tim... wrote:
"Recliner" wrote in message
...
tim... wrote:
"Roland Perry" wrote in message
...
In message , at 20:37:27 on Wed, 23 Oct
2019,
Recliner remarked:
Roland Perry wrote:
In message , at 19:05:11 on Wed, 23 Oct
2019, remarked:
On Wed, 23 Oct 2019 09:34:49 +0100
Roland Perry wrote:
In message , at 07:41:34 on Wed, 23 Oct
2019, remarked:
I wonder if dashcams storing low/uncompressed video is so it can
accurately
capture very fast movement - eg just before an accident - which
most
video
compression systems are not particularly good at.
I think it's because they don't want to have the
silicon|dollars|power
budget of compressing the video. They externalise it to users having
to
buy stupidly big SD cards.
My previous dashcam gobbled through 1.2GB for each ten minute file.
There must be more to it than that. Even cheap smartphones can do
realtime
video compression.
They produce files in MP4 format, but not very much compressed. My
phone
produces typically 150MB per minute (1920 x 1080 pixels).
So, Full HD video.
Like my dashcam (I presume the camera is essentially the same as that in
a
phone).
The hardware is probably commodity by now.
My whole dashcam only cost about £30.
That doesn't leave much budget for the lens.
The lens is quite large (1.5cm), and wide angle (170 degrees). And yes,
it's probably one of the more expensive components.
I don't see why
non focusing, non zoom-able lenses cost pennies to make
It's still a high precision optical component, probably with four or five
elements, at least one of which is probably glass. Would it also have
not the one on mine
a single moulded item
I'd be very, very surprised. You'd get horrible image quality, unacceptable
even for a dashcam, with such a basic, single element lens. The elements
may be moulded plastic, but there are almost certainly several of them.
aperture blades?
that is behind the glass not within the glass
In all my many cameras and lenses, the aperture blades are between the lens
glass elements. But a small, cheap lens like this may have a fixed
aperture, with sensitivity controlled electronically. I also assume there's
no image stabilisation in such a cheap model.