Sing Lo

I have just bought an old 575W HMI fresnel with magnet ballast. It is working fine but the double ended HMI lamp have a bit of black desposit on the glass and obvious burnt ends of the electrodes. The colour temperature has shifted below 5200K. I read somewhere that you shall replace the lamp after half of its life span becuase of colour temperature shift and the increased risk of explosion with lamp reaching the end of its life. Now I don't know how many hours the lamp was used previously, I wonder what other signs I shall look for before I replace the lamp? When you change the double-ended HMI lamp, is it necessary to position the lamp so that the electrodes are in the correct orientation and why? I ask this becuase there is a warning diagram on the front of the fresnel and the lamp was already not positioned correctly by the previous owner( a film company). If the focusing mechanism of the lamp become stiff, do i need to put a little lubricant oil to the mechanical moving parts or i shall leave them alone? Will the high temperature inside the lamp vapourise the oil and form desposit on the glass of the lamp, affecting the life of the lamp????? Final question, can you connect HMI head with SE lamp designed for electronic ballast to a magnet ballast? I have seen DE lamp heads are being mixed with magnet ballasts made by different makers. thanks in advance

here is a still using undiffused 14" fresnel as key and a small Chimera softbox as fill.

Thanks JD. I actually called up Desisti UK and they told me the same thing as well, and only normal household fuse is needed for 1kW fresnel. The maximum household current is 13amps, so a 2kW fresnel would be still no problem for household electricity. The price of lights in the USA is just so much cheaper than here.

Hi, I am thinking of importing the Mole Richardson 1KW Classic or Desisti Leonardo 1k from B&H for use here in the U.K household electricity. The cables of the US fixtures are different from the european ones. . If I fit a proper 220V CP40 lamp and change the "Edison plug" (I have no clue what it looks like) to UK household plug, will it be OK??? As far as I know, the US fresnel cable is also earthed and much thicker than the european counterpart becuase of half the voltage and double the current. The cable has different colour codes for live, nuetral and earth as well. For a 1kW fixture, what Amps fuse should I use for the UK plug? Here they stock mostly 1k fresnels made by Arri in the UK, but I prefer Mole or Desisti becuase of the bigger fresnel lens diameter,i.e. sofer light in spot position which is very important for my still photography application.

Just a suggestion from still photography point of view( I am no expert on cinematography): The window light is diffused and directional. Fresnel is directional but more like undiffused, direct sun beam. How about a softbox as key at 10-11 o'clock. (Watch the nose shadow position in the painting) Maybe you can mount your fresnel on a Chimera hotlight softbox with a speedring? It doesn't have to be big softbox, a medium source close to the subject face has the same effect as a big source further away. Use white reflector mounted low at 4 o'clock to open up the shadow area. You can adjust the reflector to the head distance (or size) to vary the fill intensity, and you judge the degree of fill visually. Alternatively you can use a small fresnel as a very weak fill, placing it close to the camera axis below the head level.

Hi, I am looking for a black background fabric known as duvateen in the UK. I believe it is the same material they use for my Arri flag..kinda fire-resistant, matt, a little bit fluffy and soft. I need highly light absorbent black background to shoot in a very small still photography studio. In a tight space, I am driven to become a spill control freak using eggcrates, softbox barndoors, flags to reduce spill onto backgrounds. At the moment, I use Colorama black paper which is not ideal. I heard black velvet is even more light absorbent than duvateen but expensive, very hard to get hold of in a large roll (besides more fabric supplies here only stock crushed black velvet which has shiny texture). Any direction to where I can buy duvateen in the Uk will be appreciated. I have checked out several still and video grip and lighting suppliers in London, none of them stock it unfortunately.

It looks like the key is a large Octa softbox at 2 o'clock. There are weak kicker lights on both light and right---in my opinion the kickers are not strong enough for the guy and girl---overall a bit too flat. The spectator highlights on the sides can be made much stronger on African skins. In still photography, the kickers can be strip softboxes or strobe heads fitted with reflector + grids. The background can be just lit by a background reflector on strobe head behind the talents mounted low pointing up to creat fall-off. In still photography terms, there is nothing really special or exciting about the lighting set-up of this photo.

What is a bunch of fairy lights??? Rope lights coiled up like a pancake???

