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Low contrast filter question


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#1 Hercules Fu

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Posted 23 February 2009 - 03:12 PM

Hi dear all!
I am going to start a shortfilm's project recently with Panasonic Varicam w/Pro35 and Carl Zesis HighSpeed Prime,
i got a few questions on the low contrast filter which is my first time to use.

1)Does low contrast filter work like pro-mist in the relationship of filter density and focal length?
For example when i use a 50mm lens with a 1/4 Pro-mist in the first shot,
in the 2nd shot when i change to a 100mm lens I will need to change the pro-mist into a 1/8 one in order to get the picture's continuity
does low contrast filter work in that way too?or the Filter density of low contrast filter are just indicating how much detail it reserve in the dark area?

2)Any caution on using the low contrast filter?for example avoiding flare?(just like those stuff like classic soft)

3)Can adjusting black gamma be an alternative for low contras filter?I heard someone said the low contrast filter will make a softer image on the black area,will it be very annoying/observable for some shots in the same scene are adjusing contrast by black gamma and some are done by low contrast filter?(Since sometimes i afraid i will use more than 5 filters on my 6.6"x5.6"Production matte box...)

Thanks for your kind reply! ;)
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#2 David Rakoczy

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Posted 23 February 2009 - 06:33 PM

1) Does low contrast filter work like pro-mist in the relationship of filter density and focal length? For example when i use a 50mm lens with a 1/4 Pro-mist in the first shot,in the 2nd shot when i change to a 100mm lens I will need to change the pro-mist into a 1/8 one in order to get the picture's continuity?

Yes

2) Any caution on using the low contrast filter? for example avoiding flare?(just like those stuff like classic soft)

Yes and a tad more... but that is the effect and it can look great.

3) Can adjusting black gamma be an alternative for low contras filter?I heard someone said the low contrast filter will make a softer image on the black area,will it be very annoying/observable for some shots in the same scene are adjusing contrast by black gamma and some are done by low contrast filter?(Since sometimes i afraid i will use more than 5 filters on my 6.6"x5.6"Production matte box...)

A Lo-Con does have a softening effect in it as well as does the Harrison(s). Ultra Cons lessen the contrast but do not soften near as much.

I'd better leave the video (gamma) question to the video pros.
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#3 Michael Collier

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Posted 23 February 2009 - 09:25 PM

3)Can adjusting black gamma be an alternative for low contras filter?
Thanks for your kind reply! ;)


Yes, but if it were me and I had to do lowcon in the digital realm(ie, anything done past the lens) I would leave that to the final color grade. Gama corrections in the blacks in camera lead to very strange response curves, especially where the shadow gama meets midtone gama. In post you would have more ability to remove contrast, but both methods will introduce noise into the shadows. But at least if you decide to scale it back in the grade you won't be burdened with burned in noise, like you would if you adjust your in camera settings.

This only applies to high detail recordings. RAW, HDCAM-SR, uncompressed, etc are all fine working the detail and contrast out in post. If your working in a highly compressed medium like HDV, do it in camera. You need at least 10 bits recorded to work with.

That said my preference for just about anything is glass in front of lens when possible. But as always, test. My threshold for noise isn't the same as others, and different cameras apply gama in different ways. If you have 5 filters in front of your lens, maybe you can think of other filters that would best be served with digital equivalents rather than lowcon? Color tints (tobacco, coral, grads etc) might have less impact than locon if done digitally?
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#4 Hercules Fu

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Posted 24 February 2009 - 10:32 AM

Thankyou for Micheal and David's kind answering! :P
Will Micheal consider DVC-Pro HD as high quality recording media?
becoz i had a really bad experience on the varicam's post color grade...
And i believe that the film's budget would be quite tight on the post...probably they will do the color grading in Color only....
I do want to avoid the noise come out from decontrast in post, so do you guys think Low Contrast filter would be a good suggestion?
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#5 David Rakoczy

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Posted 24 February 2009 - 10:41 AM

Sure.. Lo Cons if you want to really soften the image and bloom highlights along with lessening the contrast... Ultra Cons if you simply want to lessen the contrast without any softening. Can you go look at some?
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#6 Michael Panfeld

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Posted 24 February 2009 - 05:20 PM

Sure.. Lo Cons if you want to really soften the image and bloom highlights along with lessening the contrast... Ultra Cons if you simply want to lessen the contrast without any softening. Can you go look at some?


