"Why can't we have a metering system that produces perfectly exposed images?"
We do, it's called you. ;~)
First, we have to get to the critical word in your question: "perfectly." I'd like you to explain what you mean by that word.
What happens when I ask for such an explanation is one of two things (sometimes a combination of both): (1) the person being questioned starts to awkwardly talk in circles; and/or (2) they want the camera to not blow out highlights and then tonally compensate everything down to black.
Good luck with #2, as you and I will certainly disagree on the second half of that construct ("tonally compensate"), and so will everyone else. And a large percent of you will also ask for more saturation and contrast, and typically more contrast in the mid-range, too, where it isn't needed (take that Clarity! ;~).
I grew up on the Ansel Adams and the Time/Life photography book series, both of which worked through everything from what is in front of the camera, what lens was being used, how the camera worked, to what the film captured, how the film was processed, and how a print was made. The goal throughout each step was "optimization," but it was also clear that each step required the person in charge—that would be us, the photographers—to be making decisions. Good decisions, particularly early in the process chain. The more bad decisions you made in the early bits, like image capture, the less likely you could fix them. By contrast, making a bad decision at the final print stage just meant you were going to go back to the darkroom and try again.
What people are asking with the question above is only one step removed from "why can't we have a camera that composes for us?"
I've written this before, and I'm sure I'll write it again: back when I taught filmmaking at Indiana University one of the things I had to correct in every student's mind was that documentary films are a reflection of the documentarian's decisions, not reality. Why? Because you had so many choices you were going to make, including but not limited to when and where to put cameras, whether the cameras would be visible to the ones being recorded, and which clips you decided to put in your final edit. Hundreds of decisions go into every image capture or film recording.
Why would you want something else making those decisions for you? That just starts to make you the operator that flips the On switch for a robot. Now I don't mind having a robot clean the floors of my house, as that's not an artistic or personal endeavor at all, and I find it a chore I’d rather not do. But I do mind having a robot pointing and composing my camera, picking when to press the shutter release, and placing each Zone at a particular value. That's no longer fun or interesting to me. It probably shouldn't be to you, either.
"Where I live is relatively boring, so I'm not finding things to take photos of. What should I do?"
Welcome to existentialism.
As for photos, if things are truly boring around you, you can take photos of boring things. Those are still photos.
"What are the best settings, e.g. ISO and aperture, for getting the highest sharpness and least noise?"
I can think of two answers to this question. The first answer is the theoretical absolute: the lowest numbered ISO on the camera and the tested aperture at which MTF is maximized. Personally, I ignore the theoretical absolute answer most of the time these days.
The second answer is: the ISO and aperture that net you the best results for the situation/conditions. Oh, oh. That means you have to think (and test). It seems that many budding photographers don't want to think, let alone test. They just want someone to tell them what to use—often they really just want the camera set to "automatic"—and they then consider that golden. At least until they see the results, at which time they ask the question in bold, above.
Then there's the additional issue of whether we're talking about JPEG or raw. If you want out-of-camera-perfect results, you have a ton of other settings that you must get absolutely correct, including things like Picture Controls, Saturation, Contrast, Noise Reduction, and these days, perhaps a dozen more. If you want perfect raw conversions, then things become more dependent upon your ability to recognize issues that arise in the capture and use the right tools to deal with those.
Let me me re-direct your question. What are you trying to photograph? What's the goal of that photograph? Sharpness and noise are attributes subordinate to your answer, not the answer themselves. When I look at an image the first thing that comes to mind isn't how sharp or noise-free it is, but whether the subject matter immediately draws me in. Heck, if the photo is of a sandstorm, how would I even tell it's noisy? ;~)
For what it's worth, most of the photos you find memorable are neither sharp nor noise-free. Some are sharp and noise-free, but that isn't the reason why remember them.
So try this mantra on for size: subject first, discipline second.
“Should I use JPEG or HEIF?”
You only use HEIF if you have an HDR-enabled output device to show it on. That means you need a display that’s HDR capable; printers need not apply. Specifically: a display supports the BT.2020 Color Space and understands the HLG tonal curve (JPEG is sRGB and 2.0 gamma curve). All current iPhones, iPads, and MacBooks are capable of displaying HDR, but there’s a lot of gear out there, including older Apple gear, that is not. Again, the software running the HDR display has to understand HEIF, too.
The full answer to the question is:
- For finished images for distribution anywhere, use JPEG.
- For finished images solely for distribution on HDR-enabled devices and software, use HEIF.
- For the best information useful for post processing, use raw.
