Filters to reduce contrast, Pro mist, et al
 

I've heard that the 'pro mist' and 'black mist' series of filters have been used with some reported success for video, and would like to discuss the merits of these.
There are diffusion filters, which are typically used to remove small surface detail from the subjects ( often portraiture ). A side effect is also a slight glow effect, where bright details are caused to bloom out spatially, in a fog like manner.
Is this what we really want ? Remove details? Bloom?

I would think the main desired effect is to lower contrast.

In the world of still film cameras, the lens with the highest contrast is usually heralded as the best, and designing such lenses is an achievement. Since film can record 10 stops of image dynamic range, this is understandable.

Video is severely limited in it's dynamic range, so there lies the problem. Clipping. Blowout.

So if you want to lower contrast, how can this be done, without removing surface details, and causing misty fog effects?
You guys are not going to like this, but essentially a dirty filter on the lens does exactly this! It brings up the blacks, and without spacial ( sideways ) fogging lowers contrast without killing detail.
You don't see particulate dirt in the video image, it's out of focus. You see lower contrast. Like a lens with non-suppressed internal reflections.
The science of optics.
Does Tiffen make a dirty lens filter? :)
-Les

It sounds like you want to try a Tiffen Ultra Contrast filter. It brings up the blacks, dims the brights a little, thus reducing the overall contrast.

Basically, what we're talking about is dynamic range compression and expansion. You record a reduced dynamic range onto video, and expand it in post to get your contrast back, but with improved detail and lack of blown out highlights. I'm working on this technique at the moment and will have images to post as soon as I can get some good weather to go out and shoot...

Graeme

Looks like that might be just the ticket. I wonder if it's any better looking than a dirty clear cover glass! That would be hard to keep consistent, I admit!
I should get my hd10 on Friday, so I'll experiment.
-Les

Graeme

can you tell us more about your workflow? how are you increasing the contrast in post, and how does it look? And colors? would love to see your work.

Graeme ,
So are you experimenting with reduced contrast when taking video, and then using some luts to reshape the image contrast?
I hope there are enough bits left so banding does not become evident.
Good luck, and post some examples if you can,
-Les



<<<-- Originally posted by Graeme Nattress : It sounds like you want to try a Tiffen Ultra Contrast filter. It brings up the blacks, dims the brights a little, thus reducing the overall contrast.

Basically, what we're talking about is dynamic range compression and expansion. You record a reduced dynamic range onto video, and expand it in post to get your contrast back, but with improved detail and lack of blown out highlights. I'm working on this technique at the moment and will have images to post as soon as I can get some good weather to go out and shoot...

Graeme -->>>

Very interesting idea, I'm going to give that a try as well. What editing system are you using to improve contrast in post?

I have been testing out a Black Pro Mist 1 on my HD10 and have had some fairly decent results. The Pro Mist 1 though is a little too strong so you get alot of halo around bright whites. I am going to be purchasing a DV Film look kit from Tiffen soon that includes Black Pro Mist .5, Black Diffusion FX .5, Warm Diffusion FX .5, Soft FX and Soft Pouch. I might also try the ultra contrast filter to see what happens with that. I'll keep you posted on my results. As for post correction I am currently using After Effects and adjusting the gamma curves by dropping the blacks down and it looks pretty good. I have yet to try to replace blacks in Premiere with AspectHD but that is the obvious next step. Again, I'll keep you posted as to what happens.

I'm using some custom code I've written for Final Cut Pro, but you could use curves in any app that supports them.

I'm not using a HDV cam, just DV, but I'm thinking the same principles apply. Results so far are looking good, and I hope to get the chance to shoot enough footage at the weekend so that I can try out some of the ideas. I'll post back when I do.

Graeme

>>>Mark Jervis: I might also try the ultra contrast filter to see what happens with that. I'll keep you posted on my results.>>>

Mark,

Can you also test these filters in black and white mode?

Brian

No problem. The filters should be here on Wed. and I'll go out that day or Thursday and start getting footage and testing filters and post results of each filter.

As I 've posted here quite a few times before, the best results I've had are from simply using ND filters to cut down incoming light and give you a lower contrast picture (and avoid the white blowouts), then using FCP's 3-way color corrector, stretch the whites and mids back up again to restore and improve contrast. It works a treat. My personal feeling is that using such filters as pro-mists will excessively soften an image that is already quite soft for an HD image, compared to something like a Varicam or CineAlta.

Paul,

Specifically which brand of ND filters do you use, and where online would you recommend purchasing them?

Are these 52mm or do you use a step up ring?

Thanks,

Brian

Tiffen filters from B&H, standard 52mm, no step up ring.

Filters
 

Any kind of filter or lens which is 52mm can be used with the JVC HD10U camera ??? Is it better to put filters when you making recordings or you can do similar effects in post production?
Thanks