Best lenses for astrophotography with D7000

Hello all,

 

I am becoming increasing interested in astrophotography. Specifically timelapses, star trails and nightime landscape shots. With that in

mind I presume I'm after a wide prime. Of course I will be looking to use this lens for daytime landscape as well as general low light shots.

I currently have the 16-85 and 70-300 used with a D7000 and am looking to grow my lens collection with this function in mind.

 

Any thoughts? And please don't limit on price I am aware of the costs and have allocated myself a budget (although I am just an enthusiast)

<p>Typically, people use telescopes and adapt them to cameras, instead of regular lenses.</p>

<p>I know nothing about astrophotography but I have the manual focus Voigtlander Color Skopar f/3.5 20mm lens. This lens has a cpu to meter with the D7000. It has an infinity stop for your astrophotography and you can set your hyperfocal distance for your landscape shots.<br>

This is a very sharp lens and I believe the best current wide angle prime for DX (you can use it on FX too).</p>

<p>I guess the OP wants wide-sky astrophotography, rather than imaging a telescope's view.</p>

<p>With a DX camera, to get a truely wide FOV, you'll be into the very low teens in terms of focal length. Ideally, a lens with a 'low' aperture will let more light in.....however, as you're into star-trails, that's not such a problem as it is in imaging deep-space. </p>

<p>Nikon's 10-24mm f3.5-4.5, or 12-24mm f4 will give the angle OK.... Equally, perhaps Sigma's 10-20mm f3.5 will be OK? Maybe try Nikon's 14mm f2.8? Other's will know better. </p>

<p> </p>

<blockquote>

<p><em>"Specifically timelapses, star trails and nightime landscape shots. With that in mind I presume I'm after a wide prime."</em></p>

</blockquote>

<p>Adam, have you attempted any shots with your existing lenses? I suggest giving it a try if you haven't; it'll give you a good idea on where limitations lie and which direction to go in order to narrow your choices. <br>

<br>

Conversely, maybe you can point to an image you'd like to replicate. <br>

<br>

Of course better lenses will almost certainly yield better results so knowing your expectations will help in making a selection with the best price/performance ratio for your application. </p>

<p>Best lens? Probably that new Sigma 18-35mm f1.8. I'm looking at it very hard right now for exactly that. I would skip the single focal lenses as none will be wide enough on a D7000.</p>

<p>Kent in SD</p>

<p>The key to deep sky photography is the mount. You need to be able to track the stars with some high degree of accuracy. You will need a german equatorial mount and learn how to do a polar alignment. You can piggy back your camera on a telescope provided it has such a mount. The higher the magnification (the longer the lens) the greater the need for tracking accuracy. </p>

<p>Start here:<br>

<a href="http://starizona.com/acb/ccd/ccd.aspx">http://starizona.com/acb/ccd/ccd.aspx</a></p>

 

<blockquote>Voigtlander Color Skopar f/3.5 20mm lens. This lens has a cpu to meter with the D7000. It has an infinity stop for your astrophotography and you can set your hyperfocal distance for your landscape shots</blockquote>

<p>Thank you for this, very interesting. I'll look into it.</p>

<blockquote>

<p>I guess the OP wants wide-sky astrophotography, rather than imaging a telescope's view.<br /></p>

</blockquote>

<p>Exactly right</p>

<blockquote>

<p>Adam, have you attempted any shots with your existing lenses?<br /></p>

</blockquote>

<p>Yes I have and with differing success rates. I also found a very peculiar trait with the 16-85 lens. When focusing say on the moon, distant stars of the horizon, the distance indicator is WAY off infinity. In all cases it indicates a focus around the 1.5m range, Trying to focus on infinity yielded totally out-of-focus results. I have tested this day and night and in hot and cold conditions all with the same result. I have also found others on the net with similar problems with this lens. Although when I do get the focus right the focus is sharp although a quite noisy due to it not being a particularly fast lens. </p>

<blockquote>

<p>Conversely, maybe you can point to an image you'd like to replicate.<br /></p>

</blockquote>

<p>More videos than images but here are some great examples of the kind of work I would like to shoot for, eventually. <br>

http://vimeo.com/57130400<br>

http://vimeo.com/24456787<br>

<br>

I should note that I will most probably be using a eMotimo or a Syrp Genie with this to get some motion. Rick, with this in mind tracking the stars will have to come a little later I think..</p>

<blockquote>

<p><em>"I have also found others on the net with similar problems with this lens. Although when I do get the focus right the focus is sharp although a quite noisy due to it not being a particularly fast lens."</em></p>

</blockquote>

<p>Manual focus will indeed be more challenging in actual field use with the 18-65 lens, but if you can achieve perfect focus just once or twice, it wouldn't be difficult to mark it's position for future reference - this might be useful in the meantime, before you get a better lens, just to allow experimentation with other parameters. <br>

