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HVX-m2-Bluescreen


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#1 Micah Ellars

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Posted 10 August 2006 - 10:26 AM

Does anyone feel that the HVX with the m2 adaptor in any setup could be used to pull optimal keys?

I have seen great keys with the varicam and pro35. Why not the m2? The m2 does not seam as soft as the P+S mini 35 (to my eyes). I know that there seams to be a slight promist effect created from the ground glass. What if the 35mm lens on the HVX m2 combo DOF was very deep? Say a 18mm set to F5? The interest would be in acheiving a much wider angle of view in the HVX than possible with the digital lens available, also maintaining a rectilinear image. If anyone thinks it is possible or wouldn't mind trying with their own set up please let me know.

Thanks,
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#2 Paul Wizikowski

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Posted 11 August 2006 - 10:42 AM

In short, yea, I think it would work just fine for pulling keys.

As for testing it...not yet.
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#3 Micah Ellars

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Posted 11 August 2006 - 11:01 AM

In short, yea, I think it would work just fine for pulling keys.

As for testing it...not yet.


In short, Thanks. I wish you would elaborate on why you think it might work.

I spoke with a post house about this and they felt confident that THEY could pull acceptable keys, but they insisted that the shoot be supervised by them or whoever would be doing the post work. I am wondering if it is something that could be done in AE/Keylight without having to hand paint the mattes. That would suit an HVX production budget much better.

Anyone else feel this is do-able?
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#4 Paul Wizikowski

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Posted 16 August 2006 - 01:53 PM

My reasoning without having tested the exact setup you are calling for is this...the camera samples at 4:2:2 as oppossed to the HDV default 4:2:0. Which means you will get a decent representation of the hue blue just from the camera itself. The next major determining factor for a good key is your lighting. The lens and the M2 adapter seem almost secondary to the ability to pull an acceptable key. That and "acceptable" is a subjective term.

I would feel confident in the ability to pull an acceptable key with that set up knowing that the camera records an honest blue channel, I have confidence in my lighting ability, and I have done so with worse lens setups.
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#5 Micah Ellars

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Posted 18 August 2006 - 05:45 PM

My reasoning without having tested the exact setup you are calling for is this...the camera samples at 4:2:2 as oppossed to the HDV default 4:2:0. Which means you will get a decent representation of the hue blue just from the camera itself. The next major determining factor for a good key is your lighting. The lens and the M2 adapter seem almost secondary to the ability to pull an acceptable key. That and "acceptable" is a subjective term.

I would feel confident in the ability to pull an acceptable key with that set up knowing that the camera records an honest blue channel, I have confidence in my lighting ability, and I have done so with worse lens setups.


Thanks for the further explanation Mr. Wizikowski. I have pulled good keys on mini DV before that, aside from the lower end NLE compression used on them (premier), they looked very good. I guess my major concern is the plethera of warnings about using the adaptors for keys.

My version of acceptable is seamless. Optimal or Perfect would be a better term.

If you happen to conduct a test with that setup or any similar please let me know.

If anyone else has input please share.
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#6 AshG

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Posted 19 August 2006 - 10:50 PM

Is there a reason you would use an adapter for keying? Why not use the stock lense for those shots?



ash =o)
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#7 Mark Allen

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Posted 21 August 2006 - 01:45 AM

I've done a few shoots on greenscreen with the HVX and it was fine. I would very much recommend shooting in 1080 so you can access the 100 Mbs datarate even if you only want standard def in the end. key at the higher resolution, will do wonders.

As for using the adapter... if you're doing it so that you get a blurry edge (imagining you're in tight shots with a tight telephoto focus on eyes and want back of head or other person to be blurry) - well... you're going to have the standard problems with blurrieness on greenscreen. I find that if the blurriness is generally all in the same range it isn't so bad... though the more blurry the harder to deal with for sure. What is nearly impossible is when you have multiple levels of blurr going on. For example... two people talking in the foreground and an extra walking by in the background. well the blur level on that extra wants a totally different key (not to mention that in motion they will even be more trouble) - but you'd definitely want that other extra on a separate layer or you will have to roto.

