Proper exposure for stars, no moon?

[GPS]

Nice toy amoebahyda :-)

Metrogons and Aero-Ektars were traditionally recommended by amateur wide-field astro photographers. Better mapping lenses are available at a price: they combine wide angles of view with large relative and absolute apertures.

I have known research projects which gang up a bunch of Canon 300 f2.8 lenses pointing in slightly different directions. If you're not a purist you can always tile-and-stitch multiple exposures from smaller cameras.

Personally, I'd stitch frames from Google Sky. "Time spent waiting for the light": 0 seconds.

Struan,
care must be taken so as not to confuse the "same" notions from two different fields. The wide-field astrophotography is not the same as photography with wide angle lenses and certainly not photography with "a very wide lens" that the OP asked for.
Thus Aero-Ektars and Metrogon lenses are not regarded as wide angle lenses (e.g. 7" Aero Ektar used for 5x5 film format) in photography. In the same way mapping lenses are not an equivalent of LF wide angle lenses in their focal lengths. This is a part of the OP problem as the LF wide angle lenses do not have a sufficient physical aperture to catch higher magnitude stars in the short time he can use for non trail stars photography.
Stitching is perhaps a possibility.

[Struan Gray]

I know, I know.

But photographers wanting a sky full of start are often less pernickety than astronomers. The easily available aerial lenses will let you photograph major constellations on large sheets of film without too much effort. Deep sky nebulea are another matter.

Of course, more complex, rigorous, accurate etc solutions exist. Michael Covington's "Astrophotography for the Amateur" is a good primer:

http://books.google.com/books?id=WTKcbdR-2h8C

(The pages Chris needs are partly available in the limited preview)

[Greg Miller]

The OP is interested in stars photography with "dark landscape". He would be an uttermost fool if he sacrificed the "maximum starry night effect" he expressly wants using his aperture to include some fictive foreground in his depth of field not reachable with an open lens. But of course, in the collection of advice given (a manual barn door, a star guiding mount - both unusable for the landscape, sunny f16 rule etc.) even this one - to use the aperture for depth of field regulation - is of the same kind. Nothing is absolute - someone said something is absolute? Hmm - sometimes it rains... sometimes not...

I guess you are just more confident than I am that we all envision precisely what the OP has in mind when he states "dark landscape" or what kind of foreground he has in mind that he may or may not consider as important to the overall image; or how much compromise he is willing to accept in any of these details. My own personal experience is that the same words or phrases mean very different things to different people. And beyond the fuzziness of the English language, aesthetic vision in photography varies - Some photographers accept featureless black shadows and other require rich detail in shadows. I prefer to offer ideas that can be used, or not, at the readers' discretion. Others prefer to take a different approach.

[GPS]

...
I'm envisioning using a very wide lens and getting the equivalent of what we see with our eyes-- tons of stars over a dark landscape. Any exposure tips?

Cheers to all,

~cj

...
Some photographers accept featureless black shadows and other require rich detail in shadows. I prefer to offer ideas that can be used, or not, at the readers' discretion. Others prefer to take a different approach.

Sure, I understand - when was it the last time you saw "tons of stars over a dark landscape" with a "rich detail in shadows"? To save the OP from the fuzziness of the English language and with the same kind of logic you can also offer him tips for a dark landscape with moving lights in it (frozen in motion or not) or - spaghetti con sugo...

[Greg Miller]

Sure, I understand

No - it is pretty apparent that you are not even close. And I am pretty happy to leave it at. Peace, out.

[GPS]

No - it is pretty apparent that you are not even close. And I am pretty happy to leave it at. Peace, out.

No - it is pretty apparent that you are not even close to happiness and peace about it...

[Drew Bedo]

The stars are point sources, so stopping-down or opening up won’t affect overall exposure. The number of dimmer stars that show up will depend on the physical maximum aperture of the lens. A 150mm F5.5 will have a maximum opening of 26.7mm (150/5.6=26.7) while a 210mm f5.6 will have a physically larger maximum opening of 37.5mm (210/5.6=37.5).

Overall exposure will depend on the amount of sky-glow; the ambient light that spills over from street lights. When the film begins to fog from the sky-glow the exposure is over. Use slower emulsions and bracket. Shooting at higher altitudes will reduce atmospheric interference.

Oh yes, and BRACKET.

[chris jordan]

Hi guys, thanks for all your input. I'm trying to organize a photographing trip to Midway Island in the Pacific in September, which is reputed to have amazing night skies (being 1500 miles from the nearest light source). I'm bringing a 60MP digital medium format back, which I know is not technically LF, but the results are somewhere between 4x5 and 8x10 in quality. In addition to doing lots of daytime photographing I'm hoping to try some nighttime blended-exposure HDR images that include starry skies, with foregrounds painted with light. Back to being a novice (again...)!

[Drew Bedo]

Hey Chris; When you get back...show us some of your shots and tell us how you did them, OK?

[percepts]

Well since its digital you are using then it becomes simpler to calculate what is acceptable.

Assuming your pixel sensor is 8000 pixels wide and your lens field of view on sensor is say 80deg, then knowing that the earth rotates 1 degree every 240 seconds, you get:

((8000/80))/240) = 0.42 pixels per second.

That is worst case scenario so you have a margin of error at the latitude you will be at. How much margin depends where you are pointing the camera (north horizon or south horizon or somewhere in between). But using that formula, you don't need to know that stuff. 1 second exposure won't show the dim stars but you won't get trails either.