Increasing Flash/Strobe Output without Increasing Power

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flyinglentris
flyinglentris Contributing Member • Posts: 655
Increasing Flash/Strobe Output without Increasing Power

Flash/Strobe output can surely be ramped up in Watt-Seconds, but there's a reason why lighthouses and airport beacons use Fresnel lenses. The Fresnel lens concentrates the light beam enabling it to extend a greater distance at greater intensity. Alternatively, Parabolic reflectors achieve similar results.

I use Buff E640s and the Buff Beauty Dish is a sort of parabolic reflector. What Buff doesn't allow is a Fresnel lens. I would suppose that many would wish it as the Fresnel lens is going to be more compact than a parabolic reflector. Right? I believe so.

Certainly, parabolic reflectors and Fresnel lenses narrow the emitted light, but they should not be confused with doing the same job that snoots and barn doors do.  And while it is true that overlapping multiple flash/strobe units on the same position can increase intensity, that is not the solution I am looking for here.

I am curious as how I might incorporate at least one Fresnel lens flash into my lighting kit. What would be best? Available mod for the E640 (I don't think it exists)? A specific vendor flash unit? Which would be a best recommend? Keep in mind that this interest is not the same as looking for a cooler LED unit that uses a Fresnel lens to increase output. I'm interested in getting the extra kick to go a greater spatial distance, perhaps, outdoors or just to achieve a brighter spot of lighting in the studio for lower f/ and faster shutter.

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Ellis Vener
Ellis Vener Forum Pro • Posts: 11,733
Re: Increasing Flash/Strobe Output without Increasing Power
2

flyinglentris wrote:

Flash/Strobe output can surely be ramped up in Watt-Seconds, but there's a reason why lighthouses and airport beacons use Fresnel lenses. The Fresnel lens concentrates the light beam enabling it to extend a greater distance at greater intensity. Alternatively, Parabolic reflectors achieve similar results.

I use Buff E640s and the Buff Beauty Dish is a sort of parabolic reflector.

You are mistaken in thinking that about the beauty dishes, but Paul C. Buff, Inc does make narrow angle reflectors

https://www.paulcbuff.com/8-5-High-Output-Reflector

https://www.paulcbuff.com/11-Long-Throw-Reflector

The company also used to make a true parabolic reflector: the Retro Laser.

What Buff doesn't allow is a Fresnel lens. I would suppose that many would wish it as the Fresnel lens is going to be more compact than a parabolic reflector. Right? I believe so.

there are various Fresnel light modules tha can be used with your Einsteins. My favorite is the K5600 24” Big Eye

http://www.k5600.com/products/bigeye/index.html

Certainly, parabolic reflectors and Fresnel lenses narrow the emitted light, but they should not be confused with doing the same job that snoots and barn doors do.

You are correct and add to that list grid spot modifiers and flags.

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jlafferty Contributing Member • Posts: 739
Re: Increasing Flash/Strobe Output without Increasing Power
2

You’re also mistaken that a fresnel “increases strobe output”. It doesn’t, and once you test it should be obvious why - you’re putting a piece of glass over the head, and thus reducing output by forcing the light to pass through a medium.

The most effective way to "increase" light output using a modifier is to use a long throw, high key silver reflector. The Glow Magnum is a decent option if you’re looking to use with a Bowen’s mount strobe. There are similar reflectors made by several lighting manufacturers.

FWIW I think of the Magnum as having the optimal output for my strobes, and all other modifiers I think of as relative to that ceiling      In other words all modifiers can be thought of decreasing optimal output to some degree, with bare bulb being toward the less/least efficient end of the spectrum; then softboxes with double diffusion, and so on.

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Gato Amarillo Veteran Member • Posts: 6,222
Re: Increasing Flash/Strobe Output without Increasing Power

A fresnel will concentrate the light, putting brighter light in a smaller area -- though strictly speaking it will not change the output, just how wide the light is spread. Depending on what you are trying to do you may find the light harsh compared to other modifiers.

