or:

exterior motif
exterior setting/outdoor setting

It seems "Aussenmotiv(e)" could be understood as the opposite of "in the studio(s)" which, so one can argue, is "on location" or "the exterior location(s)".

However, a location is usually referred to as a "Drehort" and in the particular context of this question, the word "Motiv" seems to point more to the visually stunning (outdoor) vista(s), perhaps even a particular visual motif (a term used in photography to denote "sujet (french) or theme" and also anything that the camera captures).
In my opinion, this could be reproduced through a computer which would strengthen my argument for motif or vista that encapsulates the vision of the author and then is realized in the movie (not that that's how it's done usually).

I see "location" more as the film crew's workplace (Drehort) and exterior location as Außendrehort and not so much as the description of the artistically chosen (exterior) "locale" or "what is actually in front of the camera" if you will. What I mean is what Disney possibly did with "Schloss Neuschwanstein" - it's the vista that either inspired Disney or came very close to what he envisioned (possibly!). Now they could have used the real one in a movie but just the idea of it was used and expressed (that would make it a fitting motif).

Also, there is the German term "Innenmotiv" which, as the example below shows, can go beyond the simple idea of the "studio" and more towards "interior setting/scenery."
I don't really want to bring up the French term "mise en scène" here because its meanings are plentiful and not limited to the outdoors but, in a way, "Motiv" has to do with setting/scenery:
http://en.wikipedia.org/wiki/Mise_en_scene

I want to argue that here the Außenmotiv is more the visual motif/vista for a fictitious outdoor setting that represents the author's/cinematographer's (or his able secretaries') visions - a real place chosen not for its actual existence but because it resembles foremost a vista in the realm of the film and the imagination of its creators. Or, in other words, it encapsulates the director's or cinematographer's vision of the story's exterior setting or outdoor setting, here represented by the exteriors of a particular castle and its surroundings.

The following two links show that there are exterior as well as interior "motifs or settings" that are chosen before there is a location.
Especially the first example from a telenovela seems to show this quite well:

http://www.daserste.de/sturmderliebe/allround_dyn~uid,t7wk4s...

Heute "müssen" die beiden Damen übrigens noch auf eine Dampferfahrt auf einen nahe gelegenen See gehen – auf der Suche nach einem schönen Außenmotiv. Na dann: Ahoi!

http://www.muenster.de/stadt/filmservice/
interior and exterior setting (motifs):
Ob mittelalterliche Kulisse oder avantgardistische Architektur, Hafenspeicher aus der Gründerzeit oder Barockschloss in der Gräfte, ehemalige Wehrmachtskaserne oder nebelumflorte Moorlandschaft – Münster und das Münsterland bieten Innen- und Außenmotive für jedes Genre, für jedes Drehbuch.

The next example seems to see "Außenmotiv" as simply the "exterior film location" especially because it is contrasted with "studio" but after you have read the comments above, a slightly different interpretation is probably possible.
http://www.dreharbeiten.de/archiv/index.cfm?id=3688&action=d...
Außenmotiv - as exterior location and as exterior motif (outdoor vista)
Auch produktionstechnisch betritt "Bianca – Wege zum Glück" Neuland, denn bisher galten zirka 22 Minuten Sendezeit als Obergrenze, die im täglichen Produktionsverfahren zu realisieren sind. Mit großem logistischen Aufwand setzen zwei Drehteams, die parallel arbeiten, die Episoden von jeweils 42 Minuten Länge um. Gedreht wird am aufwändigen Außenmotiv Gut Wellinghoff mit Anbindung an Landschaftsgarten und Seenlandschaft und auf zwei jeweils 600 Quadratmeter großen Studioflächen.

In the following link, the exterior motif is realized through shooting at a real location and at the film studios where a partial replica was erected for the "motif".

http://www.dreharbeiten.de/archiv/index.cfm?id=3688&action=d...

