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Archive 2013 · New to Astrophotography
  
 
ITR010342
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p.1 #1 · p.1 #1 · New to Astrophotography


So, I have been attempting to get some interesting shots of the night sky with my 1DMarkIV and 300mm f2.8 IS... So far, I have not been able to get anything worth anything. I feel like such an amateur. I have seen a lot of shots of the Andromeda galaxy and others that are single shot without a tracker and with a 300mm.

My area has some light pollution, though I have been getting out away from all the light on some clear nights. I just can't seem to the settings right and just fall flat with results.

Anyone have a step-by-step or simpleton guide to getting started? I have had not much luck with any search... help an astro newbie out! Thanks!



Nov 04, 2013 at 06:43 PM
camboman
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p.1 #2 · p.1 #2 · New to Astrophotography


You'll need a tracking device with a 300mm lens.

I use a 21mm lens and need 25 seconds at f2.8 and ISO 3200 on a dark night. You'll get much more sky movement with your 300mm. You'll need to shoot at around 2 seconds or so for a sharp image at f 2.8, not doable even at high ISO.



Nov 04, 2013 at 06:51 PM
dgdg
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p.1 #3 · p.1 #3 · New to Astrophotography


Yup, you'll need a tracker with the 300mm lens. Don't bother with it yet unless you want star trails, which are very nice, but sounds like you want pin point stars.

So,
I'd start with wide angle stuff first. Use something like the 14mm samyang, esp with your crop factor camera body. Then I agree, crank up the iso to about 3200, wide open aperture, focus with live view on a bright star, re-compose, and use cable release for approx 25 sec exposure. Adjust your iso (primarily) so that the peak of your histogram is at about 1/3 the way from the far left. That's it. You can experiment with your 50mm f1.4, but your exposure times will need to be quite a bit shorter to eliminate star trails, if unwanted. Make sure you don't develop dew on your lens or images will go fuzzy. Processing is as important as taking a good image.

Then post your image here and get more feedback.
Then decide if you want to do imaging with your 300mm (using a tracker)



Nov 04, 2013 at 06:57 PM
wuxiekeji
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p.1 #4 · p.1 #4 · New to Astrophotography


Trackers are one way. Another way is to take a series of short exposures, hand-tracking the stars between stars with a tripod or home-made "barn door" tracker (look it up), fix the alignment to pixel precision in post, and add the images all up, utilising appropriate denoising algorithms in the process. It's tedious with 300mm though, you'll need to stack hundreds of shorter exposures to make it work, but it becomes significantly easier (but still not "easy") with 180mm or so. Start with a wider angle lens such as fast 35mm or 50mm prime for your first astophotography shots and work your way up from there as you succeed in building your technique. If you want to go with stacking rather than a motorized tracker, try stacking 3-4 images using a 50mm first and establish a post-processing workflow before you try to stack 100 images with a 300mm. If you are fluent with signal processing you can write code in MATLAB, Octave, or similar tools to make the alignment process automatic.

Second, check that your focus is accurate. I highly suggest using manual focus in 5X LiveView with a relatively bright star to set your focus. Autofocus is unlikely to work well, and with your 300/2.8 even a slight bit off infinity and you'll get essentially nothing in the picture. This is where manual focus lenses with hard infinity stops are useful because you can confirm their calibration in the daytime with some faraway buildings, and then just slap the lens to infinity (or wherever you measured infinity to be) and shoot at night (barring temperature changes to focus which you should be aware of if it's significantly colder at night where you are). As a bonus, good manual focus lenses suitable for astrophotography come cheap.

Third, make sure you're in a good place with as dead zero light pollution as you can get. Camping in the middle of national parks and deserts is usually a good place to be. If you live near an ocean you can also try going to a beach and shooting into the ocean where light pollution will be minimal. The Andromeda galaxy is visible to the naked eye (it looks like a bit of an oblong, fuzzy star), so if you're not seeing it with your eye, your camera isn't going to see it either. It's also not very easy to shoot good pictures of Andromeda when even the moon is out.

Also, make sure you're shooting RAW. Always. In-camera noise reduction doesn't work well for stars, and you'll want the full dynamic range to work with in post-processing whether you're doing stacking or not. If you stack images, make sure your workflow supports 16 bits or (better) floating-point images and do not use any lossy compression formats until you have your final piece.

Finally, astrophotography is also highly affected by atmospheric conditions and turbulence. You'll have to try many times on different days. It takes a lot of patience but is rewarding. Good luck with your new hobby!



Nov 06, 2013 at 11:26 PM
Yukonica
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p.1 #5 · p.1 #5 · New to Astrophotography


Yeah, what wuxiekeji said.
(Some of which I understand.)

Very pertinent advice…. all of it.



Nov 15, 2013 at 03:56 AM





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