is soften the light; use the widest setting you can (don't use the pulldown wide angle option) that doesn't shoot outside the umbrella.  With the brollys it doesn't matter.  And I don't know if your previous question was answered: a single speedlight can do just fine in a 43" umbrella.

But something is wrong, ISO 100, f/2.6 and flash at full power should be nuking your subject, even at a meter.  What are you using to trigger?  You don't happen to have any filters on your lens do you?  Do you just have the one flash?  I suggest trying another.

I don't have a filter on the lens and the flash is my only one with good manual power. My other flashes are either an old small manual  flash with only 3 power settings or another with GN55m, but that only do ETTL or full power so it could only be used to gain a stop if the Sigma is not powerful enough for some situation.  The triggering is via the camera flash, but as a commander only. This way I can set the off camera flash power from my camera but the small flash does not contribute to the exposure.
What a mess, my camera's sensor is full of massless particules that keep on trying to behave like waves!

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #11 on: August 04, 2014, 11:08:21 PM »
So I did a series of more systematic test on a new set of batteries. First conclusion, the new batteries solved the power issue. As I don't use my flashes that often, I did not realize how slow the recycling was until I put the new battery set. My bad there...

Second conclusion, the walls of the room I inteded to use for occasional shoots are too light and the flash light just bounces everywhere. I knew it would, I just did not expect it would be that bad. The room is about 3m x 4m (9'x12') so its also a bit cramped.

Finally, the wide angle coverage does even out the light significantly and the general output loss is not that bad I think. However, up to 50mm, it does not look too bad. I'll try to post the resulting images and a more thorough analysis tomorrow evening.

Thanks everyone.
What a mess, my camera's sensor is full of massless particules that keep on trying to behave like waves!

privatebydesign

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #12 on: August 04, 2014, 11:29:10 PM »
So I did a series of more systematic test on a new set of batteries. First conclusion, the new batteries solved the power issue. As I don't use my flashes that often, I did not realize how slow the recycling was until I put the new battery set. My bad there...

Second conclusion, the walls of the room I inteded to use for occasional shoots are too light and the flash light just bounces everywhere. I knew it would, I just did not expect it would be that bad. The room is about 3m x 4m (9'x12') so its also a bit cramped.

Finally, the wide angle coverage does even out the light significantly and the general output loss is not that bad I think. However, up to 50mm, it does not look too bad. I'll try to post the resulting images and a more thorough analysis tomorrow evening.

Thanks everyone.

Only way to beat that is to use lower power and put the lights very close and baffle them, either grids, flags, snoots etc.
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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #12 on: August 04, 2014, 11:29:10 PM »

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #13 on: August 05, 2014, 07:37:48 AM »
So I did a series of more systematic test on a new set of batteries. First conclusion, the new batteries solved the power issue. As I don't use my flashes that often, I did not realize how slow the recycling was until I put the new battery set. My bad there...

Second conclusion, the walls of the room I inteded to use for occasional shoots are too light and the flash light just bounces everywhere. I knew it would, I just did not expect it would be that bad. The room is about 3m x 4m (9'x12') so its also a bit cramped.

Finally, the wide angle coverage does even out the light significantly and the general output loss is not that bad I think. However, up to 50mm, it does not look too bad. I'll try to post the resulting images and a more thorough analysis tomorrow evening.

Thanks everyone.

Only way to beat that is to use lower power and put the lights very close and baffle them, either grids, flags, snoots etc.

I was planning on using the room we're setting up for our upcoming 2nd son as an occasional studio, but after trying it out, I think I will stick to the larger living room. It is about 4m x 6m and thinking of it, it also has a NorthX North East facing patio door that could be used as key sometimes. Itappeared to be more of a hassle to setup, but if I can reduce the baffling/flagging work and have more room for composing, it is probably worth it.
What a mess, my camera's sensor is full of massless particules that keep on trying to behave like waves!

Skirball

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #14 on: August 05, 2014, 11:16:26 AM »
Only way to beat that is to use lower power and put the lights very close

Exactly, as they were intended.   If your light source is a foot or two from your subject then the light that goes across the room and bounces back is going to be relatively insignificant.  For the average guy working out of his livingroom it's not going to be an issue.

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Re: Speedlite zoom setting in flash modifiers and camera ISO
« Reply #14 on: August 05, 2014, 11:16:26 AM »