Setup for manual exposure in available light - NDs vs Dual-native ISOs vs apertures etc

[kye]

I've never really shot manually, but am now contemplating it, and needed to get my head around the various situations and how bright they are, what NDs would be required, etc.  It's a basic thing but no-one seems to talk about it, and when it comes up in other threads knowledge seems to be a bit patchy, so I figured I'd do a bit of testing.

My first test was just to work out what the exposure range is of how I shoot.  I shoot in available light, so have to adapt to whatever is there.

I shot with a colour checker, just exposing the brightest patch so it wasn't clipping, across the full range of situations I shoot in.  These include in full-midday-sun, outside in the shade, inside in a brightly lit room (lit from large windows of natural light), in a small room lit by a single LED bulb (8W 800 lumens), and lit by an iPhone 13 Mini with completely white screen at full brightness at 30cm from the checker (this is a useful reference for me as I shoot a lot in blue hour or darker and often peoples faces are lit by their phones).

What I found was this:

All measurements were within a stop of being right - if a setting clipped the square I went down a whole stop.  Yes, I'm aware 1/50s isn't exactly one stop lower than 1/125s (if you care about this then you've missed the point, please immediately proceed to the DPreview forums).

My goal is to create natural looking images across these lighting levels, and was thinking that perhaps it could be done using a combination of a single vND, aperture changes, and a dual-native ISO camera.  The eye naturally closes the iris in bright lighting and opens it up in low lighting, so there is an argument that to be more natural you would also do this, so this is aesthetically relevant and also helps us out technically.

It looks like the dual-native ISOs on cameras tend to be around 3 stops apart (P4K 3-stops, P6K 3-stops, S5 2.66-stops, R5C 2-stops) although the Sigma FP seems to have 6 stops of difference between them, which seems the most useful.  Then if we said that we could use F1.4 and F5.6 then that's another 4 stops, bringing us to 7.  That would leave the vND to take up the remaining 7 stops, but in extreme low light situations like the iPhone then using the ISO above the higher native ISO seems reasonable.  Most cameras will have a usable noise level between their base-ISO and upper-native ISO, so if they have those 3 stops apart then we can probably go about 3 stops above the higher native ISO and stay within what the manufacturer deemed was an acceptable level of noise.  Especially considering these cameras all have enough resolution / codec to handle a bit of NR.  

In a sense I'd like the ability to shoot a bit wider open in brighter conditions than 5.6, but I could "buy" that by pushing the ISO at the darker end.

How do you manual-shooters who shoot in available light configure your setups with NDs?  Obviously if you're working with lights then you can just adjust them instead, but that's a completely different way of working, and you can use fixed NDs too, as you're not working fast.

[hyalinejim]

Slightly off topic and I'm not sure that it will change the results of what you're trying to find out (the range of stops you need to cover with an ND) but it's still worth pointing this out for its own sake:

2 hours ago, kye said:

I shot with a colour checker, just exposing the brightest patch so it wasn't clipping

This is not a reliable way to arrive at a technically "correct" exposure as different cameras and picture profiles will clip at different exposure levels. And we can indeed see that your settings for full sun arrive at an exposure that is two stops brighter than what the Sunny 16 rule advises.

The brightest patch on an X Rite Colorchecker is 2.5 stops above middle grey at about 90% reflectance. D4 is the middle grey patch at about 18%. You could try spot metering it to get closer to the recommended exposure, although that is pretty tough. Much easier to use a grey card angled 45 degrees towards the main light source. (However, whenever I've exposed in direct strong sunlight so that D4 is at 18% grey I've sometimes found the image to be a bit too dark for my tastes so take the idea of correct exposure as dictated by a grey card with a pinch of salt. In weaker light or in shade I've found it to be quite close.)

In the below, shot in soft evening cloudy light, the fourth brightest patch (D4) is exposed at RGB 119, 119, 119 which is middle grey in sRGB (and that would be 126, 126, 126 in Rec709)

 

[MrSMW]

Not to cast shade over the way anybody does anything, but my own approach is uber-simple.

Aperture wide open which with my lenses is f2. I like the wide open look and have done for both stills & video for 20+ years.

Set shutter speed to 1/100 (180 degree) because I shoot 4k 50p.

Indoor or outdoor after dark, no ND.

Indoor daylight, ND 2-5 by default at 2.

Outdoor average day, ND 2-5.

Outdoor super-bright day, ND 6-9.

