BASICS: Frame Rate & Shutter Speed

[Erwin Layaoen]

I am new to video and waiting for my 7D to arrive so for the meantime I am trying to learn as much as possible. So much info posted and it's getting confusing.

I do need some advice understanding the basics of selecting the shutter speeds and frame rates for certain purposes. Pros/Cons of each frame rates below.

1920 x 1080 (Full HD): 30p (29.97) / 24p (23.976) / 25p
1280 x 720 (HD): 60p (59.94) / 50p
640 x 480 (SD): 60p (59.94) / 50p.

For example, what frame rates to use if:
= web use, 2-5minute product introduction/interviews, shot indoors, controlled lighting.
= weddings, events, interviews, DVD for delivery

Thanks

[Edward Carlson]

25p and 50p for PAL land.
24p for a film look.
30p for broadcast TV/video look.

[David Chapman]

Hey Erwin,

Check out a thread I made a while back.
http://www.dvinfo.net/forum/canon-eo...ing-video.html
There were a few questions unanswered in the start of it, so I can give you the rundown.

Frame Rates
As far as frame rates go, almost everything I shoot is 1080p 24. I don't do anything for broadcast so 24p (23.976) works great and you don't have to do a telecine process for DVDs. All DVD players now can play both frame rates. BTW, when you select NTSC, only 60p, 30, and 24p are available.

The only time I will shoot 60p (in 720p mode) is when I know I want slow motion. I have it set as a custom preset so I will turn the nob to preset 3 (what I have setup). There is more stair-stepping in 720 than 1080 so I use with caution.

Shutter Speeds
Shutter speeds are a little tricky here if you don't come from a video/film background. You want the shutter to be as close to 180° as possible. Ideally, if you shoot 30p or 24p, your shutter will be double at 1/60 and 1/48 respectively. I did say as close as possible to 180° so since the 7D doesn't have 1/48, you set it to 1/50 (that's close). If you shoot 720p60, your shutter would be 1/125 (close to 1/120).

Photographers will have issues here at first. When shooting outdoors, they will instinctively crank up the shutter speed to 1/4000 or something ridiculous to keep their aperture open or make sure there is no motion blur in the photo. That's fine for a photo, but there needs to be some sort of motion blur in the video or it will look strange. In some cases this can be artistic where you may to 1/120 at 24p to get particles to be super clear in the air.

Example: Very short clip shot at 24p at 1/120 on JVC HD100:
http://yourvisualimage.com/download/Saul_recolor.mov

You don't always want your footage to look like that though—especially a bride putting on her veil. Maybe an action scene where you want to see debris flying or something.

Aperture
Now this is the tricky part (for photographers). If you are outside at 3pm and shooting 24p, your shutter will be at 1/50. You really want shallow DOF so your aperture is f/2.8. As is, your scene will be almost pure white because you are 4+ stops over exposed. This is where a photographer will increase shutter speed to compensate for exposure. The solution for all of this is an ND filter. You can get various densities to help stop down the image optically. Check the density of the filters at a camera store. They are usually numbered by .3, .6 and .9. This is 1 stop, 2 stops and 3 stops respectively. You can stack them, but you don't really want to do more than 2 or it will cause vignetting around your image (on wide angle lenses).

You can get a a newer product called a Fader ND. This lets you rotate the filter on the lens to apply any range of stops (2–8 stops of density). Almost all video cameras come with 2 ND filters in the body that do just this. To shoot video on a DSLR, you will have to get one for outdoor, daytime shooting.

Everything Else
ISO and Highlight Tone Priority are a big deal to me. I don't like added noise/artifacting in my footage and I always grade (color correct/style) my shots in post (Final Cut, After Effects, Shake, Color). I have detailed along with others about ISOs in the 7D and what they are doing. I use ISO 100, 200, 400, 800 or 1600 when shooting and I always have Highlight Tone Priority turned off. This allows me to achieve the greatest color gamut from the clip and doesn't add any unwanted gain in blacks or clipping of whites. I also use a preset for white balance. Auto white balance will change depending on where the camera is facing and can add unwanted artifacting also.

I'm currently producing a detailed "how to" video geared towards the independent filmmaker using the 7D. While only a brief chapter covers menus and 7D actual setup (who wants to watch an hour of that?), it really shows how to use it in real-world shooting environments—what scenarios to avoid, problems to look for on set, lighting and adding finishing details in post.

[Javier Salinas]

That's great help David! Thank you very much!

Is this something that you apply especially to the 7D or is something generic related to film?

I think I'd need some time and practice to assimilate it!

Do you know any link were I can get further information about this theme?

Thanks

[David Chapman]

Hey there Javier, I'm glad I could help out a little. Most of what I mentioned is related to film/video shooting overall. I use the 7D like a film camera (more so than video). The only odd thing for videographers coming from XL2's and other prosumer cameras is there is no gain control. ISO is a film speed/photographer thing—hence it's a still camera that shoots video. Increasing ISO on the 7D is the same as adding gain on a video camera.

As far as learning more, above is pretty much what you need to know to start shooting. You can only learn so much by reading. The rest takes practice and patience. You can always look up some things on Wikipedia like "aperture" or "f-stop" to see a stop chart.
F-number - Wikipedia, the free encyclopedia


All of the ISO settings took some time to research and test and aren't as easy to find. Some people (even on here) swear by the 160, 320, 640, etc but don't think about consequences of the highlight clipping. Others love Highlight Tone Priority (which I guess I would turn on if using ISO 1600+). I hate what it does. Just explore and have fun.

[Erwin Layaoen]

Thanks David for the information. I am a photographer but doing video requires another mindset. Now, let me soak it in and practice once I get the camera.

[Nigel Barker]

Originally Posted by David Chapman

I use ISO 100, 200, 400, 800 or 1600

Isn't that contrary to the received wisdom that 160, 320, 640, & 1250 are the ISO 'sweet spots' for the 7D & 5DII?

[Perrone Ford]

Originally Posted by Nigel Barker

Isn't that contrary to the received wisdom that 160, 320, 640, & 1250 are the ISO 'sweet spots' for the 7D & 5DII?

They aren't "sweet spots". They are ISOs that give better performance when there isn't much light or when shadow detail is paramount. They do this at the expense of highlight performance. The "double-o" ISOs offer a balance of highlight holding and shadow detail, and selecting the ISOs on the other side of the balance tend to hold highlights better at the expense of shadow detail.

I had a lovely opportunity to play with all these a few months ago. Very cool once you understand how it all works.