Low Light Shooting

R

Ryan McCarvill

Well-known member
Hey everyone.

I was wondering what peoples experience is with low light shooting.

I have a F2.8 28mm, an F1.8 50mm, and the kit lens. So there are just over one stop difference between the 50mm and the 28mm and two between the 50mm and the kit lens (when at 14mm).

So the ideal situation is that I can keep the kit lens at an ISO of 800 for the establishing shots. And use the 28 mm at ISO400 and the 50mm at ISO200 (or one third below that) - this obviously won't work well for low light. The other solution is that I abandon the 14mm, or keep the opening shot largely static and gain the two stops in shutter speed.

Anyway that really wasn't the question, just thinking aloud if anyone has a suggestion (and buying the Pana 20mm pancake is out of my budget at the moment).

The real question is:

So I have been experimenting with the camera and have it setup as smooth with Contrast -2, NR -2, Saturation -2, sharpness +2. I have Intelligent Exposure cranked to the max. Now on previous video camera's that I have used its been a good idea to over expose slightly to get greater latitude in low light levels and then adjust in post. I am thinking the the GH1 because of the limited codec it's probably best just to get it right in camera?

Anyway its going to be a bit of a nightmare matching the lenses in the high pressure situation of filming. Maybe I should make a quick lookup table.
 
sorry, but I read it twice and still didn't see a question. what are you asking? best to get it right in camera? what is it? exposure or the look? it's best to get both. don't rely on post. expose properly and do the rest in post.
 
Exposure, sorry. I realise I was rambling.

So previously I have slightly overexposed for low light to get a little more information in the blacks. But I am guessing with AVCHD we are much more locked in and its best to get it right in camera.

So I guess, does anyone have any tips?
 
Perform a test yourself using both methods, put it through the post path you are planning on and compare for yourself. That is the best, most concrete answer you will get. Anything people tell you here will be speculation with regards to your shooting situation.
 
well, are you over exposing your black or your whites? don't over expose your whites because then you're stuck with blown out whites. the codec is much stronger than you're giving it credit for. do you have lights? or are you just run'n gunning it? if you want your lens to match, just shoot your 50mm at 2.8 and leave your 28 wide open. it's going to be soft but at least your aperture's will match.
 
Hey Guys thanks for the answers.

I have been testing it and will do a more concrete test tonight (with various lenses, changes in fstop, etc).

Everything will be lit, but its quite a strong key light, simulating the headlights of a car, with a little bit of fill.

On thinking about it more I think over exposing by half a stop might be the way to go, as long as the whites aren't clipping, as I said I will find out about it tonight, I guess. I just wondered if anyone else had done similar tests, sort of as a second opinion to my own.

I think I want the 14mm of the kit lens for my wide so I have made a simple look up table to get them to match. A quick test just now confirmed that they match pretty well. I also want the depth of field that the 50mm can achieve wide open. Although focusing it is a *****.
 
The GH1 has it's most glaring issues with artifacts in the deep shadows just above the blacks. So you are correct in the idea of overexposing a bit so you can crush those artifacts into the blacks to make a creamier final image. But, the recipe is on a case-by-case basis. To be honest, I've found it very difficult to do. One case where I would definitely overexpose is in a scene that takes place at night and is supposed to look dark. And by "overexpose" I actually mean expose to where the meter says it's correct...and to the eye it looks too bright because it's supposed to look darker. Then darken it in post and all the noise and artifacts disappear. Just be careful with highlights, though. Don't light them too bright or clip anything.
 
interesting way of going about lessening artifacts in low light shots dvbrother. gonna have to try it some time.
 
dvbrother said:
The GH1 has it's most glaring issues with artifacts in the deep shadows just above the blacks. So you are correct in the idea of overexposing a bit so you can crush those artifacts into the blacks to make a creamier final image. But, the recipe is on a case-by-case basis. To be honest, I've found it very difficult to do. One case where I would definitely overexpose is in a scene that takes place at night and is supposed to look dark. And by "overexpose" I actually mean expose to where the meter says it's correct...and to the eye it looks too bright because it's supposed to look darker. Then darken it in post and all the noise and artifacts disappear. Just be careful with highlights, though. Don't light them too bright or clip anything.
Click to expand...

where are these most glaring issues in the blacks? wouldn't your blacks always have issues if you over expose them?
 
Car3o said:
where are these most glaring issues in the blacks? wouldn't your blacks always have issues if you over expose them?
Click to expand...

Not if you crush them in post, which is the whole point of overexposing them in the first place. I think part of the confusion is that the term "overexpose" is often thought of as "bad, wrong, lost detail", etc. While this is often the case, slight overexposure can be done intentionally to good effect. In fact, cinematographers shooting 35mm film do it all the time. Here's how it works with the GH1: midtones (i.e. pixels in the middle gray area) look fine on the GH1 when shooting at reasonable ISO's (400 and lower). They aren't prone to noise and artifacts like the shadows just above the blacks. So if you overexpose your image (and by this I don't mean blow out highlights, I just mean make it a half stop or one stop brighter than you really want it to look), or add a little more fill light to the shadows and make them a bit brighter, the shadows then move above the threshold of where the GH1 shows artifacts. But then you have to adjust your image in post because it looks like it has too much fill light in the shadows. So in post you add contrast or crush the blacks and suddenly the image looks like you intended it, with an added benefit: since none or your original image had noise or artifacts, your nice adjusted image with dark shadows doesn't have artifacts either! It works well.

But you have to be careful. I only do this in scenes that are supposed to look dark (i.e. night scenes). If you overexpose day shots or shots with a lot of bright areas, you are going to clip the image and lose a lot of detail...it's going to look like crap.
I'm no expert on it, and I'm still experimenting, but I recently shot a night scene with this approach and it turned out great, as opposed to the first time where I exposed normally and got lots of ugliness in the shadows.

Hope this helps.
 
Yep, I have found that there is a very narrow band just above black where the gh1 displays a huge amount of noise. Worse than that the noise is red in spectrum.

If you sit at the left hand side of your histogram. I.e no clipping then it seems to be a good technique to get more shadow detail that is lost by the codec.
 
I've read the term "exposing to the right" in many other cinematography forums. Maybe this is what they mean. It's a way to decrease noise. The trick of course is to avoid clipping highlights. That's where good lighting comes into play. :-)
 
Yes, ETTR without clipping your whites is a viable option for giving your sensor the most meaty signal for it to work with all the way down the chain. Then in post you pull it back to where it should be exposure-wise. The idea is that you will end up with less noise in the final image this way.
 
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