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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

The blue channel under 3200K vrs 5600K lighting...

Personally i'd like to have my sensor set to tungsten native. Will there be a way to do this? or is this totally decided in manufacturing? I'd prefer my lowest noise levels to be indoors, I'm use to working with tungsten film and its a bit easier to throw an 85 on outside if it helps reduce noise in certain color channels.
 
When Kodak only made 1 color film it was tungsten balanced, I wonder why?
 
Is there a 1/2 85 filter? I could live with the compromise of 1 stop loss Vs. a stop better blue channel performance. You could conceivably shoot at ISO 640 with this filter and get ISO 320 blue channel performance while balancing the noise of the other two channels. This might be a very pleasing look. Of course your shooting ISO would still be 320.
 
Evin Grant said:
Is there a 1/2 85 filter? I could live with the compromise of 1 stop loss Vs. a stop better blue channel performance. You could conceivably shoot at ISO 640 with this filter and get ISO 320 blue channel performance while balancing the noise of the other two channels. This might be a very pleasing look. Of course your shooting ISO would still be 320.
Click to expand...

Well none of this is still addressing the problem even in daylight (although mitigated) where you have to apply GAIN to the red channel to balance out the green. If you're going to go through the trouble of balancing through filters you might as well balance all the channels at once instead of just balancing for daylight.

I'm seeing in the LART and lots of other footage the green channel being properly exposed in the RAW but the RED is a stop darker. As a result the gain pushes it up a stop and starts to clip.
 
Jim, thanks for posting a test on a very important subject that has been ignored by the early adopters!

Every video camera Sony has ever made is "balanced" for 3200.
Note that the RGB filters in the dichroic prism are used to create the balance, combined with a little optimising in the A/D (so Im told)

This has made perfect sense for 20 years on video cameras where lack of recording fidelity has limited ability to grade after the event. The most common colour temp found in low level ambient light is 3200 so balancing ccds to this means that no light absorbing CC filter should be used to colour correct. The last thing you wan to do is add a 1 or 2 stop cc filter when you step indoors.


It begs the question as to if JJ had a choice between 3200 and 5600 on the bayer filter and AD?


The D5600 setting in general creates noise in f900 and f950s, but haven't tried it with new f900r. Kind of the reverse situation with RED.


To optimise quality when moving from outdoord to indoors one will usually remove ND filter and replace with CC filter.

A step backwards for the doc shooter, internal filter wheel anyone?


Mike Brennan
 
Majenta + 5500 Greenbox Test

Majenta + 5500 Greenbox Test

Sir Pancake said:
If shooting at 3200, creates a nosier image, relative to the native color temp of the red sensor (5000K, as I recall) then does opposite also hold true? Meaning, if I shoot above 5000K, I'm also introducing noise or no?
Click to expand...


Yes!!! Please add this test to the majenta test!!!:love:

Thanks

Pat
 
Evin Grant said:
Is there a 1/2 85 filter? I could live with the compromise of 1 stop loss Vs. a stop better blue channel performance. You could conceivably shoot at ISO 640 with this filter and get ISO 320 blue channel performance while balancing the noise of the other two channels. This might be a very pleasing look. Of course your shooting ISO would still be 320.
Click to expand...

You mean you will shoot at ISO 160, not at ISO 640. You loose about a stop by applying the filter. You need the additional light to get the additional stop on the blue channel.

And as macgregor pointed out, it should be a blue 80 series filter, not an 85. You want the blue to pass at full power. :wink:
 
Sorry didn't understood you.

Sorry didn't understood you.

Jim Arthurs said:
In this case, the screen lighting was the desired color temp + either 1/2 CTB for the bluescreen, or 1/2 Plus Green filtration for the green.
Click to expand...


Sorry didn't catch that!

Here you mix background filtration and color temp changes form 5500 to 3200.

+ 1/2 CTB doesn't make a blue screen
+ 1/2 plus green doen't make a green screen
What did you do to change color temp from 3200 to 5500 (gels on light/light/filter on cam...)?

Thanks.:clown2:

Pat
 
Can we get any feedback from Red if a tungsten balanced sensor would be possible at all?
 
I suppose a half-blue correction filter may clean things up a bit when shooting under 3200K lighting, but that's a stop of light lost, so 320 becomes 160 ASA, or let's say 200 ASA would probably be OK. Anymore than that and you wonder if there would be more noise by shooting at 320 ASA under 3200K versus under 5500K but with more underexposure (let's say, because you used a blue filter but didn't compensate for it)? Or maybe the noise would be more evenly distributed in all the channels if the image were bluer but darker, instead of orangier but better exposed?

