Looking for a recommendation for a ultra-wide angle lens

[ChrisPBacon]

I’m looking for and would sincerely appreciate your recommendations for the best prime EF-mount ultra wide-angle lens for use on Canon EOS crop-sensor (7D) and full-frame cameras (specifically 6D, and 6D Mk. II) for astrophotography.

(While there are excellent zoom lenses available, the possible risk of chromatic aberration makes them impractical.  That said, I’m a relative novice to astrophotography and still have a great deal to learn — so if you use a zoom lense for astrophotography, please let me know of your experience.)

I’m imaging asterisms and the Milky Way which require relatively longer exposures but I wish to avoid having stars appear oblong in shape from too-long an exposure; to that end, I need the fastest glass possible to obtain as much detail a lens is capable of capturing — as well as the quality of the detail that is captured. Canon’s 14mm f/2.8L is a good lens, but is it the best quality glass (assuming that cost is not a factor) on the market?  It must be heresy to ask if other manufacturers produce a better lens, but I’m willing to consider all contenders as long as the lens is compatible with my Canon cameras: price is not a consideration.

As I disable autofocus and image stabilization in taking these types of photos, a manual focus (only) lens such as those made by Zeiss is perfectly acceptable.

I’m well aware that below f/2.8, price increases dramatically: while having an equatorial mount would allow for longer exposure times without star distortion, it would create problems for foreground terrain blurring and additional post-production labor, which I’d like to avoid if possible. My 6D is heavily modified for heat reduction and has had its IR filter removed so that light in wavelengths of 656.28 nm appear in photos, but the scale of these structures make use of a telescope impractical.  Light pollution poses another difficulty with increased exposure times, so high-quality fast glass is a better option for my purposes.

Any lens f/2.0 or below, in the range of 8-18mm, might be ideal.  I would appreciate anyone with experience with this lens type sharing their recommendation.

[Tronhard]

OK, I'm curious...

From what I have read so far you are very keen on astrophotography but new to it.  How much experience do you have?

You want super clean images of the stars - for what purpose?

You want to use a super wide angle lens with no distortions.

You are not prepared to use multiple shots and stitch them together - yet as far as I am aware, short of specialist devices like the Hubble (and maybe even that) NASA stitches their images together.

It seems to me that using an ultra wide-angle lens  you are:

1. going to get lots of lens errors simply by the fact the lens is super wide angle - it's squeezing a massive circular image into a very small rectangular sensor space

2. It's going to give you one image of a lot of very tiny dots, which for the pixel size will lead to all sorts of imaging issues as the dots will be smaller than the pixels, or will branch across pixels, and a pixel is either all on or all off.

3. The pixel density on one shot will never match that of a series of images stitched together, so you won't be able to bring up sections of the sky to examing them in detail.

My nephew is a keen astronomer and while he doesn't take images himself, he is surrounded by people who do so and take that seriously.  They do not go for one super wide-angle lens, they go for something much narrower and take multiple panoramic shots.

[ebiggs1]

"it's squeezing a massive circular image into a very small rectangular sensor space"

Actually it not!  The resolution or amount of info a sensor can accept is fixed.  No matter if it is a tele or a UWA.

Right now one of the best, perhaps the best, lens for night sky work is the Rokinon SP 14mm f/2.4 Lens.  It is not just good but scary good. This lens alone will clear up many of your 1., 2., and 3., concerns.  Plus the fact lenses make circular images and sensors make rectangular images does eliminate some of the hardest to make great areas of any lens.

[Tronhard]

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@ebiggs1 wrote:

"it's squeezing a massive circular image into a very small rectangular sensor space"

Actually it not!  The resolution or amount of info a sensor can accept is fixed.  No matter if it is a tele or a UWA.

Right now one of the best, perhaps the best, lens for night sky work is the Rokinon SP 14mm f/2.4 Lens.  It is not just good but scary good. This lens alone will clear up many of your 1., 2., and 3., concerns.  Plus the fact lenses make circular images and sensors make rectangular images does eliminate some of the hardest to make great areas of any lens.

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I totally agree that the amount of info is fixed, but stars are very small and many at a distance will be smaller than the pixels, yet they will activate a whole or more than one pixel if they trigger them.

The very first question I asked is why the photos are being taken.  If it is just for general shots I would absolutely agree going with the UWA lens, but if the OP's intent is for greater detail then (according to my advice 'cos I'm not an astrophotographer), taking multiple images and merging them to get greater magnification and total sky pixel density (from using multiple, smaller images) is the preferred option.

I'm curious to see what the answer to my first question is...

[ebiggs1]

Absolutely the first question should be how are the photos going to be used.

"I'm not an astrophotographer), taking multiple images and merging them ..."

I am not either, any longer any way. I am a charter member of the Powel Observatory in Louisburg, KS.  I did a lot of photography with the 30" and other telescopes plus regular film cameras/lenses.  Astro photography is a lot of work so I now leave it to folks like Tim Camplell who is very talented, BTW.  Probably way more then me!

When you are talking merging are you think of stacking? Astro photographers do that all the time.  However for years and years the Rokinon manual primes have been goto lenses for the sky. Now the new Rokinon SP 14mm f/2.4 Lens has set a new standard, its price reflects it, too. You will need to jump into Zeiss lenses to compare.

[TCampbell]

When someone says "astrophotography" I'm never quite sure what they really mean because there are many varieties of this.  I do astrophotography -- mostly of deep-sky objects (DSO's) with the camera connected to an equatorially mounted telescope and typically don't do the Milky Way nightscape shots.

