OLPF for BMPCC or Hollywood Black Pro Mist against moire?

[Axel]

As many of you will have noticed, our little precious is prone to moire, not only in raw.

 

I have gone a long way to overcome all problems with this beast, but moire makes me sick to a point where I just want to sell the whole bundle and just stick to my G6.

 

However, the more I compare my most felicitous test shots to what I knew before, I know I would regret it forever.

 

It's time to address the issue. When I bought the Pocket, I reckoned the Sigma 18-35 with the Metabones BMPCC Speedbooster could substitute all my MFT lenses, and I sold them all (now only own the 14-42mm G6 kit lens). So there is little to compare with, mainly apertures.

 

At open aperture, moire becomes so rare, it ceases to be an issue for me. But: As was proven to me >here, the Speedbooster in this combination results in a DoF of an f1.8 in APS-C. As soon as I want a deeper field by closing the aperture two stops, the image obviously gets too sharp for the sensor, thereby introducing moire.

 

The concept of an OLPF (used i.e. with Canons 5D) seemed like a possible solution. But how? Apparently Mosaic Engineering is developing a special filter for the BMCC. Has anyone heard about efforts to create one for the Pocket?

 

The theory behind this says that moire is a sign for reduced resolution and that if you cut off high frequencies at the right values, you optimize the resolution, even though the image looks a little softer. Some say the native resolution of the Pocket is near 1920 minus 15% (for bayerfiltering or sth.l.t.).

 

With the right lenses (not too sharp ones) or with, well, actually a moderate soft-focus-filter (?) it should be possible to get rid of the annoyance once and for all. Is this correct?

 

The very same topic in BlackMagicForum resulted in recommendations for ProMist filters, here. I used to own one myself, for weddings, but since I never actually bothered to use it, I sold it.

 

Has anyone tried to use such a filter against moire?

[Bioskop.Inc]

One reason for using vintage lenses is that they aren't as clinically sharp (across the whole frame) as modern ones & so you won't be prone to running into the dreaded Mr Moire, too often.

If you insist on using these type of lenses, then yes a Black ProMist filter will help soften the image & reduce the risk of moire.

But, & there's always a but, it won't always eliminate the worst cases.

 

Although not shot with the Pocket, this person uses a Black ProMist all the time & the results are great:

 

[Axel]

I see. Do you know how I can guess the strength of the filter needed? My Black Pro Mist then was a "1", but it seemed to soften only highlights to get those kitschy shots:

... similar to the blooming-effect the Pocket was just cured from. Dead men don't wear plaid? I'm not sure if it was that kind of diffusor.

 

What about the Digital Diffusion in this Hurlbut-test?

[Bioskop.Inc]

Yeah, the Digital Diffusion did look nice - it took the edge off, without making it look too nasty/tacky.

Did you try looking for the Article that went with the Hurlbut test? He's always very useful for tips & tricks.

 

What i do know about these type of filters is that once you stop down a little the effect isn't so pronounced.

Or, the person who made the video i linked suggested a Tiffen hdtv fx, if the ProMist was too much (he was using a 1).

 

Alternatively you could remove the moire in post by blurring the chroma channel - Neat Video does a good job.

 

What i've found with the Pocket is that Moire is a Real problem when using RAW, but not so much with ProRes & so i only use RAW for shots that really need that extra boost - landscapes etc...

However, I don't think you're going to be able to eliminate it completely - especially with some types of clothes (I've had it on a pair of jeans, which totally took me by surprise).

 

Since you have the speedbooster, why not pick up a cheap Nikon Ai or Ai-s lens that isn't rated for its sharpness?

This is a good resource for rating Nikon lenses:

http://www.naturfotograf.com/lens_surv.html#rating

[Axel]

I give it a try. Ordered a Tiffen Pro Mist 1/4 (obviously from a discontinued series), very cheap. If it stops moire, I'll buy a more expensive Digital Diffusion and keep the Pro Mist as a glow effect filter. Thanks for help.

[Bioskop.Inc]

I give it a try. Ordered a Tiffen Pro Mist 1/4 (obviously from a discontinued series), very cheap. If it stops moire, I'll buy a more expensive Digital Diffusion and keep the Pro Mist as a glow effect filter. Thanks for help.

Show us your results when you get it - i'd be interested to see what it does to the Sigma & moire, of course!

[Bioskop.Inc]

Here's a really good breakdown of filters (scroll down to see the quotes from David Mullen), v.useful/interesting:

 

http://www.scarletuser.com/showthread.php?t=5941

[AaronChicago]

I'm a big fan of the Black Pro Mist 1/4. This week I plan to do a skintone test with the GH4 in 4K, with/without Black Pro Mist filter, to see how much softness it adds to an incredibly sharp picture.

[Axel]

Half an hour ago, the filter arrived. I couldn't wait and snapped it onto he Sigma ...

 

EDIT: First test looked promising, but was performed too hastily. There is still moire. Proof later today ...

 

Look at the balcony.

 

Somewhat nicer roll-off to clipped areas though, not completely useless.