80A filter vs post balancing

[J. Bernard Vallon]

3 clients have asked about this, and I've given them the same answer: the results will be about the same. Here is a basic test in case anyone else is curious.

If the sensor is natively daylight balanced, should we rate it differently under tungsten fixtures, or use an 80 filter to trick the amber into daylight?

My advice is to avoid the noise of tungsten light, rate the camera at 200 or 250 asa. You can fix the problem with the 80A, but youll loose half a stop. Seems to me to be about the same. Theoretically with the 80A filter, you might get more DR out because of how the blowout point stays generally in one place. Here are some frames:

 

[Evin Grant]

Frames?

 

[Daniel Browning]

You can fix the problem with the 80A, but you'll lose half a stop...you might get more DR

Yep. If you can up your wattage to compensate for the filter, it will be superior. If your max wattage clips some red or green highlights, then it will help. For everything else, the filter wont help.

 

[Evin Grant]

I'm experimenting with the 80D filter. It raises the temp 1000K but only cut's about a 1/2 stop. Seems to me to be a good middle ground. It's a hard filter to find but I think it may do the trick.

 

[Michael Lindsay]

A 80C saved me on one shoot...

if the Colour temp is really 3200 and you want that to be white then it can be fine (also if you want it to be warm then there is no problem at all). If you are diffusing and dimming you 'can' start to get into trouble. I had both... and a massively contrasty scene.. the filter made all the difference!

regards

Michael

 

[Miguel "Macgregor" De Olaso]

80A looses 2 stops. 80C looses 1 stop and it´s perfect for the red one.

 

[Anders Holck]

I'm also using the 80c on almost all my Tungsten setups.
It's not really the noise thats the problem with shooting 3200k unfiltered, but more non flattering skintones and sub optimal highlight clipping. DRX can sometimes help the highlights, but then it depends on the operator identifying the problem and adjusting accordingly.

I just rate the RED as a 160T by default (but still set the camera to ISO320, the 80C takes it down to ISO160).

 

[Frank Martin]

80d

80d

We have been using a Tiffen 80D for "all" tungsten situations on a current show and we are very satisfied with the results. Took four weeks to get B&H special order however
red #662

 

[J. Bernard Vallon]

Sorry for the delay between my post and the frames, I literally fell asleep with the laptop on the couch while waiting for the upload to go.

 

[Nick Gardner]

Has anyone tried an LLD filter? They were designed for film, correct for daylight with no stop loss. Just curious.

Nick

 

[David Mullen ASC]

Opposite filter -- the LLD is designed to replace the orange 85B filter in situations where you are using tungsten stock in low levels of daylight and can't afford the 2/3-stop loss of the 85B. It basically reduces some of the excess blue exposure so your printer lights are more balanced than if you shot with no filter in daylight on tungsten stock.

 

[Nelson Goforth]

If the sensor is natively daylight balanced, should we rate it differently under tungsten fixtures, or use an 80 filter to trick the amber into daylight?

My concern is that, if I'm exposing under tungsten light and using the electronics to balance the color temperature, I'm effectively 'stretching out' one or two channels to bring them up to the red level.

In my limited test under tungsten light, using an 80D (-56 mired, only about a 1/3 correction to full daylight if I remember correctly) the red and green channels clipped (stoplight on) about a stop before the blue stoplight came on. The RGB Histogram showed a significant difference in the levels of the the three channels.

I've wanted to experiment a bit more with this but haven't had the time: to try exposures without a filter, with the 80D (the only one I have available just now) and an 80A.

The difference between levels of the three color channels may possibly have no practical effect on the final picture - I was only looking at the histogram, not channel noise, etc. - but my instinct is to adjust the light hitting the sensor so that "white light" is pretty much even across the channels. I'd want to only do 'in camera' color balancing when I really needed that extra stop or two. Which is exactly how we handled it with film... if you really needed the stop that the 85 took away, okay... pull the 85 and let the lab handle it.

 

[Uli Plank]

Logically thinking, I would say: no filter can increase the energy for blue, only decrease the energy for red. So, if you one has to be concerned about clipping in the red channel: yes, it should help. But no optical filter will ever reduce noise in the blue one, if we are not yet clipping in red and don't need to reduce exposure because of such clipping.
So, personally I'd avoid filtering if my red channel is not yet clipping at my preferred exposure level.

 

[Brook Willard]

Beware of using 80-series filters that are too thick under tungsten conditions. You get the benefit of less noise, but the IR pollution can become an issue. Ran into this problem last week.

 

[Nils Ruinet]

Beware of using 80-series filters that are too thick under tungsten conditions. You get the benefit of less noise, but the IR pollution can become an issue. Ran into this problem last week.

So which one would be the best for the Red ?
Maybe the 80D is not so bad after all, it's supposed to add +1300°K, which would bring 3200°K up to 4500°K, not so far from our native 5000°K sensor... And only 1/3 stop light loss...
http://www.formatt.co.uk/glass-filters/colour-temperature-conversion/80-series-blue-filter.aspx

What do you think ?

Nils.

 

[Harry Clark]

I ALWAYS use and 80D unless I absolutely cannot afford the stop. It DOES make a difference, and 2/3 stop is not too bad.
Cheers,
Harry

 

[Brook Willard]

Like many things, there's never a "best"... just one that might be more appropriate for a given situation and a particular DP's taste.

 

[Nick Gardner]

Opposite filter -- the LLD is designed to replace the orange 85B filter in situations where you are using tungsten stock in low levels of daylight and can't afford the 2/3-stop loss of the 85B

Duh, brain fart ;-)

Nick

 

[Mike Prevette]

I'm almost always using a 80C filter for tungsten. I'm very happy with the results.

 

[Miguel Bunster]

The filter makes sense depending on what you are planning for really...clipping per se is not a bad thing...i had to jump into a movie and finish the last two weeks of principal photography so jumped in with what they had on the camera track and looking back using a 80's acb etc filter would have helped on clipping but in this movie clipping is not an issue I think is part of the style...but its true a better balanced original image will help you achieve better colro and specialy skin tones reproductions...is like when you shoot under fluos with a green spike when you try to time it out you can get really close but stills looks off and this is the case in one location I am in...tungeten fluos with a green spike and had to live with it...the other thing that helps depending on the light setup is putting some balanced light in to it so there is more "color" in the white light...done that jsut to get more information....as well like in film (havent done it in red) I testeda lot shooting tungesten and daylight uncorrected and the lab would time back and the results were really good, some stuff changes like shadow color etc and so on but in practice even when shooting a 5000k sensor under 3200k light should be fine...but testing extreme situations makes a big impactact...
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