Slow in darkness

[eimen]

Hi,

When i record a video in very good light conditions and, for example, i cross a tunnel, the video becomes slow. It slows.
Is normal?

A greeting!

 

[Nigel]

If you have it set to 60 fps then in dark conditions it will drop to 30 fps automatically to get a longer exposure time and stop the image becoming too dark.

 

[jokiin]

some cameras maintain the frame rate so that there is no change in speed but then repeat every frame, different way to tackle the same problem

 

[Gibson99]

some cameras maintain the frame rate so that there is no change in speed but then repeat every frame, different way to tackle the same problem

To a regular person who doesn't care about the technical difference between lowering the frame rate and frame doubling, the visual effect is the same.

But from a technical viewpoint, frame doubling is much easier to do on the fly compared to changing the frame rate on the fly. In fact a lot of video players probably can't handle a file that has a variable frame rate.

 

[jokiin]

To a regular person who doesn't care about the technical difference between lowering the frame rate and frame doubling, the visual effect is the same.

But from a technical viewpoint, frame doubling is much easier to do on the fly compared to changing the frame rate on the fly. In fact a lot of video players probably can't handle a file that has a variable frame rate.

dropping the frame rate I would consider to be more technically correct, frame doubling is a lot easier to work with for the end user and less confusing and is probably the better solution for the average Joe

 

[Gibson99]

There isn't a higher ISO equivalent. Since there's no shutter, ISO isn't a real thing in this (or most) digital camera. The sensor just isn't that great in low light. If you need low light sensitivity, the git1 is a better choice. Of course it doesn't do 1080p60 at all and doesn't have gyro stabilization either. But that doesn't stop me from using mine, even on my zmr250 clone (racing) quadcopter. And since I'm still learning to fly, it gets crashed a lot, sometimes at pretty high speeds. But then I also keep my camera in the waterproof case while on the quad for more protection and to mute the noise of the props/motors. So far the only thing I've bent or broken in crashes are props, landing gear, a few LEDs, and a battery pack. Camera's fine though.

 

[Gibson99]

http://www.digital-photo-secrets.com/tip/136/iso-explained/

The first comment also helps explain nicely.

 

[Nigel]

Older than the black thread.

Does anybody knows why the Git2 can not keep the 60fps stable?

That's what many people has asked and it still unanswered. I can live with the drop to 30 but it would be nice to have that question answered.

If the exposure time drops below 1/60th second then the next frame is simply not ready in time to be recorded so it has to duplicate the previous frame. The only way it can keep 60 fps is to ensure that it never uses an exposure time longer than 1/60th, but if it does then the image will become dark. I think most people think it will only become a little dark because they are used to having auto exposure in both the camera and their eyes, in reality it will quickly become very dark and dropping to 30fps is probably the best option.

 

[Nigel]

There isn't a higher ISO equivalent. Since there's no shutter, ISO isn't a real thing in this (or most) digital camera...

ISO is real, I think that article is confusing people by separating the light sensor and amplifier components within the sensor. ISO works in different ways in different sensors and may, or may not affect the light sensors themselves, but in all cases turning the ISO up increases the level of the data coming out of the sensor just as it increased the transparency of analogue film. It is a measure of the sensitivity of the sensor.

I think this issue would be solved allowing the camera to go as high as needed in the ISO scale. I believe the camera is programmed (FW) to lower the fps rate instead of going to a higher step in ISO to avoid a super grainy 60fps image.

Then, the "problem" is that there isn't a higher iso step on the Git2, or it is available, but is avoided to preserve image quality.

I'm just guessing.

People complain about loosing sharpness in low light more than they complain about dropping to 30 fps so while making use of the maximum ISO would solve one problem it would make the overall situation worse.

The solution for dark conditions is to use a more sensitive sensor, as Gibson99 does with his Git1, but I do like the 16MP photos from the Git2 - if you don't want to carry both around then you have to make a compromise.