The Milky Way shots typically are shot with a reasonably wide-angle lens (not necessarily an extreme wide angle).  For example, Sigma has a 20mm f/1.4 (around $900).  I've never used this lens, but f/1.4 captures a lot of light.  Typically you'll see the most optical issues at the low focal ratios.   I mentioned the Rokinon/Samyang lenses previously.

Regardless of what you do, image capture is followed by image processing and the latter is a bit move involved.

Details will be faint.  Every image of a Milky Way or of a Deep Sky Object (DSO ... such as a galaxy, nebula, etc.) is heavily processed because the true details are faint.  We "stretch" the histogram to make faint details more apparent.

Unfortunately when you "stretch" the data, you also stretch the noise ... making it more apparent.  This is why we also shoot lots of "dark" frames, "bias" frames, and "flat" frames (those are all categorized as "callibration" frames).  

If you create a star mask, you can do noise-reduction on the non-masked areas that greatly reduce the noise without harming the sharpness of the stars.  You can also create a range mask over the features in the image (such as the Milky Way or DSO) to guard against softening up details.  Then you can use several runs of the High Pass filter in photoshop to help improve the details in the subject such as Milky Way or DSO.

This type of photography has a longer learning curve (certainly the image processing has a long learning curve).  To be fair ... you can start to see improvements right away just learning some of the basic techniques... and it all gets better with experience.

[ChrisPBacon]

T. Campbell:

As well I’m discovering...
Thanks for your response.

I’m doing lunar and solar photography; the Milky Way; DSOs; also hunting for asteroids and comets. While I volunteer at an observatory that has excellent mentors, none of them are Canon users and I’ve moved from nature/landscape photography into astrophotography.

My goal is to reduce the amount of work in post-processing by avoiding, for example, chromatic aberration, and other errors in doing the initial photos. That means I’m using excellent glass: hence, my question about wide angle lenses: several have pointed to the Sigma 20mm f/1.4. One of my mentors reads me the riot act if I begin with what he calls one of my “Brownie” photos, and has challenged me to find my “A” game.

I well understand the process and the physics involved with shooting deep sky objects — in this case with my TEC140. Great lens, but I still have to get the photo.

The learning curve is fairly steep: I wouldn't attempt to ski on so steep a slope.

[ChrisPBacon]

E. Biggs:

I’m using my camera and lenses for solar, lunar, and wide field (such as the Milky Way, meteorite storms, aurora borealis) and/or nocturnal thunderstorm photos, and for time-lapse videos; an excellent telescope for deep sky objects; and computer capture of multiple long-duration images for processing, both stacking and merger (such as panoramas). Doing photography at  9,600’ and above 12,000’ MSL is hard on the body and brain. Nothing is worse than dragging 2-300 pounds of gear up mountain slopes to a photography site and finding out that your new lens is crappy, unless it’s to find out that your photos are all out-of-focus.

Yanno?

[Waddizzle · Accepted solution]

" One of my mentors reads me the riot act if I begin with what he calls one of my “Brownie” photos, and has challenged me to find my “A” game."

Sounds like a hint to learn more about image stacking to me.

"Nothing is worse than dragging 2-300 pounds of gear up mountain slopes to a photography site and finding out that your new lens is crappy, unless it’s to find out that your photos are all out-of-focus."

Practice taking shots with your UWA lens of landscapes and cityscapes. The hyperfocal distance on UWA lenses tends to be very short.  Learn where the ideal point is on your focus ring.  Just remember that it may shift somewhat at different ambient temperatures.  So, go outside an take photos on a very cold day.

I have dabbled with photographing the night sky using a Rokinon 14mm T3.1 with surprising good results for the shooting conditions.  There have been many complaints about the "photo" version of the lens.  Over time, I have bought three of the T3.1 cinema lenses, and they have all been fine.  I have not tried the newer Rokinon lenses, which communicate with the camera body, but are still manual focus.

[ChrisPBacon]

@Waddizzle wrote:

“Sounds like a hint to learn more about image stacking to me.

“I have dabbled with photographing the night sky using a Rokinon 14mm T3.1 with surprising good results for the shooting conditions.  There have been many complaints about the "photo" version of the lens.  Over time, I have bought three of the T3.1 cinema lenses, and they have all been fine.  I have not tried the newer Rokinon lenses, which communicate with the camera body, but are still manual focus.”

My mentor is one of those individuals who makes the best of his camera and peripheral equipment to get stunning photos: I have seen the photos he’d just taken and dowloaded onto his computer for review: he rarely, if ever, uses Lightroom or Adobe to alter or correct them. Of the 6 or 7 professionals I associate with, I’d say that he gets the most out of his camera and puts the group of us to shame. Steep learning curve stuff for me.

I just found a Rokinon 14mm T3.1 cine lens in a Las Vegas two days ago, and purchased it on your recommendation after trying it on my 6D Mk II. I’m driving to the California coast this afternoon to take some photos of the Milky Way, and to photograph the moon as it sets behind a lighthouse on the coast. That’s a great suggestion and I appreciate you offering it.

[ebiggs1]

"...is hard on the body and brain."

And why I decided to stop!  Guys like Tim Campbell, Tom Martinez and others are well suited to do it and they do a nice job and some are a lot younger.

Tom Martinez, 2016 (Jupiter, Venus and Moon)