i had many requests to explain the technical side of my starship picture, and i decided that, instead of responding individually, i'd write up a DIY. now, i'm no photo expert, and this is just how i did it. if you have a better idea or information you'd like to contribute, or if you think i've made a mistake somewhere, please let me know. i'm not here to teach -- i'm here to learn!
this method does not take one huge long exposure -- it uses a bunch of 30-second exposures which are subsequently stacked to form a final composite image.
this post assumes you know how to change camera settings (or have your manual to read up on how). it also assumes you know basic photoshop skills and perhaps something about layers and layer masks.
so, on with the show...
- a camera capable of shooting with manual settings. i used a Canon EOS 40D.
- a wide-angle lens, to taste. i used a Canon EF-S 10-22mm f/3.5-4.5 USM.
- a tripod, beanbag or other object capable of keeping a camera motionless for long periods of time. i lurve my manfrotto.
- a remote release that locks in the shoot position. i'm not fond of wireless... i use a Canon Remote Switch RS-80N3.
- a very, very dark sky, preferably on a moonless night.
- something interesting in the environment -- a building, a landmark -- to frame the sky.
- creature comforts, a blanket, flashlight, ipod, snacks, drinks, company (i had ever-patient and supportive mr.G), bug spray or warm clothing, depending on the season.
before the shoot
- get there before dark and find a good location.
- get comfortable.
- set up your gear -- mount your camera on your tripod, hook up your cable release, compose and focus your shot.
- when composing, find a way to make the sky look interesting. imagine what your trails will look like. if you're facing north, you'll most probably get a shot of the north star and cocentric circles. southern skies have broad arcs.
- focus manually just a breath before infinity. try to find a distant point of light or use the horizon, and focus on that. hint: i find it helpful to focus with live view at a magnification of 10X.
- without worrying about camera settings (you can set to auto) take a few test shots to decide on the best composition.
maximize light and minimize time between shots..
- set your camera to JPG -- avoid RAW. normally, i shoot in RAW but i don't want the camera to spend a lot of time saving a large file between shots.
- turn off your in-camera noise correction.
- use as fast a memory card as you have.
- turn off image preview. you won't need to be chimping between shots anyway.
- your camera should be on manual.
- you need a large aperture to get as much starlight in your image as possible -- i opened at my widest value of f/3.5.
- dial up your ISO to increase sensitivity, but not too much. this depends on your camera. to avoid noise, i set my camera to 400 -- beyond that, it's way too noisy for my taste.
- set your shutter speed to 30 seconds.
- white balance set to daylight (this, courtesy of anthony ayiomamitis' comment).
- set your drive mode to continuous shooting.
- if your camera strap has an eyepiece cover, place it on your viewfinder.
- if your lens has image stabilization, turn it off.
- as soon as you think it's dark enough, press and lock your cable release. your camera will start continuously shooting 30-second exposures. for how long? as long as you have patience for, as long as your battery lasts, as long as you have room in your memory card.
- stay away from your tripod. i moved it slightly midway, causing a shift in the arcs.
- relax and enjoy your surroundings. when you've had enough (i lasted 1hr-50mins) unlock your cable release.
- before or after the shoot, take an extra-long exposure (on bulb) of your composition to use as an extra layer for the surroundings in photoshop.
- if there's no hope of getting any detail from your surroundings that way, you have two options: either do a long exposure shot with your flashlight to light it up a bit or decide that any objects will just have to be dark silhouettes. in my case, the top part of the ship was lit slightly from some buildings over a hill behind me. i was lucky.
- pack everything up, check that you're not leaving something behind with the flashlight.
image stacking and post processing
- copy all your shots onto your computer. put the full sequence of shots into one folder, except for the extra-long exposures for your environment.
- download this star trails photoshop action.
- start photoshop and load the star trails file onto your actions palette. i usually just drag-n-drop the ATN file onto photoshop which automatically loads it.
- create a new, black image with the same pixel dimensions as your JPGs.
- go to file > automate > batch. select the source directory, none for output directory and hit OK. wait until the action processes all the images. when it's finished, you'll have a flat image with your star trails!
- layer on your extra-long exposure and use a layer mask to hide the sky so that the star trails will show up from the layer below. flatten the image.
- go ahead with any other post-processing you might like, to taste.
if you do experiment with this, i'd love to see it... add a link below on the comments.
happy startrails to you!
©2011 helen sotiriadis