Advice for indoor shoot on 500T

[Peter Connell]

Hi guys

I'm shooting a friends wedding on Saturday using my Arri SR1. I've got some 16mm 500T but read that if shooting in daylight conditions its effective ISO is 320? Can someone confirm this please.

I'm not a professional so any tips would be appreciated.

bw

Pete

[Brian Drysdale]

That rating involves using a 85 conversion filter on your camera when shooting daylight with 500T. You lose 2/3 of a stop, so 320ASA would be the correct setting on your exposure meter. 

[Peter Connell]

Hi Brian,

 

Do you only lose 2/3 of a stop when using the 85 conversion filter? What if I don't use it and accept the blue cast if I'm shooting outdoors?

thanks,

Pete

[Mark Dunn]

 

[Brian Drysdale]

It's 2/3 of a stop unless you use a neutral density combination filter e.g 85 ND6. With 500T stock, unless it's a very dull day, you will need a neutral density filter when shooting exteriors without an 85. 

[David Mullen ASC]

Without the 85 filter, it's still 500 ASA even in daylight though one could rate it slower for a denser negative.

Keep in mind the Sunny 16 rule -- at 50 ASA / 1/50th shutter speed, the exposure outside in direct sunlight is f/16. So with 500 ASA film, you'd be more than 3-stops past f/16 in direct sunlight, hence the need for ND filters. However, since you said "interior", you'd probably be fine without ND filters unless there is a lot of bright daylight in the room.

[Peter Connell]

thank you for the response David

[Aapo Lettinen]

On 12/19/2024 at 2:14 PM, Peter Connell said:

Hi Brian,

 

Do you only lose 2/3 of a stop when using the 85 conversion filter? What if I don't use it and accept the blue cast if I'm shooting outdoors?

thanks,

Pete

you will lose the 2/3 stops if converting the footage to proper colour balance, whether that is done in-camera with 85/85B filter or shooting without filter and correcting in telecine/scanning or in digital grading.

if shooting without 85 filter and NOT correcting the colour balance then the approximate sensitivity is 500 ISO outdoors. but you will end up with blue-ish image. if wanting to correct to normal colours then you will need to lower the blue channel level and green slightly and end up with the approx. 320 ISO no matter how you do the colour balance correction

[Aapo Lettinen]

shooting without filter and post correcting the balance has the disadvantage of potentially losing blue channel latitude because the blues become very dense and potentially difficult to scan the very brightest areas, so you may get burned/clipped/noisy highlights more easily. But it may be more practical to shoot without filters in some situations if filters are for some reason difficult to manage on-set (cleaning needs, reflections, not the right filter size available, etc). By my experience the end result is often not exactly the same (the extra amount of blue light easily creates additional in-lens reflections etc, the reds may be much thinner than would be optimal causing extra grain, etc) but it can be more than enough for most uses still.

shooting without filters is common when wanting cool dusk/twilight look but if wanting to have normal or warm colours it may not be optimal to shoot with super cool blue look and then post correcting it (leading to underexposed reds and overexposed blues which you need to reverse in post prod to get anywhere near normal colours)

if shooting without filters for normal or warm colours it should be rated 320 ISO and taken care not to ruin the highlights. if blue look is OK then 500 ISO rating would be fine

[David Mullen ASC]

I don't think that is strictly true -- if anything, rating 500 ASA at 320 ASA without the 85 filter will overexpose the blue information even more (so it's not a good solution IF you are worried about blue channel clipping), it's just that you are also giving more density to the red and green information as well -- the balance doesn't change. Correction filters don't add wavelengths of light, they cut them, so the 85 filter is mainly cutting the blue information more than the red, and not using it means the blue information now has too much exposure compared to the others, not that you've underexposed your red and green information.

Anyway, "Barry Lyndon" was shot on 100 ASA film underexposed at 200 ASA and pushed one-stop, without the 85 filter. John Alcott skipped the 85 filter on "Greystoke" and many other movies. Dante Spinotti shot "Heat" without the 85 filter, Roger Deakins shot "The Shawshank Redemption" without the 85 filter... 

I've done it myself on a couple of movies. Film negative has a lot of latitude and in printing, a missing 85 filter takes, what, maybe less than 5 points of further correction in the blue record?

When I did "Jennifer's Body" and used 200T indoors in daylight without the 85 filter, I sometimes used the LLD filter, which corrects the blue channel back a few points.