EX1 at 1/40 shutter a bad idea in low lighting?

C

carl@brazos

Member
Hello, we will be shooting a documentary in a fairly darkly lit restaurant later on this month. We will be shooting right at the low end of the camera's light ability - basically wide open with one stop of play. We will not be able to add additional lights to correct this, so I am looking for other options (in camera).

We are shooting at 1080p 30fps. I have tried several camera test in the restaurant shooting at a shutter speed of 1/40 verses our usual 1/60. This does help a little, but I wonder if there are any disadvantages to do this. Does this make more motion blur, noise, etc?

Also, are there any other camera settings we could adjust to help out?

thanks,
Carl
 
Yes, more motion blur, bit no real disadvantages otherwise.

If you have a lot of motion or fast pans/tilts, you might see more judder as a result.

Definitely not more noise. And 1/40 will not flicker with fluorescent lights.

If there is not much extreme motion in the scene, you might try "shutter off" which is the same as 1/30 shutter. It will give you an extra 1/3 stop over 1/40.

Just test the shutters and make sure you are happy with the motion blur/judder situation.
 
I would turn off the shutter completely under these conditions. I shot a gas fireplace at Chuck's Steakhouse last week and it came out gorgeous. There was barely enough light to read the menu, but the EX1 captured a wonderfully-theatrical image of the flames and the surrounding mantel, which was a stop or two above total darkness.
Shutter off is better than gain up!
 
Well, clarification please: when you say 1080 @ 30fps, do you mean 1080p30? or are you calling normal 1080i "30fps"? Because if so, you definitely wouldn't want to use 1/30th, it'll cut your vertical resolution in half.

If you're shooting 1080p, there's nothing wrong with 1/40th, it'll just be a little blurrier and a little less noisy, and about a half stop more sensitive.
 
correct

correct

Yes, I am shooting at 1080p30.

That is where I am getting confused. When we have shot 16mm film in the past at 24fps, our shutter speed was 1/48 - since we were using a 180 degree shutter. Therefore, I assumed that when we shoot 30fps with the EX1, the actual shutter speed was 1/60th. Does this not translate to video? Is this what the rolling shutter issue is?

If that is the case, then shooting at 1/30 with the EX1 would give you the same motion blur as fillming at 15fps in 16mm - is that true?


I hopefully will never have to go back to interlace again. Until the EX1, I have been cheating the look of progressive with the XL1 frame mode, and the ZU1 cineframe mode. Both looked okay, it's just nice to finally get the full progressive image and information. That is why I am trying to keep the image as pristine as possible in production.
 
For a 180-degree shutter, the equivalent exposure would indeed be 1/60th. But you can get film cameras with all sorts of shutters; I've got a couple here that have 150-degree, 156-degree, and 220-degree shutters. At 220 degrees, the 24fps exposure is probably about 1/43. Doesn't make a whole lot of difference, they all look like film.

1/30th at 30p would probably be too blurry, 1/60th would be equivalent to a 180 degree shutter. 1/40th would be somewhere around a 240-degree shutter.
 
Daniel, thanks for sharing the clip.

I plan to to shoot a 24p wedding event soon. I will be mostly on 1/48 but for the evening - I'd like to try some 1/24 shots. Some people who have tried love it. I don't care about a little blur - better than grainy, dark, muddy :)

Did you shoot progressive or is that 1080i on 1/40th?

Paul
 
Barry_Green said:
Well, clarification please: when you say 1080 @ 30fps, do you mean 1080p30? or are you calling normal 1080i "30fps"? Because if so, you definitely wouldn't want to use 1/30th, it'll cut your vertical resolution in half.

If you're shooting 1080p, there's nothing wrong with 1/40th, it'll just be a little blurrier and a little less noisy, and about a half stop more sensitive.
Click to expand...


Barry, why would you say that a longer exposure time like 1/30th cuts vertical resolution? Are you thinking of the VX2000//PD150 cameras which did in fact repeat scan lines when shutter was set slower than 1/60th?

In the EX1, resolution is constant AFAIK, regardless of shutter speed. Otherwise those shots I did with nothing but moonlight would have been blurry.
 
basspig said:
Barry, why would you say that a longer exposure time like 1/30th cuts vertical resolution? Are you thinking of the VX2000//PD150 cameras which did in fact repeat scan lines when shutter was set slower than 1/60th?

