@suresure123

It is more about the aperture continuity. Aperture change, except just how much light passes, influences the depth of focus field, contrast, flaring, unsharp area shape and quality etc. So if you want your shots to perfectly match when you edit them together, you need to control those changes. The fail safe method is to use one lens with one same aperture throughout the scene, and you have perfect matching shots where color, contrast, defocus areas etc belong to the same world whose physical attributes are controlled by the size of iris.

But those changes are also powerful creative tool, so most of film makers chose to use this to their advantage, creating on purpose visual jumps to emphasise dramatic moments and create dynamic impacts. So there is really no one rule, it depends on your creative decisions and choices.

Ideally this also works for docs, it is a bit more complicated since all those continuities in filmmaking have one goal, and that is the 'suspension of disbelief', in docs, you want to show the real world, it is sort of counter-intuitive, but basically the tools are the same, it is just the premise of real and true that changes. So all those jumps and discontinuity characteristic for documentaries can also be also a creative choice to separate stylistically from 'artificial' cinema.

There is no such thing as a good aperture for general movie making.. each scene depending on focus point, lighting .. mood would need and require different apertures accordingly.. I can't see anyone saying " I would love to shoot my next movie at f2.8!"

Also.. if you are not prepared to use an nd filter then you won't have a movie look anyway, as you will not be able to stick to the 180 shutter rule in bright light, and all your stuff will look like home movies or at best saving private Ryan...

Maybe i'm retarded but I refuse to use ND filters, I don't want anything in the way of the lens....ill wait for better light before I use an ND.

Lol! - Sorry, and how do you keep one aperture in different lighting conditions (like indoor vs. outdoor)? I think you still have a long way before you learning the technical side (and limitations) of movie making.

+what lmackreath wrote

For drama I would find that weird. I would use wider apertures as I get in tighter into a scene as we become more focused on the other person the bg blurs more, whereas in a big old wide establisher why would i use a similar f stop that meant only part of the world was in focus, unless my character was only interested in a very specific part of the world. I've hweard of directors wanting to use only a couple of lenses throughout, which again seems crazy though it will give the film a v specific look, like maybe giving everyone wider and wider faces the closer in we are. I think you need to think first why would I want to only use one f stop, what effect will it have, what effect do I want to create, rather than thinking someone once did this so maybe I should. Back to front thinking!

What I was asking is how do F Stop from 35mm film translate to f stops for m4/3 sensors. Anyway I found the answer in the end online....its about 2/3 of a stop less than say an aps-c sensor.

@Psycho I think you are wrong on a few important points along with a few others. For one thing yes you can shoot outside in daylight cause there is this thing called ISO and this other thing called not being a dumbass and pointing your camera into the sun like some home movie idiot.

Personally never needed an ND but not shooting in silly bright daylight and finding some sheltered area with some shade, plus I wouldn't think to open the aperture up...obviously. But a more realistic 4-6 stops is fine for average day conditions I've found with an iso of 200. I wouldn't want or need to be lower than that anyway.

So people missed my point, you don't jump between stops, its amateurish if not carefully used for a purpose, you're basically bouncing the viewers depth of field...I see it a bit in low budget indie flicks but in an average big budget movie you won't see 5 minute scene jump from close up shallow depth shots and then wider deeper shots. Now of course you get some more separation with camera proximity to say close ups but not some major jarring if you jump from say f1.5 close up to wider f6....yes you see it some time but it looks shit, like you are trying to create some dream sequence or something.

And so yes some DP's do try to stick to an f stop roughly. I have heard the DOP for Ex Machina say he only shot 2.8 apart from a couple of shots. You can see that in this movie quite easily, very open and soft. Generally looking at most movies I don't seem much shallow shots, a handful at most so I'm thinking around 4-6 is where you want to be most of the time and so this translates to I guess around 3-5 ish for m4/3???

I'm sorry I had to answer my own question but people tend to want to lecture and try to look smart rather than answer questions on forums...kind of annoying.

@suresure123 There's no way that you're going to achieve a 180 degree shutter in daylight at ISO 200 without using an ND filter, stopping your aperture way down, or shooting at really high frame rates - probably not even in the shade. Assuming that you're shooting 24fps, you'd need to be at ISO 50 (give or take) at f/16. At 30fps, you'd be closer to ISO 60 at f/16. Even if you're overexposing by two stops for slog or similar, you'd only be able to open up to f/8. At ISO 200, you'd be at f/32 or f/16, depending on intentional overexposure. In most cases, people don't find such small apertures to be ideal.

