I have been experimenting more with twin trail cameras for the otter videos. The cameras are still in the culvert as this is the most reliable place to see the otters, although usually in the middle of the night. The otters are well used to the cameras which are clamped on the downstream end of the pipe. The cameras are fairly close together and the otters squeeze between them.
Then they shimmy up the ramp over the sluice gate. The cameras haven't picked them up coming the other way recently.
The left hand camera is now fitted with an extra +0.5 dioptre lens and is in focus for more or less the length of the pipe (5m). The right hand camera has the standard lens and focuses beyond about 3-4m. Both these are low glow cameras working at a wavelength of 850nm but the left camera seems to respond better to the double illumination, even though it is the older of the two. The newer camera struggles to get enough infrared light at distance so here I have cropped it and pushed the exposure as much as I can in iMovie. There is obviously an imbalance in exposure and image quality but it does provide continuity.
The second time I tried was better. The otters were moving at 5.30 this morning so there was some natural light. As the cameras were recording simultaneously I also balanced it better by using the audio track from the first camera for the whole sequence. (I am learning but there is a lot to learn.) The mark on the pup's back is just a leaf.
The culvert is 75cm in diameter and the visible length of the ramp is 78cm so it is possible estimate the size of the otters. I think the mother is about 70cm nose to tail and the pup is about 60cm. The pup seems more agile every week.
No comments:
Post a Comment