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Just out of interrest......

Feb 18, 2013 12:36 AM

Hi Guys,

 

Well, the time is almost upon us, where we will be at the point to have our fist complete episode of the project completed. Whew, what a year this has been so far. So much to learn, and so much learned from the forum and those of you who are always so willing to give advice.

 

I honestly cannot wait to be able to show a completed clip or something soon, but we will have to see what happens!

 

Apart from the above waffling, I do have a quick question - something that we have touched on before, but would like to get a quick recap on.

 

We are currently shooting with a Panasonic AF101, it gives us 1080p HD footage. We then use this footage as the basis for our show. We have started talking as a team, around the use of purchasing a 4K camera sometime soon. From my limited camera experience, the plus side of this purchase would allow us to take footage, and then do post pans and camera movements. Is this the only real plus though? Would scaling factor in as well? I remember a discussion with Mylenium and Rick, I think Dave was part of it as well, where scaling was mentioned. There is a limit of the amount of scaling that can take place before artifacts start showing up - scaling both up and down. Does shooting on a 4K camera make this scaling percentage larger, or do they still apply? I think it was mentioned that anything over 20% will start to cause issues.

 

Anyway, the point of the discussion, is basically to decide on the merits of buying another camera for our project - if the pro's far outweigh the con's, then I am all for it - however, since we are not at "Hollywood" level yet, I dont want to waste money for no reason. (although it would be really cool as a conversation opener to say we have a 4K camera! )

 

Well, a great day to all, and look forward to your comments.

 

Pierre

 

By the way, I finished the Adobe Audition classroom in a book course, and I think I am forced to admit, that sound - is not an area I think I would excel in! My hat off to all the sound engineers out there - you are the rocket scientists of the film world! (in my opinion of course! )

 
Replies
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    Feb 18, 2013 11:31 AM   in reply to Pierre Devereux

    Hi, Pierre...

     

    If you put 4K footage into a 1080 HD comp, it will come in at 100% scale.  The layer will be a LOT bigger than than the comp itself.  You'll have a precise 1-to-1 pixel correspondence with the comp itself.  Thus, you can simulate pans & tilts easily.  You can recompose shots.  You can set a keyframe at 100% scale and simulate a zoom in with no worries about image degredation.

     

    And if you choose to shoot green screen of a person standing & talking to the 4K camera, you're in real luck: you can turn the camera on its side, and just use it in AE by rotating it 90 degrees in the proper direction. You can take advantage of more pixels: the subject is vertical, so why waste all those extra pixels by keeping the camera in its normal horizontal orientation? 

     

    I'd imagine you could fake a zoom in by scaling the clip from full-figure to a head & shoulders shot without going beyond 100% scale in the footage.  I used this particular trick more than once when I produced spots in SD, but shot in HD.  It works like a charm.

     
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    Feb 20, 2013 2:38 PM   in reply to Pierre Devereux

    I don't know much about 4K cameras but I know the Red Scarlet seems to be a popular choice.  You can get a model that works with Canon lenses.  It's also fairly compact so it's easy to set up and break down.  I think Sony has a nice one coming out soon as well.

     
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    Feb 20, 2013 7:16 PM   in reply to DaftlyPunkish

    It's only 2K, but I saw a demo of the ARRI Alexa when it came out and I definitely think it's worth looking at if you have the money.  Of course it all depends on your budget.  A more affordable 2K option is the Blackmagic Design Cinema Camera. Otherwise the Red Scarlet or the Red Epic are both good 4K choices over the Red One especially if you need to shoot low light.

     
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    Feb 26, 2013 7:29 AM   in reply to Pierre Devereux

    It depends on what you intend to do with the footage. If you don't intend to do much with color, then going straight to ProRes or DNxHD and baking in the color settings is no big loss. Same with transformations and going straight to an HD capture from a camera that can capture a larger frame. It's all a matter of tradeoffs, as usual.

     
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    Feb 26, 2013 8:08 AM   in reply to Todd_Kopriva

    As Todd says, it's always about tradeoffs. Christopher Nolan shoot as much of "Dark Knight Rises" on IMAX cameras using real sets and real actors. Much of the footage of the opening airplane capture was shot for real and only enhanced with visual effects because he had the budget and the crew to make it better. The big Semi Truck flip was a real truck and a real stunt because Nolan minimized the effects and maximized the reality. The difference between the effects in Dark Knight and something like Transformers (a ton of blue screen and CGI) is amazing to my eye but to some it isn't that significant. If you have time take a look at the 'work' that went into the football scene. Way more than was needed but a much better product in the end.

     
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    Mar 11, 2013 4:58 AM   in reply to Pierre Devereux

    Here are some lens and format considerations you might not have thought of. These are basic principals that apply to all photographic systems.

