LED FRESNELS? & FRESNEL vs OPEN FACE

ericparnell said:

But in it's description it says "good for use when shaping light is not necessary". Anybody know what's up with that? I would think with the fresnel lens you'd be able to shape it. It'd be great if it was a harder light source at that price! But mainly I just don't want a washed out look, need SOME shadows.

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I own a few of those Altmans. When they talk about "shaping" the light, they're referring to theatre applications. On stage, fresnel spots throw a softer beam, as opposed to an ellipsoidal spot which you can focus to a razor sharp beam and shutter off at the instrument.

For film, you generally use flags and such to shape light, so an undiffused fresnel is considered a hard light.

I'll be interested in the answers in this thread as well....I'm going to be getting some "real" lighting, down the road, and I am trying to re-educate myself as to lighting matters (as I learned today with masking and editing)

ericparnell said:

So my second question is, is a fresnel really necessary? Or could I just barn door and black wrap open face lights to focus them enough?

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Guess I could've addressed this one, too.

Depends on what you want. A fresnel will give you a (relatively) tight spot, if that's what you need. A flood will always be a flood. Doors and/or wrap will prevent side spill, but cannot focus the light the way a lens can. If you don't need a tight focus instrument for a particular reason then a flood should work fine.

Some open-face instruments - like Lowel's Omni - have limited focusing capability using a parabolic reflector.

Thanks 2001, so say I have a shoot that calls for high contrast I'm just not going to get those stark shadows without a fresnel lens?

And I'd love to hear more about your experience with the Altman's. Can you generate enough light with 4 or 5 of those to light a whole scene? Or do you typically use them in combination with other higher power LED lights? What kind of throw are you getting? Thanks for your feedback.

ericparnell said:

say I have a shoot that calls for high contrast I'm just not going to get those stark shadows without a fresnel lens?

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That is not correct. The presence or absence of a lens has nothing to do with the hardness or softness of a light source.

It's basic physics. Light waves radiate outward from an incandescent filament in straight lines. This creates hard shadows on your subject and background.

In an open-faced instrument, they radiate out in all directions equally, except as redirected by a reflector. Adding a lens, such as a fresnel, just focuses those same waves so that most of the light is more or less traveling in a single direction. But they are still traveling in a straight line, so you still get hard shadows.

To prevent hard shadows, you must break up the light waves so that they no longer all travel in the same direction. You can either do this by bouncing the light off of something, or by placing a diffusion material in the path of the light.

ericparnell said:

And I'd love to hear more about your experience with the Altman's. Can you generate enough light with 4 or 5 of those to light a whole scene? Or do you typically use them in combination with other higher power LED lights? What kind of throw are you getting?

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First, in case you don't realize it, those Altman fresnels are not LED instruments. They use a quartz lamp (typically 500w for the 6", though your link says they're rated up to 750w). LED lights are a completely different animal and you'll pay a LOT more for them.

Yes, you can light a scene with 4 or 5 Altman fresnels. You can light a scene with 4 or 5 of pretty much any type of instrument, if you know what you're doing. All the Altman cans are is a basic light source. They happen to have a lens, which allows them to be highly directional, if that is what is called for.

You say you want a high-contrast scene, but I hope you understand what an extreme look an undiffused hard light source creates on camera. It's very unnatural, like you were shooting on the surface of the moon. Unless you're going for that kind of extreme, I highly recommend at least some diffusion. A good DP can create a high-contrast look without making it look like some kind of bizarre moonscape.

My Altman and Mole fresnels are part of a lighting package that includes a range of different types and wattage instruments. Mine are 100% incandescent - no LEDs or flourescent. Not because there's anything wrong with LED or flourescent - they're great - but because incandescent fixtures are much cheaper to purchase. If I need a tight focus instrument, I use a fresnel or other type of spotlight. If I need a broad, even spill I use an open-face instrument.

Ya I didn't realize those weren't LED's. I did a search for LED fresnels and those came up, thought I found some new light. Guess I got a little excited and didn't read the fine print.

Ya in the past I typically always was diffusing with either a softbox or gels, but in purchasing lights I was just wondering if that extreme high contrast look was needed, would I still be able to do it with those lights.

But your input on the fresnel aspect of it all was great. Basic physics always bring a little clarity, thanks!

FWIW:

Lightpanels seems to have just introduced some fresnel models. No affiliation here, but I am fascinated. I like the idea but have yet to actually use them, aside from the mini/micro on camera lights. I do like those for certain situations.

http://www.litepanels.com/lp/products/sola_led_fresnel.html

Those look awesome...I notice they don't tell you the price, which always scares me.

2001 Productions said:

Those look awesome...I notice they don't tell you the price, which always scares me.

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Ya. Lightpanels are notoriously expensive.

They want way too much for the little Micro and Mini line. I think the mini pro is ~$450+. There are knock-offs on ebay, but they don't have a clean color balance like the LP models. Nor are they as sturdy or bright - but they are usable and around 50-100 or so.

Will be interesting to see where the idea of an LED fresnel goes. If some other, larger, manufacturers start heading that direction prices might start dropping. At the moment you can get a decent amount of gear for the price of a single 1x1 lightpanel.

New LED Fresnel 200W

I found this topic today and as we have a new LED Studiofresnel light I want to give you short technical informations:




The SquareLED Authentic 200 is the first LED studio fresnel


spotlight with similar power like a 800 W halogen luminaire.


It is available in two different color temperatures: First


with 3200 k similar to halogen spotlights and second with


5600 k similar to daylight spotlights.

Technical Data:

»» 200W LED module - available with 3200K and 5600K

»» Power like a 800 W Halogen luminaire

»» Beam angle: 10° - 60°

»» Neutrik Connectors

»» Temperature regulated

»» Square dimming curve

»» 38,2 dbA

»» Incl. 4-leaf barndoor

»» DMX 512


If anybody is interested in more details, just let me know. Have a nice day!