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Skill Level Intermediate
- There's a new camera available for your Raspberry Pi. It's supplied by the Raspberry Pi Foundation. It's impressive 12 megapixels and detachable lenses and so much more. But, does it really produce better pictures? Let's take a look. Hi, I'm Mark Niemann-Ross and welcome to this week's edition of Raspberry Pi Weekly. Every week we explore the Raspberry Pi and share useful tips. I'm going to assume you already know how to attach this camera to the Raspberry Pi. If not, please check out Raspberry Pi essential training in this library, there is a section that walks you through installing the old Raspberry Pi camera, which is identical to the new camera. When you consider this new camera, there are four things to think about. Sensor quality, lens quality, cost, and additional features. Let's start with the sensor. Now quality is always subjective, but we can use some analysis tools to do a comparison. This slide shows side by side RGB histograms from the two cameras. These histograms show the response of each camera sensor to red, green, and blue light. These histograms are from the images shown in the introduction and included in the example files. The two images are the same objects with identical lighting. You'll notice the histogram from the new camera is dispersed more uniformly across the horizontal axis. This indicates a more uniform response across the spectrum, which is an earmark of a better sensor. There's a lot to know about sensor quality but briefly the new sensor and camera will produce better images. Next, there's lens quality, and here's where the discussion gets much broader. Essentially, the more you spend the better the lens, and that's where this new camera is really superior. The old camera had one lens and you couldn't change it. The new camera allows you to attach different lenses, you can spend $25 on a general purpose lens or you can spend $2000 on a high end zoom lens. If you want to spend the money, you can achieve some really spectacular photography. Finally, there's the cost of the camera. The original camera is cheaper by about $20 US, plus you don't have to buy a lens. The new camera starts at $50 for the sensor board, and then you'll also have to purchase a lens. You should plan on spending at least $75 to get started, roughly twice or three times the cost of the original camera. One of the things I really appreciate about the new camera is the tripod mount. The original camera has holes drilled in the circuit board and always required some sort of board mounting. The new lens has a standard tripod mount. This may not seem like a big deal, but it sure makes it easy to use in a range of setups. But enough product review, here's some tips and tricks you'll appreciate with this new camera. Because the lenses for this new camera have both a focus ring and an F-stop, you'll need to spend a bit of time setting up. And to do that it's really handy to have the Raspberry Pi display the image until you say stop. Here's how, I go to the Raspberry Pi, open up a terminal window. Type in, raspistill -t 0 -v. When you run this command, the Raspberry Pi will display the image coming in off the camera until you hit Control C. Now you can adjust focus and F-stop and see real time effects. One thing I learned was the difference between C-mount lenses and CS-mount lenses. Both work with this camera, the only difference is the focal point of the lens. If you're having difficulty getting your lens to focus, try removing or adding the optional CS adapter. For example, the six millimeter CS lens should not be used with the C-CS adapter. If you accidentally leave it in place, you'll be unable to focus the camera. Working the rings on the suggested lenses are a bit tricky. I found it useful to start closest to the sensor but the back focus ring. Now a side note to anyone with photography experience, you'll find these lenses is a bit frustrating to work with. Rings are mislabeled and don't behave the way a standard 35 millimeter camera lens works. Here's a photo of the back focus adjustment ring. I've moved it away from the sensor body so you can see where it's located. For the six millimeter lens this ring should be snug against the sensor body. Use a small screwdriver to lightly tighten the screw. When you have that ring focused, move to the ring labeled near-far, which is actually the focus ring. The post that sticks out of the ring can be twisted to tighten and loosen the outer two rings. Tighten the post on the open close ring, then loosen the post on the near-far ring. Turn the outer two rings to focus the image. Now here's an example of how focus changes when you rotate the near-far adjustment ring. When the image is focused, tighten the post on the near-far ring. Now loosen the post on the open-close ring to affect the brightness. This is actually the aperture control, also known as the F-stop. Grab the post of the open-close ring and rotate that ring. This will make the image brighter and darker, it will also affect the depth of field. As the image gets brighter, the depth of field will shorten. When you have set this to your satisfaction, tighten that post. To capture an image use raspistill just like the old camera. For more details on using raspistill or raspivid, watch the previous sessions on these applications in this weekly course. Finally, be sure to download a copy of the Raspberry Pi camera book. Either order it online or download the PDF. Thanks for joining me for this episode of Raspberry Pi Weekly, be sure to join the LinkedIn group and check out previous episodes on LinkedIn learning. I'll see you next week with more Raspberry Pi adventures.