Then to control exposure, from a technical viewpoint, I use the waveform scope, but mostly my eye because as someone who does not at this time shoot log, if it looks right on the back of the S1H screen, it is right. Or as close as it needs to be, ie, I am looking to get it right as poss in and SOOC.

How I actually control the exposure is through the VND outdoor and indoor using ISO.

If it’s an outdoor especially frantic, crazy light scenario, I may switch to auto-ISO and just let the camera deal with it, though it tends to err on the side of over-exposure.

Shoot me, I also use AWB most of the time because unless the light is really ugly, I find it’s really good for SOOC footage.

I’m not a ‘serious filmmaker’. I have zero client brief or input. They just want a wedding film in my style so I shoot for myself and the approach above is as simple as I can make that part of the process.

[fuzzynormal]

4 hours ago, MrSMW said:

Set shutter speed to 1/100 (180 degree) because I shoot 4k 50p.

Indoor or outdoor after dark, no ND.

Indoor daylight, ND 2-5 by default at 2.

Outdoor average day, ND 2-5.

Outdoor super-bright day, ND 6-9.

Then to control exposure, from a technical viewpoint, I use the waveform scope, but mostly my eye because as someone who does not at this time shoot log, if it looks right on the back of the S1H screen, it is right. Or as close as it needs to be, ie, I am looking to get it right as poss in and SOOC.

 

Same here.  Run-and-gun doc and corporate vids.  Often at f1.8'ish.  If it passes the eyeball test, then I'm good.  Variable ND is a blessing and a curse though.  VND causes it's own issues...but it's a worthwhile tradeoff.

[MrSMW]

1 hour ago, fuzzynormal said:

Same here.  Run-and-gun doc and corporate vids.  Often at f1.8'ish.  If it passes the eyeball test, then I'm good.  Variable ND is a blessing and a curse though.  VND causes it's own issues...but it's a worthwhile tradeoff.

I may go back to just shooting higher shutter speeds again and ditching the VND's...

4 weddings into the new season and with 29 to go, my body says it's not 100% happy with my current set up.

Happy with all my gear, except the weight.

Keeping my eye on and toying with my options as I'm not sure my right shoulder especially is going to last the year...

[hyalinejim]

4 hours ago, fuzzynormal said:

VND causes it's own issues

I have to say I've been really happy with the SLR Magic on speedboosted GH5 in the 24-200mm range. I've never noticed softness, major colour cast or X patterns. But I don't need very narrow DOF outdoors in bright light. Its six stops would be a bit limiting at ISO 400.

If you wanted to shoot ISO 2000 (as in GH6 DR boost) and also wanted to shoot at f1.8 1/50 in bright sunlight then you'd need almost 12 stops of ND

There is one vari ND on the market (Promaster Extreme) that goes to 12 stops but who knows what kinds of issues it might cause? Maybe a fixed ND plus less extreme vari ND would be better.

[webrunner5]

Wow I doubt any vari ND is going to be any good doing 12 stops, Yikes. I would have to go with a different Aperture.

[stephen]

My use of ND filters is mostly for outdoor / daylight video shooting.
Almost never need them or use them for indoor or outdoor at night.
Here is my experience so far:

When shooting RAW almost any cheap VariND will do the job. Like K&F VariND
Hoya ProND hard stops ND filters are good enough for 10bit 4:2:2 log footage. They may have slight color cast but it is easy to correct in post. Basically for non RAW footage you can correct WB up to 700-800K, even 1000K but no more. Most good quality hard stop NDs will give you only 100-300K deviation (colour cast) from correct value (without ND filter). 

Last generation of VariND filters split the 1-10 stops range in 2 different filters to improve colour fidelity and avoid the dreaded X pattern at the extreme end. Based on several reviews decided to buy/try Freewill VariND 6-9 stops  (82mm). Curiously this one has no colour cast or let say no visible colour cast and keeps the sharpness of the image but the 1-5 stop one does have quite significant colour cast according to one reviewer. For this reason and based on my calculation about ND stops that need  bought only the 6-9 stops one.

Also bought 2 magnetic K&F 62mm hard stop filters - 3 and 6 ND stops.

Freewill 82mm VariND goes on my 24-70mm f2.8 Sigma or 24-100mm f4 IS Canon. K&F 3 and 6 stops on all fixed focal lenses and of course I never mix them. Both setups are giving me convenience / ease of use and also good quality. They work so well that decided to add another 62mm Freewill VariND and 2 82mm K&F. Same ND range and stops.