As for DV - I've never seen anyone do a good greenscreen key on DV unless it was stylized to nuts. The compression scheme sucks for keying and the data rate is too low.
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#8 Micah Ellars

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Posted 22 August 2006 - 09:02 AM

Thank you for your commentary. I would never dream of having anyone out of focus for chroma work. It seams that you feel that it may be possible then? And yes I would definatly shoot at least 720p. This set up would be ment for an alternative to varicam + pro35.

Think extablishing shots and all subjects in focus on half sets.

My questions I guess is this simple.

Given that you have subjects in focus with the HVX+m2(12mm lens @ f5), is the m2 going to create significant softness or any aberations which will impede upon pulling a good key? The reason, for the adaptor is the wide angle of view through the 12mm lens.

I guess anyone who has used the adaptor for any shos with great depth of field would know if they noticed faliure to acheive sharp focus, color fringing etc...
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#9 Nathan Chaszeyka

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Posted 22 August 2006 - 11:17 AM

I have a couple questions about your question....

The title of your thread says bluescreen, why have you chosen blue over green? Or is that just a misnomer?

Secondly, my experience with greenscreen work is rather limited and I primarily have been on the post side of things when working with it BUT, why do you feel it necessary to shoot such a wide angle shot? Most of what you are shooting will be empty green spaces that will first be cropped with a matte before pulling the key.

The stock lens on the HVX is completely capable of getting a full shot of the subject, why do you need the extra space in the shot? The composition of the subject can be put together by the compositor.
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#10 Micah Ellars

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Posted 23 August 2006 - 11:02 AM

I have a couple questions about your question....

The title of your thread says bluescreen, why have you chosen blue over green? Or is that just a misnomer?

Secondly, my experience with greenscreen work is rather limited and I primarily have been on the post side of things when working with it BUT, why do you feel it necessary to shoot such a wide angle shot? Most of what you are shooting will be empty green spaces that will first be cropped with a matte before pulling the key.

The stock lens on the HVX is completely capable of getting a full shot of the subject, why do you need the extra space in the shot? The composition of the subject can be put together by the compositor.


Blue/Green I basically mean chroma.

I will be shooting elaborate half sets in which the background is keyed in. This is for artistic purposes. The original plan was to go Varicam+Pro35 (which I know works). Or pruchase the HVX + m2 for a longer production time and lower cost.
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#11 Mark Allen

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Posted 23 August 2006 - 10:38 PM

I can understand your use of M2 if you're using sets with any sort of depth because you want to keep the same feel as the rest of the movie. HOWEVER.... the entire purpose of doing sets on green screen is to do the sets that surround the actor so that you don't have to use a screen at all, you just do set extensions. If you're going to have some set pieces - if they're not interacting with the actors or blocking the actors from the screen - thus alleviating the need of the screen.

I can't speak to the focus issues though as I've never used the M2 or the like.

I CAN reiterate.... 1080...... not 720p. You get TWICE the datarate at 1080 on that camera. You can say "but we only want it at 720p" - then I say, well, your composite will then be that much cleaner. Shrinking always looks better than growing. You don't want to enlarge a greenscreen composite.

my 3 cents.
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#12 Micah Ellars

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Posted 24 August 2006 - 09:01 AM

I can understand your use of M2 if you're using sets with any sort of depth because you want to keep the same feel as the rest of the movie. HOWEVER.... the entire purpose of doing sets on green screen is to do the sets that surround the actor so that you don't have to use a screen at all, you just do set extensions. If you're going to have some set pieces - if they're not interacting with the actors or blocking the actors from the screen - thus alleviating the need of the screen.

I can't speak to the focus issues though as I've never used the M2 or the like.

I CAN reiterate.... 1080...... not 720p. You get TWICE the datarate at 1080 on that camera. You can say "but we only want it at 720p" - then I say, well, your composite will then be that much cleaner. Shrinking always looks better than growing. You don't want to enlarge a greenscreen composite.

my 3 cents.


Thanks for your 3 cents. The reason for half sets is artistic, they are a must. There are model landscapes that must be shot with a correlating lens for match angle of view and DOF of subjects. Blue/green lighting will be optimal.

As said before, I know I can do it with Varicam + Pro 35, can I with HVX + m2? There is a substantial difference in pro35 and mini35 from P+S Technik and allegedly the m2 is sharper than the mini35. Perhaps the question could be answered simply based on the quality of the m2 gg. If any m2 users have input about the clarity of image and overall sharpness please share.
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