I have a Canon EOS 1200D/Rebel T5. I'm an amateur phtographer and still learning. After reading a lot about astrophotography, I tried my hand at it. I took a trip to a relatively dark place, set up on a tripod, and started taking shots using my phone connected to the USB port as a remote release/intervalometer. I took 100 shots at different places, under different conditions. Every single shot, no matter whether the stars are completely in focus or not, showed a sort of streaking in random directions (not star trailing. I used the 600 rule). Here are some examples: https://drive.google.com/open?id=0B802HQPuk5MlRTJJZEJfM2Z3REU

I have a suspicion that this shaking is being caused by the camera shutter itself. I've tried searching online for others with the same problem, but my Google-fu hasn't helped so far. Is this some kind of issue with the 1200D or is it just my camera?

P.S. Note that since I have low reputation, I can't post more than 2 links. I'll make a Google Drive folder containing a few more examples if anyone wants, and I've edited out the links in the question itself.

  • Are you using the shutter delay function? (The shutter will only release two seconds after the mirror flips up)? Note that I don't know if your model even offers this.
    – Aganju
    Oct 28 '16 at 14:55
  • @Aganju I used the 2-second delay timer sometimes, and the 10 second delay timer sometimes, but all the images have this distortion/shake. Oct 28 '16 at 15:05
  • 3
    Just some thoughts: How long were your exposures? How sturdy is your tripod, and did you weight it down? What sort of head does the tripod have? Did you allow your kit to cool down to ambient temperature? It can take a least 30 minutes.
    – Mick
    Oct 28 '16 at 15:24
  • 1
    What is the shutter time on those images? Also how was the camera set up (tripod, height, head type etc.). Also was it windy that night? My thinking is that the camera wasn't secure enough in the mounting. Also what was the tripod anchored to and does the lens have an IS/VR system? But we'll need more info to say for sure. Oct 28 '16 at 15:24
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    @salmonlawyer, there is a difference between 2-second-timer and 2-second-mirror-lockup. Basically the Mirror moves up and then the camera waits for the vibrations to end, before it takes the shot. Timer only means that the shot is taken in two seconds - without locking the mirror up - so you still have the vibrations, just two seconds later
    – Aganju
    Oct 28 '16 at 16:06

Just my opinion, but mirror slap and MLU issues don't tend to create as much motion as I'm seeing in your second shot. I'd suspect the issue to be more with your tripod or tripod technique. You may also want to check that you're not inadvertently tugging on the USB cable that's connecting your phone to your camera whenever you take an exposure.

A small, tippy four-segment tripod, like the Velbon I habitually use, sucks for longer exposure work, particularly in any kind of wind. I tend to use my Velbon for 360-pano work, because it's small, light, and portable and I'm generally shooting in daylight with fast shutter speeds or indoors without any wind. But when it comes to night-time shooting, I drag out my big heavy three-segment Manfrotto, which is far more stable, and has a ballhead that can actually lock securely and support the weight of my EF 400mm f/5.6 + 5dMkII without any bounce or drifting.

If you're using a telephoto lens that has a lens collar, use the collar. This will definitely help minimize "bouncing" of the lens/camera combination by putting the majority of the weight at the balance point.

If the lens has IS, make sure that if you turn it on, that the lens's IS version is compatible with tripod use (the first generation of IS Canon put in its lenses introduced more shake when used on a tripod).

With a tripod, the lower to the ground you want to go, the more stable the set-up usually is. Having the head extended, or the legs fully-extended may be introducing some instability. If it has a hook, add weight to the center column. If you can spread the legs out at a wider angle, consider doing that.

Also, when you calculated the 600 rule, did you include the crop factor?

Just me, but I'd say, first off, test your tripod technique indoors. If you're still getting blur/shake, then maybe it's time to look at the camera.

  • Thanks for the extensive answer. I'd noticed the issue at the very start of the shoot. I kept the camera on multiple flat surfaces such as rocks, all to get the same result. The tripod I have is cheap, sure, but it doesn't sway or shift when I lock it tight. So far, no shake when shooting indoors. I also made sure the USB cable had maximum slack. Besides, I was using the 18-55 lens, which doesn't add much weight. Also, I had tried some of your suggestions during the shoot. The tripod doesn't have a hook, but I had minimum extension, widest leg settings, etc., all to no avail. Oct 29 '16 at 5:51
  • I also forgot to add that I'd read that the 600 rule applies to APS-C sensors, while the 500 rule applies to full frame. Oct 29 '16 at 6:07
  • @salmonlawyer. To me, if it's fine indoors and bad outdoors with identical technique/settings, then it's probably a technique/environment issue and not the camera. Are you moving about or touching the camera during the exposure? Did you try using just the timer instead of the phone to trigger the shutter or a regular cable release/remote?
    – inkista
    Oct 29 '16 at 18:12
  • I can't tag inkista for some reason, but, I did think that might be the issue, so I put it in 10 second timer and released the shutter several times.One of the images in the link is from that set as well, though I'm not sure which, since most of the exposures are of the same spot of sky. I'm not sure if I did so in live view, now that I think of it. Could it be that just because I didn't put it live view, that this issue could be occurring?? Oct 30 '16 at 17:23
  • @salmonlawyer Doesn't seem likely. My guess is still that it's a tripod-stability issue. You're going to need to narrow down your testing, and keep better notes/records while you shoot in this debugging/learning phase. When you're testing indoors, is everything else identical to what you did while you were out night shooting? (e.g., iso/aperture/shutter speed, how you release the shutter, focal length, lens, etc?)
    – inkista
    Oct 30 '16 at 22:49

After a bit of experimentation (a couple of months after asking the question), I discovered that it was, indeed, the fault of the Canon lens. Basically, I have the older lenses with a weirdly buggy version of Image Stabilisation.

