Moire and IR pollution when shooting black and white

[zwarte_kat]

Dear everybody,

I am eyeballing a pocket cam for personal doc work, I have my fs100 for paid jobs and am fine with it for now, no hassles.

The thing is, i want to shoot a piece in black and white, since I am doing a collaboration with a photographer who shoots black and white film.
I wonder, will IR pollution still be an issue with B and W?
I once had a Leica M8, which also had IR problems, but it was said that letting through the IR light actually improves the black and white image. How is this when using NDs?

Then moire, since a lot of it is distracting colours, would shooting in BW also reduce this problem to neglect-able levels?

I also expect delivering in BW also allows me to get away with shooting in darker locations. I don't mind a healthy amount of grain (again, personal work here). What are people's experiences here?
I plan to shoot in prores film BTW.

I have been eyeballing cameras like the GH4 and a7s for pro work, but as much as I am impressed with their sharpness and spec sheet, I am not that crazy of the images I see coming out of them.

I was thinking of just an BMC pocket with 12mm 1.6 hyperprime or olympus 12mm 2.0, to keep things focussed.
I already have all the add-ons, EVF, Power, rig, Mixpre-d, mics, lavs etc., because I had the BMC EF before I sold it and now the FS100 which I make my living with.

Any tips in general for BW doc shooting on the pocket? Any examples? (yes I googled!)

Cheers!

[nickjbedford]

I wouldn't think it as much of an issue, but as far as I understand it doesn't just change colours, it also changes contrast in the image.

I would be inclined to treat IR pollution just like you would in colour. That being said, I've only ever used a maximum of ND 0.9 + a CPL filter and I don't believe I've noticed any IR so far. Once I go beyond ND1.2 perhaps I will notice it.

As for B&W tips, you really need to pay attention to light and shadow, more so than in colour work. The way you process your colour images into B&W will also determine contrast and luminance throughout your shots. Colours in the scene still play a role in your image so keep that in mind.

It may be helpful to adjust your EVF/external monitor to show your image in B&W too.

[jtfarabee]

IR pollution is prone to affecting shadows and dark objects, which can lower the contrast of the image once to translate to B&W. It could be really useful, but it can also make it harder to get really deep blacks. Most B&W film stocks respond better to shorter (blue) wavelengths vs longer (red) ones. Which means if you want to match B&W film (unless the photog is shooting panchromatic, which I doubt), you should turn down the red channel output when converting to B&W. This will take anything red (or polluted by IR) and darken it in the final image. That's great if you want that thing to be dark, but it can change the character of the shot if you have one dark object that is being affected by IR pollution and one that isn't. In that case, the two would appear to be different shades in the final image. So, like I said, it can be a really useful way to mess with contrast in monochrome, but you have to be careful.

Regarding moire, whether or not it affects the image in B&W depends on which color channel(s) it is affecting, and how you treat those channels in the grade. If it's on the red channel, and you push that down to emulate a monochrome film stock, the moire will be lessened. If it's in the green or blue channels, it will most likely still show up, as those channels carry more weight in a typical B&W "look"

I hope all of that makes sense.

[zwarte_kat]

Many thanks for the useful points!
BTW I really like creating BW images from colour images, you can play around with the colours, making them darker or lighter, especially in lightroom this is a breeze!

I wish there was a thread with BW work from the BMCCs.
I actually wish there were more focussed threads like these, for example Docs, shorts, videos with a certain lens, landscapes etc.!
rangefinderforum.com does this very well.

[nickjbedford]

A music video I just finished is going to be released probably next week. Graded in B&W with FilmConvert. Keep an eye out if you're curious.