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Author Topic: fresnel attachment or pulso spot?  (Read 1508 times)

frfr

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fresnel attachment or pulso spot?
« on: July 13, 2016, 09:01:24 AM »

Hi,
I am wondering what difference there is, in terms of light quality, between a fresnel attachment (Bron Flooter, Elinchrom S35, Bowens 6000, etc) and Bron Pulso Spot (or whatever fixed fresnel adapted to Broncolor flash tube like Desisti).
Obviously there is difference in flash tube design and positionning of it. A standard pulso head will fit on fresnel attachment, the top of the flash tube is facing the fresnel glass. On a fixed fresnel head the flash tube will be lighting from the side.
From what I read online fixed fresnel will produce harder light and more contollable gradation, is that right? Any comparative experience?
Thanks,
François
« Last Edit: July 15, 2016, 12:49:32 AM by frfr »
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UlfKrentz

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Re: fresnel attachment or pulso spot?
« Reply #1 on: July 15, 2016, 01:02:47 PM »

Hi,
I am wondering what difference there is, in terms of light quality, between a fresnel attachment (Bron Flooter, Elinchrom S35, Bowens 6000, etc) and Bron Pulso Spot (or whatever fixed fresnel adapted to Broncolor flash tube like Desisti).
Obviously there is difference in flash tube design and positionning of it. A standard pulso head will fit on fresnel attachment, the top of the flash tube is facing the fresnel glass. On a fixed fresnel head the flash tube will be lighting from the side.
From what I read online fixed fresnel will produce harder light and more contollable gradation, is that right? Any comparative experience?
Thanks,
François

François,

Ideally the light source in a fresnel spot should be a point source. Unfortunately flash tubes cannot be manufactured this way, they are always a tube and come in different mechanical designs. Those used in fresnel spots are usually tubes that are wound in a small diameter to get a compact light source. They are not only emitting the light from the side there also is a mirror behind the flash tube that reflects to light back to the source, to increase the light output towards the fresnel lens. There are dedicated fresnels that work very well and unfortunately some that really perform bad. Regarding the attachments, pro is you can use your head in other fixtures when you don´t need a fresnel, con is the flash tube is usually a ring type that leads to a "donut projector", to prevent this they should at least be used with a frosted dome which makes the light source bigger, so yes they get kind of softer. Flood / spot position also has great impact on shadow definition (with flood being harder and spot being softer) as well as diameter of the fresnel lens. A lot to explore :-)

One thing they all have in common they chew A LOT of power, efficiency is really bad, so shooting moving objects can be risky due to longer flash duration. All that said, fresnels do have a very unique light fall off and a fantastic light quality that makes them hard to replace, I like them a lot. Hope that helps.

Cheers

Ulf

BAB

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Re: fresnel attachment or pulso spot?
« Reply #2 on: July 15, 2016, 08:38:55 PM »

Ulf
I have a question also.  I recently watch a video of a famous Hollywood photographer adjusting the real fresnel lights on a set and noticed the small amount of light just glancing off the subject and how fooled with the lighting for some time until he was satisfied, he then instructed the subject not to move. So with a strobe based unit how accurate or should I say easy would the strobes modeling light be to position compared to the tungsten unit?
Also is the effect normally sought after from tungsten at 3000K to create the image Possible to produce with the 5500K light?


Thanks


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UlfKrentz

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Re: fresnel attachment or pulso spot?
« Reply #3 on: July 16, 2016, 11:01:47 AM »

Ulf
I have a question also.  I recently watch a video of a famous Hollywood photographer adjusting the real fresnel lights on a set and noticed the small amount of light just glancing off the subject and how fooled with the lighting for some time until he was satisfied, he then instructed the subject not to move. So with a strobe based unit how accurate or should I say easy would the strobes modeling light be to position compared to the tungsten unit?
Also is the effect normally sought after from tungsten at 3000K to create the image Possible to produce with the 5500K light?


Thanks

Hard to say without having watched what he was doing. My guess would be he used the light quite close and feathered, in this case small changes of the position will have great impact. This is completely fine for beauty closeups but quite limiting for the model when doing other stuff. IMO Tungsten / Daylight fresnels don´t have an "effect". Probably Tungsten fresnels may have a better optical quality because of the point light source which does not apply for their flash counterparts. HMI´s have a similar point source but are very bright for the same lens diameters and not suited for close up positions. And of course if you use them in BW photography the warmer CT will render different tones from colored subjects which can be achieved by filtering camera or the daylight to achieve the same look.

Cheers,

Ulf

frfr

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Re: fresnel attachment or pulso spot?
« Reply #4 on: July 20, 2016, 08:21:04 PM »

Thanks Ulf for your explanations, that clarifies what I've read online!
Best,
François
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