Außendrehorte
Als Außenmotiv für das fiktive Hotel „Fürstenhof“ dient ein privates Schloss im oberbayerischen Dorf Vagen. Zusätzlich existiert eine Filmvilla auf dem Gelände der Bavaria Film GmbH in Grünwald-Geiselgasteig, die seit März 2006 den renovierten Westflügel des Fürstenhofs darstellt. Dazu wurde die Fassade der Villa Mann, im Jahr 2000 als Kulisse für den historischen Fernsehfilm Die Manns – Ein Jahrhundertroman erbaut, nach dem Vorbild der Originalkulisse renoviert und umgebaut. Die Kulisse wird auch von innen bespielt. In den Wintermonaten wird bei schwierigen Wetterverhältnissen wegen der Nähe zum Studio hauptsächlich hier gedreht.

The next link speaks of "outdoor vista" which comes close to how I would like to interpret it.
http://www.gallifreyone.com/review.php?id=2006-01&page=3
outdoor vista
New York and its air traffic was a spectacular outdoor vista of the sort we don't often see in TV or movie s.f. in that it looks amazing and cool and is at the same time a really great-looking place to live.

The following bilingual text uses exteriors for Aussenmotive.
http://www.c-films.ch/marcello/pdf/marcello_pressekit_de_en....
Aussenmotive / exteriors

Outdoor or exterior - are words that seem to be required for this translation. Of these two, "exterior(s)" in the singular or plural could work by itself in the sense of "set(s)" if you want to contrast it with "interior(s)" no matter what these interiors are. But the word exterior by itself would not encompass what I explained but be rather limited to the castle's outer properties or the actual location.
I am sure there was also an interior motif (expressing a vision for the interior setting) which is probably mostly realized at the studio(s) but not necessarily so.
Calling it "exterior setting" would expressively move it closer to my interpretation.
Going with "outdoor or exterior vista (or even motif)" is something I tried to argue for but there are certainly not too many examples (although outdoor vista is indeed used).
Finally, deciding on exterior location would IMO move the term more towards the location of the shoot (Außendrehort) and away from the theoretical/artistic concept of "Motif." I would not use it but you could certainly argue for it.
Hope this helps.



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Note added at 10 hrs (2009-01-31 02:27:03 GMT)
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corr.:* *
Outdoor or exterior - are words that seem to be required for this translation. Of these two, "exterior(s)" in the singular or plural could work by itself in the sense of *"SETTING(s)"* if you want to contrast it with "interior(s)" no matter what these interiors are.

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Note added at 1 day8 hrs (2009-02-01 01:12:52 GMT)
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@Helen:
Thanks for your input.
I am afraid my interpretation of "Außenmotiv" goes beyond "exterior" in the sense of outside of a building or "exterior location" as in outdoor set.
The German term "Motiv" simply conveys more to me than that and in my opinion can easily include what you are proposing the term "motif" stands for in visual arts - a cue, a theme/sujet, and yes, repeated. It can also "serve" as a motif, why not - even if at first sight, it might not seem to be spectacular.

You say a vista is just a view.
When you establish/choose a certain view or vista in movies, you also think of what it will convey thematically or at least in what way it will relate to the other elements of movie making (it does a great deal for mood; it is always present when acting happens, music, etc.) - anything will help establish, influence or be part of a theme and motif. One could call it "visual outdoor/exterior motif" but I don't think that's absolutely necessary. It is very complex and important because it is to be the visual background (well I wouldn't call it background/Kulisse but "integral element") that relates to acting and the rest of the filmic elements.
Vista is just a view you say, and again, a vista is just a view at first sight but it is a complex element in film.

I do not claim general acceptance of the meanings of the terms I propose and my proposal of exterior motif/vista is certainly an extended/expanded (maybe creative) version of what could generally be understood under these terms but I tried to convey what is meant with "Außenmotiv."

I have no problem with your comments but I invite you to follow my argumentation.

http://tviewlalabplus.blogspot.com/2007/10/visual-styles-of-...
motif
http://www.rewindvideo.com/tiki/tiki-read_article.php?articl...
motif
http://movies.nytimes.com/mem/movies/review.html?res=9F0CEED...
vista(s)