 

[eimen]

Thanks you so much!!.

I will try with 1080p 30fps, because in the same ride on motorcycle i cant change the iso.

A greeting!!

 

[kamkar]

I am sure the firmware can be set to do 60 FPS and no frame doubling at night, but then the exposure cant go below 1:60 second, and since the camera is already using the highest ISO value at this stage you will just see much darker footage as a result.

And truth be told then night footage is rubbish on just about any camera as they drop to so slow exposure timings all you can film or take photos of with a good result is things that don't move or move very slow.

To have a chance of getting a fairly good chance of something that move or if the camera is moving, day and night you really have to use a exposure faster than 1:500 second, but that's more than 100 times faster exposure than any dash or action camera use in low light.
And really to get that really crisp capture of something at speed you can do better with even faster exposure times.

so we just have to wait a full or half decade before we have a chance of perfect low light captures, at least when we talk about cameras a regular mortal human can afford to buy.

Much more light sensitive sensors.
Wider ISO range.
Thats what we need in a tiny sensor in a tiny camera.

 

[jokiin]

locking it to 60fps would just mean very poor low light footage

 

[Gibson99]

yeah the only other alternative is a physically larger sensor. and i think that's why the git3 is going to have a larger body instead of sticking to the gopro form factor.

I only own both models because I was an early product tester for both models. If i had to choose one, i would choose the Git2, but then i very rarely record anything at night. but then i'm also not a "videophile" (i'm assuming that's the video equivalent of an audiophile - one who can detect minute differences in audio reproduction). I am just a regular guy that likes to get new perspectives using the camera attached to my quadcopter, mountain bike, or race car. in fact in the car i review the footage immediately after each run (autocross) to learn from my mistakes, not so much to show it to friends.

 

[kamkar]

I think it would be nice to have some action cameras that's tailored to low light, at least as tailored as you can with current tech.

And then leave the daytime to the mega FPS and 4K cameras.

Only problem is i would have to get one of each as i love to slow some action down, but i would also like a camera i could use in really low light.

I dont even know the IS that seem to work so nice in the daytime, do it still work in low light situations, or do it need to have clearly defined borders of the frame to work ?

 

[Nigel]

I dont even know the IS that seem to work so nice in the daytime, do it still work in low light situations, or do it need to have clearly defined borders of the frame to work ?

Gyro Stabilisation works fine at night on the Git2: http://www.pinkbike.com/video/445451/

 

[jokiin]

Gyro Stabilisation works fine at night on the Git2: http://www.pinkbike.com/video/445451/

looks good, I think anyone that doesn't think that's good enough probably has unreasonable expectations of what the hardware is capable of

 

[Gibson99]

I dont even know the IS that seem to work so nice in the daytime, do it still work in low light situations, or do it need to have clearly defined borders of the frame to work ?

I agree with Nigel, even with the lens covered up and you shake the camera you can see it trying to stabilize the image. I saw it when the lens was covered in snow after crashing my quadcopter.

 

[Psychosystema]

Can Gitup reply whether it's possible to have a mode for low light (so frame doubling), and turning it off (constant 60 fps)?

What I find jarring is when you enter a dark area such as a tunnel or forest for a short while and the Git2 already starts to frame double - to me it's very annoying.

 

[kamkar]

Yeah low light for dashcams or action cameras do not mean after sunset, add some grey clouds to block out the sun and cameras are dropping exposure times and if need be FPS to make usable footage.

Just driving into a forrest with overhanging trees and the shade it make will mean major changes to the settings a camera use.

 

[gitup]

Can Gitup reply whether it's possible to have a mode for low light (so frame doubling), and turning it off (constant 60 fps)?

What I find jarring is when you enter a dark area such as a tunnel or forest for a short while and the Git2 already starts to frame double - to me it's very annoying.

This depends on the SDK, I don't think Novatek will change this, we did checking this with them before.