Incidentally, I saw this was done in an outdoor location film set directed by Woody Allen today. They filmed Evan Mcgregor right under Brighton pier using two giant HMI fresnels (possibly 600mm 18K) with diffusion screens on barndoors mixing with daylight. They used hugh white reflector to bounce the light from the fresnels as fill. It was very interesting to watch the lighting set-ups in big budget film...I kept a sketch of the lighting diagram...

The reason for feathering is to create light fall-off, shadows and hence drama. This technique is useful in low-key lighting to bring out form, texture or mood. I think feathering makes the light harder not softer. If you light subject with the edge of the beam, the effective size of the light source is smaller looking from the subject's view point. Usually the feather beams of light from a fresnel or softbox covered with eggcrates have less wrap-around effect, sharper edge transfer ( rapid transition from highlights to shadows) than a softbox by itself.

Well, the explaination is: In conventional fresnel, the lamp is very close the the lens at full flood position. If you look at the fresnel lens with a sun glasses, you can almost see the bright shape of the lamp itself at full flood. So the apparent size of the light source is almost same as the lamp. Now the hardness of the light and the sharpness of the shadows depend on the size of the light source. At flood position, the light is harder and dimmer.If you set the fresnel to spot, you can see the whole lens is bright so the size of the light source is the same as the diameter of the lens. At spot position, the light is softer and brighter. People think the shadows of fresnel set to full spot is sharper with naked eyes, because the contrast between the highlight and shadows is larger when the beam is brighter. With iris focus fresnel, the distance between lamp and lens is fixed. The spread of the beam is controlled by variable size iris that looks the same the as the aperture blades in a camera lens. At spot position, the iris is closed down to smallest hole, so only the inner circles of the fresnel lens is being used and the apparent size of the light source is small and hence hard light...etc and vice versa. ...at least this is my theory anyway.

Yeah, I own two type of fresnels and they behaves very differently; my 14" fresnel has conventional focusing by moving the lamp backward or forward relative to the lens like what you use in cinematography. The 8" fresnel has variable iris focusing system which I have never seen being used in motion picture. In convetional focusing fresnel, the light quality is soft and brighter in spot position with soft shadows; the light is hard and dimmer in flood position with hard shadows. This is to do with the change in apparent size of the light sources when you move the lamp closer or far away from the lens. Now the interesting thing is that the irs focusing fresnel behaves the exactly the opposite; the light is hard and dimmer at the spot position with sharp shadows, the light is soft at full flood!!

I first read about the description of "defocused spot" in "Hollywood Portraits" by Roger Hicks and Christopher Nisperos; can be bought from Amazon: http://www.amazon.com/gp/product/081744020...ce&n=283155 Here a paragraph from the book: "Feathering: Very often, though far from invariably, movie stills were not made with spotlights focused tightly and shining directly onto the subject. Rather, the spot was defocused somewhat, and the edge of the light beam was used, a technique known as feathering." After thinking about it, I believe " defocusing a spot" means setting it to flood position in Roger Hicks' own terminology, which is misleading and incorrect in my opinion. A fresnel is not out of focus even in full flood position for sure! I often use feathering technique with softboxes and beauty dishes to create controlled fall-off and dramatic transitions from highlights to shadows on people's face or to accentuate texture of the clothes. I am yet to try it with fresnel. But I would imagine a double open scrim can do the same job, even though the shadow-highlight edge transfer is not neccessary the same effect as feathering.

Hi, This is my first post. I am a still photographer and lurker here, trying to learn and seek inspirations from cinematographers. I am a big fan of hard lights. I have been researching and practising the lighting techniques of 1930-40 Hollywood Silver Screen style still portraits. I have a 14" and 8" fresnel spot attachments for still photography strobes. I hardly found any information on fresnel usage techniques in still photography forums; most folks there only know how to use soft lights. I have read a literature somewhere that a fresnel spot can be made out of focus or defocused and the feathered beam can be used to light the subject. I am very familar with the technique of feathering but I can't get round in my head how can you make a fresnel out of focus????? in other words: What is the exact definition of a fresnel being in focus??? :unsure: You cannot say a fresnel is in focus or out of focus by looking at the shadow sharpness, because the shadow definition depends on several factors: the shadow sharpness is continuously changing from soft to hard when it is moved from spot to flood positions, and also it is affected by the subject-to-light distance and the size of the fresnel lens. Unlike a hard-edged spot attachment for gobo projection, a fresnel has a gradual soft beam edge, so the concept of a out-of-focus fresnel is very puzzling for me. thanks.