Time lapse

Depending on how cold it is I may get changed into my down suit first as there is nothing worse than trying to get your kit set up while you are shivering with the cold. The next thing to do is to get your tripods out and cameras set up with the lenses that you are going to use and put the dew heaters on. My advice regarding these is that you never know when the lenses may dew up so have the heaters on all the time because once they’ve dewed up it’s too late and you’ve lost valuable imaging time. When focusing I have already determined on my lenses where the infinity focus is which you can do during daytime hours by focusing on a very distant object, to stop the focus ring from moving during the night when I move the cameras between clips I use a bit of gaffer tape on the focus ring.

Deciding on the exposure length is going to depend on the focal length of the lens and I tend to follow the “500 rule” in that for a full frame camera like my Sony you divide 500 by the focal length of the lens and that gives you the maximum exposure time before you get star trailing so if I’m using the 12mm lens that’s 500/12 = 41.6 so I shoot at 40 seconds. For the 24mm lens it would be 20 seconds. If you are using a crop censor (APS-C) camera then you need to further divide this by the crop factor eg 1.6 so for an APS-C camera with a 12mm lens it would be 500/12/1.6 = 26 seconds. Once you have decided on the exposure time the shutter speed should be set to “bulb” as the intervalometer will be controlling the exposure time and number of exposures.

Everything on the camera and lens needs to be set to manual including focus, ISO, aperture, exposure, colour temperature, etc. Any noise reduction should be switched off as well as exposure preview otherwise this will eat up the battery and cause unwanted light. Also, for the very best results you must shoot in RAW and not jpeg, this makes the processing much easier and you get better results. The colour temperature should be set for cloudy or daytime as this can be adjusted in processing.

The most important thing is to get as much signal as possible so always use the longest exposure that you can without getting star trailing and the widest aperture possible then adjust the ISO until the bulk of the histogram is in the middle or to the right of the screen, each camera will have its optimum ISO, with the Sony cameras I have shot as high as 25,600 ISO and got good results.

On the intervalometer you have settings marked Delay, Long, Intvl and N. The delay is how many seconds before the actual exposures start being taken after starting the intervalometer, Long is the exposure length, Intvl is the time in between each exposure and N is the number of exposures. The Delay doesn’t really matter but I routinely set it to 5 seconds, I then set the exposure time taking regard to the 500 rule, I usually set the interval to about 5 seconds, this allows the image to be transferred to the memory card before starting the next exposure, the N setting can be a bit confusing as most intervalometers only go up to 99 and more often than not you will need much more than this so set it to “0” and the intervalometer will carry on taking pictures until you switch it off. Once you’ve done this you can sit back and have a coffee and do a crossword, read a book or watch a movie on your tablet/phone, etc while the camera is doing it’s work.

Regarding how many exposures to take you want to aim for about 375-500 exposures per clip, this will give you a 15-20 second end video clip playing at 25 images per second. If you are doing a “Holy Grail” time lapse which can run for up to 16 hours and you end up with a clip well over 1.5 minutes you may need up to 2,000 images (more on this later).

Each clip is going to take in excess of 3 hours+ to shoot, depending on what time of the night it is and how tired I am I may have a sleep on my bed roll, setting the alarm on my phone just before each clip is due to end. It is then a case of setting up the cameras somewhere else utilising areas of interest to add impact to your clip, puddles and reservoirs are great for this as when the water is calm (can be all the time as in a puddle or periodically with a reservoir) you get get some nice reflections of the stars in the water. If you are using a lens ball you focus on the image in the lens ball which throws the background out of focus which is very effective, also the image in the lens ball is upside down and reversed so it moves opposite to the sky, again it creates an interesting effect.