<br>

I'm sure you're aware that noise is a function of ISO setting, aperture setting and exposure time, which is in turn determined by what you want to achieve at a technical and aesthetic level. There is an optimal combination for every desired goal and a "fast" lens (with 1 stop advantage) will often only make a marginal difference. <br>

<br>

For example, capturing a picture of a patch of night sky, and assuming good seeing conditions and low light pollution, opening up the lens will give you more and brighter stars, but all else being equal the perceived noise level will remain the same. This is because the stars won't occupy enough image area to "mask" the dark skies where noise will be more prominent. <br>

<br>

The first timelapse video you pointed to appears to use a combination of techniques including local lighting with its brightness matched to (long) exposure time to achieve near perfect blend of local trees and rocks with the sky and stars. There are very little black areas with no light so masking is achieved to optimize signal-to-noise ratio. </p>

Thanks Michael,

 

Yes I thought of marking the lens too but if you turn the focus ring to its extreme, left or right. One it has reached infinity

(or just beyond) it just keeps on turning meaning unless you are carful this technique won't work on this lens. It really is an

apparently idiotic feature as it essentially renders the focus distance indicator useless. Or even worse actually gives you

totally wrong information. I have wasted at least one precious night in Patagonia finding this out. However I may be

missing something.

 

Yes I am aware if the influences on noise and I am quite sure I haven't mastered them as we'll as I could. Certainly more

experimentation is needed on my part. However I live in Dubai where stars are rare meaning when I do get to see them I

have traveled far (Patagonia) to see them and losing nights through trial and error is costly and frustrating.

 

So I'm just trying to give myself a head start with at least an ideal lens fit for purpose.

<p>Being both a photographer and having an interest in astronomy, based on my experiences I'm going to be a little controversial and say I don't think it's worth spending a lot of money on a lens ONLY (or mainly) for star trails.<br>

There's only so many star trails you can do without getting bored of them, and I think you'll pretty quickly want to move on to more specific astrophotography, for which as stated above you've got to have a telescope with motor drive and either a camera adapter or CCD.<br>

If you want the lens anyway for landscapes, then choose one for the landscape use - it will be perfectly good enough for star trails too.</p>

<p>Bear in mind that the visibility of a star (which is going to appear as a point no matter how much you magnify it with anything you're likely to attach to a camera) depends on the absolute aperture of a lens, not the relative aperture. With a shorter lens at the same relative aperture (f-stop), stars will appear dimmer relative to any sky glow. In other words, don't go too short. (I've taken whole sky shots with a fish-eye, and you get galaxies before most individual stars show up.) Don't be surprised if you can see more stars at the long end of your 70-300 than with, say, a 24mm f/1.4. Most telescopes have pretty slow apertures by photographic standards, but they show up stars because the absolute aperture can be enormous. If you really want star trails, a longer lens pointing uphill at something distant may work better than something short and nearby.<br />

<br />

Deep sky photography is another matter. I've had some success with a 200 f/2 (full frame) and trying to remove star trails is post-processing - I'll be in Bali in a couple of weeks and I have vague designs on the Carina nebula - but as Rick says, it's not really the tool for the job, especially since a fast telephoto is a lot more expensive than a big refractor. But I'm assuming this isn't the aim if we <i>want</i> star trails.</p>

<p>Chris, Andrew</p>

<p>I should probably point out that star trails are at the bottom of my list of uses for a possible new lens. I agree that if I were after that alone the lenses I already have would probably suffice.</p>

<p>I am specifically after time-lapses of the the night sky capturing the movement of the stars (Earth) whilst including some native scenery that unquestionably places you within a given location. Baobab trees, glacier, mountain, ice etc in the foreground. As raised earlier this will also be aided by gentle lighting of the said foreground. <br>

Andrew, some really good and new points to me here. Could you please explain what you mean by "absolute aperture"? Is this a max aperture? So an interesting approach would be to use the long end of the 70-300 capturing a scene off in the distance. I presume this would give some exaggerated or flattened perspective to the shots too. <br>

I guess I am looking for guidance on which lens work best with the D7000, which would be suited best for my purpose and then some finer points on coma etc. Though a lot of useful info has already been laid out and much appreciated.</p>

<p>Adam, please let us know how your project turns out and what equipment you will have used. I am also interested in doing the same, and I have a D7000 as well. A few reasons I haven't tried it myself yet: 1) Every time I have planned on doing so, the sky clouds up and/or 2) trying to find a place where I feel relatively safe while spending a few hours there doing a time-lapse.<br>