     

    1. Perspective is controlled by camera position. The common misconception is that a wide angle lens gives you different perspective than a telephoto. This is not the case. A wide angle lens gives you a wider angle of view, but the perspective, the relationship between foreground and background, and the apparent movement between foreground and background objects is exactly the same with any lens if the camera position is the same. Think of focal length as a cropping tool.
    2. The larger the image sensor the more shallow the depth of field. An IMAX camera has a very large image area. A 35mm film camera has an image are about 1/8 the size. A 16mm film camera has an image area about 1/4 the size of a 35mm film camera. Put a lens on each of these cameras that gives you say a 40º angle of view, set all of the apertures to f5.6 and the depth of field with the IMAX camera at a focus distance of 1 meter will be a few millimeters, the depth of field with the 35mm camera will be a few centimeters, and the depth of field with a 16mm camera will be pretty close to a meter. Shoot the same scene with a typical smart phone camera and the depth of field will be several meters. It makes no difference what kind of sensor you have, the larger the sensor, the shorter the depth of field for the same angle of view and f-stop.
    3. Sharpness or clarity is not 100% dependant on sensor size. The amount of resolution you can get from an image sensor or a sheet if film comes from the physical structure. Extremely small image sensors can be manufactured with amazing resolving power. The better (means more expensive most of the time) the quality of manufacture the better the image.

    Why am I giving you this information. When shooting miniatures depth of field is always a problem. In many cases you are trying to simulate full size sets. This means more light for a smaller f-stop or smaller image sensors. When shooting film there is a limit of how much you can do with a 16mm negative so most minature work in film has been done with 35mm or even 65mm cameras. With electronic cameras, especially good ones, you can get amazing resolution from smaller image sensors. If it were my project I would stay away from large sensor cameras. A good 2/3 inch camera will give you the same approximate sensor size as a 16mm camera while a Red or an Epic will have a sensor that is close to 24mm so it will give you about the same depth of field as a 35mm film camera. For the same depth of field the Red is going to require twice as much light as a 2/3 inch camera.

     

    Another problem you face shooting miniatures is that you have to scale the camera position like you scale the miniatures. What do I mean by that? Typically, when I'm shooting a dialogue scene between two actors I'll have the camera about 3 feet or 1 meter or less from the actors. This perspective is similar to what you get when you are talking with someone face to face. The perspective of the close camera invites us into the actors world and makes us more a part of the conversation. If you want the scene a little more detached you move back and shoot with a longer lens. If you want the scene more personal, you move in.

     

    Now consider the same problem when your minature set is 1/4 scale. If you want the same perspective, the same feeling of intimacy, then your camera position isn't going to be a meter away from the puppet, it's going to be 25cm. This means it's going to be very difficult to get a big camera in the scene to achieve the same perspective. This also throws a whole new set of problems with depth of field. The closer the focus point the shallower the depth of field. If f 4 gives you what you want for a look at 1 meter, then you're going to need something like f 11 to get that same depth of field at 25cm. Change the image sensor size from 24mm (typical large or full sensor size) to 2/3" (typical professional HD video camera) and then a shot from 1 meter with a full sensor camera at f4 will have about the same depth of field as a shot with a 2/3 or 1/2" sensor from 25cm.

     

    I once produced a training film for Weyerhaeuser Paper company where we used a big minature railroad set. The only way we could get a camera in and around that minature set and achieve the perspective that I wanted was to use a Kenworthy Snorkel. We also had to use 2K and 4K HMI's to light the set because there was so much light loss through the snorkel and I wanted as much depth of field as I could get. Here's a shot of a snorkel system on a mineature set and this is how they work.

     

     

    I hope this gives you something to think about.

     
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    Mar 12, 2013 3:58 AM   in reply to Rick Gerard
    The common misconception is that a wide angle lens gives you different perspective than a telephoto. This is not the case... Think of focal length as a cropping tool.

    I tend to agree with people who share that misconception, and here is a brief example why.

    Shot taken with 50 mm lens:

    AE. Kitchen. 50 mm.jpg

    Shot taken with 35 mm lens from the same distance:

    AE. Kitchen. 35 mm.jpg

    Here is the overlay (never succeeded in matching):

    AE. Kitchen. Overlay.jpg

    What am I missing?

     
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    Mar 12, 2013 7:04 AM   in reply to Fuzzy Barsik

    If you have the exact same camera position with a perfect lens = exact same perspective. Light not passing through something or near something that bends it travels in a straight line. The miss-alignment you're seeing is lens distortion. Shoot the same two shots with a set of Zeiss Primes and the match between a 35 and a 50 will be much much closer. Few pro's will cough up the nearly $4K per lens for these amazing lenses but many, included yours truly, will rent them when there's enough budget in the production. Even the difference between a consumer and a professional Canon or Nikon lens is significant. If you use the Optics Compensation to correct the barrel distortion in your 35mm lens you should get a nearly perfect overlay in the 5 minutes it took me to do this with your shots.

    Screen Shot 2013-03-12 at 6.35.41 AM.png

     

    By the way, the first clue that there was lens distortion is that the line created by the edge of the refrigerator door is not straight in either shot. Sorry your lenses are not perfect.