Most modern cameras when shooting LOG or RAW start at 400 to 800 ISO range. For example my BMPCC 4K base ISO is 400 and my Panasonic S1 base ISO is 640. Having in mind the sunny 16 rule, those are 2 to 3 stops more than base 100 ISO, another stop more comes from the fact that instead of 100 shutter have to use 50. Usually shoot at 24 FPS. And another 2-3 stops come from apperture where typically f5.6 and f8 are my preffered ones when shooting outside at Super35 or FF. When shooting people apperture has to go down to F2.8 on Super35 and f4 on FF. Those are typical and most used appertures in cinema and movies. So 6-9 is just perfect and can stay 100% of the time on my 24-70 f2.8 or 24-100 f4 lenses. Apertures like f1.4 or less or even f2 at FF are almost never used in cinema as it is very difficult to manual focus at closer distances and focal lenght around 40-50mm or more. The strongest ND filter you can get is 10 stops. 

Two K&F 3 and 6 stops filters are used the same way. By stcking them can achieve 9 stops of ND and have the convinience of 3 stops of ND as well if needed. But as said this is rarely the case.

To obtain correct exposure:
    - when shooting scenery use apperture variations from f4 till f11 + ISO variations. Overall this give me 5 stops of tollerance which is more than enough. 
    - when shooting people and apperture is locked at f4 or f2.8 can change only ISO. Changing lighting is most of the time not an option. 

In both cases when using the VariND filter will use the 3 stops it gives me first before apperture and ISO.

Most modern camera have huge lattitude - up to 6 stops with Panasonic, so underexposing a stop or over exposing a stop or two are almost never a problem

I use also only 3 white ballance points - 3200 typicall for night shots, 5600 for daylight and 4400 for something inbetween. And it works quite well for me in both RAW and 10bit 4:2:2.  

[stephen]

P.S. If am using fixed focal lenses and changing them during the shoot 2 hard stops (3 and 6) magnetic ND filters is the way to go. Gives both good quality and convenience quite rare when using ND filters and on limited budget. Bought K&F just to try the concept and it worked. Overall am  pleased with quality as well. There are better but more expensive magnetic ND filters.

[stephen]

P.S.2 - Forgot to say that when using the hard stops ND filters will use them to adjust exposure in steps of 3,6,9 stops. And  then use aperture (if possible) or ISO to fine tune in between the 3 stops steps.  

I use Dual ISO or second (high) ISO mostly at night. For daylight shoot use the first base (lower) ISO but will not shy away to increase it with 1 -2 stops in order to tune the exposure. Or just overexpose / underexpose a stop or two depending on camera that use. Most cameras tolerate better overexposure. 

[hyalinejim]

I've just checked my 82mm SLR Magic 6 stop Vari ND at 24mm on full frame versus shooting with no filter and can make the following observations:

- there's no sharpness loss
- there's a colour balance of 350 Kelvin and it is constant throughout the range
- it vignettes in 3:2 but it wouldn't be an issue for 16:9
- the polarisation effect gets progressively worse as you stop down. I wouldn't notice it unless I made the comparison but it's there and it's annoying

However, I do love the convenience of using a Vari ND to fine tune exposure. I wonder would the optimal solution for something like the GH6 be a constant ND to get you most of the way there and then a light Vari ND that's as free of artifacts as possible to get the rest of the way?
 

[webrunner5]

I would stack constant NDs before I would do a Vari. They make the small add on holders now. Good constant ones are not cheap though. But if handled right they last forever.

[hyalinejim]

Yes but for run and gun the difference between dealing with constant NDs and a Vari ND can be the difference between getting the shot or not. I'm not a fan of the polarisation effect of the variables at all, but the convenience can't be beat. Best of all of course would be an internal electronic ND!

[MrSMW]

2 hours ago, hyalinejim said:

However, I do love the convenience of using a Vari ND to fine tune exposure. I wonder would the optimal solution for something like the GH6 be a constant ND to get you most of the way there and then a light Vari ND that's as free of artifacts as possible to get the rest of the way?

Yep, that is exactly how I would do it with a base iso of 2000.

Re. colour cast etc, I use the Freewell’s and haven’t see anything that bothers me.

If there is anything, it’s so minimal and constant, it isn’t even a consideration.