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Cameras and Lenses

ciechanow.ski

171–180 of 241 posts

Re: Cameras and Lenses

#171
post #140

Earlier quoted context omitted.

Indeed! We like to think of light as photons, traveling in rays in straight lines. That's geometric optics and works great for most purposes in photography. Physical optics takes into account the wave nature of light. This becomes important when the size of the lens becomes small (eg pinholes) ... there's diffraction around edges and pixels receive contributions from many points in space. Geometric optics lets you mo…

Thanks for weighing in. My kid and I are really enjoying The CuCoo's Egg!

I read that a few times when I was younger. It's such a great story, and I've always been meaning to revisit it as an adult. When my kids get a little older I'm sure we'll enjoy it.

Re: Cameras and Lenses

#172

Earlier quoted context omitted.

“They” is historically understood to be plural. Some information fidelity is lost if “they” can mean multiple people and a person. Language is hard, so I understand the need for compromise. “Zee” could be used to avoid gender centric labeling while maintaining language clarity.

That is not true. Singular they has been in use as long as plural they. It has always been understood to be usable in either situation.

I'm sure there are examples, but in common use it is understood to be plural and has been used that way in all writing for a long time.

Re: Cameras and Lenses

#173
post #7

Although I knew most of technical aspect described having immersed myself in Photography several years ago, I cannot express properly how GOOD this article is. The sliders and diagrams are brilliant for helping a layperson understand how it all works. Kudos!

+100 because I came here to post exactly what you did. I just bookmarked this to share with my tween who's getting interested in photography and starting to ask things like "Why that camera?" and "Why this lens?"

Re: Cameras and Lenses

#174

Earlier quoted context omitted.

I'll share something with you. The level of consideration you have for people who are no more than 1% of the population is admirable. Very admirable, in comparison with the actual large problems that I'm sure you pay 0% attention to each day, and do make assumptions about. So very admirable that you go out of your way to bring this to the level of everyone having to select a pronoun in their dropdown menu because you…

You're lashing out in anger. Calm yourself. It seems like you dislike trans folk. I'm not sure what they did to hurt you, but I suspect your fears and hate are the result of conditioning. What harm is it to use singular "they"? It avoids assumptions. It also avoids sexism. Do you want a world where all contributions are assumed to come from men? You've got a lot of fear and anger. Reflect on it. Let it go. I don't kn…

Your rhetorical style is very harmful to the people you claim to support. You received criticism for your interactions and you immediately redirected that towards hatred for "trans folk" in an effort to smear the person who said it.

> What harm is it to use singular "they"?

That's not what the OP is saying. Because of course there's no harm in any pronoun. But there is societal harm in acting high and mighty about how saying "they" is somehow making a better world and then acting like a prat when called on it.

> regressive labels. ... people will be all sorts of genders. They won't be bound by yesterday's norms.

No, modern twitter activism is just making a bunch of crap up, and this over-concern on properly labelling everyone's gender expression just harms actual transexual people with actual body dysmorphia.

What people who harp on pronouns miss is that pronouns are not used to refer to someone's gender but their sex. I can see your sexual characteristics from across the room, and referring to them is a good way to narrow down who I'm talking about. "That's her there, the tall one in the red dress". Nobody is going to say "That's zir, the one who is only sexually interested when they're romantically attracted to someone, and whose gender expression varies with the weather." Not only is it a bunch of totally irrelevant and inappropriate discussion for most settings, but it's invisible and thus worthless in a referential sense.

The pronoun warriors are invariably not sexually dysmorphic, they're just deconstructing their parent's mores. They're today's goths, not some miraculous new human evolution. If they manage to do something new and valuable - if for instance Harry Styles actually looked good in a dress - all they'd end up doing is expanding the normal dress code for men, they wouldn't actually be creating a new identity. And this isn't helpful because society explores these things (copying elements of one sex's traditional styles in the other sex's new style, etc) via fashion designers and manages to do it without attacking each other's moral character and making queer/intersex people into political pawns.

> It seems like you dislike trans folk. I'm not sure what they did to hurt you, but I suspect your fears and hate are the result of conditioning.

If they had displayed any hate, and they did not, it would have been caused by conditioning from vocal jerks, not from trans people living their lives.

> Would you be a stuffy gender policeperson, or will you just let people be who they are?

Okay, in what way are people not already 100% allowed to express their gender? (In the USA, Canada, etc...)

To someone in the Q-adjacent community who has been through Tumbler and Twitter, you're incredibly transparent. Everything you say is divisive, rude, harmful because it distracts from actual problems, and because it makes this nonsense seem important. You're clearly a justice warrior, not someone who works for justice.

> You've got a lot of fear and anger. Reflect on it. Let it go.

And you're doing this in the name of a community who was doing just fine on their own. Trust people to speak for themselves. Don't pick fights in their name.

