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Extreme Macro back lighting techniques


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#1 Dom Lake

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Posted 04 April 2017 - 08:42 AM

Hi all, here goes my first post on this site!

 

I've taken on a last minute brand promo for a drinks mixer shooting on Friday.

Director wants intricate/intimate extreme close macro shots, looking down the neck of the bottle as its poured etc.

 

Now I have devised a lighting setup, but just wanted to get see if I could get any other opinions on this one.

 

I was basically planning to fill the scene with a soft over the top light, possibly a sky panel.

Then bring in a cold side light, maybe a 1k hmi gelled, then a strong back light to get strong edges and contrast on the bottle and glass.

 

He's after everything at a higher frame rate (nothing extreme, only 150fps) so I'm aware I'm going to need a lot of light for this one. 

 

Any thoughts would be much appreciated

 

Cheers!

 

 

 


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#2 Michael Rodin

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Posted 04 April 2017 - 10:06 AM

Are you shooting on a studio stage? I'd get tungsten lights - much cheaper and better color.


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#3 Dom Lake

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Posted 04 April 2017 - 10:16 AM

Are you shooting on a studio stage? I'd get tungsten lights - much cheaper and better color.

The location is a Bar in London, not ideal for this type of shoot I know.

 

What makes you say get tungsten lights?


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#4 Michael Rodin

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Posted 04 April 2017 - 10:30 AM

For a price of couple larger Skypanels and small HMIs you can get (at least in Russia where I mostly work) a sizeable tugsten package with a 10Ks, 5Ks, smaller fresnels and some 50-100Kw of soft light. It needs heavier distro though - not as much a problem on a stage where you have multiple high-current connection points. But on a day location HMIs will be cheaper and easier.


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#5 Simon Wyss

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Posted 04 April 2017 - 10:56 AM

We need more information to be able to help, at least me.

  • Which film oder sensor format?
  • Which range of object size? If we stick to object height—ten inches, four inches, one inch?
  • Does it really have to be 150 fps?

At that speed you have 1/163 s exposure time with digital capture, 8 % blankout time assumed, or

1/300 s exposure time, a 180 degrees shutter opening angle assumed. Say, you shoot at ISO 500

setting/film speed and want to light for f/16, you will need about 70,000 lx with your object.

 

Now, with each magnification order you lose the square amount of light density, in other words

you have to open the iris from f/16 to f/5.6 at scale 1:4 and to f/2.8 at scale 1:2, always with that

70,000 lx. At 1:2 object height is around 31 mm with 35-mm. Academy aperture. The area is about

1/3000 of a square meter, leading to the problem of how to achieve 70,000 lx in that small area. At

scale 1:1 you are at f/1.4!

 

A 1kW HMI PAR brings maybe 25,000 lumen. Depending on the divergence angle it must be set

at a certain distance for 25,000 lumen on one square meter. Three such lamps would bring you

75,000 lumen on a square meter. It will become kind of warm there under.

 

But it’s feasible.


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#6 Dom Lake

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Posted 05 April 2017 - 05:34 AM

We need more information to be able to help, at least me.

  • Which film oder sensor format?
  • Which range of object size? If we stick to object height—ten inches, four inches, one inch?
  • Does it really have to be 150 fps?

At that speed you have 1/163 s exposure time with digital capture, 8 % blankout time assumed, or

1/300 s exposure time, a 180 degrees shutter opening angle assumed. Say, you shoot at ISO 500

setting/film speed and want to light for f/16, you will need about 70,000 lx with your object.

 

Now, with each magnification order you lose the square amount of light density, in other words

you have to open the iris from f/16 to f/5.6 at scale 1:4 and to f/2.8 at scale 1:2, always with that

70,000 lx. At 1:2 object height is around 31 mm with 35-mm. Academy aperture. The area is about

1/3000 of a square meter, leading to the problem of how to achieve 70,000 lx in that small area. At

scale 1:1 you are at f/1.4!

 

A 1kW HMI PAR brings maybe 25,000 lumen. Depending on the divergence angle it must be set

at a certain distance for 25,000 lumen on one square meter. Three such lamps would bring you

75,000 lumen on a square meter. It will become kind of warm there under.

 

But it’s feasible.

 

Wow, thanks for your input!

 

We're shooting digital on two FS7's - S35 format at native 2000iso which will help us, so its less of an issue that we will need masses of light.

 

The objects will be glasses and spirit bottles, so probably around 10 inches in height.

 

The director is after that slow motion look but we're on a shoe string budget, so no option to hire in a dedicated camera.


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#7 Robin R Probyn

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Posted 05 April 2017 - 06:23 AM

150 fps is no problem with the fs7.. Ive shot alot at 150 on the F5.. ( fs7 with a side LCD screen and PL mount).. 1/250 shutter is fine..   you have to be in XAVC codec for S&Q to function in these camera,s..   

 

If you want to go to higher frame rate .. you would need an F5 with the RAW recorder. R5 or R7... then you can go up to 240 fps..  Ive not had flicker from sky panels or Astra,s..  might be worth doing a quick check with your HMI.. just in case the ballast is dodgy.. 

Tungsten under 1K can give you flicker problems with high speed.. watch for any florrie/sodium lights in shot.. even way in the background .. can ruin the whole shot.. shoot a test in your location for sure..  


Edited by Robin R Probyn, 05 April 2017 - 06:24 AM.

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#8 Akos Baranya

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Posted 05 April 2017 - 06:26 AM

I was under the impression that tungsten is the safest to use with high fps, is this only valid for >1kw lights then? I've been using 2.5k softlights, 1k 2k and 5k fresnels without a problem so far.


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#9 Robin R Probyn

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Posted 05 April 2017 - 06:51 AM

Yes smaller the 1K to 2K is risky..(some say only 5K is really safe)..can be a problem as the flicker is from the smaller filament "on off".. i.e. AC current..with bigger lights /filaments thermal retention.. this effect is less .. its still bight between waves.. AC powered anyway..   DC wouldn't be a problem.. you can look it up on the inter web .. its amazing how many people thing tungsten lights dont flicker.. till they have to re shoot.. 


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#10 Simon Wyss

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Posted 05 April 2017 - 09:46 AM

A 1kW HMI PAR brings maybe 25,000 lumen. Depending on the divergence angle it must be set

at a certain distance for 25,000 lumen on one square meter. Three such lamps would bring you

75,000 lumen on a square meter.

 

I made an error. 1kW PAR, not HMI PAR. HMI lamps bring about triple or four times that.

As a consequence you’d be off with three times 300 W HMI.

 

At 10 inches object height you have about 1:8 ratio (not scale). So you’re back at

f/11 to f/8. Enjoy it!


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