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A question on exposure


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#1 Matthew Day

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Posted 19 March 2006 - 11:49 AM

My camera only 'reads' film up to 160 ASA. If I want to use vision 200t should I just adjust the exposure manually using an external meter? that should work, right??

matt :huh:
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#2 santo

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Posted 19 March 2006 - 12:11 PM

Put your film in the camera and shoot away. Modern filmstocks like V2 200t can take a minor overexposure like that with absolutely no problem and will likely benefit from it in the grain reduction department. But don't take it from me, ask Kodak or anybody else who has actually shot this film in super 8. I always shoot 200 at 160 to make sure I don't underexpose the film -- which is death to super 8 in negative or reversal.
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#3 Chris Keth

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Posted 19 March 2006 - 12:32 PM

My camera only 'reads' film up to 160 ASA. If I want to use vision 200t should I just adjust the exposure manually using an external meter? that should work, right??

matt :huh:



I routinely shoot V200T rated at 160EI anyway, so that would work perfectly fine. It will also work just fine, as you say, to meter with an external meter and set the lens iris manually.
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#4 Filip Plesha

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Posted 19 March 2006 - 01:00 PM

which is death to super 8 in negative or reversal


Regarding reversal underexposure

It's actually better to underexpose reversal slightly. It keeps the highligts from blowing out, gives stronger blacks and gives more saturated colors.

Same effect you get with slightly overexposing negative

Of course it's because reversal and negative are two sides of one and the same chemical image.
Either you develop one and bleach the other, or develop other and bleach the first one.
Because of that the effects of exposure variations are reversed.
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#5 santo

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Posted 19 March 2006 - 01:21 PM

You obviously have not shot any super 8 reversal in some time (if at all), Filip, and are basing your answer on old textbooks from the 1950's which are refering to Kodachrome 35mm slides.

I've spent a great deal of my time on super 8 boards debunking such foolish notions and will continue to debunk them with examples and factual information for as long as it takes to save super 8 filmmakers a whole lot of wasted film. Afterall, nobody did it for me and it really pissed me off.

Here is a thread where I debunked this stupid idea and proved it conclusively to be false:

http://www.cinematog...hl=underexposed

I will admit to a typo here, unfortunately. I typed overexpose when I meant to type underexpose in the line "slight over-exposure or reversal reduces grain, increases sharpness" in the second paragraph. My mistake. Morons jump all over stuff like that when people prove them wrong.
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#6 Matt Sandstrom

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Posted 19 March 2006 - 02:40 PM

come on, *if* you want deeper blacks and *if* you want to avoid blown out highlights, and *if* you want more saturation then it's obviously "better" to underexpose. the grain issue is non-conclusive as i see it. you get more grain from underexposing but deep shadows also hide grain, so again it depends. simple as that. when was the exact time when eveybody suddenly stopped shooting tests? when i was learning that's all i did, and still do before every major shoot.

/matt
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#7 Alessandro Machi

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Posted 19 March 2006 - 02:51 PM

Overexpose or underexpose what?

The reason there is so much scuttlebutt over this issue is that there is no actual starting point that everyone agrees on. For instance, I tend to like slight overexposure based on what my camera meter reads when I have taken a reading off of a caucasian face. I can call that overexposing the shot when all I've really done is correct an incorrect reading. Also, the eye-piece is sent some of the light that otherwise would have gone to the film. When metering, it makes sense to add a bit of overexposure (perhaps a 1/2 stop) to compensate.

However, when it can be bad to "overexpose" is if an actor's face or hair will lose detail, aka blow out. So over and underexposure also relates to the amount of contrast in the scene. The less contrast in the scene, one actually gains a bit of film latitude. If the shot is very contrasty, one actually has more choices because no matter what f-stop they choose within a range, something in the shot won't come out very well because of the high contrast, sometimes that is exactly what the filmmaker was going for, other times it is not.

There is no one answer that handles all situations. If one is looking for a very general rule, slight overexposure is acceptable if detail has not been "blown out" as a result.
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#8 Filip Plesha

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Posted 19 March 2006 - 03:11 PM

You obviously have not shot any super 8 reversal in some time (if at all), Filip, and are basing your answer on old textbooks from the 1950's which are refering to Kodachrome 35mm slides.

I've spent a great deal of my time on super 8 boards debunking such foolish notions and will continue to debunk them with examples and factual information for as long as it takes to save super 8 filmmakers a whole lot of wasted film. Afterall, nobody did it for me and it really pissed me off.

Here is a thread where I debunked this stupid idea and proved it conclusively to be false:

http://www.cinematog...hl=underexposed

I will admit to a typo here, unfortunately. I typed overexpose when I meant to type underexpose in the line "slight over-exposure or reversal reduces grain, increases sharpness" in the second paragraph. My mistake. Morons jump all over stuff like that when people prove them wrong.



good work on that one

trying to debunk the increase in color saturation using plus-x film lol
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#9 santo

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Posted 19 March 2006 - 04:32 PM

when was the exact time when eveybody suddenly stopped shooting tests? when i was learning that's all i did,


Good point. And I encourage people do their own tests. It will only take one roll of reversal with documented testing to see how things really are.
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#10 Matt Sandstrom

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Posted 19 March 2006 - 04:43 PM

Overexpose or underexpose what?

correct exposure is when objects that reflect 18% of the light register as medium grey on the film. if it registers brighter you've overexposed and of it registers darker you've underexposed. the way you use the word is common and acceptable but it's hardly even related and has nothing to do with this whatsoever.