     
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    Mar 12, 2013 7:09 AM   in reply to Rick Gerard

    No needs to apologise, Rick. That were lenses for cheap point-and-shoot camera I had at hand.

    Thanks for the clarification.

     

    P.S. The edge of the fridge door in the shot taken with 50 mm lens is a straight line - check the gasket contour in e.g. Adobe Illustrator.

     
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    Mar 12, 2013 7:54 AM   in reply to Fuzzy Barsik

    Pretty straight... at 800% I see about 2 pixels of distortion on that edge. Not bad for a consumer lens.

     
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    Mar 13, 2013 5:57 AM   in reply to Pierre Devereux
    I have a feeling I am making a terrible fool of myself with this question, and I am missing something very obvious!

    Well, my turn was yesterday. You are on duty today...

     

    What you're probably missing is the following: 4096 x 2304 is 2.133 times larger than 1920 x 1080. So as to get the same object size inside 1920 x 1080 frame (composition) while shooting 4k you should move your camera away accordingly. Try shooting your puppet from both original distance and this newly calculated one with Full HD frame, import footages into AE, drop the latter into 4k comp, scale to fit, drop 4k comp into 1080 comp and compare the result side by side at 100% view. Here is what I've got (guess which one is which):

    AE. Scaling HD to 4K.jpg

     
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    Mar 13, 2013 7:27 AM   in reply to Fuzzy Barsik

    The shot on the right was taken from farther away. Even if the resolution was as good as he one on the left the perspective (notice the width of the shadow and the curve on the top of the battery) is different. See my comments on camera position and perspective.

     

    With the kind of detail that is in Pierre's sample images you can probably get away with some scaling up. You'll get even better results with 3rd party software like Magic Bullet's Instant HD which now includes Digital Anarchy's Resizer.

     

    Pierre, you said you "fit" the footage to the 4K comp. Using AE's "Fit to Comp" is a BAD IDEA... Fit horizontally or fit vertically. When placing scaling footage it is imperative that you have the X and Y scale values exactly identical. Even if one shot has rectangular pixels and the comp is square, never FIT video to a comp frame. Always Fit Horizontally (Shift + Ctrl/Cmnd + Alt/Option + h) or fit vertically to a comp, or just scale the footage.  I didn't see much if any distortion in your samples so I'm assuming you just scaled up your footage.

     

    Having a little extra room when shooting miniatures is a good thing. In all of the work that I have done I have never had the need to have 4X the room in a shot that you would get with a 4K camera. The big advantage of a 4K camera is that you have access to more data for color correction and other effects like keying. You will get much better edges.

     

    Speaking of edges, keyed edges go bad really quickly when you scale up footage. If you end up doing that then it's imperative that you scale up and pre-comp or render before you key.

     
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    Mar 13, 2013 4:14 PM   in reply to Rick Gerard

    Pierre,

     

    I know you're pretty set on using green screen and I wholeheartedly understand why so many people prefer it over other background replacement methods, but I still think there's something to be said for using a rear projection screen with a good short-throw projector (or HD projector if you have the budget and room) and doing your background replacement in camera.  Of course I've always preferred in-camera techniques to hours of post-production work and part of me likes rearscreen projection simply because it's a dying art, but I think you might be surprised at how good it can look.  In the industry they call it the poorman's process, but I think if it's done right it can look great and it might actaully end up saving you a lot of time and money on the post production side of things.

     

    As of late, I've been using rear projection for a bunch of animated and live action projects, and although it has a very unique look, I think it can work wonders for many scenarios.  Here's an example of an experimental animated/live action film in which we used a rear screen projection for all the stop-motion scenes of the rabbits.  And, because we weren't keying we were able to get perfect definition on the edges of the rabbit fur, something that would be a lot harder if we were using green screen.

    Since there was no depth in the background projection, which was just a digital photograph of trees, we added some branches in the foreground and shot through a piece of glass that had some hand-painted grass on it.  We did both of the dolly shots using a huge motion-control rig, which you probably won't have access to, but if you decide to shoot any of your miniatures in stop-motion there are alternatives to traditional motion control like moco camera sliders.  I say this because if you have the time, you might consider shooting some shots in stop-motion using moco as an alternative to live action, because you'll be able to shoot at whatever f-stop you like simply by compensating with a long exposure.  You can also repeat camera moves, doing different passes for all the lights to composite later and you can do all this with a simple DSLR (which will shoot 4K or higher in stop-motion) and some frame grabbing software like Dragon Frame.  Another way of getting perfect mattes in stop-motion is to use a front light / back light technique.  I realize this could potentially change your entire budget and approach, but I think it could definitely be useful for a few key shots where you really need the the depth of field.  Of course, everything depends on your aesthetic.  Let me know if you're interested in any of these suggestions and I can give you more info on how to do this stuff.

     
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