Some of the best in camera forced perspective I've seen in movies is in The Lord of the Rings. They even created moving platforms that moved with the camera so everybody and objects would stay in the correct perspective. Thanks for all the great videos!
Yes, those were absolutely amazing - shooting a static scene is one thing, but actually moving the camera and still keeping up the illusion is crazy. They show a lot about how they did the whole thing on the "behind the scenes" DVDs in the extended edition - those are totally worth it (also for all the miniatures work they did).
Yup, that is from the extended edition DVDs - basically 4-5 hours of stuff like that for every movie. Amazing to watch and I actually enjoyed it more than the movies themselves :-)
I wrote the field of view calculator app for the LOTR films. It was basically all the calculations in the spreadsheet in this video wrapped up in a handy app the VFX artist could use when breaking down a shot. They would previz the rig to make sure everything would work before the set was built. We weren't even sure if moving the camera was possible until we got a motion control rig in and hooked up a slaved platform. We scaled the platform movement directly off the camera movement in the motion control software. We could move the camera around and the platform would move to keep everything aligned. Brian Van't Hul who came up with all this is a genius.
You should have so many more subs, views and Patreons. You create very insightful, clear, concise and informative content and I'm very grateful to have found your channel. Please keep up the good work!
Fantastic! I am a still photographer but I have always been interested in film making. After more than 30 years I still learn new things all the time. Let me say that your videos are both educational and inspirational at the same time. I'll be trying this out in the near future as it has started the gears turning in my head! Thank you!!!!
Thanks John. I have been waiting for this since our “discussion” on SPFX re: forced perspective. Another great lesson. BTW, my favourite forced perspective has to be from CE3K with the Cotapaxi ship in the desert.
Welcome back, John. Coincidentally I shot footage this morning for a quick tutorial/discussion on forced perspective and shooting for "Giant/Ant" sized people.
I'm hoping to try and make a small war movie, and since I have no money for a an actual war I was thinking of building miniatures and models and using forced perspective. Thanks for this video. The depth of knowledge you go into is always great
Thank you for yet another great video. Always wanted to know the math behind it, though I doubd I'll actually be using it any time soon. I hope people will flok to your patreon page to support you guys ;)
I can tell you that as an audience member there is something magical about asking "how did they do that?" And something satisfyingly about finding out the answer when it's something other than "with a computer". 🎥
You should start asking the question "How does a computer do that"? Then we get into some truly magical stuff. As Arthur C. Clarke said, "Any sufficiently advanced technology is indistinguishable from magic." It always feels bizarre to me that now we live with magic devices in our pockets, we are more impressed with parlor tricks. I guess it's because they are easier to understand. But once you start to question the magic, how we're taking a glorified adding machine and making them do all sorts of things, you can start to appreciate the artistry in the magic. This is a video we did on one of the topics. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Qx_AmlZxzVk.html
Filmmaker IQ Thanks for responding (I love the channel). I did watch that video and I do agree that we live in amazing times, I just think there is something cool about praticle effects.
your channel is absolutely fantastic. it so good that I binge watched all of your episodes, there is not a bad one in amongst them all, I just love the premise and stile of your content, one of the best channels on RU-vid,, its a great solid starting place hope that you keep it up, and THANK YOU
Great video. I guess the best solution comes down to what the merrit of the scene should be. If it involved a lot of reaction between foreground and background, this setup has the advantage that it can be filmed very naturally, where a green screen solution would have to be carefully timed - which totally takes the fun out of shooting it - or shot with two cameras (as has been done in Fraggle Rock).
The fun of doing forced perspective practical instead of as a green screen composite is having a movement that surprises the audience. My favorite example is this scene from 'Top Secret'. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-QJoTBlDfVhk.html
Very good and In-depth explaination! Im a true belieber in getting fx shot in camera as well. Its almost always better and a true sign of craftmanship.
Forced perspective is a classic means of cheating the eye; even big budget blockbusters use it. In THE EMPIRE STRIKES BACK, the opening shot of the Star Destroyer is ILM's idea of forced perspective; they built the MODEL huge in front and smaller at the back to give the sense of a giant ship all in focus. Nobody notices unless they're a special effects nerd who has to know, like me.
Most calculators give angles in degrees, or can be set to do so, the conversion from radians to degrees is not needed in most cases. However, Excel does output in radians and conversions are needed for spreadsheets.
I'd be willing to bet that no one would be able to tell the difference. The default assumption is that it's all greenscreen now... only when people find out it's forced perspective do they get "amazed" - I think that's saying something about how good greenscreen techniques have gotten.
