Jump to content

Blue Screen Test


Recommended Posts

  • Premium Member

Backlight is mainly a solution to the problem of blue or green spill, but theoretically, the lighting on the subject should match the background plate, so if the background is a landscape on a heavily overcast day, a hard backlight on the subject doesn't make a lot of sense.

Link to comment
Share on other sites

  • Premium Member

>David doesn't need anyone to speak for him, but with due respect, he was only making a suggestion regarding personal taste, not misleading anyone with a rule on technique (which is what you are implying).>

 

I never said he was misleading anyone, and while I didn't make it clear, I was not talking to him but making a comment in general about his 'contextless' comment. I do so because there are so many misconceptions and outright myths about compositing for film and chroma key for video. I know I teach this stuff to thousands of people each year from beginners to 30 year pros. Three weeks ago I got a call from a well respected DP at 2:30am my time who was doing a transfer of some spots he shot for a major multinational retailer. He was terrified and wanted to know if he was going to have to reshoot because the folks at the transfer house said he had an awful lot fo back light that they couldn't correct. When I delved into his reasoning (he was mostly shooting film up till now and was beginning to shot high end HD, his response to why so much light was, "I always heard you had to use more with video so I over compensated." So when a person throws a statement out there that has little context other than telling folks not to 'forget' something as if it is a necessity, I feel the need to tell folks what I show every seminar I give, most of what folks think they know about compositing is sometimes based on hearsay and has no real reasoning. Sort of like me telling a group of campers about to go into the woods where I just came out of not to forget their gun. It can be confusing to many. If your in NY in Feb. give me a ring and I'll invite you to my event. I shoot a real mock composite TV commercial for the group and then edit it in front of them, and along the way ask them to ask me to do everything they know about composites so I can try all the options suggested and in the end show them in first person that nine out of ten 'rules' of doing blue/green/matte/compostiing have no real basis and can in many cases get you in more trouble than help. But as I said you can not learn much about doing composites unless you have experienced the product throughout the process form production to finished product. There is this tremendous need to learn how to do green screen. I think it has more to do with a need for many folks to be able to mimic the effect even though they really don't need to do it for any real reason, but it satisfies a need to feel part of the crowd. Nothing wrong with that, but they need a good foundation. I am amazed how each month the top ten key words that link folks to my site are the word green screen or some other composite word. I just looked and in the last three days alone out of the top ten keywords folks used searching the web that drove them to my site, here are how many involve some form of compositing term and the number of hits and ranking:

 

1. green screen lighting 141

 

2. lighting for green screen 119

 

3. lighting green screen 93

 

7. how to light a green screen 61

 

 

If I did the top fifty keywords, 40% of them involve some from of compositing term. Bottom line. There is a tremendous need for beginner knowledge and I want to make sure as many folks (outside of those that have preferences, but do so from experience) know as much from both sides as they can.

 

>Speaking of myths about keying/backlight, it isn't true that backlighting was always used pre-digital for bluescreen separation as a rule. Check this out (DIAMONDS ARE FOREVER, 1971):>

 

My discussion of myths involves perceptions and not realities. The perceptions are the myths. Doesn't mean they have not been done, just that saying they 'have' to be done perpetuates something not necessarily true.

 

>So even pre-digital there were really no rules to lighting the perfect bluescreen figure, just preferences.>

 

There are no rules in life but I wouldn't teach my kid that if he drives safely he will not be killed in an auto accident. It's about having a good foundation. Skipping the first ten chapters of the operators manual will teach you a lot but you will be missing out on quite a bit.

Link to comment
Share on other sites

  • 3 weeks later...

Little did I realise that a single line should promote such a response.

David Mullen, of course, is on the case. I only humbly mentioned 'backlight' in the sincere hope that the originator of the topic might need to employ it. Since. looking at the question. We are in the confines of a British prison cell. The keylight, during daylight hours would be the single window, high up on the outer wall. Of course, were it a night interior a coarse single source centre light. In any event, a backlight may be of some use to 'wash' out the spill from the screen scarcely an additive exposure. Whatever happens, at least these days (using video) one can see the composite result on the playout monitor. Unlike, my time when I might spend the night kneeling and praying (and me an atheist too) that the bath would be spot on. As I write to you from what is affectionately known as 'The Cutting Room' I am blessed. Never before could I write,shoot and post an entire production. We all live in the most exciting of times. Please treat my original post as a fart from a dinosaur. Perhaps you may look out for my forthcoming dissertation "The exponential properties of knicker elastic for the manual rostrum cameraman." Anyway. I wish you all a Happy Christmas and a prosperous and creative New Year. Just shoot it................

Link to comment
Share on other sites

  • 2 months later...

Ok, so, several months down the line, it's being made.

 

26th March.

 

One query I had was about copyright music. I want to cover the first 20 seconds or so from 'Queen - Too much love will kill you'. We can record our version of it, that's not a problem, but I was wondering if using our own recorded version of it (about the first 20 seconds worth) would infringe with copyright laws?

 

Thanks for any advice.

Link to comment
Share on other sites

The Visual Effects forum probably isn't the best place to ask this, (;)) but no, you probably can't legally do it. Licensing the original track would probably be higher than your entire budget. Realistically, you're unlikely to get sued because no one knows who you are, but it's entirely possible that if people start liking your film, you'll have difficulty getting a distributor because of this issue. Distributors will expect you to already have dealt with this, and will not be jumping at the chance to pay your licensing for you. On the other hand, if you don't expect to ever get distribution or make money for it, then go ahead; you probably won't ever encounter any issues.

Link to comment
Share on other sites

  • 2 weeks later...
  • 1 month later...

Does anyone here know the focal length conversion factor for 2/3" HD ccd's?

 

I've tried searching but I can only find 2/3" stills camera sensors, which are a diffrent ratio, so the 17mm focal length that I was using comes up at like 68mm or something.

 

Any help?

Cheers.

 

 

ps.

I've started rotoscoping, coming out ok.. needs more work. I'll post a previz when it's "previsable".

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...