I'll be shooting a job involving miniature (a train) and real people.
The plan is to shoot the miniature, which I still don't know the scale of, at the escalated frame rate, and shooting the real size people at the normal rate.
My first idea was too shoot the model train with the Revolution System, and the real people with a prime lens.
Will I need to escalate the lens as well, or do any kind of maths for the Revolution system, or a 24mm in the Revolution System is a 24mm on a prime lens?
I imagine that I will need to escalate the distance between the camera and the actors... but with long distances... can that be cheated and not noticed?
It seems that I will need tons of light to get the right depth of field... I guess that it is a normal thing to light a model with 24kws around it... (trying to create night on it)... Any ideas of better fixtures for here?
Many Thanks in advance,
Director of Photography
Dennis Murren does a good summary of scale and speeds in the ASC manual once you figure out your train's size (the bigger the better, generally). There are a few discussions about miniatures in the edited pages (thanks David) which would be a good starting place. Many more in the members archive as well.
You can do some cheating (depending on the action required), provided you have the camera angles correct. Get the angles wrong and it will never stitch together seamlessly. Without oversimplifying, the more your performers move around (walking across the frame etc) the less scope there is for cheats and the more precisely you'll need to match scale distances and fov. Camera angle, lighting and dof will need to match whatever the case. Of course, there are others on the list who have done way more of this than I ever will, so hopefully they'll chime in too.
Thanks very much for your advice.
I actually just bought the VES book which I find pretty interesting...
Unfortunately the model is pretty small (1/22.5) for a train.
We will do some test (with the frazier lens) for frame rates as the train is electric one and, if I escalate the frame rate, it won't be fast enough. Production and the director are thinking about reducing the frame rate to make it look faster, but I'm afraid that it won't get the gravity/weight feeling of a real size train...
Any experiences on undercranking the camera to get that kind of effect? Does it look any good?
I'm pretty convinced that, if people have been using the frame rate formula for ages, we are not going to reinvent the wheel here...
Director of Photography
It isn't just the frame rate that needs to be adjusted, but ALSO how far the train travels in frame to be equivalent to the "real" distance a train would travel at the desired speed. I also suggest that you add weight (actual weight, like lead) to the train so it doesn't jump around and look fake. And finally, for the scale you're shooting, you need to scale the lens you're shooting the miniature with to the lens you'll shoot the live action. There is a lot to be considered and it's not simply "over crank."
>> And finally, for the scale you're shooting, you need to scale the lens you're shooting the miniature with to >> the lens you'll shoot the live action.
Jumping in late... having missed most of the earlier part of the thread...
I will say that distances scale, lens angles of view do not... So if I shoot two people standing in front of a greenscreen with a 24mm and they are ten feet away from me on a porch, when I shoot the house the porch is stuck to I use a 24mm - if they were ten feet away and I have a 1/12 scale house then I shoot it from ten inches away... if the camera was three feet off the ground then my lens center needs to be 3" off the ground etc....
Note that with some snorkel lenses, the focal length of the lens at the end of the snorkel does not provide the same angle of view that the same focal length would on the camera, so make sure you are matching angles of view, not just focal length numbers.
rule of thumb... distances scale - angles do not... so if camera was tilted ten degrees up then the matching angle is ten degrees up etc etc...
As far as speed, there are several issues in play....
one is the physics of the action of the train.... the overcranking (for which the formula is only a guide, not graven in stone) is to try and get the right weight for moving things... explosions this is very important.... static shots where nothing moves it is not important at all... we often shoot miniatures in motion control at one frame per second or even slower if necessary to get the depth of field.
One other issue for speed of train is how many scale feet it is supposed to travel in how many frames.... if it is supposed to be moving 40 miles per hour in real life (that would be about 59 feet per second)
then if it takes three seconds for the locomotive to get from left of frame to right of frame it is supposed to have travelled 180 feet more or less.
If your scale train is 1:22 scale you need the train to travel eight feet in three seconds of screen time (seventy two frames of film)
On the one hand you want to overcrank to get the train to feel like it has some weight, but you also need enough f/stop to get the right depth of field ... and the train might not travel well quickly...
so you may end up finding a slower frame rate where the train doesnt fall off the track but you get eight feet of travel in seventy-two frames.
