Scans or photos of negatives will generate a negative image.
What are you all using to convert your negative image into a positive image?
Seems to me that isn't so easy...

Several posters have proposed ETTR and EBTR, but those don't help in low light, unless it's a stationary subject and you have a tripod, since in order to expose to the right, you need at least one of: a faster lens, a slower shutter, or higher ISO sensitivity. If you crank ISO, you are not winning with ET/BTR, because there you are raising the noise floor as much as you will does it in post. If you have a faster lens, or can handle a slower shutter, then you already don't have a low light problem (although ETBTR would then be applicable).

I go smaller. I keep my RX100vi in my go-bag to have with me most of the time. Great pics, very small, no extra lenses, and battery recharges in camera with a USB cable from almost anywhere (even a solar panel when I'm in a multi day hike or bike ride).

One advantage of using Lightroom as a raw processor is that you can use the same tool to do all the cataloging and keywording, and also the cropping and other post-processing effects all in a *non-destructive* environment -- meaning that all the results of your work are stored as a list of edit commands in a .XMP sidecar file, while the original raw file is left unchanged. Then if tomorrow or next decade you find a better way forward, you haven't lost or overwritten your original files. A side benefit is that updating your backup after editing requires only updating the tiny .XMP files (a few kBs) in the backup set, not the original data (10s of MBs).

To the extent that other raw processors are non-destructive editors, same benefit applies; photoshop is not, so you end up with at least two, and potentially many, copies of all the pixels with slight tweaks.

Now if Lightroom were only a little faster, especially with those 50MB images...

If you convert to DNG, it's hard to go back to the raw files (without losing all the work you might have done cataloging or developing shots). Instead, one benefit of hacking the camera exif tag, if it works, is that when the new version of LR comes out that knows about Z6, you can revert the tag and refresh metadata into LR, the raw files will be processed properly, but you won't have to re-import them so that all the cataloging, keywords, and development adjustments still apply.

Quite possible that you can tweak the files to look like Z7 files and import them in the interim.
The following worked for my new RX100M6 (I don't have a Canon to discover the right tag to change):
/usr/local/bin/exiftool -sonymodelid="DSC-RX100M4" <files>

Obviously, experiment with one file. Some features probably won't work (there's obviously a reason Adobe didn't declare support), but there's chance this will work...

This camera, like most with long zooms, sacrifices close focus with tele-zoom (as you zoom in, the close-focus shifts further out).
Usually, the largest image is achieved with the lens as wide as possible and the camera at the close-focus distance that matches.

Next thing I might try is rebooting your computer - to reset the graphics system.
Or maybe turn off (temporarily) "use graphics hardware" in Lightroom.
It could be a rendering problem and nothing to do with the capture.
That the export is clean makes me hope for this outcome.

Good point. That is another alternative. But not one I'm attracted to. I'm not a great fan of the OEM converters. I don't like taking all the adjustments out of the tool I have learned and become familiar with, and I'm not a fan of huge tiff files to import into lightroom...

Non cellphone cameras have one subsystem that controls exposure (PASM, ISO, bracketing, flash, etc.) while a completely separate subsystem controls focus (area, mode, tracking, etc.)

Here are some ideas for integrating those two systems to make some tasks easier.
In particular, informing focus settings based upon depth of field derived from aperture settings, or vice versa.

Set Focus Nearpoint

Landscape photographers often want to include foreground elements as well as distant features all in sharp focus. Three existing approaches are to focus on the near point and “waste” half of the depth of field nearer than that; use a rule of thumb like focusing on some object that you guess is half as far again as the distance of the nearest object; or pull up a smart phone app to calculate DOF and set focus manually (which is next to impossible on most cameras since there is no mechanical or electronic distance scale to rely upon).

What if I could set the back focus button to “near point focus”, and have the camera acquire focus on the near point I'm trying to shoot, then automatically shift focus further out so that the measured near point is just within the depth of field range. Remember that the camera knows what aperture it will choose for the exposure, and it knows the focal length of the lens, and so it can trivially calculate the depth of field, as long as it knows the size of the circle of confusion I am willing to tolerate. In addition, upon performing back button nearpoint focus, the camera could flash a warning if the depth of field does not include infinity as well.

Focus x to Infinity

In a variation, in P mode perhaps, the camera could evaluate the depth of field required to span focus across the designated nearpoint out to infinity, and use that to narrow the aperture as necessary to make the depth of field sufficient.

