Comment by frognumber | Hacker News Reader

Comment by frognumber | Hacker News Reader

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#confidentlywrong

Most modern cameras can stream video to a computer through a proprietary protocol. These are implemented under Linux in gphoto2, and in other OSes, through some proprietary tool. During the great webcam shortage of covid, many companies made special, flaky Windows utilities to allow those to be used for web conferencing. Very few can natively as a USB Video Class (UVC) device. This is Canon's version:

https://www.dpreview.com/news/4796043082/canon-s-new-softwar...

Now, for Canon, it's a monthly subscription:

https://www.usa.canon.com/cameras/eos-webcam-utility

As a footnote: The general rule-of-thumb is about f/11 is where you start to notice diffraction limiting sharpness on full frame. That's a rule-of-thumb, and you're welcome to not step down below f/8, but calling f/9.5 "abysmal" is more than a little over-the-top. But no, a phone will not compare to a full frame with a $2000 f/1.2 lens. But it's quite competitive with a kit lens.

I had to board an airplane so I couldn't type a full reply earlier. Diffraction limits are different based on the sensor size, pixel pitch, and the lens optics, and diffraction affects sharpness even with a more open aperture, it's just limited in comparison to the impact of increasing depth of field as you stop down. Part of composing a scene is choosing how you want to balance DOF / sharpness, which can go in many different directions depending on what you're trying to achieve.

It's simply not the case to say that diffraction doesn't affect sharpness below f/11, and diffraction is not the only impact that can affect outcomes from stopping down, when you stop down you are letting in less light over the same sensor area which affects almost every aspect of exposure, and has to be compensated for either by increasing ISO which increases noise or by reducing shutter speed which limits motion compensation when shooting handheld, all of which can affect the level of detail that is rendered sharply in a frame, either due to blurring or due to unrecoverable noise.

Generally, my personal preference is to stop down enough to get a sharp frame edge to edge across the center when trying to capture wide scenes, and no more, on many lenses f/4 is enough, generally no more than f/6.3 is required. You begin making serious tradeoffs as you stop down further, especially if, like me, you shoot handheld almost always, and often manually focus (e.g. subtle movements can affect your critical focus distance).

Your rule of thumb is largely irrelevant, you should be making these decisions each time you make an exposure to achieve whatever artistic effect you are going for.

Video features are manufacturer and model dependent. Nowhere in my comment did I say that they use UVC vs requiring software. My Nikon Z8 as an example can be used with OBS over USB very easily, but you must install a driver and utility.

Regarding Canon, true enough, they gimp their products to be greedy. That's why https://www.magiclantern.fm/ exists.

Your general rule of thumb is irrelevant. There are many optics tests done of available modern cameras, including phones. Phones get nowhere close to the photographic quality of a proper camera, but are totally fine for viewing on another small screen or small prints.

My wife has had prints of photos taken with her phone hanging in galleries, but even she (who prefers a phone as an artistic style preference) would never dream of printing anything larger than a 5x8 from a phone. My photography prints on the small side tend to be 12x18, and I often print as large as 40x60. A photo from a phone is simply unusable for me.

Then you have issue with reading comprehension. The whole point of the discussion was this:

"The time to do this was about a decade ago. Apps, open formats, open USB protocols, open wifi / bluetooth protocols, and semi-open firmware (with a few proprietary blobs for color processing, likely) would have led things down a very different trajectory."

And the rest of your posts also misquote what I said and, ironically, just as often, what you said. There are also minor technical errors: diffraction limits are basic physics. It's a simple relationship between (a) the radius of the circle of confusion (in units of angle); (2) the frequency of light (in linear units, typically nanometers); and (3) the radius of the aperture (in linear units, typically mm). There is no voodoo with "sensor size, pixel pitch, and the lens optics." Most of your post is taking statements like a basic rule-of-thumb of what you need for decent photos and exaggerating to statements like "diffraction doesn't affect sharpness." Of course it's easy to beat up a statement if you misquote it. That's called a strawman.

So I think I'm done here. Give me your downvote, and I'll argue somewhere else.

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