Friday, 4 October 2013

What fisheye for fireworks video?

When recording fireworks from a moderate distance, it pays to have a wide lens to capture the whole view. Generally, fisheye lenses tend to be the widest afforable lenses. In this article, I compare two fisheye lenses for video recording fireworks from a close distance.

The camera systems I used were:



Left: Sony NEX-3N with Yasuhara Madoka 180
Right: Panasonic GH3 with Samyang/Rokinon 7.5mm f/3.5



Both lenses are 180° fisheyes. However, they are still fundamentally different. The Yasuhara Madoka 180 is a circular fisheye, while the Samyang/Rokinon 7.5mm f/3.5 is a full frame fisheye. The difference is best exlained by the illustration below:



Here are the two videos, and I'll explain how they were made below.

Sony NEX-3N with Yasuhara Madoka 180




The Sony NEX-3N does not have any means of manual control for video recording. So I just set the ISO to the max (3200), set the lens to f/4 (the largest available), and focused on infinity. Then I pressed the red video button to start the recording. And that is all I can do.

The camera was recording video at 1080p, 25fps. The camera sets the exposure automatically, and dynamically during the video. Mostly, the shutter speed used was 1/13s, meaning that every second frame is identical.

Already at the scene, I saw that the video recorded with the Sony NEX-3N with Yasuhara Madoka 180 should have been angled more upwards, to capture more of the sky. However, the tripod head I had brought along didn't support this. I guess this underlines the importance of preparing before doing this type of recording.

The Yasuhara Madoka 180 is, as far as I know, the only circular fisheye made especially for a mirrorless camera. Yasuhara have announced that they plan to release it also with a Micro Four Thirds mount, however, I don't believe they will. The reason is simple: The lens has a too large image circle, covering more than the Four Thirds sensor surface. It makes no sense to release a circular fisheye lens which produces a too large image circle, it means that the output is not 180° all around, and the images just look stupid.

For video recording on the Sony NEX-3N, the image circle is slightly clipped on the top and bottom, since the video frame (16:9) is smaller than the APS-C sensor, which has a 3:2 aspect ratio. When taking still images, you still get a circle covering the whole frame, here is an example:



Panasonic GH3 with Samyang/Rokinon 7.5mm f/3.5


Here is the same video recorded using the GH3 and the Samyang/Rokinon 7.5mm f/3.5:



The Panasonic GH3, unlike the Sony camera, has a number of manual video controls. I used the Creative Movie mode, identifiable with the film camera icon. Using the Manual exposure control (M), I set the shutter speed to 1/25s, and the ISO to 6400, the maximum for video recording. I used 25fps, 1080p video mode. The Samyang/Rokinon lens was set to f/3.5, and I focused on infinity.


For Panasonic cameras, this type of manual exposure control is available with the GH-series of cameras, in addition to the more reasonably priced Panasonic G6.

The video stream done with the Panasonic GH3 with Samyang/Rokinon 7.5mm f/3.5 doesn't cover all the fireworks. The big bombs burst over the image frame, hence, I should probably have set up the camera slightly further back.

Conclusion


Even if these modern cameras can record video at amazingly high ISO (3200 and 6400), its still just barely enough for recording fireworks videos using fisheye lenses with moderate maximum apertures.

In previous fireworks video, I speeded up the video stream to twice the speed, to get more action, and make the video more interesting. This time, I thought the fireworks were quite good even at normal speed, so I left it like that.




2 comments:

  1. Well, well, the Nex produced nicer video! Mostly because of the misadventurous camera positioning. the GH3 was set missing too great part of the scene... Besides, youtube compress the strema so heavily that differences melted away...

    ReplyDelete
    Replies
    1. Yes, the circular fisheye comes handy when being very close to the fireworks. Most of the time, one wouldn't be allowed to go this close.

      I guess most people would tilt the camera upwards to capture more of the fireworks, but I like seeing the launch as well.

      The best compromise is probably to move further away.

      Delete