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Overexposing negative suitable for sunsets?


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#1 Patrick Cooper

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Posted 29 November 2006 - 04:19 AM

I'll be shooting some Fuji 16mm negative film in the near future for the first time. From reading this forum, it seems highly recommended to overexpose neg film slightly to reduce grain and to guard against accidental underexposure. Thus, I have decided to overexpose the majority of the footage by half a stop. However, is this practise suitable for filming sunsets or should this particular subject matter be exposed normally? It's just that i am used to shooting slide film in still photography and by instinct, I would never normally overexpose a sunset so I can avoid washed out colours. For those of you who have filmed sunsets on negative movie film, how do the colours turn out when overexposed - and by how much? Or do you usually prefer to expose sunsets normally with neg film?
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#2 Stuart Brereton

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Posted 29 November 2006 - 04:28 AM

Overexposing neg in this way is usually combined with 'printing down' at Print or TK stage, to compensate for the overexposure. Your graded footage should not look overexposed, just slightly tighter grained.
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#3 David Mullen ASC

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Posted 29 November 2006 - 11:29 AM

Patrick, you're somewhat confusing two different issues. You rate a stock slower than normal to end up on average with a denser negative that prints "down". That doesn't mean that you don't expose a subject according to how you want it to look, so if you want a face to look two-stops underexposed, then you underexpose it two stops ignoring the fact that you might be rating the stock 1/3 of a stop over.

I did a feature where I rated Fuji Eterna 500T at 320 ASA (2/3's of a stop over), but I still underexposed moonlight scenes by two stops. But actually on my negative, therefore, the scene was underexposed 1 and 1/3 of a stop from normal.

So you may rate a stock slower than normal... but that doesn't preclude you from then underexposing a sunset sky to hold more detail in the brightest areas so that it doesn't look washed out. You may decide that you like shooting 50D stock at 32 ASA for the look, but you still might then underexpose a sky by one-stop to hold more bright detail & color (so in actuality, you are really underexposing by only 1/3 of a stop.)
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#4 Patrick Cooper

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Posted 30 November 2006 - 01:51 AM

Thanks David. For the sunset shots, I plan to shoot subjects as silhouettes against a sunset so naturally I would not want to overexpose these particular shots. I would prefer to meter normally from the sunset sky in these instances using the true asa speed of the film.

By the way, how did those moonlit shots turn out? Was there an increase in grain from the underexposure?
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#5 David Mullen ASC

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Posted 30 November 2006 - 02:17 AM

Thanks David. For the sunset shots, I plan to shoot subjects as silhouettes against a sunset so naturally I would not want to overexpose these particular shots. I would prefer to meter normally from the sunset sky in these instances using the true asa speed of the film.

By the way, how did those moonlit shots turn out? Was there an increase in grain from the underexposure?


Why would it be grainier if I left them dark-looking? The shots would print at the same numbers as the normally exposed shots. If I have a normal scene but in one corner there is a shadow that is two-stops dark, is that shadow grainy? If the shadow side of a face is two-stops darker than the key side, is that shadow side grainy?

It's when you have to make something underexposed lighter in timing that the grain comes up -- in other words, too much underexposure, too little density, requiring printing at lower printer light numbers (or brightening in post.)

Of course, that doesn't mean that I never occasionally underexpose too much...

I'm still not sure you understand the difference between how you rate the film versus how you expose a scene. It all revolves around what you consider the optimal density for your "normal" scenes, around which you under or overexpose for effect. Rating a stock slower than normal doesn't preclude you from shooting a silhouette shot using that rating. The real question is what density do you want for what set of printer lights. Do you want your sunset shot to print in the mid 20's, low 30's, high 30's, etc.? Let's say you rate the stock normal so that it normally prints at 25-25-25. So using this rating, you underexpose the sunset shot to make things silhouette. Assuming you exposed correctly for that effect, the shot would still print at 25-25-25.

But let's say you rated the stock 2/3's of a stop slower so that a normal shot prints at 35-35-35. And then you underexpose the sunset shot for a silhouette but it still prints at 35-35-35.

Well, the sunset shot that printed at 35-35-35 will have deeper blacks, less grain, and richer colors than the sunset shot that printed at 25-25-25. So you underexpose for the silhouette effect you want, but you still want enough density that in order to look "correct", it prints slightly higher than normal (i.e. you have to print it down.)
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#6 Corey Bringas

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Posted 30 November 2006 - 04:03 AM

David,
I typically rate my film stock slower as well. Do you usually rate it 2/3 of a stop slower or a full stop? From doing some tests at school I found that the blacks look blackest and whites whitest at one full stop. What is your opinion?
Thank you,
Corey

Why would it be grainier if I left them dark-looking? The shots would print at the same numbers as the normally exposed shots. If I have a normal scene but in one corner there is a shadow that is two-stops dark, is that shadow grainy? If the shadow side of a face is two-stops darker than the key side, is that shadow side grainy?

It's when you have to make something underexposed lighter in timing that the grain comes up -- in other words, too much underexposure, too little density, requiring printing at lower printer light numbers (or brightening in post.)

Of course, that doesn't mean that I never occasionally underexpose too much...