What happened is that the IS on these lenses keeps trying to correct for movement, even when there may be none. I tested it indoors by exposing for a long time in a semi-dark room and focusing on specular highlights on an object (reflections of light on a shiny surface). With IS enabled, I saw weird drift in the highlights. With IS off, there was no drift at all.

I successfully managed to take photos of the galactic center by disabling IS. They may not be great(focusing issues which can't be helped), but it was fun to take them anyway. I forgot to answer my question though. I hope anyone who is still following this question forgives me for this. Sorry!

  • 1
    You generally shouldn't use image stabilization when shooting on a tripod.
    – Eric S
    Jan 19 '18 at 16:45
  • @EricShain Thing is, it was always on by default, and I hadn't turned it off till that point. Still a camera newb here. Sorry... Jan 19 '18 at 16:49
  • Defaulting on is generally a good idea since most people shoot handheld.
    – Eric S
    Jan 19 '18 at 17:07

From the shape of the star trails in your photos, and given the fact that you have a relatively short exposure time, I am almost certain that the problem is caused by mirror shake. With longer exposures, the "trails" caused by mirror shake will be much less noticeable. However, with short exposures (and 12 seconds is a short exposure in astronomical terms), the period during which the camera is vibrating represents a larger percentage of the total exposure time, and any star "trails" caused by mirror shake will be more evident.

One way to overcome this problem is to set a much longer exposure time on the camera and control the exposure yourself by covering the lens with something suitable and then gently removing the cover and replacing it after the required exposure period while the mirror is up. You need to allow plenty of time for any vibrations to die down. Remember that the mirror movement will cause the whole set-up to vibrate.

Do not use the lens cap as the cover. You need something that will cover the front part of the lens and that you can leave sitting on the lens. A plastic container of some sort painted matt black on the inside would be ideal. You could possibly even use a dense black cloth. All you need is something that will keep light out and that you can gently remove and replace without disturbing the camera.

Let's say that you want to make 15-second exposure. Set your camera for 60 seconds (if you can). That will give you plenty of time to do what you need to do. Press the shutter release and immediately lift the cover off the lens but keep it covering the lens. Allow 15 seconds for any vibrations to die down and then remove the cover completely. After the required exposure time, introduce the cover again and wait for the shutter to close. If all goes well, you should have a vibration-free image.

  • 1
    The first example may be only mirror vibration, but the second example has a lot more than just mirror slap going on!
    – Michael C
    Oct 28 '16 at 17:03
  • Why go to the trouble of covering the lens? You can get a wired shutter release for about $5-10, set the camera to mirror lockup, and then wait up to 30 seconds between the time you lock up the mirror and the time you release the shutter.
    – Michael C
    Oct 28 '16 at 17:05
  • I had thought about a mis-aligned star tracker (or astronomical mounting), but the OP doesn't mention that at all. Also, he mentions the "600 rule", which implies a static mount.
    – Mick
    Oct 28 '16 at 17:07
  • @MichaelClark If a wired release is possible with the mirror locked up, then that is obviously the way to go.
    – Mick
    Oct 28 '16 at 17:08
  • @MichaelClark You may be right. The whole set-up may have been moved when the second exposure was taken. We really need to see more examples.
    – Mick
    Oct 28 '16 at 17:12

Stars are super distant: If an object’s distance is more than 3000 times its diameter, it appears as a point. A 10mm coin viewed from 30,000mm (30 meters / 100 feet) appears to the unaided eye as a point with no discernible dimension.

All stars thus appear as pinpoints of light. As starlight filters through earth’s atmosphere, it must pass through different densities of moving air currents. This action causes the star to appear to change its position. In other words, the light rays from a star are caused to zigzag. This is called scintillation. Scintillation plus camera vibrations and optical inaccuracies are the culprit.

  • Your explanation does not account for the fact that all the star trails are the same shape and size, and are aligned in the same direction. How can scintillation (which is a real but random phenomenon) cause this?
    – Mick
    Oct 28 '16 at 17:04
  • @ Mick -- Of course you are right! Just chalk this up to an old man’s rumblings. Oct 28 '16 at 19:18
  • Do the star trails look like coma (or some other lens distortion)?
    – Mick
    Oct 28 '16 at 19:23
  • Coma is a monochromatic aberration related to spherical aberration. Coma is independent of aperture and never occurs on axis, always in the field. The coma is actually a series rings much like Newton rings. However the rings are incomplete and only about 16% of the circle is seen. These partial circles blend together forming a hard central spot with a tail like a comet. I think this is not coma, just vibration during exposure. Oct 28 '16 at 19:47

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