as far as I know camera raw has always been like that, you need to convert it to 16bits.
No it wasn't.
Pre-update, PS CC ACR's filter version opened 32bit file, kept it internally linear, like it does for raw photography, but applied sort of tonal compression in its default '2012 engine' (setting available in 'Camera calibration' tab, second to last). Basically, f*cking it up more or less depending on exposure and dynamic range of said 32bit file, but some liked the look.
There was also a workaround, as 2010 engine was able to work with them fine, provided you zero-ed all the tonal values plus curve (which by this point had default s-curve contrast). You could then use the fantastic highlight compression parameter to tonemap your image (seriously, ACR has the best available tonemapper for highlights)
I am pretty sure both options were accidentaly left loopholes, as the same ACR engine didn't allow for this in Lightroom. Ironically, Adobe, instead of fixing this correctly and adding 32bit support, just removed it altogether. Did anyone expect better :- ) ?
But to point, there is no way to edit 32bit files in Photoshop properly anyway, and actually, in no raw converter on market either (as the highest .raw available is linear 16bit on medium format cameras like PhaseOne, or top level cinema cameras from RED).
Maybe Corona guys can finally develop real image editors for 2017 given they will now have funds and manpower :- ). Sorry, couldn't resist.
Other solutions: Corona VFB (what I use these days) or linear compositors (Fusion/Nuke/AE...), plugins (Arion).
PS: Btw, there is commonly held (incorrect) opinion that common 16bit file formats retain access to extended dynamic range. They don't, the moment you downsample to 16bit mode in Photoshop the access to your dynamic range is lost. Only 16bit (half-float) .exr file (and raw files not openable directly in PS) has dynamic range, and that one gets treated as 32bit one in every application, since they correlate it to linear state.
The only reason you would use ACR as filter on clamped image is to access the micro-contrast 'clarity' filter.
