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Night lighting and sharpness question


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#1 Eugene Lehnert

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Posted 24 August 2005 - 03:27 PM

I am going to be shooting a night scene in two weeks. I have access to 3 650 watt Arris and a 2K Blonde. I'm shooting with 7218 at night with a SBM Super 16 bolex with a prime and zoom Switar lenses.

Originally I wanted to light for an f-stop of 5.6 and overexpose the film by 2/3 stops. I wanted my backlight to be 1-stop overexposed and my key to be 3 stops underexposed. But I realized that I would need to have my backlight (650 watt Arri) about 8 feet from my actor so I was thinking of lighting at a 4.0 and overexposing by 1/2 stop instead. This way I could keep my backlight about 15 feet from my actor giving him more room in the scene allowing me to shoot wider shots.

My prime's lowest f-stop is a 1.6 and my zoom is a 1.9. I'm trying to make my image as sharp as possible and at the same time attempting to suppress as much grain as possible witht the lights I have.

I am using the Blonde with a 1/8 CTB on it to light the trees behind him in this scene that takes place at night. I am also using a Chimera softbox on a 650 Arriflex as the key and that is all. We will also have a smoke machine on set too. The scene has the actor digging a hole in the ground using the car lights as his light. So I wanted to then back that up a bit with another Arri to make it look like the car lights were lighting up more of the scene.

Any opinions would be appreciated.
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#2 John Pytlak RIP

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Posted 24 August 2005 - 03:52 PM

With 7218 rated EI500T, you only need 10 footcandles on your main subject to get full "normal" exposure at T/2.0. (Assuming 24fps with a 170 degree shutter opening). Since it sounds like the scene calls for your actor to be working at night, you will likely print/transfer the face fleshtones quite dark anyway, so it's likely you could "get away" with some underexposure. I suspect that getting a key of only about 5 footcandles at T/2.0 should give you enough exposure that you will see some detail in the face when printed darker, yet keep relatively good "rich" blacks in the background.
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#3 Matthew Skala

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Posted 25 August 2005 - 09:48 AM

In my experience, night photography is all about the location. A key issue being whether or not there is existing light at the location, and how deep into the composition those lights are. If your in the city you should be able to find a location with plenty of ambient light. If your in the forest than its all about the lights you have available to you.

With existing light I find an aperture that would work without any additional lighting so that I get plenty of detail in the background (usually a 1.4 or 2.O and if we are lucky a 2.8, with 500 speed film) than we bring in our lights for the actors and set them according to that stop. Shooting at a 4.0 would result in the background dropping off. However if all you have is trees in the background and you can light them, great. And as the saying goes, "if all your going to have is a black background than why bother shooting on location."

Hope this helps, peace
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#4 Matthew Skala

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Posted 25 August 2005 - 09:52 AM

(Assuming 24fps with a 170 degree shutter opening).

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The standard shutter angle opening is 180 degrees. :)
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#5 Eugene Lehnert

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Posted 25 August 2005 - 10:01 AM

Forgive me if this doesn't make sense, but I want to rate the 7218 stock at 375ASA therefore overexposing by half a stop. I want to shoot everything at a 2.8/4.0 split. I know 40 ft candles would be normal then at 4.0. So I want my backlight to be at 80 ft candles and my key/fill to be 5 ft candles. Then I would print the final print down half a stop.

This is a night scene so my ratio between backlight and key/fill will be 4 stops. Only two lights on our actor other than the lights from the car. But the scene will be foggy as well and I plan on lighting the trees in the background under 2 stops with a Blonde 2k with a 1/8 CTB gel on it.

I'm using a Bolex with RX lenses. I just want to make sure I am shooting my film for the best possible blow up to 35mm with what I have available to me.

Does this all make sense?
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#6 John Pytlak RIP

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Posted 25 August 2005 - 10:42 AM

The standard shutter angle opening is 180 degrees.  :)

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For whatever historic reason, most of the published Kodak data is based on a 170 degree shutter (1/50 second) rather than 180 degrees (1/48 second). Not a significant difference in most cases.
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#7 John Pytlak RIP

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Posted 25 August 2005 - 10:59 AM

Forgive me if this doesn't make sense, but I want to rate the 7218 stock at 375ASA therefore overexposing by half a stop.  I want to shoot everything at a 2.8/4.0 split.  I know 40 ft candles would be normal then at 4.0.  So I want my backlight to be at 80 ft candles and my key/fill to be 5 ft candles.  Then I would print the final print down half a stop.

This is a night scene so my ratio between backlight and key/fill will be 4 stops.  Only two lights on our actor other than the lights from the car.  But the scene will be foggy as well and I plan on lighting the trees in the background under 2 stops with a Blonde 2k with a 1/8 CTB gel on it.     

I'm using a Bolex with RX lenses.  I just want to make sure I am shooting my film for the best possible blow up to 35mm with what I have available to me.

Does this all make sense?

