What determines Light Sensitivity?

mjmcneese

mjmcneese

Veteran
I love my HVX, but man, it sucks in low-light situations. I keep thinking about getting a 35mm adapter, but the last thing I want to do is loose more light!

Shot with an HPX3000 last week and was amazed...

So, what determines how well a camera does in low-light? Sensor size? Sensor technology? Recording format? Lens?
 
Mike McNeese said:
So, what determines how well a camera does in low-light? Sensor size? Sensor technology? Recording format? Lens?
Click to expand...

Sensor size and the technology behind it are the culprits. The other options are simply things that reduce exposure for various other reasons.



I'd argue that it's not the lens. The lens effects your exposure. If you count the lens you might as well count shutter speed, framerate, etc.

Film emulsions and cameras with removable lenses are good examples. The asa/iso is not rated with the glass in mind.

Film stock speeds are based on chemical technology and size of grain.
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Right...what I'm saying is that if you put up an HVX vs something like a VariCam, EX1, or HPX500, the HVX is the worst with all other things being equal. Even with some of the cheapest glass on the bigger cameras.
 
The lens is the ONLY means by which light strikes the sensor. Given two equal cameras, the one with the lens of larger diameter, and better glass will gather more light. Since we are talking primarily here about cameras with fixed lenses, they become a factor. The 72mm lens on the DVX gave it a HUGE leg up on it's competitors in low light.
 
PerroneFord said:
The lens is the ONLY means by which light strikes the sensor. Given two equal cameras, the one with the lens of larger diameter, and better glass will gather more light. Since we are talking primarily here about cameras with fixed lenses, they become a factor. The 72mm lens on the DVX gave it a HUGE leg up on it's competitors in low light.
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Yes, because it is a fixed lens the "overall ability" to see in the dark, in part, is due to the maximum aperture of the camera lens. But the lens is part of the exposure formula not camera sensitivity. Lens restricts light therefore cant be sensitive to it. I'm assuming the lad was curious about chip sensitivity.

The fixed lens aspect can make determining what is camera sensitivity vs. exposure formula confusing.

The reason it is part of the exposure formula and not the sensitivity, is because the camera ASA/ISO would change when you would close the camera down. The lens could only be part of the ASA/ISO if the camera sensitivity were to be rated at wide open aperture, and you always shot wide open.

You are right about the overall ability to see in the dark, but as far as variables which are responsible for a cameras sensitivity, the lens is not one of them.
 
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Ok, I get where you are coming from now. With these consumer cams with fixed lenses, I tend to see the camera as an overall system, giving one the ability to compare camera 1 to camera 2.

In terms of iso/asa you are of course correct. Unlike film cameras though, our video cameras have fixed iso's, so I tend to see other factors having more weight. I can't pop out my 250D and go to a 500D like I could with film.

In your scenario, sensor size, and construction become the only factors. Though I would wonder if you would include sensor noise reduction since that would give subjectively more latitude by keeping darker footage less noisy.
 
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