2 questions concerning fstops and filming

[Shanec8mm]

I got a roll of reg 8mm film back from walmart yesterday and and it is really dark. I shot the film indoors using a single very bright 650watt movielight about 10 feet away from the subject and set the camera fstop at 4 I used cinechrome 40 which I set the ASA to 40 and focused at 10Ft, and it is still very dark, did I need to open the lens to 1.8 to get more light ? because I think it would have brighten things up alot. later in the film I shot the same scene using 5.6, it was worse too too dark. also my last roll I used outside and some scenes where dark. If I was to film outdoors using cinechrome 40 #85 filter and and fstop of 5.6 what would the finished film look like ? oh yes I was filming at 18fps. I am really looking for nice very bright imagines for viewing because the reg 8mm format is smaller than super8 so more light I think helps. thanks
shane

[Evan Kubota]

Did you use a lightmeter? Using 40ASA film with a single 650 watt light sounds like an f/2.8 at most - more likely an f/2 or f/1.4.

[Shanec8mm]

no I don't own a light meter so just trying to use alittle guess work and get it close. So maybe I should move the light clsoer to the subject when filming with a single 560watt light ? sounds so. so a wider aperture is what I though too when watching the movie, it looked like some scary movie with the dark contrast, plus my girlfriend and i where in full halloween costume at the time, and she had her faced painted white so she looked kinda scary because her face was the lightest part in the movie eveything else was either black or not darker.
shane

[super8man]

What camera were you using? It mayhelp in determining how to expose correctly.

Cheers,
Mike

[Shanec8mm]

I am using a Bolex S-1 camera

[Joe Gioielli]

Shane, don't drive yourself crazy. Get a lightmeter. You can get a very good analog meter for less than 200 bucks. If you are on a tighter budget, you can find something for around 50. Check at your local camera store.

It just makes life alot easier.

Good luck with filming!

Joe

[super8man]

That helps...the Bolex S1 is really oriented toward bright daylight conditions. Using f4 under a single flood sounds like for sure you would get underexposed results (like you experienced). If you had of been using an XL super 8 camera with a f1.2 or faster lens and a shutter that is bigger than 160degrees - like a 220 found on many XL Chinons, you would have seen better results at f4. Remember, your effective shutter speed on that camera is about 1/43 of a second which is pretty fast for your application you mentioned. Having said that, if you were to use that same camera at an NHL hockey game, I bet you'd get pretty cool results! Hey, tis the season...gotta run, Hockey Night in Canada is on!!!

Best,
Mike

[Shanec8mm]

so basically if I'm to film indoors with my bolex S-1 with a single floodlight I need to open the aperture all the way and outside something like 5.6 or maybe 8 ? i wondered why it seemed so dark with 4 and a singlelight but when I get some film in a few weeks i will try to reshoot the scene with the aperture open fully which on my camera is 1.8 and if outside in bright sunlight i will try somethinglike 5.6 think this may work anyone ? thanks guys for the help
shane

[audadvnc]

Outdoors is --much-- brighter than indoors. I've found that the difference between direct sunlight and open shade is typically 4 stops, and shade to indoor may be another 3 or 4.

If you don't have a lightmeter, remember the "Sunny 16" rule: at noon on a sunny day you get proper exposure at f/16 when you set shutter speed to 1 / ASA. So, if you're shooting ASA 50 film and your 24fps movie camera takes 1/50 second pictures, you'd be setting your exposure to f/16. When I tried it, I found it works.

[tlatosmd]

If you don't have a lightmeter, remember the "Sunny 16" rule: at noon on a sunny day you get proper exposure at f/16 when you set shutter speed to 1 / ASA. So, if you're shooting ASA 50 film and your 24fps movie camera takes 1/50 second pictures, you'd be setting your exposure to f/16. When I tried it, I found it works.

1/ASA means 1 divided by speed, right? If that would be the case, ASA50 would mean f0.02.

[Evan Kubota]

It's not an equation in the strict sense - f/16 is the suggested aperture *at* 1/50 second exposure with ASA50 film. The number is a rule of thumb and doesn't mathematically correlate with the exposure time. For example, if the film was ASA25 (as K40/Cinechrome 40 would be outside with the appropriate filter), the camera's actual shutter speed is closer to 1/50 second at 18 fps than 1/25. The difference would be approximately equivalent to one stop, so if the rule calls for f/16 at 1/25 second exposure, f/11 at 1/50 should be approximately correct.

[audadvnc]

1/ASA means 1 divided by speed, right? If that would be the case, ASA50 would mean f0.02.

No, I'm saying that, using ASA 50 film, you'd shoot 1/50 second at f/16.

[super8man]

Keep it simple:

With an SLR: buy 100 ASA Kodak Gold Film...go outside on a sunny day...set your f-stop to f16 and set your shutter speed to 1/100th of a second (that's the 1 over the ASA bit) and get perfect pictures everytime.

Witha movie camera: Bolex has a fixed shutter of 1/45 abouts so with 40ASA film, set fstop to 1/16 and shoot outside...if you need a filter that redices the light, you have effectively reduced your asa to 25...so, you have to shoot at f8 while your shutter blinks away at 1/43rd...

Don't worry, everyone screws up on understanding ASA and f-stops and shutter speeds. Double double toil and trouble, Cauldron burn and cauldron bubble....something wicked this way comes.