There are a number of generic fresnel attachments on the market, some of which could probably be adapted to your flash -- check ebay or Amazon.

Gato

Travis Burnside Regular Member • Posts: 251
Re: Increasing Flash/Strobe Output without Increasing Power

Just for a laugh, here's my $5 option involving a page magnifier:

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flyinglentris
OP flyinglentris Contributing Member • Posts: 655
Re: Increasing Flash/Strobe Output without Increasing Power
1

jlafferty wrote:

You’re also mistaken that a fresnel “increases strobe output”. It doesn’t, and once you test it should be obvious why - you’re putting a piece of glass over the head, and thus reducing output by forcing the light to pass through a medium.

Oops!  Yes, the thread title is in error.  But the body of my initial post is not.

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elliotn Senior Member • Posts: 2,031
Re: Increasing Flash/Strobe Output without Increasing Power

jlafferty wrote:

You’re also mistaken that a fresnel “increases strobe output”. It doesn’t, and once you test it should be obvious why - you’re putting a piece of glass over the head, and thus reducing output by forcing the light to pass through a medium.

I'm puzzled. Surely a fresnel have the ability to increase the brightness on the subject by several stops (compared to a standard reflector)?

flyinglentris
OP flyinglentris Contributing Member • Posts: 655
Re: Increasing Flash/Strobe Output without Increasing Power

elliotn wrote:

jlafferty wrote:

You’re also mistaken that a fresnel “increases strobe output”. It doesn’t, and once you test it should be obvious why - you’re putting a piece of glass over the head, and thus reducing output by forcing the light to pass through a medium.

I'm puzzled. Surely a fresnel have the ability to increase the brightness on the subject by several stops (compared to a standard reflector)?

What jlafferty is pointing out is that the Fresnel has no control over the light output of the flash/strobe unit. And that is correct. What the Fresnel does is concentrate the light into a narrower beam and thereby, increases brightness. Output remains the same. It's words, but words are important as they convey meaning. My thread's title is therefore wrong and misleading. My BAD. It was not intended to be wrong. It's just the way it come out of my pointy little pinhead, erroneous. I admit.

Again, flash output is NOT increased. Brightness within a smaller area is. This also can make shadows harder as it is ultimately a smaller (albeit brighter) light at a greater distance. It would then, be advantageous to use that distance straight on so that shadows are hidden behind the subject. This would be easy if the distance forces small light to subject angles or none at all when the light is next to the camera.

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jlafferty Contributing Member • Posts: 739
Re: Increasing Flash/Strobe Output without Increasing Power

Sure. Just as the standard reflector “increases” the light output reaching the subject when compared to bare bulb, or a softbox with double diffusion. But in reality the light output isn’t changing, just the efficiency of how it’s preserved - the same number of photons are coming out of the bulb in each case.

elliotn wrote:

jlafferty wrote:

You’re also mistaken that a fresnel “increases strobe output”. It doesn’t, and once you test it should be obvious why - you’re putting a piece of glass over the head, and thus reducing output by forcing the light to pass through a medium.

I'm puzzled. Surely a fresnel have the ability to increase the brightness on the subject by several stops (compared to a standard reflector)?

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Ellis Vener
Ellis Vener Forum Pro • Posts: 11,733
Re: Increasing Flash/Strobe Output without Increasing Power
3

elliotn wrote:

jlafferty wrote:

You’re also mistaken that a fresnel “increases strobe output”. It doesn’t, and once you test it should be obvious why - you’re putting a piece of glass over the head, and thus reducing output by forcing the light to pass through a medium.

I'm puzzled. Surely a fresnel have the ability to increase the brightness on the subject by several stops (compared to a standard reflector)?

It might, depending on the design of the Fresnel and how well you focus it, in but only over a smaller area.

