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.

about a stop to stop and a half

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?

129 views and nobody has anything to add?

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?

BE

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.

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.

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.

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!

George/

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.

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.

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.

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?

That's exactly my experience too and I'm starting to wonder if this is the best the camera can perform with shadows? Either no detail in the shadows or noise.

Obviously, this won't work with night scenes.
Interesting comment from Piotr. Really haven't played much with crushing shadows. I don't shoot, much, in very low light and have no experience with it and the EX1.

This is it exactly. The curves are all amplifying (stretching) the lower quartile values. The more of the scene that registers there and the darker it is, the more this amplification will show noise, unless the curve is flattened and or compessed. It is all a matter of amplifying darks.

Could you explain it in layman's terms?

Thanks.

Randy's not making much sense to me. Seems like any dark scene will have a gradation from crushed black up into grey. Somewhere in there, there's gonna be some real ugly noise. I don't like the low light noise on the EX1. It's almast as bad as my HD110.

Well, yes but surely not as bad as the HVX200 or HV20.

It's just the nature of the 4:2:0 MPEG2 codec. Not much to do with it.

Well, the HVX200 is supposedly 4:2:2 but it's worse in noise and low light.

OK, perhaps these are too extreme to illustrate what I mean, but which one do you like better?

And yes - Bill is right that on the gray scale, even with the darkest areas crushed down to the floor along with any noise, the noise will appear elsewhere - but somehow I still prefer the crushed one for its "Nighty" look.

Hi guys,

What are your settings here? What gain and what gamma (curve)? If the curve is modified by other PP settings, please let me know. I am typically shooting towards the right, but this has me wainting to do some tests.

Also, Piotr, did you have sharpening on in these shots? Pretty heavy halos are present around the couch. Sharpening off is pretty well a must where noise is an issue, as you end up sharpening the noise.

Underexposing never produces noise for me. If anything it helps (at least 1 to 1 and 1/2 stops)...its only the overexposing that does it. I'm shooting a really pretentious artsy fartsy black and white short and underexposing by 2/10ths of a stop to really enhance the chiaroscuro lighting by adding contrast and it looks better than a contrast filter added in post:D

My few early experiments there were the same. Also, helpful to reduce black gamma (which should really be called lower value gamma) and will help to reduce noise which is more apparent in the lower values. I haven't tested below 1.5 stops down, but you will not likely need to go that low to achieve a low key look if you back off the black gamma (which is actually pretty pumped up by default).

Hi guys. I'm revisiting this subject at the moment and was wondering if you all agree with Eric here. 4 to 5 stops under 18% grey is all one should go in order to avoid noise? Or will this also depend on the type of gamma selected (cine, std etc)?
It's interesting to note that the RED ONE also has the same bottom of 5 stops under 18% grey before noise kicks in really bad.

Thanks for posting those images Piotr.
I'm a little worried about the halos too, but the one on the right looks much nicer than the one on the left.

What I don't understand is why everyone's hellbent on producing the "film look" in camera when there's so much fabulous image and colour control available in post these days.

I prefer to shoot correctly exposed footage whenever possible and crush the blacks or whatever else I want to do in post. That way I keep my options open with the original footage.

Crush your blacks, or blow your highlights in camera, and you're stuck with it forever. Where there's no detail, there's no detail but correctly expose in the first place and you can have fun as long as you retain the originals.

Enlighten me someone!

Andy I'm with you on this. My main concern when shooting is not blowing highlights because you can't retrieve those in post.

Getting the widest dynamic range is important to maximum flexibility in post.

Of course there certainly is good reason to paint as much as possible in camera too. Some DPs want to have as much control of the source they hand to the post people. Sometimes they deliberately want to limit their options. Sometimes one might feel in camera processing can avoid issues that might happen when processing in post.

That said, I'd like to have maximum options in post.

It is nice that with the EX1 we have choice though. Tailor to your workflow. That's flexible!

Think many of you pixel peep too much.