/matt
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#11 Filip Plesha

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Posted 19 March 2006 - 05:28 PM

correct exposure is when objects that reflect 18% of the light register as medium grey on the film. if it registers brighter you've overexposed and of it registers darker you've underexposed. the way you use the word is common and acceptable but it's hardly even related and has nothing to do with this whatsoever.

/matt


Really even that can be relative

It also depends on where that object is located and what is your artistic intention.
For example, there are two obvious ways of exposing a sunny day shot: exposing for the shadows (skylight) or exposing for the sunlight. Now its one scene, from one angle and there are two "correct" exposures, in fact there are more than two because you can go for anything in between the two kinds of metering.

Now if your goal is to get your gray card to appear medium gray on film by all means, wherever it is placed, then there is a correct exposure, but when you are shooting something, you don't let the position of your gray card dictate the exposure and look, instead you let the look you are after dictate where you put the gray card.

What further complicates the issue is low-light level photography, which compleatly throws out gray card as a dictator of correct exposure, because in those cases you are trying to match the exposure to the way your eyes see something. So instead of exposing a dark room with light from a TV so that the whole room is "correctly" exposed, you underexpose it to make it look dark as you eyes see it.
Same goes for moonlight photography, "correctly" exposed, moonlit scenes would appear as if shot on sunlight, minus the skylight, but the goal is to make them dark as your eyes see it, so you underexpose the film. In that case that is "correct" exposure.

It's very relative
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#12 Alessandro Machi

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Posted 19 March 2006 - 05:47 PM

Overexpose or underexpose what?



correct exposure is when objects that reflect 18% of the light register as medium grey on the film. if it registers brighter you've overexposed and of it registers darker you've underexposed. the way you use the word is common and acceptable but it's hardly even related and has nothing to do with this whatsoever.

/matt


But not everything in a shot will register 18% because they all have their own densitys. Which gets us back to, Overexpose or underexpose what?
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#13 Matt Sandstrom

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Posted 19 March 2006 - 07:52 PM

amazing. when somebody talks about what kind of exposure a certain emulsion likes to acheive a certain results it's obviously the technical definition that's being referred to. if you could reduce the negative effects of underexposure by calling it a stylistic choice cinematography would be a much simpler craft...

/matt
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#14 Matt Sandstrom

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Posted 19 March 2006 - 08:08 PM

But not everything in a shot will register 18% because they all have their own densitys.

and are you saying that this would somehow contradict what i just said or what? i'm afraid you're gonna have to explain that again.

Which gets us back to, Overexpose or underexpose what?


duh, everything. while there are new ccd chips these days that can selectively expose different pixels differently that option just isn't available for the super 8 shooter. either you overexpose everything that's in the frame, or none of it. i don't want to come across as patronizing since obviously you must know this. i'm just curious what you're after.

you're obviosuly just confused since the word overexposure can be used in many different ways. a better term to use when you exposure an emulsion differently to decrease grain, increase contrast and so on is "to rate it differently". instead of saying that negative likes overexposure you can say that it likes to be rated slower. this is what we're talking about. do you see now how your reflected readings and different brightnesses are completely irrelevant?

/matt
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#15 Alessandro Machi

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Posted 20 March 2006 - 02:48 AM

Overexposure and underexposure relates to the priority one places on something in the shot.

If there is a black man and a white man in the same frame, I can both underexpose and overexpose each one at the same moment in time, however, if I say one or the other has priority, than the term overexposure and underexposure has a different meaning.
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#16 Jonathan Benny

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Posted 20 March 2006 - 03:53 AM

Overexposure and underexposure relates to the priority one places on something in the shot.

If there is a black man and a white man in the same frame, I can both underexpose and overexpose each one at the same moment in time, however, if I say one or the other has priority, than the term overexposure and underexposure has a different meaning.


I think its about how one chooses to rate the stock and how that effects where the individual elements fall on the curve. How the individual elements within the scene fall in terms of chosen exposure is ultimately determined by how one rates the stock. So I believe that once you have placed all your elements in the scene at their particular values, it can be said, that the whole scene is then shifted in exposure depending on how you rate the stock.

When I am rating '18 at 320, I am factoring in an overexposure of 2/3rds of a stop before I have even started lighting the scene or placing priority on anything. So if I'm placing a face at 2 under the stop, I am still overexposing it by 2/3rds of a stop over where it would have been had I rated the stock at 500.

This to me, is equally important in achieving a certain a look as placing individual elements within the scene on the curve.

Just one view,

AJB

Edited by Jonathan Benny, 20 March 2006 - 03:56 AM.

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#17 Alessandro Machi

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Posted 20 March 2006 - 03:39 PM

I think its about how one chooses to rate the stock and how that effects where the individual elements fall on the curve. How the individual elements within the scene fall in terms of chosen exposure is ultimately determined by how one rates the stock. So I believe that once you have placed all your elements in the scene at their particular values, it can be said, that the whole scene is then shifted in exposure depending on how you rate the stock.

When I am rating '18 at 320, I am factoring in an overexposure of 2/3rds of a stop before I have even started lighting the scene or placing priority on anything. So if I'm placing a face at 2 under the stop, I am still overexposing it by 2/3rds of a stop over where it would have been had I rated the stock at 500.

This to me, is equally important in achieving a certain a look as placing individual elements within the scene on the curve.

Just one view,

AJB


This is interesting, and revealing because it shows that we all have a different priority factor. If I feel I can trust the internal camera meter to be reliable, meaning it's consistent even if it's inaccurate, then I can calculate an exposure very quickly for every set-up that I do. My terminilogy is therefore linked to the internal meter in the camera even though that is just a starting point.
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