I think it's apparent that films look different from decade to decade (films made in the 50's look like they were made in the 50's, 60's from the 60's, 70's from the 70's, etc, etc.) Why is this? Is it due to the cameras used, the film stock, the way the film was processed, a combination of factors? Can the aesthetics of a particular era be replicated using digital tools (ie. can a film shot with digital cameras be made to look like it was shot in the 80's)?
It's a combination of factors but it's more of a spectrum than you suppose.
Look at ESB the hairstyles are less funky, the lighting is a little more sharp, Vader is a bit more polished and detailed and it feels less seventies more eighties but ROTJ is the only Star Wars film actually made in the eighties (not unless you count the Ewok films).
Back in the old days, there was more time spent immersing an audience in the movie world before the primary action began, now audiences are used to immediate and unrelenting action from start to finish.
When movies were filmed with technicolor cameras, they had an entirely different look and feel than movies today. This is because of the increased lighting, the different choices with regards to costume and staging, as well as the technicolor technology itself, which made for a bright, highly contrasting picture compared with the more muted hues of today's movies.
Special effects back then often warranted scenes being built around them, whereas today cgi is placed into the frame wherever it is deemed necessary.
And of course, in 77 a portal opened in space-time which allowed untold magic to escape into our realm, resulting in Star Wars, The Thing, Blade Runner, ET, The Dark Crystal, Alien, Back to the Future, The Princess Bride, and many other movies which were obviously Truth given Form, before the portal was closed in the late eighties.
You probably don’t recognize me because of the red arm.
Episode 9 Rewrite, The Starlight Project (Released!) and ANH Technicolor Project (Released!)
I am assuming you are referring to the "look" of a film outside of things like fashion. This boils down to two factors: production design, and more importantly cinematography.
With production design, it's mainly just style and taste of the time. However, you have to account for materials, mainly plastics, that have only existed recently. When it comes to makeup--whether it's just regular makeup or prosthetic effects and stuff--the chemicals used have changed over the years, so films from different eras use different materials. Mold making, even the types of wood used to make sets have changed, so that it's easier to work with and easier to do complex designs.
Cinematography is a bit more obvious, and again comes down to style, but also technology. Things as simple and taken for granted as kino-flo flourescent lighting were only really introduced in the 1990s, and completely changed the "look" of a lot of films. You had the elimination of arc lights, the elimination of sound blimps making cameras lighter and more moveable, steadicam which really only came around at the end of the 1970s and wasn't commonly used until close to the end of the 1980s. Also film stock: the chemical composition of film stock is constantly changing--even today--so films from certain years are shot on the same two or three types of stock, which effects sharpness, grain level, contrast and colour. You also have matters of taste, so some years filters are in style and some years they are not. Some years handheld camerawork is more acceptable, and some years it is not. It comes and goes. It also depends on studio versus location, which are lit slightly differently and affect shot choice. Also, things you don't think about like cranes, dollys and wireless technology effect what types of shots cinematographers can do--for example, remote focus pulling is relatively recent, so it's only in the last 20 years that you could do really crazy shots because the operator and focus puller didn't have to be strapped beside the camera.
As to whether these can be replicated--you can, but it's a bit difficult. Technically it should be perfectly possible, but I think people who try to do so don't fully understand why films from a certain time look a certain way, so they only get it "mostly right."
The 2006 George Clooney film "The Good German" took great pains to shot the movie as "1940's style" as possible.
http://www.imdb.com/title/tt0452624/trivia?ref_=tt_ft
The Steve Martin comedy "Dead Men Don't Wear Plaid" is another good example. They had to carefully match up sets and the lighting of many a classic film noir, for it to appear Martin's character was in the same scenes with the likes of Bogart. (No Forrest Gump level CGI in 1982.) They were fortunate some of the guys who actually lit those films were still around.
It's probably not impossible to use old lenses with a digital camera. HD video would have manipulated to resemble the film stocks of a certain era.
On the flip side of the same coin, I've seen music videos shot with ancient broadcast gear to get that vintage tv look.
Where were you in '77?
I have a - probably impossible - dream of becoming a director someday, and since my aesthetic film tastes pretty much range from the 60's-80's, it helps to know what it would take to make my own movies look similar.
I appreciate all the answers, everyone - thanks!