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jlafferty Contributing Member • Posts: 739
Re: Increasing Flash/Strobe Output without Increasing Power
2

Thanks for keeping the dialogue civil

But to reiterate, your post assumes or implies that brightness is relative to another modifier. Like… a fresnel is brighter, maybe, but brighter than what? It’s certainly not brighter than a high output reflector.

flyinglentris wrote:

elliotn wrote:

jlafferty wrote:

You’re also mistaken that a fresnel “increases strobe output”. It doesn’t, and once you test it should be obvious why - you’re putting a piece of glass over the head, and thus reducing output by forcing the light to pass through a medium.

I'm puzzled. Surely a fresnel have the ability to increase the brightness on the subject by several stops (compared to a standard reflector)?

What jlafferty is pointing out is that the Fresnel has no control over the light output of the flash/strobe unit. And that is correct. What the Fresnel does is concentrate the light into a narrower beam and thereby, increases brightness. Output remains the same. It's words, but words are important as they convey meaning. My thread's title is therefore wrong and misleading. My BAD. It was not intended to be wrong. It's just the way it come out of my pointy little pinhead, erroneous. I admit.

Again, flash output is NOT increased. Brightness within a smaller area is. This also can make shadows harder as it is ultimately a smaller (albeit brighter) light at a greater distance. It would be then, be advantageous to use that distance straight on so that shadows are hidden behind the subject. This would be easy if the distance forces small light to subject angles or none at all when the light is next to the camera.

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jlafferty Contributing Member • Posts: 739
Re: Increasing Flash/Strobe Output without Increasing Power
1

FWIW I’m mostly making a point about this because I was surprised the first time I tested a fresnel among a mix of other modifiers and found it wasn’t the most  efficient (as I’d assumed it should be).

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elliotn Senior Member • Posts: 2,031
Re: Increasing Flash/Strobe Output without Increasing Power

flyinglentris wrote:

Again, flash output is NOT increased. Brightness within a smaller area is.

Sure. And more so with a fresnel than with a long throw reflector.

flyinglentris
OP flyinglentris Contributing Member • Posts: 655
Re: Increasing Flash/Strobe Output without Increasing Power

jlafferty wrote:

FWIW I’m mostly making a point about this because I was surprised the first time I tested a fresnel among a mix of other modifiers and found it wasn’t the most efficient (as I’d assumed it should be).

That's good feedback for sure. The Fresnel can be much more expensive and if a throw modifier works better and is cheaper, lighter and easier to use, the only reasons to use a Fresnel would be if it provides some other quality of the light beam as incentive.  Might, for example, the Fresnel provide better feathering?

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flyinglentris
OP flyinglentris Contributing Member • Posts: 655
Re: Increasing Flash/Strobe Output without Increasing Power

elliotn wrote:

flyinglentris wrote:

Again, flash output is NOT increased. Brightness within a smaller area is.

Sure. And more so with a fresnel than with a long throw reflector.

Well, that's really the crux of the arguments here and what the post sought to expose.

Is the Fresnel better than a long throw, a parabolic or some other similar modifier?  Which is better and why?

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elliotn Senior Member • Posts: 2,031
Re: Increasing Flash/Strobe Output without Increasing Power

flyinglentris wrote:

elliotn wrote:

flyinglentris wrote:

Again, flash output is NOT increased. Brightness within a smaller area is.

Sure. And more so with a fresnel than with a long throw reflector.

Well, that's really the crux of the arguments here and what the post sought to expose.

Is the Fresnel better than a long throw, a parabolic or some other similar modifier? Which is better and why?

To be honest I don't know, and I don't have the appropriate gear here to test.

Jlafferty might be correct, and a long throw reflector might put more light on the subject.

But I suspect it depends on the fresnel, and how it's set up.

Whilst it's not the same thing, I have a simple torch here (US = flashlight), and when used with its lens (not a fresnel lens) it is 8 stops brighter than when used in bare bulb mode. I can't see any reflector beating that.

flyinglentris
OP flyinglentris Contributing Member • Posts: 655
Re: Increasing Flash/Strobe Output without Increasing Power

elliotn wrote:

Whilst it's not the same thing, I have a simple torch here (US = flashlight), and when used with its lens (not a fresnel lens) it is 8 stops brighter than when used in bare bulb mode. I can't see any reflector beating that.