You could be right. I like seeing and knowing that that thing I am looking at is for the most part living in a real space. Green screen has made things that are technically impossible, possible. I like them both and like seeing both used in conjunction with each other.
great video, but I'd (nerdily) like to point out (i. e. at 4:35) that the output is NOT in radians. Unless, of course, your calculator is set to radians by default. Actually, it's dimensionless, since all units cancel out. But if your calculator is set to rad as default, it will output everything in radians. (imho, calculating in radians is a nuisance except when further trig operatins involve lots of pies and cakes :-) )
Thank you for your promt answer, but what I meant was that your statement was wrong; the inverse tangent usually is NOT given in radians, you do NOT have to convert. Most calculators (or sin / cos/ tan tables) already give the answer in degrees. Not radians. Math nerds and electonic engineers then convert these answers to radians. And only if they need to calculate with standard circles and pi.
Everyone should check out "Darby O'Gill and the Little People" that used forced perspective to its fullest... back in 1959. The effects used on that film It were a big inspiration to "The Fellowship of the Ring" 40 years later.
If you turn the moon+thumb calculation around to what arm length you'd need for that shot (without altering the other variables) you get an arm lenght of about 83in or 210cm :D
I was concerned when he said some "basic" geometry would help explain. Then he dipped right into "basic" trigonometry. What I got out of it is that the tan radials of the reflecting obsidian triangles are bigger than they appear in mirrors.
John, I wish you would do a deep dive into Fair Use, and publisher's abuse of creators fair use claims. The disparity of legal power in the US legal system, with a highlight on the variation of rights available to written, audio and visual art forms
I got into it more in my Copyright video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4b_5MO04qGg.html Fair use is a defense, it is asserted when there is a claim of infringement. I've seen abuse in every direction, not just the big publishers As for the US legal system it's getting better as a copyright small claims is in the works. Also realize that copyright isn't a U.S. only thing. Most of the basics are dictated through international treaties.
This will probably only work for non-moving shots (or possibly also panning the camera vertically around the great circle of a sphere encompassing both the glass and the model), but: I wonder if instead of using a filled martini glass on the front focus, you use that cut-in-half martini glass, change the braces for the model into a half-clear-half-glass bowl, and then fill *that* with dyed water and have the model swim... Of course, they would have to agree to that, and then you'd have to make sure the half-glass part of the pool reflects light similarly to a proper martini glass using your lighting setup, but I wonder if it would allow you to do things like allow the girl in the martini glass to *use* the martini itself as part of the scene =P
For a moving shot - you need to rotate the camera lens on it's nodal point. This nodal point is where there is no parallax in the pan - that way everything stays in perfect perspective. As far as the idea of having a split half - so the front half is small scale and the back half is full scale - sure it would work - but at that point why not just have a fully scaled up martini glass and just have the talent sit in it with liquid?
At that point, you'd have to find a way to force the perspective of the giant glass onto the table, and interact the other actors with the objects on the table. I guess with RC robot technology and some *really* clever synchronization between actors and RC operators you could do it while still forcing the perspective... (Of course now I'm completely in the engineer's mindset, which is what I wrote my first comment coming from anyway =P )
Worth knowing the apparent width of The Moon changes due to any number of factors, where it's at in its orbit around the Earth and the angle at which it is to the horizon. There's plenty of times the moon appears in the sky positively HUGE; but it's not that much closer to the Earth (not enough for the change, at least) but where it's at in relation to the horizon the light from it gets distorted in a manner when it passes through the atmosphere that it appears much larger.
+Brian Straight the moon at Horizon being bigger is merely an optical illusion. When it's near the horizon you have visual references which makes it appear bigger but in actuality it's exactly the same size as when it's high in the sky. If you don't believe me just try the thumb test and you'll see it's still only one third the width of your thumb at moonrise. I always do this when I'm amazed at the size of the moon only to be disappointed. Now there is something called supermoon when the moon is at the apogee. But then the moon only appears 14% bigger. So it goes from half a degree to 0.6 degrees. Not really that much of a difference but the closer distance makes the supermoon much brighter.
Off the wall question: Could you do a video about curtain openers? I've been in love with the vintage Wehrenderg theaters music and film clip(s) since childhood!.. which has made me wonder why, how, when did they start and evolve!.. hope you see this comment! take care and your videos are extremely badass!! Peace..
