I don't understand, aren't lens sized by their focal length?
Also, the lower resolutions offer the same 170 deg. FOV on the GoPro. Did you mean "That's HOW they get wider viewing angles..."? And even so that doesn't make sense to me; how do you possibly get a wider FOV by cropping the sensor?!?
Yes, lenses are sized by their focal length. I can only assume that calculator assumed a set diameter of lens.
Yes, that's how they get wider angles. When you crop an existing sensor, using only a portion in the centre of it, think about what that does to the angle between the edge of the portion of the sensor, that's doing the capturing, and the outer edge of the lens.
The Replay XD1080 looks like a cool little camera but I can't see as being a good first camera. It would be a great backup or second camera. I can see a bunch of advantages like the size, FOV and image quality but the disadvantages out-weight the advantages.
Disadvantages I see:
Non-replaceable battery
No way to aim the camera (laser or LCD screen)
No standard 1/4-20 thread to use regular tripods
uses micro-SD
Doesn't look like there's a way to delete just one file off the SD card
remote control is always nice
There's no camera out there that is perfect.
Here's a review of the Replay XD1080
http://www.webbikeworld.com/motorcycle-video-camera-reviews/replay-xd-1080/
I agree that the lack of a replaceable battery is a weak point. It's one of the limitations, that comes with the size and form factor. I've been told that they are developing a USB cable connection for it, that can be used for constant power. Or I could buy an extra end cap and cable, then machine one up myself. Weather resistant USB power connectors are about $7.00, at Princess Auto.
*EDIT* Correction: They've now added the hard-wired power option, for the Replay XD1080, to their accessories list. http://replayxd.com/product/xd1080-hardwire-car-adapter-with-audio-in-4-meter/
The camera has a built-in HDMI output, so it can be aimed by live viewing the output via any screen capable of HDMI input, like a widescreen TV. I've done this. It makes getting the angle right, when mounted to a helmet, a trivial exercise. The HDMI connection also has additional possible benefits such as being able to use commercially available HDMI external microphones or even HDMI transmitters, for live reception.
Yes, there is no standard threading for a tripod. If you want to use a tripod, then you can attach one of the plastic mount shoes to a quick release plate.
It isn't the only camera using Micro-SD. The same can be said of the Contour and even the Drift uses Micro-SD, despite it's larger physical size. It's a necessity, when you make a smaller camera, and Micro-SD is becoming more common.
You can delete just one file off the card but it requires connecting the camera to a computer, or removing the card and putting it into a reader. Both a Micro-SD card reader and a Micro-SD to SD adapter are included in the kit. The camera is set up to record files that are 1/2 hour long and starts a new file, after that time, without missing a frame. At first I didn't like it, but I've come to appreciate that feature.
Remote control is nice, but not necessary for my application. I'd never use it.
No, there's no camera out there that's perfect, but I can live with the compromises that I make when using the Replay XD1080.