Focus Bracket

For macro photographers, the depth of field problem can be even more severe - a depth of field of just mm is normal. A modern technique is focus stacking - shooting several images at different focus to stack to build sharpness across the whole subject.

But for most cameras, manually cycling focus through a range in small measured steps is very hard - even if you know what step size is appropriate for the aperture you have chosen.

It would be great if we could have a focus bracket mode which automatically chose, and shot, focus steps to overlap the depth of field of each shot from the designated near focus point to a preset range.

I could imagine using a control to set stack depth of field (in cm) to 1, 2, 5, 10, 20, 50, 100, etc, or (in feet/inches) to .5”, 1”, 2”, 4”, 6”, 1’, 2’, 5’, etc., just like you set the parameters of an exposure bracket.

Set Circle of Confusion

Anticipating the objection that depth of field is not absolute, since at either limit, the scene is not perfectly focused, but is not defocused “enough to matter”, obviously the photographer would have to set up the size of the circle of confusion (the size of the circle on the sensor within which a point of light is blurred) that is acceptable, from a size of one pixel, up to the more conventional definitions of 1/2000 of the sensor diagonal (about 0.03mm for a full frame sensor).

Summary

A few simple additions to camera firmware would add some cool features for serious photographers, particularly landscape and macro photographers, to be able to use focus more creatively with better automation. The usage model would not be a big reach for anyone who is accustomed to back button focus and spot focusing on the critical point of the subject, or anyone who uses exposure bracketing.

So you plonk down the cash to get that shiny new camera, start shooting, but Lightroom won't read the new RAW files...

Three options: shoot jpg for 8 weeks until Adobe gets its act together; get Adobe Raw to DNG converter; or use Exiftool to tweak the raw files to change the camera model to match something lightroom knows about.

What I would like to understand is whether raw converter is doing anything meaningfully different than mapping the file to a camera model lightroom already knows about?

Here's the thing: suppose the camera has some nifty new feature that requires a change to add something extra to the raw file - perhaps 15 bits per pixel instead of 14. In this case, lying to lightroom and claiming this to be the old model of the camera is going to fail badly - the pixels aren't going to read out right. But even if Adobe can do the work to update raw converter to digest 15 bit pixels, lightroom still needs to be able to do something with 15 bit pixels. And if Adobe converter mashes them down to 14 bits, there's loss of data. Or if it pads them to 16 bits the files are larger than they need to be. In any case, either it's just convincing lightroom that it already knows about the structure, or its changing the structure in a way that is no longer "raw"...

In which case, the exiftool trick seems better, if the new format is similar enough to an existing format, since there are no new files to create and manage, and when lightroom is updated, it's trivial to tweak all the already loaded raw files to their proper camera metadata.

But if there is no similar enough format, I wouldn't want to use raw converter either, since it has to be changing the raw data to be acceptable. Maybe on a temporary basis, but if you make edits on that DNG, getting them back to the raw file in the future is a one-by-one laborious copy settings and paste, not my idea of fun...

I've just started doing this, and I got to wondering whether I ought to use A mode to ensure that bracketing is with variations in shutter speed or ISO so that the depth of field is identical across the bracketed images?

For a given sensor size - e.g. 43mm diagonal for full frame - the greater the flange distance, the wider the flags diameter need to be in order not to vignette - especially wide angle lenses. All of which contributes to weight.

Hence smaller flange enables smaller diameter, enables smaller wide angle lens design (no retro focus optics, and smaller lens barrel near the mount).

You can see this with the availability of small pancake lenses of about 20-35mm focal length for use on ff mirrorless lenses, not available for dslrs.

But it's a pretty edge case thing for most of us.

Try hanging with two hooks each a few inches in from the end of the wire.

Then, if you do live in a seismic active area, a third book in the middle, but upside down, and about half an inch lower than the other two, to hold the wire down if the wall shakes.

Very low light focusing is weak.
Manual focusing is equally tough.
There's no stop at infinity for most of the lenses for this camera.

However, it (the A7R2 at least) has a digital focus distance display in the viewfinder, at least for some lenses (all the Sony lenses, plus my Zeiss primes, at least).
It's tolerably accurate. But it's probably worth calibrating the distance in broad daylight to make sure.