Honestly 1:22 is a very small scale train - if the shot is too close the detail may not hold up too well... but then again it might work just fine... but you might end up shooting a slow frame rate and a very slow moving train to make it work
obviously you have to work to get the lens in the right place... if the lens is supposed to be three feet off the ground, the lens center needs to be about one and five/eigths inches of the ground - which is
hard to do with a four inch diameter lens... unless you cut the set or use a smaller lens or a mirror or etc etc
Test Test Test
That's what experienced miniature shooters do - it's the best way to find out what works:-)
la based dp
vfx and other stuff
>> Thanks Mark,
I'll suggest them to put some lead on the test. Thanks.
I made the maths already for he distances, depending on the train speed, but if we are shooting at the right frame rate, the scaled train (an electric toy) won't get as fast as the maths say it should, so we will run the camera at slower speeds (now with lead on it) and hope for the best...
Will I need to escalate the lenses even if I use a Frazier or a Revolution lens systems? It seems to me that the field of view (angles) should be the same in one and another... Like it would be on the tilt of the camera.
Director of Photography
Thanks so much for your quick reply.
Testing today, so I will apply those advises.
Director of Photography
Charlie Herranz wrote:
>> Will I need to escalate the lenses even if I use a Frazier or a Revolution lens systems? It seems to me that >>the field of view (angles) should be the same in one and another... Like it would be on the tilt of the >>camera.
I cant remember if you have to do anything to the Revolution. I am pretty sure that the Frazier lens focal lengths have a different corresponding angle of view from the same focal length directly on a S35 filmback or gate...the optics are more complicated than just a relay lens.
You can test this at the rental house
One thing to think about.... people always measure distance to the film plane and that is fine for focus but not always for image size calculations - but obviously that doesn't work with a snorkel (it doesnt work with a zoom either from the standpoint of angle of view or field of view by the way... (put a prime and a zoom on the same camera at the same focal length and the zoom seems tighter.... well...the business end is closer to the subject )
Use what people call the nodal point of the lens (actually there are two of them except with a pinhole lens and you want the rear one)... You want the point where if you panned or tilted at that point there would be no parallax shift in the image between near and far objects.
In practice, with prime lenses, that is pretty close to where the iris is physically in the lens.
You can set this up with a chart on the wall or just a few coffee cups on the floor and put the camera on the floor. Get the lens with the frazier in the same place as the lens directly on the camera and figure out if it is wider... if you cant find a match between angle of view of the frazier and your lens for shooting the foreground then make a framing chart and shoot with both lenses from the same place so you can see how to crop one of the images to fit properly with the other. This is not the perfect solution but it will get you closer to making it all match.
Something to remember: perspective is not determined by focal length - it is determined by position in space... all focal length change does is magnify the image (of course when you magnify you are excludiing material but the relationship in space between the objects you are shooting hasnt changed)
So if camera is in right place - perspective will match once you crop the wider of the two lenses to match the field of view of the narrower one...
so same idea with miniature.
Obviously best if you can shoot both with exact same lens but if you cant this is a way to think about it so you don't make a mistake.
Lots of stuff to think about but at the end of the day, if it looks good it is good:-)
Go onto Youtube and look at some of the amateur videos shot on train layouts. Some of the better ones are excellent and may give you some setup ideas.
I don't know if this works for your project, but compositing in elements that are difficult/impossible to scale will often go a long way in selling a miniature. Generally, that means smoke, fire, and water spray. Also, executing those three things well are not too problematic for an good, experienced compositor. Other options (though a little more labor intensive for post) would be fabric or flags waving in the wind, or things like hanging/swinging chains or ropes.
Director/DP & animator
>> ... compositing in elements that are difficult/impossible to scale will often go a long way in selling a
>> miniature. Generally, that means smoke, fire, and water spray.
That is a great idea, thanks for the tip. I will pass the info to the team, and see what we can do.
Thanks everyone for all this advises... much appreciated!
Director of Photography