Flame tests in low light

[Sanjin Jukic]

Flame tests in low light

There are latest "rumors" here in Vienna between DPs (some of them are my customers) that R1 has a heavy problem at shots in different high contrast low light conditions with flames.

The "theory" is that OLPF glass makes sometimes a "mirror" reflex effect that cause a strange kind of 'flares" or call it whatever you want.

Also the "rumors" here said that the same you can see at SI-2K footage but with Arri D21 there no any artifacts in that case at all.

I saw examples with R1 and SI-2K from particular test but not one from Arriflex D21 unfortunately.

As my experience is concerned I would say it is mostly lens issue but who knows.

I'm not an optical engineer to judge things like this.

So have a look at my "quick and dirty" test examples with flames where I didn't discover any big issue but at the end I'm not an expert:

Shot on RED1 with Canon FD 85mm f/1.2 @ f/2.8, 320 ISO, 25 fps, 1/50 shutter, reflective (crystal stones) background.


1. Q&D Test H264 1080p footage>>>

Shot on RED1 with Leica-R 50mm f/1.4 @ f/2.8, 320 ISO, 25 fps, 1/50 shutter, matte watercolor art-black paper background.


2. Q&D Test H264 1080p footage>>>

Shot on RED1 with Leica-R 60mm Macro with 1:1 adapter, f/2.8 @ f/2.8, 320 ISO, 25 fps, 1/50 shutter, macro detail.


3. Q&D Test H264 1080p footage>>>

Shot on RED1 with Leica-R 60mm Macro f/2.8 @ f/5.6, 320 ISO, 25 fps, 1/50 shutter, camino wood fire flames.


3. Q&D Test H264 1080p footage>>>

 

[David Mullen ASC]

You need to shoot bigger and brighter flames to see problems in most digital cameras -- the candle flames you shot are too tiny, and the fire you shot fills the frame and you exposed for the fire -- try shooting an overexposed campfire from a distance so it's a bright spot in the frame, or a burning torch, etc., surrounded by blackness, to see any ghosting problems, etc.

 

[Sanjin Jukic]

You need to shoot bigger and brighter flames to see problems in most digital cameras -- the candle flames you shot are too tiny, and the fire you shot fills the frame and you exposed for the fire -- try shooting an overexposed campfire from a distance so it's a bright spot in the frame, or a burning torch, etc., surrounded by blackness, to see any ghosting problems, etc.

David,

thanks for a tip and also I saw the same as you said at my friend's/customer's footage

that I do not have now and even would not be able to get authorized for the show here but I'm aware of it.

It's too late now in Vienna but tomorrow evening I'll try make overexposed test from a distance...stay tuned...

Also forget about to repeat camin fire again because I did that footage last June at one mountain house in Austrian Alps...

 

[Charles Angus]

If you're referring to Geoff's comments about this at CML, he was (IRRC) shooting a big flame from a fire eater wide open at T1.3. So, the flame was probably a few stops brighter than the flames you shot, and he was shooting 2-4 stops wider open...

 

[Sanjin Jukic]

If you're referring to Geoff's comments about this at CML, he was (IRRC) shooting a big flame from a fire eater wide open at T1.3. So, the flame was probably a few stops brighter than the flames you shot, and he was shooting 2-4 stops wider open...

I haven't seen yet his flame tests but also I can shoot at f/1.2 that is T/1.3.., using fast Canon FD FF35 lenses...

actually I can remind it I started with f/1.2 that was too bright anyway or

over-exposured and stopped down to f/2.8 and zebras at flames were still on the EVF and preview monitor...but stay tuned...

 

[Steve Sherrick]

Don't know if these help

 

[Conrad H]

Steve, what was your lighting set-up for the campfire scene?
On the wide? On the medium shots?

Conrad

 

[Mick van Rossum NSC]

Sanjin, it is a good subject, I had major problems shooting big firebars for an action movie, these flames were 7 stops over, so I shot some underexposed plates as well for comp. I am talking here about 1,5 meter high fires on a nighshoot, and purple flares where all over the place. I was able to correct some of it in CC but still it was the first time where I was not be able to find a solution. Stll not sure if it was OLPF related or IR....

 

[Sanjin Jukic]

In the morning I look "carefully" in the test files and "detected" one ghosting.

Bur still I couldn't get any answer what caused that ghosting, could be the lens, OLPF glass, IR pollution, or...(???).

Tonight I'll try again with another setting that has a bunch of bigger candles, also use Hot Mirror filter (Formatt), etc...

Stay tuned.

At the moment have a look this "ghosting" processed in a different LUTs and download 4K DPX Log file to try yourself.

Download 2K DPX Log file>>>>

A crop detail from 4K test image, shot on R1 with Leica-R 60mm f/2.8 @ 2.8 Macro using 1:1 macro adapter

PanaLog2Lin LUT in Shake, shot on R1 with Leica-R 60mm f/2.8 @ 2.8 Macro using 1:1 macro adapter

TrueLight FilmLight LUT in Shake, shot on R1 with Leica-R 60mm f/2.8 @ 2.8 Macro using 1:1 macro adapter

GenArts Sapphire Film Effects>> Film Negative 5245 stock>> Film Print 2383 stock in Shake, shot on R1 with Leica-R 60mm f/2.8 @ 2.8 Macro using 1:1 macro adapter

 

[Steve G]

Sanjin, you won't be able to replicate the issue that is there with all digital/video cameras unless you use flames that are at least a meter long. Even with big candles, the wick will be too small. Don't go burning down your flat !! If you lived near an oil refining factory you could possibly get the effect from filming the burn off. The ghosting that you see on the test above is probably lens flare. You will get that with all lenses on all formats.

 

[Sanjin Jukic]

Steve,

one oil refining factory ÖMV is in Schwechat a city north-east of Vienna known for the Vienna International Airport,

also the refinery looks like a city from "Blade Runner" sort of SF movie. Maybe I'll go there soon and shoot big oil flames...

 

[Zac C]

Steve, what was your lighting set-up for the campfire scene?
On the wide? On the medium shots?

Conrad

To the best of my memory on that shoot we had two 1k flo's from either side, and a 500-650? through the fire onto them, then for the closeups the fresnel through the fire at them