I had planned on using my Nikon 10-24 lens.</p>

<p>I actually have already done a bunch of timelapses with my D7000 and 16-85. Here are two, obviously not astrolapses but illustrate changing from bright to low light. I used After Effects and GbDeflicker to compose and <em>attempt</em> and remove flicker.</p>

<p>I will upload the astrolapses I have done in both Patagonia and Oman. Probably the two safest places in the world where you only need look over your shoulder for Pumas or Arabian Leopards.</p>

<p>Both in Dubai<br>

<a href="https://vimeo.com/56518772">https://vimeo.com/56518772</a><br>

<a href="https://vimeo.com/54800610">https://vimeo.com/54800610</a></p>

<p>Hi Adam. "Absolute aperture" is my abuse of terminology - there's probably an official way of saying it, but...<br />

<br />

I consider the f-stop of a lens to be the "relative aperture": if the lens were simple, it would describe the size of the entrance aperture in relation to the focal length of the lens. I use "absolute aperture" to describe the (virtual) diameter of the entrance aperture in absolute terms.<br />

<br />

For a longer lens, the entrance aperture is usually a close approximation to the size of the front lens element. For, say, a 300mm lens at f/5.6 (with your zoom), the theoretical entrance aperture is about 300mm/5.6 = 54mm (ish). Canon's 70-300 (at least some of them) takes a 58mm filter, which is a pretty good approximation. Nikon's version has a somewhat larger thread, but it's stepped back from the lens quite a bit.<br />

<br />

Similarly, the front element of a 200 f/2 is very close to 100mm in diameter; Sigma's 120-300mm f/2.8 takes a 105mm filter thread (300/2.8 is about 107, but all numbers are a bit approximate). A 50mm f/1.8 has a front element about 28mm across, though it's buried a long way inside the lens, and it takes a much larger filter.<br />

<br />

For shorter lenses, especially retrofocal designs with good coverage, this heuristic doesn't work - effectively, not all the light hitting the front of a lens gets to the sensor. That's why a 14mm f/2.8 ought to be able to make do with a lens that's only 5mm across (and, in a compact camera, this would be the case), but the Nikkor 14-24 is enormous. Still, <i>virtual</i> aperture size follows the formula.<br />

<br />

For the sake of simple numbers, let's look at a 50mm f/2 lens and a 100mm f/2 lens - entrance apertures 25mm and 50mm respectively (when used wide open). For most distant subjects, while four times as much light hits the 100mm lens (twice the width and height), the image is also spread out by a factor of four (the image is twice the width and height), so image brightness is controlled by <i>relative</i> f-stop. This is the same reason that a teleconverter reduces your relative aperture - it spreads out the light while magnifying the middle of the image.<br />

<br />

With a star, the 100mm lens still has four times as much light hitting the front element, but the point of light hitting the sensor is still a point of light - it's too small to spread out. So an orange sky lit by street lights has its intensity controlled by the <i>relative</i> aperture of the lens (f-stop), but the brightness of a star is controlled by the <i>absolute</i> aperture of the lens (f-stop x focal length). Don't be surprised to find stars brighter at 300mm f/5.6 than at 70mm f/3.5 for this reason, even if the sky glow is dimmer.<br />

<br />

Of course, you may want the foreground to be brighter as well if you want landscapes, but there's always flash//floodlights. :-)<br />

<br />

In terms of coma, KR claims that the 85 f/1.4 AF-S is well corrected for coma. Otherwise, smaller (relative) apertures help with most lens aberrations - for example, the 300 f/4 is extremely well-corrected, despite being quite a simple design in comparison with, say, a 200 f/2. The difficulty with getting the foreground in a longer shot - apart from that you don't get much sky, so you might have to aim at a single constellation - is that it's hard to include much foreground along with the sky without shooting horizontally - and shooting horizontally is the way to get a lot of atmosphere between you and the sky. This is, at least where I live, a bad thing. Hence, depending where you are, getting low and shooting up at the subject might help - if you're somewhere with more geography than the flatter regions of south-east England, where I live. But it sounds as though you'll be going to places that might have less light and atmospheric pollution than I have to suffer.<br />

<br />

Good luck, and I hope that helps!</p>

<p>Hi Andrew,<br>

Sorry for the very late response but I just wanted to let you know that I read, re-read and then read again you message above. I wanted to thank you for taking the time to give such an eloquent explanation (even with a bit of your own jargon thrown in) to my question.<br>

The information was invaluable and I very much appreciate it. <br>

Thanks again,<br>

Adam</p>

<p>Adam, I found a very informative discussion at http://www.lonelyspeck.com/lenses-for-milky-way-photography/.<br>

Dunno why PN site won't let me post an actual link rather than a URL. Oh well...</p>

 

<p>Excellent link, thank you Bill.<br>

Much appreciated.</p>