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Comment by asdff | Hacker News Reader

I don't know why pros who already have gear would move to mirrorless. Its a step back for them. Battery life gets slashed by 2/3rds at least. AF is probably worse. Plus now you need to buy into a new lens ecosystem for the first time in 40 years.

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Like many technologies, the first couple of mirrorless cameras were a step back from DSLRs, but the fundamentals of mirrorless design have allowed them to rocket past the capabilities of any DSLR.

Take a look at the Nikon Z9, which is a professional mirrorless and shutterless camera.

It can take essentially infinite shots without wearing out. DSLRs need maintenance every few hundred thousand shots, which sounds like a lot, but some pros take 10-20K per day. Timelapse videos especially are murder on DSLRs and can take big chunks out of the shutter mechanism lifetime.

The lack of moving parts means it can be totally silent and take full-res shots at 30 fps without mirror blackout. Lower-res shots can be taken at an astonishing 120 fps, which allows photographers to capture fleeting moments that would be missed otherwise.

Focus is as-good, if not better than any other DSLR in the world. E.g.: eye-tracking auto-focus is generally not possible on DSLRs because they can't use the full-resolution sensor while the mirror is down, and eyes are too small to recognise with the phase-detect array.

They've thrown in 4K and 8K HDR video capture as well, because why not, and this works with the viewfinder. That's not possible on DSLRs because the mirror blocks the viewfinder in video mode.

I shoot weddings/portraits with a Z6ii (mirrorless, $2k) and a D850 (widely regarded as the best DSLR ever made, was $3k - now less). The D850 has much higher resolution.

I’d much rather use two Z6iis. The only reason I haven’t upgraded is because I’m anticipating a Z6iii soon and I’d love for it to be ~33mp as I think that’d be the sweet spot for me.

The autofocus advantage is huge, and the viewfinder is typically much easier to see. Yeah, I need to swap batteries at least twice as often. One battery still makes it through a 2 hour portrait session just fine.

Isn't AF significantly improved since the sensor always receives signals?

I think this is true, in my experience it is. Only difference might be speed of acquiring focus but that could have just been lens and general camera differences, not because the core concept is slower.

I'm (somewhat sure) the DSLR allowed for a separate light path to a separate AF sensor, so now it has to be integrated into the same sensor which has some cost in terms of sensor area and resources devoted to AF vs. regular imaging? Not an expert so please someone correct me.

As far as I understand it, there’s no AF “sensor” on mirrorless cameras apart from the image sensor itself. They just adjust the focus until maximum contrast is achieved - but obviously it’s more complex than that.

You don't have to think about the physical image sensors as just an array of sensors with 1:1 correspondence in the final picture. There was always a lot of computation in between - bayer filters with more green pixels, different grid patterns, multiple sensors per pixel, more pixels on the sensor than in the actual photo and so on.

Recent sensors have AF phase-detect sensors built into the image sensor, by splitting one "pixel" into two sensors (and having lots of them; sometimes in Canon sensors more than half of the pixels have this functionality; on some cameras you can extract the raw image including the different data on those pixels for bigger resolution). The difference between phase detect and contrast being that a phase-detect sensor will give exact values on how to adjust the focus, whilst contrast detection needs focus hunting in small adjustments, so it's slower.

Does that affect overall sensitivity?

Probably yes, as it means less actual sensor surface, so it's a tradeoff between better focus and noise. But it's hard to quantify without comparing electrical signals.

It’s a separate path, the sensor is under the camera (this allowed it to work with film). 2 sensors per autofocus point which it tries at align. It’s actually kind ofvv be amazing it works.

Gordy details, but the image helps see:

https://photographylife.com/how-phase-detection-autofocus-wo...

On camera sensor focusing was slightly different “contrast detection”. My understanding is modern cameras integrate those phase detection sensors on the image sensor itself. It might effect image quality but nobody notices and focus is fast and reliable. It’s tech that works well so generally nobody cares how it works.

https://www.usa.canon.com/learning/training-articles/trainin...

Yes. Parent is leaning on the conventional wisdom of 10 years ago regarding mirrorless.

The AF on my a7 III is nothing short of miraculous compared to any mirrored camera I've ever used, even in light where I'm shooting at 128k ISO, 1/125, 2.0f. Quick and accurate locks every time.

I shot 1000+ photos over 3 hours at an event last week, and honestly I couldn't even tell you how much battery I used. Because I wasn't paying attention, because it's a non-issue. Even if it was, batteries are cheap, small, and easy to swap.

The only buy-in is the body and an adapter. AFAIK, all of the systems work fine with their SLR predecessor's glass. Pros already change bodies periodically to get the latest features (nowhere near annually, but probably one body every 2.5-5 years, and they'll have 2-3 bodies used in paid gigs).

And the bodies are relatively cheap at ~$2000 (half that for a previous generation or enthusiast grade body). Lenses tend to start around $1000, go up to $10k, and a pro will have 10 or more of them.

The reasons are pretty clear: 1) Clearly better lenses for the first time in a generation. 2) Smaller, lighter camera's (to go with better and smaller/lighter glass), and 3) Your old glass works with an adapter, and 4) Focus is better than the DSLR World, even looking at a D6 or similar as the baseline.

AF is better since it's based on the actual image and not a reflection from a mirror that may or may not be tweaked

Battery life is solved, you get 1000+ shot with modern mirrorless, batteries are $20 a pop

A few advantages: silent shooting for events like weddings, smaller and lighter bodies and lenses, new lenses with faster / silent AF, fewer moving parts (less to break and smaller batteries).

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