Your "torch" is an interesting analog as it incorporates both a reflector (behind the bulb) and a lens (in front of the bulb).

Earlier, the 5600 Big Eye was mentioned and I looked at it. $2141.00 is the price tag on it, but the interesting thing is that the light source can be any, tucked away inside its canvas housing and behind the Fresnel lens. Oddly true, the Buff EInstein E640 looks like it will fit in there with a reflector attached to it, doubling the beam acuteness, perhaps, and its intensity.

Yes, your "torch" analogy is a thought tickler.

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rumple
rumple Senior Member • Posts: 1,165
Re: Increasing Flash/Strobe Output without Increasing Power

Travis Burnside wrote:

Just for a laugh, here's my $5 option involving a page magnifier:

I love it.  Have you done comparative light meter readings at, say, 10'?

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Ellis Vener
Ellis Vener Forum Pro • Posts: 11,733
Re: Increasing Flash/Strobe Output without Increasing Power
3
  1. Yflyinglentris wrote:

jlafferty wrote:

FWIW I’m mostly making a point about this because I was surprised the first time I tested a fresnel among a mix of other modifiers and found it wasn’t the most efficient (as I’d assumed it should be).

That's good feedback for sure. The Fresnel can be much more expensive and if a throw modifier works better and is cheaper, lighter and easier to use, the only reasons to use a Fresnel would be if it provides some other quality of the light beam as incentive. Might, for example, the Fresnel provide better feathering?

The main thing advantage a Fresnel spotlight has over a long throw reflector is that the Fresnel is focusable*. This is very useful.

*the exceptions to this rule are the Profoto Pro and Acute pack and head systems   and all of Profoto’s reflectors; Speedotron Blackline packs  with 202VF and 204VF heads , and late model Balcar systems with Zoom heads.  With the Profoto Pro and Acute heads the reflector moves back and forth along the head,; with the Speedotron Blackline VF heads the locking collar on the head spins forward or back on a helical track; and Balcar moved the flash tube and modeling lighting assembly back and forth.

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Sailor Blue
Sailor Blue Forum Pro • Posts: 14,741
Re: Increasing Flash/Strobe Output without Increasing Power

Any metal bowl reflector causes the light from the flash/strobe tube to spread out more and more with distance, thus the brightness decreases with distance.

A narrow beam or long through reflector simple causes the light to spread out less than the regular metal bowl reflectors. It is still necessary to illuminate the subject to the desired brightness, it is just possible to do it with the subject further from the light with the same power.

A Fresnel* is just a type of lens and it allows you to focus the light. This means you can illuminate the same area 6' or 60' from the light. You can also use a Fresnel lens to throw a spot of light on a subject.

*The Fresnel lens is named after the man who invented it so it is a proper name and should be capitalized.

You should all be very familiar with a Fresnel lens, they are used in every hot-shoe flash that has a zoom. In this case the Fresnel lens moves closer or further from the flash tube so that they focus the light from the flash tube on the area that matches the area captured by a lens on a FF DSLR or 35mm camera.  The focal length scale on the flash matches the focal length of the lens on the FF camera.

It is possible to buy a Bowens adapter for PCB lights and a low cost Bowens mount Fresnel lens. Just like with the hot-shoe flash, the Fresnel lens moves closer or further from the flash tube to allow you to control the size of the area illuminated.

Cheetah Stand - Low Profile Bowen Speed Ring Insert for Paul C. Buff Softboxes

eBay - Fotga 10x Focus Bowens Mount Lens Studio Light Condenser Mount Adjustable + 4 Colorful Filters for Flash LED Light Photo Studio Photography

eBay - Aputure Fresnel 2X Lens Mount for Aputure 120D Mark ii Aputure 300D Aputure 120D Light Storm LS C300D and Other Bowen-S Mount Lights Lens + Oneshot Cleaning Cloth

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