A look at the Raspberry Pi High Quality Camera
/I’m beginning to wonder why we need “proper” cameras. My smartphone can now produce pictures that I can use for just about anything. And now you can get a high quality camera for your Pi. You can even swap lenses like the professionals. We are looking for something we can use to track robots, and so I thought I’d get one and see how well it works. I bought the “telephoto” lens because it seemed to be higher quality, but you if you can track down “C-mount” lenses (they are used in CCTV and video cameras) you can have what ever kind of lens you like. There is also a “wide-angle” lens which I’d quite like to have a play with now.
The camera connects to the Pi in just the same ways as previous cameras, but there must be an awful lot more data going down that little ribbon cable. I attached my camera to a Pi 4 and had a play. First thing I did was point the camera out of the window and take a picture. I got a 6.5 Mbyte Jpeg image. The top right hand corner of it looked like this:
This is not the entire picture. This is a tiny crop of the top right hand corner. There’s a lot of chromatic aberration going on (that’s causing the purple fringes) but detail is pretty good. Watch what happens when I stop it down a bit though.
Suddenly the image is much, much better. “Stopping down” means reducing the size of the hole that lets in the light. This means that the lens has to do less work and so I’d expect the image to be a lot better. The downside is that a smaller hole means less light, so the sensor takes longer to capture an image. This can lead to blur unless you use a tripod or increase the gain in the camera and get more noise.
I don’t particularly want to show you the view from my window, but what I will say is that the camera is doing a good job here. Once I’d taken some pictures out of the window, I took some of my desk.
This is the entire image of a corner of my desk. The minimum focus distance is not great for the tele-photo lens, at about 15 inches.
This is a 100% crop of the above picture, which should give you an idea of how much of the frame the branches above took. It should also give you and idea of the great quality of this lens and sensor combination.
This is a crop of the same image taken with the lens aperture wide open. This shows that you can get some lovely “out of focus” effects with this camera.
Good things to know:
There’s a really good book about how to use the camera. It’s a free download from MagPi Magazine here.
if you want to use the camera preview with VNC remote desktop you have to enable direct capture in the Troubleshooting Menu of VNC Server.
if you want to use VNC remote desktop to a Raspberry Pi with no HDMI monitor connected you have to use raspi-config to set a specific desktop resolution using the Resolution Option in the Advanced settings.
You can adjust the lens distance using a tiny spanner, but I’ve not done this. So it might be possible to get even sharper pictures.
The picture quality of the high quality camera is very good. But then again you’ll be paying around 100 pounds for the sensor-lens combination and so you’d expect something pretty impressive. I’m not sure how much the sensors in mid-range compact cameras cost, but I’d expect them to be around the same quality.
The “telephoto” lens that I got has quite a narrow angle of view, so if you want to do general stuff I’d suggest getting the wide angle lens instead.
Things will get properly interesting when these devices get into the hands of all the smart people that like to play with Raspberry Pi. There is considerable scope for some very interesting devices and if you want programmatic access to a very high quality image you’ve got that now.