Increasing Flash/Strobe Output without Increasing Power

Started 4 months ago | Discussions thread
Ellis Vener
Ellis Vener Forum Pro • Posts: 11,785
Re: Increasing Flash/Strobe Output without Increasing Power

Sailor Blue wrote:

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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Living and loving it in Pattaya, Thailand. Canon 5DS R & 7D - See the gear list for the rest.

I have one of those low cost Fresnel spotlight s and while you can use them for a flash like an Einstein, they are actually intended for use with Bowens-S Mount LED lights where the LED is a small flat element flat against the backplate of the lighting instrument.

In other words, yes it will work but it is not optimal because the flash tube is well in front of the focus point of the lens.

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Ellis Vener
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