Try this solution, originally courtesy of user malowz, repeated by user John Cline in this thread:
https://www.vegascreativesoftware.info/us/forum/overexposure--94837/
I think you'll be very pleased with the result.

Try adding this FX chain:
Invert > Levels > Invert
Then go to the Levels FX and adjust the gamma slider. This will tame the overexposed whites without affecting the mid and dark tones. If this doesn't work, it is likely that the image was so overexposed that it clipped and there is no information to be retrieved.

 

Mike

Thank you for your reply. So do I do any action on the Invert section? Or literally just open them, and then adjust the gamma slider on the LEVELS section?

Just open. Move the gamma all the way to the right. Magic happens.

Reason for edits: I was going to say also you can mask the pale sky, chroma key it and replace with sky blue, but had second thoughts, just quit while you'r ahead.

Just tell me when to stop...

Some of the detail in the clouds may be gone forever, but who looks at cotton balls for sharp detail.

Just tell me when to stop...

Some of the detail in the clouds may be gone forever, but who looks at cotton balls for sharp detail.

Wow! Thank you so much for taking the time to do this. You are incredible.

Just open. Move the gamma all the way to the right. Magic happens.

Reason for edits: I was going to say also you can mask the pale sky, chroma key it and replace with sky blue, but had second thoughts, just quit while you'r ahead.

Thank you for your advice.

@john_dennis

@Rainer
 

Only for my understanding:
What does the "Invert FX" in this case - can you explain that?

Thanks in advance
Walter

I occasionally save a tip or two that are useful, copy and paste doesn’t always work, in this case I believe I may have transcribed, so many thanks to Malowz, please correct it Malowz if needed ...

Overexposed...by “Malowz”

Put 3 FX filters ... An “Invert” at 100%, a “Colour Corrector”, and an “Invert” at 100%.

Then lift up the gamma of the colour corrector in the middle.  This darkens highlights first, in a logarithmic fashion, similar to an iris closing.  You can also put a colour corrector secondary to select reds and lower the gamma a bit.

White Balance ... by “Malowz”

Put 4 FX filters ... Invert, Levels, Levels, Invert. 

Put both “Invert” at 100%.  

In one “Levels” select the red channel and in the other “Levels “ select the blue channel, green remains untouched.  

Adjusting the gamma slider, you compensate the gain on each colour channel.  

Using the in/out sliders, you can fine tune the blacks and white points of each channel.

@rs170a … many thanks for posting the suggestions in the earlier posts. I had some overexposed seaside shots which I was really struggling with. Following applying the Invert Levels Invert suggestion, the overexposed shots in question are now usable, far exceeding my attempts via other FX means. The improvement is almost miraculous. In some shots without a sky horizon, it would be difficult for the casual viewer to even guess that the original shot was overexposed. Thank you again.

I did do a little color correction via Colorfast 2 on some shots to add a little warmth, but tomorrow I'll try the added points re color channels in Levels as posted by JN_.

In addition to this brilliant tweak, I might suggest taming the highlights ( possibly after more precisely defining them via a mask) with NewBlue Colorfast2, which I really find very useful.

@daniel-t2081 and @Dexcon, very glad that I could be of help in your time of need 😁
In all seriousness, thanks goes to Malowz for coming up with the technique. I've used it several times and it's definitely a lifesaver!

Mike

Found the trick some time ago and always wanted to try it.

Today, while creating a new video I've found "over-exposed" fragment. Tryed the hint and really do not understand the idea.

For me it looks like it is possible to get very similar results using Curves. Did I miss anything?

Found the trick some time ago and always wanted to try it.

Today, while creating a new video I've found "over-exposed" fragment. Tryed the hint and really do not understand the idea.

For me it looks like it is possible to get very similar results using Curves. Did I miss anything?

Thank you for taking the time to post this. In your opinion, which method do you think gives the best final product?

I do not know. I've just tried it and noticed no differences with Curves. Probably I missed something important and want to find out what exactly.

@fifonik ... just as a matter of interest, how long did it take to take you to do the Curves approach in comparison to the Invert-Levels-Invert and a slider adjustment approach? Which was quicker?

Not really understand your question. I have not even tried to get the same results.Well, it took about 2 seconds for each as you can see on the video. Is this all only about simplifying of the process?

@fifonik

I only asked because you previously wrote:

I've just tried it and noticed no differences with Curves

... and ...

For me it looks like it is possible to get very similar results using Curves.

From that, I took it that you had tried both approaches as you found little or no differences between the two. Hence, given that you say that you've tried both approaches, which for you was the quicker approach to achieve the same/similar result? Yes, it's about simplifying the process - if the Invert-Levels-Invert (I-L-I) process takes less than a minute to do and the Curves approach takes, say, 5 minutes of adjustments, then the I-L-I approach would logically be the first approach to use and the Curves (and possibly other FX) approach would be if I-L-I doesn't work all that well.

I see. Thanks.

I have used this sequence (invert, color corrector, invert) more times than I should admit to, and it really gives me great results. When I first got my drone, before I had ND filters for it, this was a super-important tip.

You can get the same results using curve, but much with more difficulty, cause using gamma slider it uses a "mathematically-perfect" logarithmic curve, something very difficult to do manually adding points on curves.

you can also use Gamma with "Color Corrector" filter instead of "Levels", cause they use different processing methods (one uses RGB and other HSL i believe). may make a difference in very saturated or very overexposed images.

after that, selective filters processing only the over-exposed areas can enhance some parts, like sky, skin tones, etc.

my attempt:

@malowz

Great tips thanks a lot, I have used to advantage with some very poor SD material, fast, easy.

My experience is that one can get similar results with Color Curves, but with a lot more work.

Invert / Levels / Invert is a one-knob solution for uniformly over-exposed pictures or videos. 

Sometimes, I don't want to walk through the kitchen to get to my seat in the restaurant.

Thanks everyone. I got the idea. For some reason at the beginning I thought that the I-L-I trick somehow only modifying over exposed areas.

I'm using both Levels and Curves. When I see no heavily over/under exposed areas, I'm using Levels. With over/under exposed areas -- Curves. Sure, the Curves are harder to use and it was real pain at the beginning. Now it is not too hard for me but anyway harder than Levels. In my experience, I almost never applied just logarithmic curve as I have never had fragments like OP where everything over-exposed (I had something like this on scanned old films).