I had thought of posting this in the Bad Movies forum, but it seems appropriate here.

On the new Star Trek IV DVD, there is a text commentary by Michael and Denise Okuda. At one point in the movie there is a shot of the Earth with the obligatory starry background. Okuda explains that you would not see this in real life due to the brightness difference; that if you set your camera to properly expose the Earth, the much fainter stars won't register on the film. He explains that you see it in the movies because the filmmakers put it in mostly because it looks good.

It's nice to see this explanation show up in a popular medium.

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Jeff Schwarz
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Argh!! They booby-trapped their sun!!****--Invader ZIM

Well, okay, but what about that whooshing noise the Enterprise makes as it flies? I suppose you're going to tell me that's not real, either...

We'll have to break the bad news to you about tribbles some day...

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If you can't dazzle 'em with dexterity, baffle 'em with BS.

Personally, I disagree with that. I think that photos from real spaceflight, showing just a black background are far more aesthetic. When they add the starfield, it just becomes cluttered.

That is cool of Mike to say that, but doesn't surprise me. He reads this site! He told me when I met him in March. :-)

I was in Hollywood just this weekend. I got to interview Charles Ziarko, and while my colleagues were working through some details I got to go with a tech to inspect Stage 16 at Warner Brothers, the largest soundstage in Hollywood. When I get some time I'll do a structural analysis to see whether that stage could actually be made into a vacuum chamber.

Unfortunately my plans to meet with Richard Maibaum didn't pan out. He, like everyone else, was on vacation.

Oh, and for you Jack White fans:

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"Facts are stubborn things." --John Adams
Clavius Moon Base

I've been meaning to ask this:
What about the human eye? Can the human eye discern the stars in space even though they do not register on film?

The answer is "kind of". Which is to say, the eye has a greater dynamic range than any photographic film I've worked with, so there will be cases in which the eye can see stars (in combination with other things) where film cannot.

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"Facts are stubborn things." --John Adams
Clavius Moon Base

So that's a sort of defense for all those films that show stars. They're not documenting what the camera would see, they are trying to show you what it would look like if you were there. Plus, if we are going to suspend belief long enough to accept that a group from the future in a stolen alien spacecraft visit Earth to collect whales, then arguing over whether or not the stars are correct seems just a tad nitpicky.

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Admin of the new and very much improved Apollohoax forum

Another thought... If these are 23rd Century cameras, maybe they do have the exposure lattitude to record bright objects and stars at the same time...

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Things are only impossible until they're not!-Captain Jean-Luc Picard

Admin of the new and very much improved Apollohoax forum

Could be. I mean the bird of prey they're in can image two whales at a distance of 600 nautical miles based on a radio beacon. And we're talking an image that fills the viewscreen not just a pixel or two.

If it can do that, why not properly expose stars and the sunlit face of the Earth at the same time?

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Jeff Schwarz
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Argh!! They booby-trapped their sun!!****--Invader ZIM

Exposure latitude is like salt. Not enough, and you don't like the results. Add some and you've got a tasty dish. Dump a bunch in and it's no good again.

What you want is adaptive exposure. Some kind of system that "knows" which nuances you're interested in and places the breadth of the latitude there.

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"Facts are stubborn things." --John Adams
Clavius Moon Base

I was thinking about that too. But I imagine that even with the human eye the stars wouldn't be as bright as they appear in Star Wars, or Star Trek. Am I right?
2001 may have gotten it right, though; the stars are sometimes visible, but barely.

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"The moment we want to believe something, we suddenly see all the arguments for it, and become blind to the arguments against it." -George Bernard Shaw

The problem with 2001 is that the starfield moves to convey the impression of the motion of the spacecraft. That is, "Discovery" is seen to be moving forward because the starfield is moving backward on the screen, Star Trek fashion.

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"Facts are stubborn things." --John Adams
Clavius Moon Base

Slightly on-topic:

One thing that I keep noticing is that for some odd reason, in the TV shows the Enterprise generally has a forward viewscreen in approximately 35 mm film aspect ratio. Yet when the exact same ship appears in a theatrical film, the forward viewscreen suddenly has an aspect ratio more consistent with 75 mm film. Perhaps it's only coincidence that the aspect ratio of the viewscreen always matches the aspect ratio in which Star Trek is being filmed at the time.

{Waiting to see an IMAX Star Trek film, where the forward viewscreen will be almost perfectly square.}

The 'whooshing' is authentic. It's caused by impingement on the viewer's spacecraft of X-rays from the matter-antimatter motor. The radiation levels are harmless but they induce acoustic shock waves from thermal expansion of the outer millimeters of the hull.

(tongue OUT of cheek) My favorite starfield faux pas is in the opening of Star Wars IV when we see the receding spaceship from the spinning escape pod. The spaceship diminsihes in angular size with distance -- but the SFX folks made the starfield ALSO diminish in size. If it had merely rotated and stayed the same size (as it should have), while the spaceship diminished, it probably would have freaked out the audience -- then again, the SFX team might just not have understood the universe.