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Comment by bmurphy1976 | Hacker News Reader

bmurphy1976

I love this! I've been using mine as a webcam for a couple months now (among other side-projects). You need a different lens though.

The 6mm fisheye lens is crappy and the distortion is terrible. The 16mm lens is higher quality but the zoom makes it difficult to use as a webcam.

I bought the 6mm M12 portrait lens from https://commonlands.com/products/portrait-6mm-m12-lens which works much better. Being M12 it's not the best form factor, but it has a rectilinear picture and the framing is what you want for a webcam.

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I wouldn't call the 6mm 'fisheye', not on the tiny sensor on the HQ camera. Accounting for the crop factor, it's similar to a 35mm lens on a 35mm camera. Wide-angle, for sure, but not 'fisheye'.

I agree it's not amazing as a lens, but it's passable and cheap. Certainly better than the tiny webcam lenses on the majority of sub-$80 MSRP webcams.

I also have a Tamron 8mm f/1.4 C mount lens that is a bit sharper, and also renders things a little nicer, though it's a little tighter framing. Not bad if you can put the camera back a few feet, but would be cramped in a tight space.

Do you have any examples of this? I've been interested in building this Pi camera using a lens with a shallow depth of field, but it's very hard to figure out a lens to get that will work with the Pi, look right if mounted from around 2 to 3 feet away, and have a decent quality picture.

After spending a bunch of time researching, I got this feeling if I pursue this project I'll end up with hundreds of dollars of bad lenses and just wish I would have bought a real DSLR or mirrorless camera that connects via USB.

If you really just want that bokeh, it's going to be much easier and look a lot better with a DSLR air mirrorless. I typically use my Sony a6000 with a 30mm f/1.4 lens at f/2.0. You won't be able to get the same kind of background separation using the tiny sensor on the HQ camera.

I bought a Tamron 1.4 8mm lens that gives a similar effect to what my Sigma 30mm E mount lens gives at f/4 or so, if it's positioned about 2' away.

>it's very hard to figure out a lens to get that will work with the Pi, look right if mounted from around 2 to 3 feet away

This is why I purchased a Commonlands lens instead of a variety of others (including Arducam). The owner has gone through the trouble of taking a consistent photo of the imatest pattern for each lens they are selling, i.e. this:

https://cdn.shopify.com/s/files/1/0273/9273/7398/products/ce...

and measuring the amount of distortion and listing it as part of the specs.

That gave me a really good idea what the picture was going to be like before I purchased the lens, and the product I received accurately reflects what was shown in the image.

It also showed me that even a small amount of distortion (2%) was too much for my use case.

Did you also need to buy the M12 Lens to CS mount camera adapter for this to work with the Raspberry Pi HQ camera? https://commonlands.com/products/m12-to-cs-adapter?variant=3...

Yes, you need some kind of adapter. I bought theirs and it works fine.

Isn't the example footage in this video using the fisheye lens? Where is the distortion? https://www.youtube.com/watch?v=8fcbP7lEdzY

Here's a picture taken (not by me) with the 6mm lens:

https://www.reddit.com/r/RASPBERRY_PI_PROJECTS/comments/gnww...

It works well as a macro camera for super close up pictures, but otherwise it's pretty terrible when compared to my other lenses.

I don't know which lens Jeff used in his video, I would have to rewatch it and I'm not inclined to do that. If he used the 6mm lens he would have likely cropped the image or used post-processing to remove the distortion.

Processing the image is a solution, but it has tradeoffs and I'm not sure how easy it is to do it in real-time on a rapsberry pi zero.

> I don't know which lens Jeff used in his video, I would have to rewatch it and I'm not inclined to do that.

He uses the "official" 6mm lens.

I use it daily for video and I just loaded it up and re-checked - I don't see distortion like in that reddit posted image. I see something very similar to the examples in Jeff's video. I highly doubt he'd have post-processed the video, that would be extremely misleading. In the context of similarly priced webcams that are available to buy in 2020, I find it very usable and not at all terrible. But I do appreciate it's all subjective.

I don't believe he's using the lens without some kind of post processing.

I think you need to take a closer look at your lens, perhaps you bought a different model. I'm not the only one complaining about the poor quality of the official 6mm lens:

https://www.raspberrypi.org/forums/viewtopic.php?t=272658&st...

Every picture and video I've taken with my 6mm lens has this distortion clearly visible.

I'm certain lens which I have, it's the same as Jeff's. It works just fine as a webcam with the object of focus in the centre.

I am bad at evaluating what's a good video or not.

Would you the “official” 8mp raspberry pi cam (2.1) is worse than a dell laptop webcam ? (as in: not worth my time reusing one to have a movable camera for zoom calls ?)

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