In the EX1, resolution is constant AFAIK, regardless of shutter speed. Otherwise those shots I did with nothing but moonlight would have been blurry.
Click to expand...
I'm referring to 60i mode. Shooting slower than 1/60th on any 60i camera results in field doubling. 1/30th on 30P = full res. But 1/30th on 60i should result in field doubling.
 
I'm trying to understand why there would be a necessity to double the scanlines like this. If the camera were scanning 60i, why would it matter how long the shutter is open? I would think that the doubling of scanlines is an arbitrary design desicion, not a matter of physics of the scanning system, because if a shutter is open for the whole frame, the system would still scan both fields, though any motion between fields would be captured in alternate scanlines, would it not? I just don't see any physical principal dictating why scanline doubling would be required for slow shutter. Perhaps you know the reason?
At any rate, this is another test I want to try on my EX1. You've piqued my curiosity.
 
In this day and age, is there really ever any need or reason to shoot interlaced footage anymore?

I haven't shot interlaced since May of last year. I don't miss it, with its attendant production headaches, either. :)
 
basspig said:
because if a shutter is open for the whole frame
Click to expand...
Ah, there's the problem right there. In interlaced, there is no such thing as a "frame". That's a convention used by NLEs, but in interlaced there is a constant stream of 60 fields, not 30 "frames".

Think of it as a 540/60p system and it'll make a lot more sense, and that's a more accurate description of how it works.
 
basspig said:
In this day and age, is there really ever any need or reason to shoot interlaced footage anymore?
Click to expand...
Interlace should have died when we went to HD, but Sony insisted on keeping it alive. And so we have it with us today.

Interlace exists because the bandwidth to send a full 1080/60p signal isn't there yet. So that's why we had 720p vs. 1080i -- some people argued for a full-frame progressive image (at a necessarily smaller frame size for bandwidth reasons); others wanted a larger frame size (with the necessary compromise of slicing into fields instead of showing full frames). And then there's marketing; everybody knows a bigger number is "better" than a smaller number, right? So 1080i became known as "full HD" even though it stinks on ice as compared to 1080p or 720p.

One can only hope that if we ever make a transition to UHD, interlace will finally die the death it richly deserves.
 
NO such thing as a frame, yes, however, one would thing that as the CMOS samples a field, then the alternate field, if the shutter were to remain open for the duration of two fields, the images would still combine into a 1080 line frame, just the same as they would if the shutter were only open for the duration of one field. I'm probably missing something here, but I can't think of any technical reason why the fields would be duplicated just because the shutter remains open across fields.

I wonder if the new 32 megapixel ultra HD that Japan is testing is interlaced or progressive? They apparently are working on a system that puts Red and everything else to shame. Think of it: 32 megapixel picture--all in motion! That's more than the most expensive Canon SLR and as much as some view cameras with digital backs.
 
matthew77 said:
Yes, more motion blur, bit no real disadvantages otherwise.

If you have a lot of motion or fast pans/tilts, you might see more judder as a result.

Definitely not more noise. And 1/40 will not flicker with fluorescent lights.

If there is not much extreme motion in the scene, you might try "shutter off" which is the same as 1/30 shutter. It will give you an extra 1/3 stop over 1/40.

Just test the shutters and make sure you are happy with the motion blur/judder situation.
Click to expand...

i am curious, why would 1/40 result in more judder? i can see why it would give more motion blur but it strikes me as resulting less judder. i could be wrong of course.
 
Test it and see. You may not agree.

It's definitely a perceptual thing (probably related to the blur and perceiving the interval between blurred frames) and does not seem logical. But many people on these forums (myself included) find shutters fatter than 180° start to appear juddery, "shutter off" being the worst case.

My ideal shutter for smooth motion is around to 220°. More open than that and things start to get too blurry and fast motion starts to appear juddery.
 
Have you tried increased GAIN ?

Have you tried increased GAIN ?

Hi Carl, did you try increasing the GAIN setting to get more exposure? If you don't get the exposure (or amount of motion blur) you want with an increased shutter angle, this might give you what you want. I know at some point noise starts to enter in the the equation, but +6 db is pretty clean.

Also, if you go into PICTURE PROFILES and fiddle (my technical term,sorry) with black settings etc, you may be able to improve the image and get what you want. A little goes a long way, as this is a really easy way to mess up things. Thankfully, there's always the default settings to go back to.

In my experience, the EX1 really loves low light, so you may be in its wheelhouse with that moody restaurant shoot. Good luck and let us know how it goes.
 
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