Happy Belated Holidays, and I hope the New Year is off to a good start for everyone. It's been a while since my last post, but I've had a lot of little projects in the works, and now they will start trickling in to the blog.
Today I want to continue discussing time lapse photography. To be honest, I'm still a bit mystified by time lapse, and based on some of the experts at Timescapes.org, it's no wonder. Although there is a lot which can be learned about shooting time lapse, getting that beautiful sequence relies, in large on luck. The members of the Timescapes.org forum have some great information up, but I've decided to continue shooting more tests with my T2I.
I've been comparing the different automatic modes on the camera, to figure out their best applications. Below is a video comparing the Av mode with the Tv mode. Neither of these clips have any color correction or de-blinking applied, they are straight out of the camera.
Av Mode: So Av mode is the cameras aperture priority mode. You set the desired aperture, and the camera automatically adjusts all other settings like shutter speed. The down side to using Av mode is it can make for an inconsistent time lapse. Look at the first clip, there are some sections where the lights on the cars are nice and streaked (there was less light in the shot so a lower shutter speed was used) and some shots where you can make out distinct details on the cars (there was a lot of light in the shot, so a faster shutter speed was used). The advantage to Av mode is it's ability to define your depth of field. If you were to shoot a time lapse of the sky, this is less of an issue since your lens will be focused to infinity, but if you have objects in the foreground and background, you will want to lock your aperture, otherwise you will see the focus change from shot to shot.
Tv Mode: Tv mode allows you to set the shutter speed, and automatically adjust the other elements, such as aperture to properly expose each shot. The plus to Tv mode is it allows you to have consist ant motion capture from shot to shot. Look at the second clip, the cars passing by the church all have that beautiful streaked look, except for the ones which got stuck at the light. Tv mode in my mind captures the essence of time lapse by allowing you to control how motion will be perceived in your final video. The down side to Tv mode is the automatic changing of aperture. If your lens isn't set to infinite, you will see the focus and depth of field shift between shots, which is really annoying. However, I've had no complaints shooting extremely wide shots, or sky shots in Tv mode.
Comparison and Other Thoughts: In comparing the two different modes in the above video, the blinking seems much more apparent in when using Av Mode. Although it's possible that nights conditions contributed to the blinking, the two streets had similar lighting and traffic flow. Although you can still notice the blinking in the street lights in the Tv mode clip, it's much more subtle.
Tv mode has become one of my favorite auto settings when shooting at an infinite focus point. Av mode would be useful if I were keeping one particular object in focus through out a time lapse, but I'm just not crazy about the change in motion captures. I find it distracting to see images go from streaky to clearly defined. However, which mode you use will depend on the effect your looking for and the circumstances under which your shooting.