+Rev. Dave Moorman the tangent is in reference to the object we're trying to measure the angle of view of. Tangent line being the line that intersects the farthest edge of our object at only one point. The circle that I drew is only as a visual representation of the entire field of view and a hint to thinking of these as trigonometric functions. Although we can calculate the radius, we never do because it is never needed. Calling them radius lines would be confusing because we really don't care about the dimension of the circle. ;)
I am coming back to this for the math. But it seems like the metric spreadsheet is messed up. I am trying to shoot a still so focus stacking will help me, but I am get the distances right. Shooting with 1:25 and 1:500 scale models at once becomes tricky.
Thanks for the video. I'm facing another challenge. How can I know the distance and camera height I need to use if I have to create an elf/dwarf character which is about half the size of a normal person. And have him standing in the same frame as normal person. I don't think that one is possible in camera, which is OK, I can cut him out and move him in photoshop. But how to know the correct perspective...
So to make the moon/thumb thing to work in-camera, you'd just have to back away from the thumb until it, too, was ~0.5° (so, 75-80 inches away, instead of 28), then re-frame the shot, right? Obviously too long to be a real human arm but wouldn't require photoshopping the moon in.
Great video as usual Mr Hess! Though you might want to plug your new Patreon page in your next video, and tell people what they rewards there are etc since they might be confused about the link just randomly popping up in your description!
Is there a way to calculate using maths the perspective change of the reduced filed of view? As much as I research and re-investigate I can't find the answer: Why does the plane compression of reduced field of view occur? Why does the same background compression happen even in any lens if we crop and re-frame the central part to reproduce the angle of view of a telephoto lens? Why is it that even in asimple vists and live when we frame a distant object it looks closer to us like the ponzo illusion at Lakeshore Road, Port Colborne, Ontario, Canada? are both visual effects related? Is it related to the ponzo illusion, the moon illusion or which visual effect?
Let's see if I understood the math and the calculations work out. If I photograph a 20m high church on the horizon at 5km with the moon behind it I would have the church at .23 degrees and the moon at .52 degrees… That's why those spectacular photos of the moon on the horizon If in another photo I take a portrait with an angle at 50cm, the eyes-nose-mouth part measures 10.29 degrees and the ear area measures 12.79 But if they are 5m away, the relationship is 1.03 degrees for the face and 1.47 degrees for the ears. That's why it gives the impression that the telephoto lens "makes you fat." Am I right?
I don't have the calculations in front of me but I think you're getting it. At some point in the video I think I graphed the relationship and you notice how at short distances the angle of view changes very quickly. That explains why close up wide angle shots exaggerate features. Remember it's not the lens that's doing the compression, it's the distance. There lens focal length just determines the field of view. The angle of view of an object and it's relative angle to other objects is solely controlled by the distance
Awesome detailed explanation of an awesome in camera effect!. One question: You've mentioned that you used a full frame Canon 5D mark II,...but for the videio portion, what is the sensor size on the Black Magic Camera that you used?
Thanks for the quick response. So, micro 4/3 ?,....I thought it had a super 35!. Even better!, because, the reason for my original question is that I was wondering if I could replicate this experiment on another micro 4/3 camera, like the GH4. Thanks a bunch for the info. This is truly exceptionally fun and educational channel!
+Onpex actually much easier to accomplish with smaller sensors because they use wider lenses and the DoF is naturally wider. That's why you see all those tourists and the leaning Tower of Piza shots
Go to the page we have on the course - then scroll down to "sauce" and the link to the spreadsheet is the first one in the list filmmakeriq.com/courses/science-forced-perspective/
+confiscator you mistake me for a grammar Nazi. I could care less... In that I do care a little... But really not that much. Etymology fascinates me. Words and grammar are constantly changing and I'm okay with that.
Meh, yeah, I get you. But I suspect that's not what's going on here. I suspect you just don't know what it means to beg the question; fair enough, but that's not me mistaking you for a grammar Nazi. That's me mistaking you for curious.
green screen and post always looks like green screen and post. Even in modern big budget stuff the cgi cheats look like cgi cheats. (I find it distracting as a viewer, more so on the small stuff that would have been easy to shoot live.)
Filmmaker IQ I see. Then you have distance and width on the wrong sides of the fraction bar. Width is the opposite side and distance is adjacent. Width should be on top and distance should be on the bottom.
Man I even wrote the formula correct in the thumbnail, everywhere right except for that one spot... sheesh, I guess it's time to break out the cat-o-nine tails.