So where do the Schneider DigiCons fall in relation to the Tiffen Ultra Cons and Lo Cons? Thanks
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#7 David Rakoczy

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Posted 24 February 2009 - 06:04 PM

Not sure... never used them.
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#8 Krzysztof Wlodarczyk

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Posted 22 September 2009 - 04:50 PM

So where do the Schneider DigiCons fall in relation to the Tiffen Ultra Cons and Lo Cons? Thanks


I used DigiCons and was really happy about the result, they seem to look like Tiffen Ultra Cons - probably different name for simmillar patent. If you want to reduce contrast use either of these. IMO have them always in your HD set for some extreme sittuations (high contrast scenes). When I tested the UC lately I had to color correct the image on set - as it was making the image a little greenish. I know many people here leave everything for post - but remember that (pre)grading in the camera lets you work with the image before it gets the compression of the format it's recorded on (tape/disc etc.)
Low contrasts make the highlights glow - so use them if this is the desired look.
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#9 Tim O'Connor

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Posted 27 September 2009 - 01:26 AM

I used DigiCons and was really happy about the result, they seem to look like Tiffen Ultra Cons - probably different name for simmillar patent. If you want to reduce contrast use either of these. IMO have them always in your HD set for some extreme sittuations (high contrast scenes). When I tested the UC lately I had to color correct the image on set - as it was making the image a little greenish. I know many people here leave everything for post - but remember that (pre)grading in the camera lets you work with the image before it gets the compression of the format it's recorded on (tape/disc etc.)
Low contrasts make the highlights glow - so use them if this is the desired look.


I haven't heard of this (UC making an image greenish) but I have not much experience with them either. Do you or
does anybody know why this would occur?
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#10 Krzysztof Wlodarczyk

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Posted 28 September 2009 - 07:28 AM

I haven't heard of this (UC making an image greenish) but I have not much experience with them either. Do you or
does anybody know why this would occur?


I noticed it while testing filters for tv series I've just started. I was having two matched cameras connected to the same HD-CRT monitor pointed at the same subject in exterior. I was testing filters by putting them on one camera, and switching channels on monitor to see the difference. The one with ultracon had less contrast and a was a little more green - probably because of flare from bright areas in the frame. There was no direct light hitting the lens. I worte earlier that it's not a big problem as I can fix it on a paintbox.
So "The greenish image" is not the issue here, it's fixed without any problem in the camera and these filters seem to work very well with digital. We decided to use them on this production along with SoftFX set - it gave us less contrast and softer look. Only thing that we have to be aware using two filters most of the time is the double reflected image. But usually shifting mattebox does the job.
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#11 Tim O'Connor

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Posted 28 September 2009 - 09:17 AM

I noticed it while testing filters for tv series I've just started. I was having two matched cameras connected to the same HD-CRT monitor pointed at the same subject in exterior. I was testing filters by putting them on one camera, and switching channels on monitor to see the difference. The one with ultracon had less contrast and a was a little more green - probably because of flare from bright areas in the frame. There was no direct light hitting the lens. I worte earlier that it's not a big problem as I can fix it on a paintbox.
So "The greenish image" is not the issue here, it's fixed without any problem in the camera and these filters seem to work very well with digital. We decided to use them on this production along with SoftFX set - it gave us less contrast and softer look. Only thing that we have to be aware using two filters most of the time is the double reflected image. But usually shifting mattebox does the job.



That makes sense, thanks.
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