DSLR Movie Exposure?

R

RTLdan

Member
Hello all!
I'm a newbie interested in DSLR movie making, specifically trying to achieve the filmic look I've seen a lot of Canon 5D users emulate. I had a chance to sit and mess with a DSLR, and I read a lot of info online about photography concepts in general. As I messed around with taking photos and applying what I had read, I suddenly began wondering about video.

If I understand correctly, in photography we can use shutter speed, ISO, aperture, and filtering all together to properly expose our shot. For instance., we could use a faster shutter speed to help compensate for a higher F stop. I'm sure I'm simplifying this, but try to bear with me...

Ok, great! We have a lot of ways to get the shot properly exposed in photography.
But let's suppose for a second that we are doing DSLR video and we want a sort of filmic look. For starters, if I understand well, we will probably be using a 180 degree shutter angle -- or the DSLR's closest equivalent (for a 24fps video, 1/50th on some cameras). We'll also probably want a shallow DOF which means we might choose (or be limited to with some lenses) an aperture setting of F/4. Well, so considering we already know we want those sort of settings, what are we left with except for ISO to help us with exposure? Sure, we can use ND filters if we have too much light, but what if we have too little? How are we to achieve proper exposure? From ISO alone? Ideally you would light a scene, but what if you were unable? Are you stuck with an underexposed shot? Is there something I'm missing here?

All help is greatly appreciated, and thanks in advance for listening to another newbie try to figure out the basics! :)

-Daniel
Portland, OR
 
Hi El Director!
I appreciate your reply. I definitely understand that it would be a perfect example of a time to bring in some lighting, but just to reiterate part of my original question...

"Ideally you would light a scene, but what if you were unable? Are you stuck with an underexposed shot? Is there something I am missing?"
Click to expand...

So if you can't bring in lighting, is ISO your only possible exposure control for DSLR video (under the conditions I already posed in the original post) or is there some other setting I'm unaware of/forgetting?

Thanks again!
-Daniel
 
Assuming you don't want to change your shutter speed, or your aperture, and can't bring in any additional lighting tools... then yes, you'd be down to ISO.

edit: mechanically speaking, that is. of course, you can under-expose and bring it up in post, or you can switch cameras to something with a higher dynamic range, or you can implement HDR shooting if you have it, or you can... well, you get the idea.


However normally in that case, the exposure would be more important than the DOF, so you'd just open the aperture. If you've opened up all the way and have the ISO as high as you're willing to go, then you can change the shutter speed (no, it's not recommended... but if you have to get the shot, you have to get the shot). If you've done all that and you still can't get the shot... then you've picked a poor location, buddy.
 
As previously stated, use shutter speed to get the motion look you want, use aperture to get the DoF you want, use lights, ISO and ND to get the exposure you want. If you can't bring in lights, or put any more ND in front of the lens, then ISO is the only thing you've got. /// You may like this: http://www.similaar.com/foto/tuten/600.html
 
Wow - a newbie post where the guy has a basic understanding of the elements of exposure - NOT trying to be a snarky jerk, but dude, you should read some of the stuff we see from people who've grabbed a DSLR and are planning their first feature and wondering why the focus and exposure keep changing, and why the shot is so wobbly...

The wonderful thing about DSLRs is you can just go out and shoot a sh*t-ton of stills and video while you play with the controls. Learning to shoot in the film days took a lot of waiting for the lab (or drumming your fingers in the darkroom).

That's my real newbie-advice. Shoot like crazy until you're not even thinking about buttons and knobs - you're adjusting stuff before it even occurs to you. Shoot as many stills as you can, try to find the one beautiful angle in a boring room or setting - the still is where it starts. A great eye trumps a technical wizard every time - only one can be taught, after all...
 
Hey everyone!
Thanks so much for your advice! Will be taking this knowledge with me and using it shoot, and shoot, and shoot some more until it's a natural process :)
See you all in another post!
Long live DVXUser!
-Daniel
 
I wouldn't think so much about having aperture set always at f/4 to achieve constant depth of field. Although f/4 will always give you the same exposure value (or close enough to it) with different lenses given a constant ISO and shutter speed, longer lenses generally need to be stopped down much further than wide lenses to achieve a similar-looking depth of field. For example, with my 20mm lens, at f/5.6 nearly everything appears in focus. With a 200mm lens, f/5.6 shows a very shallow depth of field.

My best advice would be to set the aperture based on depth of field appropriate to the shot you need to achieve. Contrary to what a lot of DSLR shooters seem to think, shallow DOF and focus pulls aren't always the right answer for every shot out there. Luckily though, shots made using wide angle lenses generally tend to favour deep focus (outdoor establishing shots for example), and those made with long lenses tend to favour shallow focus (close-up headshots). Those are by no means strict rules though... as I said, pick the depth of field most appropriate for the shot you need to make and go for it - use Filters and ISO as necessary to affect the exposure (I personally don't like to go any further than 1/40 or 1/60 in a squeeze).
 
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