1080p, 4k, 60fps? What does it mean?

[postits]

Im looking for a camera i can mount on a motorcycle helmet that has good low light and can be used to pick out license plates. I dont really understand what any of the terms mean.

I assume higher fps means more frames and hence more chances to get a clear shot of a plate. I know 1080 and 4k relate to screen size but i assume that also relates to resolution.

Im thinking about getting an action cam that does 1080p 60fps. Is it worth it?

 

[Deaned]

For now, I'd say, 1080p and 60 FPS (frames per second ) will get you the best output. Normally having 4K (which is 4 times 1080p resolution) will obviously get a better image quality, also when downscaled to back to 1080p, but with less FPS, a higher file size and a need of more computer power when editing. My GoPro records in 4K, but only at 15 fps, which makes the video look a bit jerky when compared. There's also editing programmes that won't output to 4K video (Windows Movie Maker as an example). If needed, you can go down to 1080p 30 FPS. It will look good too, but it won't be as high file size, with one downside being that it's not as "optimal" if you'd wish to slow down the video when editing. All summed up, 1080p 60 FPS is a very good choice.

 

[postits]

thanks dean. Is there any objective way to measure how well a camera will resolve things going at high speed (camera shake) bluriness, smeariness etc?

 

[kamkar]

If you use 60 FPS the camera cant go below 1:60 second exposure timing, and i do think all dashcams drop below that at least at night but i allso think they do that on overcast days.
A rule of thumb in photography say that you should not go below 1:250 second exposure time with a handheld camera, so when dashcams drop down to 1:60 or even 1:30 second there is a good chance of motion blur in the footage.
This is offcourse more pronounced at the edge of the frame, witch is where us dashcam users see a lot of action.

Allso all dashcams and action cams witch have the option for 60 FPS footage or even higher will trottle back automatic if it get too dark, the higher FPS you use the more light is needed.
Same with taking a picture with your digital camera, if you use 1:30,000 second exposure time you will need a lot of light and a large aperture that let a lot of light thru to the CMOS chip.

Out dashcams can only play with ISO and exposure times to try and get us good footage, the aperture is fixed by the lens the camera use.
So even on a nice sunny day you can be in a situation where the camera will find it hard to produce perfect images, and if it then get cloudy and dark it will be even harder for the camera to get optimal footage.

The optimal for dashcams and action cameras would be if we could get 4 x more light sensetive CMOS chips.

 

[Street Guardian USA]

Check out the Innovv C3, has interesting mount options, good night quality. It's Full HD but not 60fps. You won't find many super compact 60fps options quite yet.

 

[RockThinking]

For now, I'd say, 1080p and 60 FPS (frames per second ) will get you the best output. Normally having 4K (which is 4 times 1080p resolution) will obviously get a better image quality, also when downscaled to back to 1080p, but with less FPS, a higher file size and a need of more computer power when editing. My GoPro records in 4K, but only at 15 fps, which makes the video look a bit jerky when compared. There's also editing programmes that won't output to 4K video (Windows Movie Maker as an example). If needed, you can go down to 1080p 30 FPS. It will look good too, but it won't be as high file size, with one downside being that it's not as "optimal" if you'd wish to slow down the video when editing. All summed up, 1080p 60 FPS is a very good choice.

I think you answer my questions that how to deal with 4k videos as if do not have a 4k monitor to review.
Seems like 360 degree videos, looks very attractive, but there is a paint process required.

 

[russ331]

Im looking for a camera i can mount on a motorcycle helmet...

Mobius is a popular choice with bikers. Here's an example of one integrated within a helmet, which neatly avoids the "dick with a GoPro on his head" look...

http://www.rcgroups.com/forums/showpost.php?p=30149182

 

[jokiin]

which neatly avoids the "dick with a GoPro on his head" look...

I believe the technical term is 'Teletubby'

 

[mollydog]

kamkar1, some very good points, just one point I'd like to make, I was always told about exposure/shutter speed (with photograph), the shutter speed should not be lower (longer time) than the focal length of the lens, therefore, with a shutter speed of 1/60th, a lens with a focal length of 60mm will be OK, 60mm having an angle of view of 33° the wider angle of view of the lens the more slower shutter speed one can get away with

in 35mm terms

lens angle of view
focal
length

12mm 113°
15mm 100°
16mm 97
19mm 87
21mm 81°
24mm 74°
25mm 72°
28mm 65°
35mm 54 °
40mm 48°
45mm 44°
50mm 40°
55mm 36°
60mm 33°

as most DVR's have a lens with an angle of view of 120° a slower shutter speed should be OK, lets not mistake 60 FPS for an exposure of 1/60th, this is how I was told

 

[kamkar]

well what i know if photography is just very basic knowlege from a add on class in the 8 or 9 grade, i myself have allso been taking useable pictures with < 250 second exposure time.

Back then we wound the raw film up on cartridges ourself, think it was 400 asa B&W we was given in school, if we wanted slower or faster we had to buy it ourself
For a while i think i did 120 B%W pictures every week, and then develop them myself in photo class

I have started to trow out all my old paper pictures, first betch was around 30 Kg of pictures and negatives.

 

[Nigel]

as most DVR's have a lens with an angle of view of 120° a slower shutter speed should be OK, lets not mistake 60 FPS for an exposure of 1/60th, this is how I was told

That is true, and also most dashcams are not handheld, but mounted on your car springs with movement well damped by your suspension dampers (shock absorbers) so you can have much slower exposure times.

However we do use them for recording motion, often high speed motion, not static scenes and so the required exposure time is normally dependent on your speed far more than anything else.

It is important not to confuse fps for exposure time, they are completely unrelated. To get a sharp image of fast moving objects you need a short exposure time, the fps (frame rate) is irrelevant. A fast exposure requires either a high sensitivity sensor (ISO rating), a bright lens (eg f1.8) or good lighting, or preferably all three.

A high fps will give a smoother video which remains reasonably smooth when viewed in slow motion.
A fast exposure will give less motion blur.
A high resolution will give sharper images but only if there is no motion blur and the camera has a lens to match the sensor resolution.

The definition of 4K given above is wrong, however there seem to be many definitions depending on what the manufacturers are trying to sell, it's a bit like 720p video being described as HD.

720p HD can be described as 1.2K
Standard HD can be described as 1.9K.
The mini 0806 can be described as 2.5K based on it's 1080 21:9 cinema mode.

To achieve true 4K from a dashcam will require a very good quality lens, certainly if you want it to remain sharp right into the corners of the image as the mini 0806 does.

 

[mollydog]

very good points Nigel, I thing we are both on the same track, 60FPS is not the same as 1/60 shutter speed,

and the wider the angle of view the more camera shake we can get away with

I'm not sure if these DVR's have a set shutter speed or/and aperture and has the firmware to control the exposure,

 

[country_hick]

I know a dash cam comes on and off when 12 volts is applied.
Beyond that is a dash cam comparable to the standard small handheld cameras sold at best buy and walmart for $100 or less as far as resolution and night capability are concerned?

 

[jokiin]

Beyond that is a dash cam comparable to the standard small handheld cameras sold at best buy and walmart for $100 or less as far as resolution and night capability are concerned?

Sort of, the handheld cameras aren't made to be used in the same type of environment so performance is much different, a dashcam needs one setting to cover as many usage conditions as possible, the handheld products don't need that as you can adjust accordingly each time you use them