Sing Lo

For weak eye light, I would try to roll a few meters of rope light into a coil like a pancake and tape it on a white/ silver foam board reflector disc. You can make a poor man's Kamio Flo by making a donut shape reflector with a coil of rope light. OK the only downside is that it is tungsten, and weak in output. This is my idea. Cheap and cheerful :P

I tried that with Dedo DP Eye set with diffusion glasses on the front of Dedo zoom projection attachment. I cut an "eye mask" shape on cine foil and insert it on the Gobo holder, then adjust the level of diffusion to soften the edge of the glow area.

Anyone has used CD or CST fresnel for cinematography? Desisti and Arri both make CDM lights (150W and 250W respectively). It is designed for architecture applications but I wonder why it is not widely used in film/video? IN CD, they have built-in high frequency ballast, available in 3200K, 4200K, 10,000 hours life, cold restrike, CR>90. In CST, 250W = 1000W tungsten output, a Desisti tech rep told me that they can take MSR daylight lamp giving 5600 deg!!!! It costs substantially less than a HMI kit. It sounds very attractive for me.

You are right, probably Hamburg frost (the lightest frost) has the same level of diffusion as a frost fresnel glass; so it is not much point. You just get a hard edge circle of light if a fresnel is used without the lens. I am thinking of cutting a donut shape hamburg frost to be clipped in front of the fresnel with no lens so that only the edge of the beam is diffused; the rest of the beam is undiffused...I don't know if it might work. It is quite difficult to dismount the lens door of Arri studio 2K so I will try the Mole.

thanks for the advice. I will try to remove the lens of my Mole Michardson fresnel which seems quite easy to do. The Arri studio 2k lens seems a bit complicated to dismount and I don't trust myself that I can put it back correctly. Maybe I will try to put Hamburg frost on the fresnel without lens to soften the hard edge of the beam.

I am looking for a broad hard light source with soft edge beam that can give a very well-defined shadow of a character on a wall; like scenes in the old film Noir mysterious lighting or BW Dracula movies. I own several 650w, 1kw, 2kw Arri Studio fresnels and 150W Dedos. Only the Dedo can give sharpest shadow at full flood but it is not powerful enough. My bigger fresnels are too soft for such application at full flood and there is no enough room to move it far back to give sharpest shadow. I have tried the trick of light the subject with the edge of a fresnel beam to give better shadow definition but it is much dimmer. I have no experience with par or open face, so I don't know if they can create sharper shadows than focusing spots. Any suggestion of tungsten lights would be appreciated (small HMI fresnel can give very sharp shadow but it is out of my budget). thanks

40 degrees crates are better buy. The downside of very deep eggcrates (20 degrees) are their steep price, large light loss and the dramatic change in light quality: the light is very directional and it loses the wrap-around quality of softbox. So you get deep shadows on talent's face unless appropriate fill is applied.

Inverse square law doesn't apply to eggcrates...it follows some other "non-linear" law. From my experience with Chimera fabric grids, 40 degrees eggcrates has -2 stop loss, 20 degree eggcrates: -4 stops, depending on the dimensions and type of your softbox. There is a free eggcrate calculator to work out the light loss you need in Lighttool web site. The good thing about fabric eggcrates are that they can be folded up and light weight....ideal for location. It is very quick to set up.

With soft light, I often use very fine Lighttool eggcrates (20 degrees) on Chimera softboxes to shape and manipulate the light; sometimes I add Chimera softbox barndoors as well if i really go for ultra tight control. Eggcrates beats scrims and flags in term of space and set-up time for soft light. But I agree scrims are useful. I have experimented with Noir style as well using hard lights. I tried to use a "finger" (long and thin scrim) mounted on an articulated ball-jointed arm to create shadow on forehead. But I ended up spending all the time fiddling the position of articulate arm and small movement of the talent threw the shadow out of place.....people don't have the patience to wait around for your creative exercise. With hard light, I have more success with barndoors and gobos than scrims. That's my limited experience anyway.

thanks Michael for the suggestions, This technique of overlapping scrims to create a gradual gradient is interesting. I am also interested in localised manipulation of light on peoples faces; e.g. "light surgery" techniques of using scrims to reduce the brightness of prominent fore head/ bald head or to make a round face to look narrow; I have experimented and practised all these techniques with a dummy head. But it always time-consuming and difficult to set up the grips without the scrims getting in the way of the camera view. It is always the time constrain which stops me trying out these techniques in practical shoot. ...the light surgery techniques require very precise placement of the scrims and lots of grip heads and Hollywood arms..

Can anyone suggest real world examples of the creative applications of open-ended black double scrims for both hard and soft light? I am particularly interested in the creative use of scrims in producing certain lighting effect in a scene rather than the obvious applications like compensating the fall-off of brightness when the light is pointing at an angle to a background, or the the actor is walking towards the key. Sometime ago I bought some Matthews open-ended double black fabric scrims and a few single, double open-ended wire scrims for Arri and Mole fresnel spots. But I have never used them in actual shoots because I find barndoors are quicker and easier way to control hard light. Any thought on this would be appreciated.

