Video evidence: why we need a wide field of view.

This is just a quick blog article prompted by my seeing a post from a twitter user who had a close pass video knocked back after submitting it to one of the police online submission programmes. The video is here. I’ve started it from just before the overtake, but you can view the full video:

The video showed what, to me, was clearly a very close and dangerous pass and ought to have been pursued. However, I can see why the police might have felt the evidence was not sufficient to establish that an offence had been committed beyond reasonable doubt in a court of law. Whilst there are lots of cues in the video to show that the passing vehicle was far too close, there is nothing in the frame of the video to show the position of the bicycle. The viewer is required to judge the passing distance from the perspective of the van and from an estimate of the bicycle’s position, which leaves some room for doubt; the distance is inferred by the viewer rather than shown directly by the video. A further element of doubt enters into this because we know nothing about the field of view of the camera, so there is nothing there to show that the van is level with the cyclist when it comes into the frame.

Here is an example of a close pass that was accepted and pursued by Greater Manchester Police. In the following, I have cropped the video so that the frame is 720p, which is the same frame size as the one above (although the resolution is 1080p), rather than the 960p that I usually use:

Just like the Addison Lee one above, this is clearly a close pass, but it has all of the same problems due to the absence of any part of the bicycle within the frame. My helmet camera has a very wide field of view of 170 degrees, so it is looking almost sideways at the edges of the frame. This means that anything at the edge is still alongside me, but it is difficult to understand that just by looking at the video here.

In my own submissions to the police, I use a 960p format, which has the advantage that I can get the handlebars and front wheel of the bicycle in the frame whilst still including the road in front, with the result that the same video looks like this:

Here, there is absolutely no doubt that this was a very close pass. Based on the reference images that I showed in my earlier article on the quality of video evidence, I can say with confidence that this car was 0.5 metres away from me.

A counter example (Added 20/11/2022)

The above example shows a case where there can be doubt introduced about a real close pass if the field of view is too narrow. Here is an example that shows why the police might be reluctant to take forward a case.

This video, taken with a narrow field of view, certainly looks like a close pass, and looks very similar to the first version of the video in the previous example:

However, when we widen the field of view and include the handlebars of the bicycle in the shot, we can see that there is absolutely no problem:

I think it is important, if we are to help the police to help us, that we provide the best evidence possible, and that means paying attention to the field of view of our cameras and what we get into the frame to remove that element of “reasonable doubt”.

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