Fresnel Lens Size?

Discussion in 'Lighting Equipment' started by james_moore|12, Feb 14, 2009.

  1. Hello everybody! I've read comments here stating that one wanting to attempt to create portraits in the classic Hollywood (or fashion) style of, say, Hurrel or Horst (and others) would need to use large fresnels of 12 inches or more - "the bigger the better"! However, I've recently seen examples of some beautifully lit work done with only 3" fresnels! That's quite a difference in size! It's understood that the power of the light must be adequate for a suitable exposure (in this case on slow to medium speed 120 film), but I'm beginning to wonder if truely such a large lens is really necessary in all situations. How much (and what) advantage is gained as the lens size is increased? Could one take the middle road with maybe the ARRI ST1-1k, (which has a 7' lens)? Could it serve as a first light for someone wanting to learn and pursue fine-art portraiture informed by the pre-war style? Thanks so much!
     
  2. A fresnel spot has a bright centre, fading out towards the edges in a columnated way that I believe to be unique; whether that can be achieved effectively with something as small as a 3" diameter lens is, I feel, very doubtful but as I've never used one of that size I'll leave that to others to answer because my own experience is limited to a couple of different makes - the bron which as an adjustable iris and a diameter of (I think) 13" and the Lencarta which has a diameter of 9" and which has a focussing arrangement and barndoors instead of an iris. Both are excellent.
    I've also used tungsten fresnels, a long time ago and they were all around the 12" - 15" range and they were excellent too, although of course with all the problems that go with tungsten lighting.
     
  3. The tungsten fresnel used by Horst/Hurrell era had old fashion single filament lamps. Those bulbs were much bigger than modern quartz halogen bulbs which are very compact, having several pre-focused filaments arranged in the same plane. In those days, bigger fresnel lens and housing were needed to acommodate the bigger bulbs. So it is quite possible that a 500W fresnel in the old days had lens as big as a modern Junior Arri compact 2KW.
    I have many fresnels from 4" to 13". The bigger the lens, the bigger the light source and hence the softer the light. But you can still use fresnel as small as 3" to re-create Hollywood style portraits. Hurrell often used 500W or even 200W fresnels...he rarely used 1K fresnel. I have the Arri 1K ST-1, it is too powerful for portrait if it is not diffused and is fully focused (spot)...in fact it can set fire to a piece of black paper at a close distance at 1-2m or give your model's face a tan. People always got this mis-conception that hot light is not that powerful at 1KW. This is not true in the case of fresnels when they are focused to a tight spot of beam.
    You don't have to use tungsten fresnels to re-create Hollywood style stuff, grid spots or standard reflector with barndoors/snoots for strobes can do the same spot lighting effects. Arri fresnels are very expensive but built like tanks.
     
  4. You've made some very good points but I can't agree with this statement. The effect is totally different
    You don't have to use tungsten fresnels to re-create Hollywood style stuff, grid spots or standard reflector with barndoors/snoots for strobes can do the same spot lighting effects.​
     
  5. personally I think this is a mostly trival, boring and dull topic. to me dublicating retro is as boring as the technical level of digital imaging and lighting.

    a continuous light is not a pulsed light source (e.g. xenon flash).

    for some nice illustrative pictures see e.g. slides 14, 15, 20, 21 in this presentation:
    http://www.physics.gatech.edu/gcuo/UltrafastOptics/OpticsI/lectures/OpticsI-23-Ultrafast%20Optics.ppt

    or if you prefer some nice short-story, e.g. wikipedia has one:
    http://en.wikipedia.org/wiki/Dispersion_(optics)#Group_and_phase_velocity

    so always funny to hear some typical photographer statement like this:
    "You don't have to use tungsten fresnels to re-create Hollywood style stuff, grid spots or standard reflector with barndoors/snoots for strobes can do the same spot lighting effects."​
    Of course vintage fresnels are not very hi-tech [0], their washed-out rather "soft-spot" luminous intensity distribution looks roughly like this: http://en.wikipedia.org/wiki/File:Laser_gaussian_profile.svg

    Based on this washed-out "soft-spot" effect some photographers constantly think this is the very same as the washed-out "soft-spot" of a xenon-flash. However sometimes it does looks quite similar.

    Since this is a complete vintage/retro thread i will try my best not to be off-topic and therefore conclude with the immortal Richard Avedon statement: "I think all art is about control - the encounter between control and the uncontrollable."


    [0] random examples what is technical standard today, cf. e.g. http://www.highspeedfilm.de/dedocool.html or http://www.etcconnect.com/product.overview.aspx?ID=20254, etc.


    ps: a related recent and IMO interesting - albeit german - discussion: http://forum.fotografr.de/topic/einsatz-von-dedolight#post-296
     
  6. Sing and Garry are right in stating you can do the same with strobe, but I think the effect will be different.
    Jesse
     
  7. Generally, the size of the Fresnel lens is a function of the physical size and power of the luminaire. The big ones are used to cover a larger area so they are used further away. The job of the Fresnel lens is to control the beam of the light in a more subtle way than a reflector alone. A fully flooded Fresnel lamp will produced even illumination across the coverage area. Spotted up,it is intense in the centre and falls away rapidly off axis. Fresnel lamps have a sharp edge to the shadows, which is often desirable. Sometimes, the edge of the beam ( the so-called fall off) can make an interesting light source.
     
  8. so always funny to hear some typical photographer statement like this:
    I also find it funny you sounds like one of the typical of photographers who think himself knows better and dismiss any lateral thinking. I don't believe in any dogmatic approach to lighting.
    I use both tungsten and flash fresnels all the time. I currently have 7 fresnel spots, I prefer fresnels over grid spots any day. The effect is indeed very different. I wrote you can use grid spot but i don't mean it is the best way. There is nothing like the real fresnel.
    You find this topics of duplicating the retro lighting is dull and boring that means you don't have any idea what's up in the current fashion photography. Help yourself by buying copies of Italian Vogue, Numero..etc.
    Just look at what Mert and Marcus did with a simple strobe reflector and cine foil to duplicate the Hollywood lighting. Ali Mahdavi uses a household light bulb as spot light....you are only limited by your imgaination.
     
  9. I'd like to thank you all for taking the time to respond to my question. I will give strong consideration to your thoughts and suggestions.
    Is it the consensus, as Sing Lo suggests (and his beautiful work seen online bears out the fact that he knows a thing or two about fresnel lighting!) that the 1000W ST-1 is too powerful for portrait work? I was under the impression that it was always preferable to have a too powerful light - that could be moved back - than a dimmer one that may not offer the DOF when needed. What lens size and wattage would then be recommended as an effective first fresnel light? And - is there any reason why it couldn't serve as my first light?
    Thanks again!
     

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