is there a way to show blown highlights BEFORE taking shot

I thought I read somewhere that there was a hack to allow you to see blown highlights in the viewfinder of the Nikon Z9 BEFORE taking the shot (for stills shooting, not video) but I can't seem to find a way to do that. Does anyone here know?

Ditto for stills shooting in Canon R5.

I believe the Sony a1 does show you zebra for still shooting, is that correct?

Thanks,
Roberta Olenick

I can't speak to Canon or Nikon, but most, if not all of the Sony mirrorless cameras can display Zebras to warn you of clipping highlights. 

Here’s a “hack” that is not exactly what you want, but may help:

https://www.uglyhedgehog.com/t-722527-1.html

https://www.dpreview.com/forums/post/65652133

Joe

Every mirrorless camera from the dawn of mirrorless that I've ever used (Sony, Panasonic, Fuji, Olympus, etc...) can do this so there has to be a standard way of doing it on a Nikon, perhaps by enabling zebras.

In my online search, it appears that Nikon is the only manufacturer that does not give you highlight exposure warning prior to the shot on their mirrorless cameras - that's absurd and downright stupid.  The whole point of mirrorless for a nature photographer is that you are seeing the image in the viewfinder that the sensor is seeing making things like this easy.  The so called workaround is to turn on an in viewfinder historgram (or rear LCD) which will give you a composite histogram that you can see prior to the shot so that can give you some indication of whether or not you are overexposing but since it is a composite, you still don't know if you are blowing a single color channel.  Think of a Cardinal against a dark background.  You could cook the reds but since there is little info in the blue and green channels, the composite might look OK.  Some cameras, like Fuji's for example give you blinking highlights, blinking shadows and an RGB histogram prior to the shot...

Thanks everyone..

The canon R5 does show you an RGB histogram in the view finder but no highlight blinkies until after the shot is taken. I have an R5 and would love to be able to see blinkies or zebras for still shooting if someone knows of a way. I’ve only been able to find zebra for video. The RGB histogram can take up quite a bit of space in the viewfinder which is annoying and it would be easier just to be able to quickly glance at blinkies.

Thanks for the possible hack for the Z9. I had borrowed is Z9 but I’ve given it back so can’t try it right now.

Just another case of arrogance by Canikon - they are alone in not offering such a simple thing that is nothing more than a few lines of code.  Other cameras brands give you not only blinkies but programmable zebras that allow you to set the threshold for when the "blinkies" occur - this is not a high end feature, it's in their lower level cameras too.

But Nikon does not offer this either as far as I can tell for still shooting, same as Canon.

I have not tried video on the Z9 but I can get zebra on the R5 for video.

That’s why I wrote Canikon

Zebras are just as useful in still photography as they are in video even though they originated in the video world.  They are never off on my cameras which make them available in both video and still mode.

You do have two sizes of the histogram to choose from, the larger display and a smaller display which I have up all the time. It can be toggled off as well if you don't want to see it. Nice that they have both choices, of a regular histogram or a RGB histogram.
Zebra's for photos is something most Canon users have been asking for and they gave us zebras for vids. So maybe in a future update that would be nice.