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For a night scene with limited lighting available, I'd go for the T/2.0 opening and accept the shallower depth of focus in favor of a more solid exposure and more shadow detail in the background area that you can't light adequately for a 2.8/4.0 split.
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#8 Eugene Lehnert

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Posted 25 August 2005 - 02:44 PM

For a night scene with limited lighting available, I'd go for the T/2.0 opening and accept the shallower depth of focus in favor of a more solid exposure and more shadow detail in the background area that you can't light adequately for a 2.8/4.0 split.

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If I am able to light the background area with a 2k Blonde underexposed by two stops why would I need to shoot nearly wide open? Do I not sacrifice sharpness?

I am shooting labor day weekend and there will not be a moon out. I could see shooting wide open to get some background detail from that but since there will be very little light other than what I am using. I will be shooting in upstate NY where there will be little to no light pollution. I would like the 35mm blow up to be as clean and as sharp as possible.

I'm learning so I just want to understand all the reasoning for this. On a night without any moonlight will I see much of anything even if my lens is wide open?
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#9 John Pytlak RIP

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Posted 25 August 2005 - 03:08 PM

If I am able to light the background area with a 2k Blonde underexposed by two stops why would I need to shoot nearly wide open?  Do I not sacrifice sharpness?

I am shooting labor day weekend and there will not be a moon out.  I could see shooting wide open to get some background detail from that but since there will be very little light other than what I am using.  I will be shooting in upstate NY where there will be little to no light pollution.  I would like the 35mm blow up to be as clean and as sharp as possible.

I'm learning so I just want to understand all the reasoning for this.  On a night without any moonlight will I see much of anything even if my lens is wide open?

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You're not really sacrificing "sharpness", just depth of field. Since you only have one person to focus on, you probably don't need to have lots of depth of field --- you probably want the background to be slightly out of focus to put the attention on the main subject anyway.

If you are out in the woods and light the background trees with only a 2K, not getting enough exposure will lose all the detail in the trees farther away, thowing them into a "black hole" where details don't even record on the film, with a bunch of lighted trees near your action. Opening up your lens allows you to use the 2K to light more trees to a lower intensity. The background will be more evenly illuminated with enough detail recorded on the film to suggest the action is occuring in the naturally lit nightime woods, rather than an artificially lit small area of the woods.

Bottom line, if you don't really need lots of depth of field, open up the lens to allow using your limited lighting in more creative ways. To get a "clean and sharp" blow-up, I would favor getting a solid exposure rather than lots of unneeded depth of field.
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#10 Eugene Lehnert

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Posted 25 August 2005 - 04:07 PM

You're not really sacrificing "sharpness", just depth of field.  Since you only have one person to focus on, you probably don't need to have lots of depth of field --- you probably want the background to be slightly out of focus to put the attention on the main subject anyway.

If you are out in the woods and light the background trees with only a 2K, not getting enough exposure will lose all the detail in the trees farther away, thowing them into a "black hole" where details don't even record on the film, with a bunch of lighted trees near your action.  Opening up your lens allows you to use the 2K to light more trees to a lower intensity.  The background will be more evenly illuminated with enough detail recorded on the film to suggest the action is occuring in the naturally lit nightime woods, rather than an artificially lit small area of the woods.

Bottom line, if you don't really need lots of depth of field, open up the lens to allow using your limited lighting in more creative ways.  To get a "clean and sharp" blow-up, I would favor getting a solid exposure rather than lots of unneeded depth of field.

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Good to know. Thanks for the advice. I should have shot more tests. I just didn't think I could get much detail in the woods at all without a full moon.
I also kind of like a contrasty image when everything falls of quickly. It seems to make all the blacks look darker. I guess it then makes it all look like it might be on a set but I dont' know if that will be a terrible thing.

I was also under the impression that it is best to shoot a stop or two obove wide open to get the sharpest image possible. And since I was going to do a 35mm blow up and the fact that I am using older equipment like the Switars that this would be the best way to get the best picture possible.
Thanks.

Edited by Eugene Lehnert, 25 August 2005 - 04:11 PM.

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#11 Matt Pacini

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Posted 25 August 2005 - 05:33 PM

"...  I just didn't think I could get much detail in the woods at all without a full moon.  ..."

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Pretty much irrelevant what the moon is doing.
It's not going to be enough light to measure an exposure anyway. If I were you, I'd pretend there is no such thing as a moon, and figure on nothing showing up on film that you're not lighting.
MP
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#12 John Pytlak RIP

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Posted 25 August 2005 - 08:19 PM

Good to know.  Thanks for the advice.  I should have shot more tests.  I just didn't think I could get much detail in the woods at all without a full moon. 
I also kind of like a contrasty image when everything falls of quickly.  It seems to make all the blacks look darker.  I guess it then makes it all look like it might be on a set but I dont' know if that will be a terrible thing. 

I was also under the impression that it is best to shoot a stop or two obove wide open to get the sharpest image possible.  And since I was going to do a 35mm blow up and the fact that I am using older equipment like the Switars that this would be the best way to get the best picture possible.
Thanks.

<{POST_SNAPBACK}>


Yes, using a lens wide open may sacrifice a bit of sharpness (depends on the lens). But again, in this particular case, I'd go for getting better exposure from your limited lighting for such an outdoor challenge. Avoid underexposure.
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