Invest in a decent set of ND filters and the quality of your output won't be negatively impacted in any serious way.

@suresure123....maybe borrow or hire a variable Nd and go shot some footage with and without nd, and make a comparison. You won't die wondering that way

"There is no compulsion to shoot in blaring mid day sun IMO outside unless you are trying to capture JFK being shot"

Yep, I think that's exactly what Abraham Zapruder said, and he didn't use ND either, point taken.

There are so many generalisations in the op's comments....

"most films dont have shallow shots"??? how can you say that? " Shallow focus looks great in photography....but not so useful in cinematography" are you kidding?

"For one thing shutter speed is a major tool for exposure" - Yes it is but its clearly not for you as you dont use nd filters!

At the end of the day you mention films and seem to be keen to shoot footage that is film like, well I am sorry but you cant do that in my experience in the outdoors in good light without nd filters to control your exposure. If you didnt use an nd filter sure you could shoot at whatever aperture you wanted, but then your shutter speed will be all over the place and make your work home video like. nd filters arent there just to give you super shallow DOF, they are used to control lighting and achieve constant control over your footage, regardless of location and lighting...

You basically ask two questions:

1. do you think keeping a steady f stop is a good idea and would you do it for a documentary? Personally I'm done with shallow focus wedding video looking stuff and want to shot my doc as similar to film as possible."

Again, you are contridicting yourself.. on one hand you want to shoot your docs as similar to film as possible but yet you dont use nd filters? Keeping a constant f stop during a take is correct, but changing it between scenes will is a choice based on what your shooting and what mood\focus you are going for...

1. Maybe another whole subject but how to people keep a consistent look in terms of ISO/grain, lighting etc across a whole movie or documentary. I know with Docs people expect jumps in media but if you wanted to maintain a standard exposure and grain how would you go about it in terms of settings? Would you ride the ISO up and down or aperture?"

And again...this question can be answered with the user of nd filters!, with an nd filter you can control your exposure , allowing you to keep a constant iso\shutter speed\aperture

You had two or three perfect polite answers to your very ambiguous question and then reply back with attitude because you didnt like the answers you were given???

Oh, and shooting black and white does not magically mean you dont need an ND filter....

Hey quit with the attacks. I don't use ND filters, never have, probably never will.........breath and get over it.

And sorry but most movie really don't have extreme shallow depths of field. Go watch one and tell me if the background falls into bokeh overtime an actor is shown in his environment. You absolutely do need to get stops right in terms of spacial activity so there can be some mild out of focus of the background vs the foreground without going to soup....this is what was talked about in terms of 3-6 is area as a 'general rule' DUMB DUMB DUMB....

When the Canon 5D mk2 came out 9 years ago the prosumer community were going shallow DOF mad and shooting everything wide open full frame. That has slowly gone away over the years and people now realise that it is more of a creative choice to choose out of focus backgrounds rather than use it as a feature of the particular camera or lens...

I cant agree with you thought that "most movie really don't have extreme shallow depths of field". if any DOP in any film wants to make the viewer focus on a person in a scene they will invariabally shoot shallow to focus out the backgrund distractions for the viewers eye to concentrate on the actor in question. It might not be used shot after shot, but it is used, and its used a lot, and more so now in TV shows especially. Shows like Suits, Girls, Game of Thrones etc, they all use it...and a lot!

if you dont want to use nd filters that is fine, you can shoot however you want , but the constant film look you strive for I dont believe can be acheived wihout proper control of your exposure...if you want to use a single aperture for a whole project in many different lighting condtions then there is no way you can control your shutter speed without an nd filter, which means your footage will look ameraturish and change from scene to scene

"Personally I'm done with shallow focus wedding video looking stuff and want to shot my doc as similar to film as possible."

Since you want a film look you will need a camera with the same ISO range that film stocks are available in. That means a camera with an ISO as low as 25 for shooting in bright conditions. Otherwise you need ND filters on a digital camera to get the same exposure settings as film, at a higher ISO (shutter angle, f stop etc) .

Personally I'm over the constant reference to "film look" as it is completely meaningless when one looks at the variety of "film looks" that have evolved during the long history of filmmaking.