I have Matthews, Arri and Avenger grips. I prefer Matthews flags, scrims and clamps. Avenger stuff are good too... I never have any problem with their heavy duty C-stand and grip heads. If I am not wrong, Arri grips are actually made by Avenger part of the Manfrotto company italy. I notice Avenger and Arri grips are the same..they just stick Arri labels on the grips.

If you set the HMI at full flood, you get very sharp shadows anyway. I think it is unwise and risky to open the HMI fresnel lens while it is burning ; besides I think most HMI fresnel has a safety micro switch on the lens door to disconnect the ballast/ignitor and stop people doing that. It easy to get sharp pattern but it is hard to schieve the realism and subtle effects. I have tried all type of tree projection gobos for Dedo, and projection of large Chimera window pattern and Mathrews metal cocularsis cello with a large fresnel. In all cases, I found the tree patterns unsatisfactory: too fake unless I de-focus the pattern completely. I have tried to paint tree pattern on a large sheet of thick accetate. In the end, I think a dead tree branch is most the realsitic but inconvenient method in practice.

A 575W HMI fresnel would take less power than a 650W tungsten and would be about 2-3 times as bright, but cost several times the price. If you stick a full CTB gel to a 1K Arri, you will get daylight. You can still get usable power from the Arri 1kW despite the loss of 2 stops from the CTB. That's poorman's alterenative to HMI.

HI DAVE, That makes sense, I forgot that the scrim close to the lens won't create shadows anyway. :lol: I have been experimentating stacking two large mesh cookie patterns (homemade) placed two meters in front of a fresnel, it creates some very funky Moire pattern.

They are very rugged little lights. Once I dropped my dedo 150W with built in transformer 6 foot to the ground while the lamp was burning. To my surprise, the bulb was all running good after the strong impact, except the screw at the back door was bent. I prefer DLHM4-300 over DLH4 becuase the bulit-in transformer is completely cool to touch and avoid burning my fingers when I adjust the light angle. The tiny back plastic screw of DLH4 is the only cool component to touch...If one thing Dedo light can be improved, I would say they should include the option of attaching a small handle like the Lowell 650 fresnel. I highly recommend the Dedo projection attachment as part of your kit; i love it very much.

A dimmer actually lengthens the bulb life if it sets at about 70% dimming because the filament operates at lower temperature. It only shortens the bulb life if you turns the dimmer very quickly; the filament gets thermal shock if the current suddenly changes rapidly. I wonder if anyone ever stacks both a double wire scrim and a single scrim in front of a fresnel lens?? I wonder if it will create Moire pattern (optical interference between the two scrims meshes) ?

It should be all right with a heavy duty, true magnetic 110V to 220V step-up transformer like these (never use cheap solid state travel voltage convertor): http://www.110220volts.com/power_converter...CFQJuFQodXk5JMQ I got a 800W one which weights 6kg--quite heavy for travel. I would go for a minimum 800W rated transformer which is more than enough for 3 Dedos. The 50Hz and 60Hz difference should not cause flickering with tungsten light. Even the high frequency ballast of Kino Flo can run on both 60Hz and 50Hz given the right voltage conversions. (unlike HMI electronic ballast which may cause problem)

The answer is no if the light is a 1K fresnel. You can only put a 750W or 500W (only in the USA) on a 1K fresnel . 650W fresnel has different lamp base as 1K. On the other hand, you can put a 300W on a 650W.

Do you know where can I buy semi-glass mirror? I assume this effect is different from the Kirk light right? From your information, you can make the pupil glow like a cat eyes in the dark?

My 150W Dedolight tungsten lamp shielding has slightly different design. The black shield is built inside the globe holder on the aspheric lens side, instead of coming with the globe. So I would say your lamp black shield should face the lens.

Cheers kenny, this 2 minutes safe window is all new to me. Here is a quote from "Set Lighting Technician's Handbook" by Harry Cox which is not quite the same advice :unsure: : "The electronics of most newer ballasts take this into account and have better hot restrike performance; often, however, an older magnetic ballast cannot produce sufficient voltage and you have to wait the lamp has cooled (2 or 3 minutes) before you can restrike." I will wait 15 minutes for the cooling of the globe; to be safe than sorry.

thanks Walter, I have been reading your tutorials on the use of cucaloris to produce dappled background.

Thank you very much for the answers. I would avoid hot re-striking completely. I heard that the permanent clouding of the globe is something to do with crystallisation of the quartz glass after many hours of use. One clouding is formed, the structural property of the glass may be weaken and the globe will be proned to explosion during strike. I also read that frequent turning the lamp on and off with cold strikes would also reduce the life of the globe significantly. I guess the electrodes burn faster during ignition phase when there is large current passing through them before the choke action of the ballast kicks in.

Is it true that the hot restrike capability of a HMI light fixture depends entirely on the bulb itself? Or it depends on both the bulb and the ignitor ( or the ballast)? My Osram 575W HMI bulb has definitely re-strike capability according to the manufacturer's data sheet but I am not sure if my lamp head ignitor step-up transformer has the capability to rise the voltage automatically from 5kV to 25-30KV during hot restrike. It runs on a fairly modern magnetic ballast that I can't any information about its capability and specifications. I dare not to try a hot re-strike in case something unpredictable may happen..or I am just paranoid. :unsure: ..Handling EHT device always makes me nervous although the ballast has ground test button. Hope someone here can advice. thanks.