Timelapse shutter speed rule of thumb explained

The widely accepted rule of thumb for shooting timelapses is that your shutter speed should be 1/2 your interval. What this means is if you are shooting one shot every 3 seconds, then your ideal exposure is 1.5 seconds.

WHY?

The point of shooting timelapses is to end up with video at some point, right? Film cameras have dealt with this issue for some time now. In a film camera, a piece of film rapidly advances one frame, stops, is exposed to light, then the exposure stops, the film advances and the whole process begins anew. This process can occur 12, 24, 30 or more times per second. The camera needs some time to move the film into position, so it spends some time with the shutter closed (moving film) and then it spends some time with the shutter open (exposing film) The standard for a long time now has been to spend half of the time exposing, and half of the time moving film (not exposing.) On film cameras the shutter is often on a shaft and rotates through the film plane. Thus a 180 degree shutter literally is a half circle that blocks the film from getting light half of the time.

180 degree shutter

WHY?

Well, that’s still a good question. Digital cameras can go from practically 0 degrees up to literally 360 degrees. The big difference is in what it looks like. Motion blur is what this is really all about. Regardless of your exposure or frame rate, a shorter exposure will have less motion blur on it. On the flip side of the coin, a longer exposure will have less action occur when the lens is ‘closed’ and it will look less strobe-like. The balance between those two things is how people decided on a 180 degree shutter, and that brings us back to shooting stills.

When shooting a timelapse, if your shutter speed is smaller than half of your interval then your video will start to look strobey. What I mean by that is that there is a continuity gap from one frame to the other. If the video is of a car driving, then the distance that the car moves between frames will increase and the resulting video will look jumpy.

If your shutter speed is larger than half of your interval you will end up with more motion blur. Trails will occur behind moving objects. This is generally less of a concern because our minds are much less confused by trails than by strobing. Strobing can be dissociative, while motion blur is more like an artistic statement.

In conclusion: Like all rules, this rule of thumb is meant to be broken but it can never be ignored.

Addendum: When you are shooting video in movie mode, this should also guide your shutter choices. If you shoot 720p 60, then you should have a shutter speed of 1/125, and if your are shooting 24fps, then it should be 1/50. Feel free to deviate but know what will happen if you do.

Canon 7D firmware 2.0 and 2.0.3 released


Canon released firmware v2.0.3 for the 7D recently. Go here to find it. It fixes some things broken by the 2.0 update.
The 2.0 firmware enables a bunch of new features. Here is the canon site explaining everything. My favorite options are the higher burst rate, higher max iso, and the manual audio levels.

Oh, and while you’re at it – check out Magic lantern on the 7D. It’s finally making some progress!!

Weird banding on Canon 7d explained!

The other night I was out filming traffic. I ended up getting a really weird camera artifact. It looks like a dark bar that rolls through the shot from bottom to top. At first it made me freak out a bit, thinking that the camera was somehow broken. I eventually figured out that it is the result of A) a flickering light source and B) the right (wrong) shutter speed. I think the streetlights were tungsten bulbs, but they may have been HID bulbs. Whatever they were they definitely had a flicker to them.

I read somewhere that ideally you should shoot a shutter speed that is double the frame rate. This gives you a 180 degree shutter and it should look very similar to film. The way that I made these bars appear was by changing the shutter speed away from 1/125 when I was shooting 720p60. I have ideas as to why this creates the banding, but they are all theories. If you have any more insight pleas tell me in the comments!
Moral of the story: keep the shutter speed at twice the frames per second. Change the aperture, or buy a faster lens!

Slow motion from the 7d. 720p60 to 24p How-to

There were a few different stages of excitement that I went through after getting my Canon 7d. First I played around with all of my manual nikon lenses (using an adapter of course). Next I marveled at the settings and the live view feature. Finally I decided I wanted to go out and shoot some slow motion video. This is fairly easy to do seeing as the camera shoots both 720p and ntsc at 60 frames a second. The software side of slowing things down required some thinking, but it’s easy once you get the hang of it.

Here is what I (and the wisdom of the internet) have come up with.

Continue reading

Canon 7d test video

canon 7d test shoot

here’s a quick video I put together with my new dslr: the Canon 7d. I’ll run down my gear and workflow in a lil bit, but for now, here’s the vid.
Canon 7d test / Coffee facts

Cheapest follow focus ever for canon 7d / 5d mark II

51W5SN8J+lL._SL160_

Ever since I have fallen in love with the Canon 7d dslr, I have been fantasizing about making a legit follow focus for a dslr. It allows you to have more control over the focusing, and a smoother camera because your rotation is in a different axis as the lens. (You may hear more of my traditional FF plans in a few) In the meantime I saw a vimeo clip that had this little gem of an idea in it. For quick focus pulls a lever like this can’t be beat, and it’s dirt cheap as well!
rack focus for canon dslr

Here are all of the parts from the old home depot. Simple stuff. It totaled around $6, and it’s enough to make 2 and have parts left over.

worm screw

The first step is to cut out a few teeth in order to make room for the bolt.

Continue reading

$17 Arduino-based nikon IR intervalometer + code

invervalometer_4

This is one of those projects I’ve been working on for quite a while now, but never well enough to actually put it in a box! Well.. it still has no box, but it’s much closer to a boxable form.

It is a RBBB arduino clone (but any arduinowillwork) with an ir led, a potentiometer, a resistor, and some perfboard. The perfboard is as much there to help provide a little bit of wire strain relief as it is to provide a place to mount the pot. The code simply reads the pot input and converts it into a delay() function. Then it fires the IR led with the nikon-specific magic to tell my d40 to shoot.

Here is an example of one of the timelapses I have shot.

Continue reading

powering a nikon d40 from an ac outlet

I have been shooting a lot of time lapses lately. The biggest problem with that is battery life. I have a very ghetto hack to power the camera from a cell phone charger, but I am looking for a more permanent solution. I found a fotodiox battery grip on amazon that has an internal battery, and is able to charge from the wall. Getting the right answers out of the vendor has proved to be difficult, so I’m afraid that I may just have to buy it and try it. Does anyone out there in internet-land have this already? And can anyone tell me if it will run from ac power? I am looking at multiple day long shoots, so changing batteries (and bumping the camera each time) just isn’t an option.


Here’s the link to the grip – Any opinions?