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Old March 26th, 2008, 06:38 AM   #1
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How many stops under can you get away with?

For those of you out there shooting low light stuff with your EX1 like night externals and low key lit scenes, how many stops under do you feel you can get away with before noise kicks in? I have rated my EX1 at about ISO 400. ISO 200 with the Letus Extreme when I had it in my possession.
Thanks.
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Old March 26th, 2008, 06:50 AM   #2
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Originally Posted by Michael Maier View Post
For those of you out there shooting low light stuff with your EX1 like night externals and low key lit scenes, how many stops under do you feel you can get away with before noise kicks in? I have rated my EX1 at about ISO 400. ISO 200 with the Letus Extreme when I had it in my possession.
Thanks.
about a stop to stop and a half
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Old March 26th, 2008, 07:41 AM   #3
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Hi Phil,

That's it really?
A stop difference is a 2:1 contrast ratio. A stop and a half is 3:1. This is quite low contrast. You seem to have shot stuff with way more contrast than that with no apparent noise judging by the stuff on your blog.
Specially if the camera has 10 stops of dynamic range as indicated by Adam Wilt, I would expect to be able to go much deeper than just 1.5 stops before seeing noise. Maybe you misunderstood my question?
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Old March 26th, 2008, 05:11 PM   #4
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129 views and nobody has anything to add?
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Old March 26th, 2008, 05:46 PM   #5
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maybe explain your question. I thought Phil's answer made sense and was similar to my findings. Do you mean something different than what he answered?

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Old March 26th, 2008, 08:13 PM   #6
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Well, I thought the question was pretty clear, but here it goes. I have rated my EX1 at ISO 400. So let's say my meter tells me at ISO 400 I need to have my EX1 lens set at f5.6 for a given amount of light. How many stops could I go down before I start seeing noise? This is what I wanted to know from other users. What are their findings on this matter? If you say 1 stop under it would mean that under f4 you would see noise already, which is somehow hard to believe, reason I thought my question was maybe misunderstood.
What did you understand by my question?
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Old March 26th, 2008, 10:13 PM   #7
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Originally Posted by Michael Maier View Post
Well, I thought the question was pretty clear, but here it goes. I have rated my EX1 at ISO 400. So let's say my meter tells me at ISO 400 I need to have my EX1 lens set at f5.6 for a given amount of light. How many stops could I go down before I start seeing noise? This is what I wanted to know from other users. What are their findings on this matter? If you say 1 stop under it would mean that under f4 you would see noise already, which is somehow hard to believe, reason I thought my question was maybe misunderstood.
What did you understand by my question?
You are not going to see noise simply by underexposing. You are going to see noise if you use the higher gain settings or try to recover your underxposed stops in post.
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Old March 27th, 2008, 02:49 AM   #8
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Michael,

You can see noise anywhere in the image - even in the brighter parts - if you look hard enough.

So the answer to your question is a bit subjective. But let's assume you're referring to the "reasonable man" (to borrow a term from the law) threshold for when noise becomes unacceptable.

"How many stops could I go down before I start seeing noise?" is ambiguous to me. What kind of meter are you referring to? If you are using a spot meter, you are probably asking more about latitude that over/under exposure. You can probably go about 4 to 5 stops under mid grey in your spot readings before the metered areas disappear in the noise floor.

If you are speaking of an incident meter, and you are shooting a typical scene (no major contrast), and you are planning to correct the "underexposure" in post by brightening the image, then I'd have to agree with Phil - you can probably gain a stop or a stop and a half back in post before the images look too horribly noisy, compared to a properly exposed typical scene.

Hope this helps.

Last edited by Eric Pascarelli; March 27th, 2008 at 03:47 AM.
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Old March 27th, 2008, 05:28 AM   #9
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Originally Posted by Randy Strome View Post
You are not going to see noise simply by underexposing. You are going to see noise if you use the higher gain settings or try to recover your underxposed stops in post.
I disagree. Anything underexposed with the EX1 has noise and lots of it.
But I was not talking about how many stops I can get back in post. I was referring to on set or in camera stops.
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Old March 27th, 2008, 06:28 AM   #10
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Micahel,

There is a big thread about "better pictures by underexposing" (or something) around the forum. Maybe you can get some info from there.

Other than that I'd say that when you set your own standards of acceptability, as you should, what good are other people's opinions really? Better to just go out and shoot some footage!

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Old March 27th, 2008, 06:58 AM   #11
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My experience is that underexposing you can get away with provided you crush (compress) blacks; otherwise the noise will hit - even without using gain. By how many stops? Well, there is no single answer to it, as each scene is different and so may be the camera settings.

BTW I personally love this look; with high colour saturation and blacks considerably crushed - without a single trace of overexposing even in the picture's brightest areas - you can get closer to this elusive "film look", especially in conjustion with 25p mode and controlled DOF (edge enhancement should also be avoided by turning detail off).

I adopted this approach after a considerable period of trial&error experiments wih the V1E, which is much noisier in low-light; the EX1 is so much more sensitive that in many indoors situation you can strech blacks to see more detail, and still stay safe from noise - but nevertheless I'm still using this technique as I like the picture; it's sort of dense and juicy.
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Last edited by Piotr Wozniacki; March 27th, 2008 at 11:07 AM.
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Old March 27th, 2008, 08:43 AM   #12
 
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It really depends on the level of shadows in your scene. If you have "black" in the scene, 1.0 stop under will cause noise in some form. Any attempt to recover crushed blacks in post will cause very noticeable noise. Occasionally, I shoot 1 stop under. I would be very careful of shooting lower than that.
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Old March 27th, 2008, 08:59 AM   #13
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Bill,
Do you usually prefer to slightly over expose or under expose? I remember somewhere Phil bloom saying he shoots a half stop under but some other people say its better to shoot slightly over.
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Old March 27th, 2008, 09:16 AM   #14
 
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As long as I don't blow out highlights, I prefer to shoot on the right side of the histogram. As I said, above, recovery from underexposure results in noise with a 4:2:0 codec. If I see 100% zebra, I've gone too far. Recovery from slight overly bright footage is pretty easy and painless, as long as the hot spots aren't blown.
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Old March 27th, 2008, 10:06 AM   #15
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Originally Posted by Bill Ravens View Post
As long as I don't blow out highlights, I prefer to shoot on the right side of the histogram. As I said, above, recovery from underexposure results in noise with a 4:2:0 codec. If I see 100% zebra, I've gone too far. Recovery from slight overly bright footage is pretty easy and painless, as long as the hot spots aren't blown.
I'm curious how you do that with a scene with lots of dark shadows or with night exteriors?
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