I'm still not sure you understand the difference between how you rate the film versus how you expose a scene. It all revolves around what you consider the optimal density for your "normal" scenes, around which you under or overexpose for effect. Rating a stock slower than normal doesn't preclude you from shooting a silhouette shot using that rating. The real question is what density do you want for what set of printer lights. Do you want your sunset shot to print in the mid 20's, low 30's, high 30's, etc.? Let's say you rate the stock normal so that it normally prints at 25-25-25. So using this rating, you underexpose the sunset shot to make things silhouette. Assuming you exposed correctly for that effect, the shot would still print at 25-25-25.

But let's say you rated the stock 2/3's of a stop slower so that a normal shot prints at 35-35-35. And then you underexpose the sunset shot for a silhouette but it still prints at 35-35-35.

Well, the sunset shot that printed at 35-35-35 will have deeper blacks, less grain, and richer colors than the sunset shot that printed at 25-25-25. So you underexpose for the silhouette effect you want, but you still want enough density that in order to look "correct", it prints slightly higher than normal (i.e. you have to print it down.)


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#7 Patrick Cooper

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Posted 30 November 2006 - 04:18 AM

"If I have a normal scene but in one corner there is a shadow that is two-stops dark, is that shadow grainy?"

No

"If the shadow side of a face is two-stops darker than the key side, is that shadow side grainy?"

Nope

I'm assuming for your moonlight shots, you wanted a dark, moody look so the printing numbers throughout the film would have been consistent so that those particular shots remained dark and moody ? (without any increase in grain) if that was the effect you were going for in that scene?

When I underexpose for the sunset silhoutte shots on film that i have rated half a stop slower, I gather it's best not to underexpose too much so that I still retain some density in the negative if my goal is to produce fine grain images.

Thankyou for the explanation on compensating in printing for alternatively rated film - of which I could underexpose or overexpose from that rating while still maintaining the same printing numbers when printing. Though I plan to have this film telecined. I assume the same principles apply in telecine?

Edited by Patrick Cooper, 30 November 2006 - 04:21 AM.

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#8 David Mullen ASC

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Posted 30 November 2006 - 09:48 AM

Though I plan to have this film telecined. I assume the same principles apply in telecine?


Sort of. A little extra density is always helpful even with scanning / telecine, but you don't quite get the same benefits of "printing down", the deeper blacks. Black level is more a function of what you set in the video transfer. Saturation is also controllable that way. So you don't need to overexpose as much with a telecine transfer compared to printing. And too much overexposure causes some video noise in the highlights on some telecines because of how dense the negative is in the brightest areas. Bright skies particularly have this problem.
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#9 Sam Wells

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Posted 30 November 2006 - 10:11 AM

When a CCD basd telecine like the Spirit blows out the image, it really does - like a CCD camera.

If the sun is in the shot I personally would be careful how far I went with overexposing....

-Sam
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#10 Patrick Cooper

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Posted 30 November 2006 - 10:50 AM

"When a CCD basd telecine like the Spirit blows out the image, it really does - like a CCD camera."

My gosh - uughhh!

I was planning to overexpose Fuji Eterna 250D by half a stop the majority of the time - I hope this will create just enough density for a nice looking telecine. Would 2/3 of a stop overexposure be the theoretical limit for telecine before burning out and noise becomes a problem?
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#11 David Mullen ASC

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Posted 01 December 2006 - 01:15 AM

"When a CCD basd telecine like the Spirit blows out the image, it really does - like a CCD camera."

My gosh - uughhh!

I was planning to overexpose Fuji Eterna 250D by half a stop the majority of the time - I hope this will create just enough density for a nice looking telecine. Would 2/3 of a stop overexposure be the theoretical limit for telecine before burning out and noise becomes a problem?


No, that should be fine assuming you don't accidentally overexpose way beyond that.
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#12 John Pytlak RIP

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Posted 07 December 2006 - 02:34 PM

The KODAK VISION2 Color Negative Films have tremendous overexposure latitude, and should hold detail in the highlights even with a stop or two of overexposure.
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#13 Tim Terner

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Posted 07 December 2006 - 06:27 PM

I did a feature where I rated Fuji Eterna 500T at 320 ASA (2/3's of a stop over)


Surely that is half a stop over
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#14 Andrew Koch

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Posted 07 December 2006 - 06:47 PM

Surely that is half a stop over


No, David is correct. Rating 500 ASA at 320 is 2/3 of a stop over. Unless there is some crazy stock with a weird asa that I have never heard of, ASA ratings are always in increments of a third of a stop (ex: 125, 160, 200, 250, 320, 400, 500, etc..) So if you want to overexpose the stock by a half a stop, you would be rating the film at some strange ASA. I guess it would be something like ASA 375 (just a guess, my math skills stink). It would be easier to just rate the the stock either a 2/3 or a 1/3 slower and print down accordingly. Just a suggestion, otherwise you will have to find a weird asa for your meter if it even supports that.
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#15 Tim Terner

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Posted 08 December 2006 - 12:53 AM

No, David is correct. Rating 500 ASA at 320 is 2/3 of a stop over. Unless there is some crazy stock with a weird asa that I have never heard of, ASA ratings are always in increments of a third of a stop (ex: 125, 160, 200, 250, 320, 400, 500, etc..) So if you want to overexpose the stock by a half a stop, you would be rating the film at some strange ASA. I guess it would be something like ASA 375 (just a guess, my math skills stink). It would be easier to just rate the the stock either a 2/3 or a 1/3 slower and print down accordingly. Just a suggestion, otherwise you will have to find a weird asa for your meter if it even supports that.


That makes complete sense, thanks Andrew
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