For night interior scenes, though, I think most people would like to have more speed than 160 to 200 ASA that to work with. But for bluescreen / greenscreen work, the blue filter (or HMI lighting) may be a good idea -- though I wonder if the background plate has to have the same low noise level. Would it look odd to composite clean foreground objects into a noisier background plate?
 
My 2nd ever post on this forum was me suggesting you should optically filter Red to get it to roughly the right colour temp... I believed that the sensor would not deliver optimally without optical filtration.. I've subsequently lamented the lack of space that would make a filter wheel possible (doubly so considering the ND issues with such a fast camera in bright light)

I have thought about it quite a few times and have pixel peeped the blue channel of a lot of the footage... My conclusion is that apart from blue screen work. I will rarely optically correct interior tungsten work.. Tunsten film is pretty jumpy in the blue channel.

UNLESS somebody creates, or points me to, a filter which would be the opposite of a LLD.. (Mr Mullens et al may like to help me here).. A filter with minimal stop loss that just help in only a subtle but worthwhile way.. I suspect this is unlikely. Any thoughts?

I also would like to have a peep at footage with a recorded colour temp in excess of 13000 K.. I'm ordering a filters to deal with this scenario.

Regards

Michael Lindsay

PS LLD is a filter that takes out allot of UV and a bit of blue but doesn't need any (?) stop adjustment with film..
 
Dyes in a prism system are very very different than what goes on a sensor.
Added to that is the natural sensitivity of the silicon. In general you'll find the blue channel is less sensitive (not only with sensors) but the trade off is losing color saturation in blue or losing overall sensitivity. Would you rather have an iso 80-100 camera that's tungsten balanced or an iso 320-500 camera (with the option of filtering optically if you want)?
 
David Mullen ASC said:
I wonder if the background plate has to have the same low noise level. Would it look odd to composite clean foreground objects into a noisier background plate?
Click to expand...

It would in most instances I would think. But you can always add/match grain/noise later. But pulling a solid key is worth it's weight in gold. I wish I had the countless hours of my life back, tweaking noisy keys from stuff shot with F900s.

IMHO, if the Red can pull off really clean Green Screen footage (via reasonable methods) it could be one of it's strongest selling points, especially on heavy EFX films/commercials.
 
Deanan said:
Dyes in a prism system are very very different than what goes on a sensor.
Added to that is the natural sensitivity of the silicon. In general you'll find the blue channel is less sensitive (not only with sensors) but the trade off is losing color saturation in blue or losing overall sensitivity. Would you rather have an iso 80-100 camera that's tungsten balanced or an iso 320-500 camera (with the option of filtering optically if you want)?
Click to expand...

This is pretty much what I figured. There is no free lunch. Has anyone tried noise reducing just the blue channel in AE or Shake?

You guys are right, I had a brain fart. I want an 80 series not 85.
I'd like to know what the optimal magenta/blue mix would be to achieve the perfect balance under 3200K sources. This could be useful even if it is only for keys or bright studio situations.
 
Tresch said:
Sorry didn't catch that!

Here you mix background filtration and color temp changes form 5500 to 3200.

+ 1/2 CTB doesn't make a blue screen
+ 1/2 plus green doen't make a green screen
What did you do to change color temp from 3200 to 5500 (gels on light/light/filter on cam...)?

Thanks.:clown2:

Pat
Click to expand...

All lights for the shoot were tungsten. The screen lights were full CTB + 1/2 CTB when shooting the bluescreen as daylight. Full CTB + 1/2 plus green when shooting the greenscreen as daylight.

When shooting for tungsten balance, .6ND was used in place of the full CTB to keep the stop in the same ballpark and 1/2 CTB added for the bluescreen, the same only with 1/2 plus green for the greenscreen.

Sorry about the confusion. I do have the CC correct on the lighting, just a bad job of explaining...
 
I find it cute the 'discovery' that lighting a scene with more blue light produces a less noisy blue channel.

Think of the extreme case: light a scene with a red laser. How much noise do you think you'd have in the blue channel if you wanted the scene to look white? Hm. Quite a bit methinks.
 
So maybe people with more lighting experience can weigh in on how feasible it is to light everything for daylight all the time. And assuming you can't afford HMIs, would you save money using twice as much tungsten lighting and color-correcting it (and any practicals) with gels? What are the low-budget options for getting daylight color temps indoors?
 
Evin Grant said:
I'd like to know what the optimal magenta/blue mix would be to achieve the perfect balance under 3200K sources. This could be useful even if it is only for keys or bright studio situations.
Click to expand...

Magenta is so viper... :)

With the strong red bias in tungsten, magenta would bias more towards red/blue and less green when what you want is more blue and maybe a bit more green but probably not necessary.
 
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