Since the LGBTQ institutions have been taken over by the woke they've pushed gendered nonsense and the public isn't blind. Mental breakdowns over pronouns, putting men in women's prisons, etc. Your behavior here is part of a pattern that has reduced LGB acceptance over the last few years, and while Trans acceptance is superficially up, it's at the cost of hateful wars against transexuals, for instance.

I know an ~60yo MTF who was savagely attacked online, under their actual name, for saying that they were tranSEXual because they knew they were biologically male and wanted to be a woman. They were told their language was hateful and they were "killing us!" even though they nearly lost their job, and were being bullied in a way that actually causes people to kill themselves. This is an actual person who spent the last four decades living as the other sex, fighting actual discrimination back in the day, and the mob wanted to cut them down for not toeing the woke line.

The effect of this allyship is similar to Portland, where white Antifa activists are using BLM as an excuse to riot. There's a 'funny' video of a black officer saying he's been racially insulted more during the BLM riots than in their entire career before that. He continues to say that every time a black person tried to speak to him - to ask about his actual views and rational for being an officer - that white BLMers come and physically block their interaction. The rioters don't want anyone to find a middle ground and solve anything because they're using black people to justify their anarchist cosplay. "Oregon Public Broadcasting reports Wednesday that black members of Portland’s Black Lives Matter movement are tired of their anti-racism demonstrations being hijacked by the mostly white “Antifa” anarchists and are working to separate the two movements as protests continue."

Similarly, I've never seen the pronoun police display actual concern for anything other than their ability to control people.

Reflect. Stop. Thanks.

Re: Cameras and Lenses

#176

Earlier quoted context omitted.

Well yes but you're still going to need a sensor as large as the aperture of the lens you want to simulate, which makes it a non-starter for phones.

Yea, this type of image recording has huge compromises but I personally find it really cool.

So do I! If I had a bit more photography budget I'd try them out.

Also, I'm excited about cameras with dual/quad pixel AF, that are kind of a hybrid between lightfield and traditional cameras. I wonder what kind of sorcery one would be able to do with the light field data in those cameras!

Re: Cameras and Lenses

#177

> Alternatively, we could increase the sensitivity of the sensor which is described using the ISO rating. Umm well, not really. The sensitivity of a digital CCD or CMOS sensor never changes; it has one 'native ISO' equivalent sensitivity and that's all. It creates the same output signal in response to a photon every time. Varying the pseudo-ISO simply varies the gain of the downstream post-readout amplifier. That's w…

Only some camera sensors are isoless

Re: Cameras and Lenses

#179

The only thing better than a pinhole camera is a pinhole camera with multiple holes. Let me explain: When you have two holes (apertures), their images would likely overlap (depending on the arrangement). Imagine you took two photos from a few millimetres apart to the left and to the right, then you superimposed them. Some areas would look ok (as both views saw the same distant object) and some would be less ok (of ob…

> That "infinitely many overlaps" I was talking about happens with lenses too and is essentially a convolution where you convolve the image with itself (actually many different perspectives of itself if I am correct). Which is just the Fourier transform. That statement is a bit muddled, let me unpack it. The infinitely many overlaps thing can be expressed mathematically as the convolution of the image with a function…

I suspect the GP comment is referring in context to the use of the Fourier transform to efficiently implement convolution.

Re: Cameras and Lenses

#180
post #153

> Alternatively, we could increase the sensitivity of the sensor which is described using the ISO rating. Umm well, not really. The sensitivity of a digital CCD or CMOS sensor never changes; it has one 'native ISO' equivalent sensitivity and that's all. It creates the same output signal in response to a photon every time. Varying the pseudo-ISO simply varies the gain of the downstream post-readout amplifier. That's w…

There are also "dual native ISO" sensors. Still different apmplification levels, but in this case it is before ADC. See https://www.youtube.com/watch?v=g8hHFt3ChZ8

"Dual native ISO" sensors don't perform different amplification before the read out amplifier or anything like that.

With an image sensor you get to decide between high sensitivity and high capacity (how much light it can detect before saturating). So a highly sensitive sensor can handle less light before clipping (which makes sense).

This trade-off can be tweaked by changing the size of the photodiode (bigger diode -> more sensitive), but also electrically - simply add capacitance in parallel to the photodiode. This requires more energy, i.e. more photons, to change the voltage over the photodiode, which is what the readout measures.

Dual native ISO sensors simply add another transistor (as a switch) in series to extra capacitance; this allows them to switch between low-capacitance (high sensitivity, but saturates faster) and high-capacitance (lower sensitivity, can handle more light).

Edit: Haven't watched the whole video but his core explanation in there seems to be that Dual ISO means the sensors has a PGA (programmable gain amplifier) -- almost all sensors use that approach, and that's what is controlled by the ISO setting in them.

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