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Why use two cameras?

Hans Ham

Junior Member
#1
FPV flyers use 2 cameras because the HiRes signal of the recording camera takes too much bandwith. But is it possible to take the HD signal from the recording camera and convert it to low resolution and use that for your FPV? I guess that will reduce weight and may improve image quality.

I do not mean the all-in-one camera from Boscam, because I would like to be free in my choice of camera, OSD and transmitter.

Is this kind of module available? Just a video signal converter? I think this would be a nice topic!!
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#2
Lag.

Most DVR cameras have beautiful video out, but 100's of miliseconds of delay between the image and real life.

If you're flying something slow and stable it's not that big of a deal. You learn to fly ahead of it, although that mental exercise can be a bit more taxing -- that can steal the fun out of it :(

If you're flying something fast around obstacles, you'll hear the *SMACK* before you see what you just hit.

BTW, Welcome to the forum!
 

finnen

Senior Member
#3
Lag as pointed out, but a couple of other reasons as well:

Reliability, a simple board cam works as long as it gets voltage, while it is possible for a gopro to freaze and crash. It can also run out of battery if you forget to charge it.

Modularity, I don't always want to fly with a heavier, more expensive and fragile HD camera. My miniquad frequently flies with just the board cam, saves a little weight and I don't risk destroying a mobius (the board cam is much more protected in that type of frame).

Flying with a gimbal. It can be difficult to fly a quad with a gimbal from the gimbal mounted camera. You have no idea how the quad is tilted, or even the direction on a 3-axis gimbal. In that case you might want to fly the quad from a rigidly mounted board cam instead.

But it is of course possible to use the same camera for both recording and fpv. Both the GoPro and the Mobius have live video out cables that you can connect to the video transmitter, and I don't believe the cables cost much. Some people do that, for just the reasons you point out.
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#5
It's flyable but painful. a Glider or heavy lifter with Alt hold would be fine with it, but otherwise, I'd avoid it.

I started with a Mobius and hated it. It didn't actually start being fun until I switched to a board camera.
 

Cyberdactyl

Misfit Multirotor Monkey
#6
Yes the board cams are basically instantaneous. . . maybe a 30ms delay. My GoPro has around as 300ms delay. Threading through trees is absolutely hopeless using a GoPro.

The GoPro reminds me a lot of the 56K dialup days of online FPS gaming. The card camera is like high speed broadband cable. ;)

I suppose you could adjust using basically the same techniques used in the old PC shooter days by 'lag-leading' (basically as Crafty said, by flying in the future half a second), but where it becomes truly impossible is when you have to change your mind on a flight path through trees and such, at the last second.