How many stops do you need?

[Gavin Greenwalt]

With 23 stops you could film the sun being sucked into black hole.

hahaha, not quite but you could definitely shoot a candlelit face in a cave with the sun setting behind.

 

[Clint Johnson]

Of course the ultimate limitation is the dynamic range reproduction capabilities of the TV transmission and display technologies. It's a vast understatement to say that TV isn't currently capable of displaying anything approaching 14 stops. And digital cable is often so compressed that the images often look like moving abstract paintings with blobs of pixels shifting around the screen.

Yes, even though I have a relatively good 1080i display that is reasonably well adjusted and receiving only moderately sucky compressed HD content over Expressvu satellite... not so much with the 14 stops... closer to that 4 stops I disparaged.

But it is getting better and it looks like the new crop of 1080p projectors can reproduce some nice colour and dynamic range. Plus it is getting more common for people to skip a season during the first window and just rent the DVDs when they become available (this will translate to Blu-Ray and/or HD-DVD in the coming years). The dimwits who are scheduling network television pretty much force this with the shifting air days and times, random hiatuses and preempting for anything that will get another tenth of a share RIGHT THIS SECOND. Network Weasel: "What do you mean we lost two full shares when we brought the show back after being off the air for five weeks? How could we have seen that coming! I guess we better cancel it now." (but I'm not still bitter about Firefly).

Aaaanywayyy...

If you aim for the best that television can deliver (or will deliver over the next couple decades), then the ancient 21" CRT with drifted magnets and faded phosphors (which hasn't been adjusted since the salesman cranked the brightness and contrast all the way up in the showroom) might not let it look much better than an indifferently shot sitcom, but it shouldn't look much worse. And they probably would notice or care anyway... they would just bitch about not seeing all the picture because of that darn letterboxing!

As the home theatres become closer to (and in some cases exceed) the quality of public theatres, it behooves us to create material that measures up to this. There is also the very real possibility that some theatres will decide to start projecting television shows. I'm thinking that some of the smaller theatres in the bigger cities could fill seats with a Lost or Heroes (American Idol would fill the most seats but I don't want to think about that). They wouldn't be able to charge admission but the theatres make most of their money off bushels of popcorn, sheet of plywood sized chocolate bars and ten liter pails of pop.

Clint (giving the parentheticals some love) Johnson

 

[Andrew M.]

And digital cable is often so compressed that the images often look like moving abstract paintings with blobs of pixels shifting around the screen.

Greg, I love your expression, exactly, blobs of pixels, lol.
Finally cable is pushing true DVD (720x480) picture quality over HDTV channels.
Maybe, once we have 4KTV they will push HDTV format to the home then?
And they have audacity to call it HDTV!

Few things to know:
Stops and bits go hand by hand, since extra bit in the data sample is double of information and one stop is double of light difference.

So 12 bits gives you 12 stops if sensor is capable of >12
Don’t mix it up with the lenses capability of 22 or more stops.
Sensor may be 12 stops but outside intense lighting condition may be so bright that you have to use high stops just not to blow up the highlights.
What I just mentioned above is obvious for most of us, but it is good to mention.

BTW never point camera sensor in to the intense infrared source, like melting stoves, don’t point it towards guys fixing/switching communication fiberoptic patch cords, melted glass processing. Etc.

I always ask myself the question, once the CMOS technology will deliver 22 stops (22bits) why anyone will need 22 stops on the lenses?

 

[GlennChan]

Flare in the lens will limit the # of stops you can record.

2- For HDR work, you want a lot of stops.

HDR is relevant for things like adding digital filtration / diffusion... the most accurate (and better looking) methods will do processing in linear light + HDR.

3- You also want a lot of stops to emulate what the human eye would see; or you can use a wide exposure latitude for artistic effect.