A new name in affordable lenses offers an 11mm fish-eye with excellent mechanics and optics for ultra-wide astrophotos.
TTArtisan 11mm f/2.8 Lens
Astrophotographers make use of every focal length lens available, with the widest being fish-eye lenses that take in a full sweep of up to 180 degrees (°) of sky. While they are specialized lenses, fish-eyes allow unique images not possible with any other lens, even using techniques such as shooting panoramas.
Spending a lot on a lens that might see only occasional use puts a fish-eye way down the lens wish list of astrophotographers. But at only $215 U.S. for most camera brands, the new 11mm fish-eye from China-based TTArtisan is an attractive choice. Of course, it wouldn’t be worth much if the image quality and construction were poor. In testing a unit purchased from B&H Photo, I was pleased to find the TTArtisan 11mm f/2.8 performed very well on both counts.
Affordable Fish-Eye for Mirrorless
The TTArtisan lenses are part of a new generation made only for mirrorless cameras. None of their lenses, including the 11mm on test here, will fit on DSLR cameras. They are designed to make use of a mirrorless camera’s short “flange distance” from lens to sensor, which allows for a compact lens yet with fast aperture.
The 11mm I tested was for Canon’s mirrorless RF lens mount, but versions of the same lens are available for Nikon Z, Sony E, and Leica L and M mounts.
All the TTArtisan lenses are also purely manual, requiring the user to set the focus and aperture. Unlike some more advanced manual lenses, the no-frills TTArtisan models do not have any electrical contacts for communication with the camera. As such, the camera metadata does not record the lens focal length or aperture.
The 11mm TTArtisan is a full-frame fish-eye, meaning it fills the frame with an image I measured as 140° across the long dimension of the sensor, albeit in a highly distorted scene with a curved horizon. By comparison, circular fish-eye lenses cover a full 180° of sky, but fill only the central circle of the frame. They are even more specialized than full-frame fish-eyes.
The curved horizon of a fish-eye makes it less suitable for traditional nightscapes. However, the ultra-wide field is ideal for capturing sky-spanning displays of auroras for those lucky enough to see them, especially in time-lapses where multi-segment panoramas aren’t feasible.
The fast f/2.8 aperture of the TTArtisan 11mm makes it easier to use shutter speeds short enough to freeze the motion of an active aurora, or to shoot 4K videos of auroras, as many mirrorless cameras are now capable of doing.
A fish-eye is also great for taking in the Milky Way from horizon to horizon and for circumpolar star trails. I’ve also used such lenses during total solar eclipses to capture the passage of the Moon’s shadow across the sky.
Optical Tests
While subjects such as auroras are forgiving of soft images, Milky Way photos demand stars be sharp corner to corner. The 11mm TTArtisan does quite well. When used wide open at f/2.8 stars do exhibit astigmatism at the corners that elongates stars into radial streaks, though images are still tight and not bloated by spherical aberration.
There was little, if any, coma, the aberration that flares stars into winged seagulls, and only a small degree of lateral chromatic aberration that adds colorful fringes to stars. Performance was consistent at all corners; there was no sign of defective lens de-centering.
I compared the TTArtisan 11mm to two other full-frame fish-eyes: the long-discontinued auto-focus Canon 15mm f/2.8 and the manual-focus Rokinon 12mm f/2.8 ED ($370 to $500 depending on lens mount).
When shot wide open at f/2.8 the old Canon 15mm was rife with coma at the corners. The Rokinon 12mm had less off-axis coma than the Canon but it was mixed with some astigmatism and softness. The TTArtisan had worse astigmatism than the Rokinon but crisper star images overall.
Stopped down to f/4 all the lenses improved at the corners, though the TTArtisan still showed some astigmatism. The Rokinon 12mm does provide a slightly wider field of view than the 11mm TTArtisan, despite its 1mm longer focal length.
At the frame centers all three lenses were sharp wide open, and showed little flaring from a bright off-center Moon. There was no evidence of longitudinal chromatic aberration adding blue halos around bright stars. Overall, the TTArtisan presented images that looked very sharp, making this a fine lens for Milky Way images.
When using a clip-in light pollution filter (an Astronomik CLS) in my Canon Ra camera, the lens now had to be set to about 1 meter to focus on stars, due to the focus shift introduced by placing the filter in front of the sensor. (Filters in front of lenses produce no focus shift.)
However, while some lenses behave badly when refocused with clip-in filters, the TTArtisan still showed good star images across the frame, trading the astigmatism at the corners for mild coma and some image softness.
As do all lenses of its type, the TTArtisan exhibited darkening of the corners, or vignetting, in this case by about 1.3 stops at the extreme corners at f/2.8, and just less than one stop at f/4. This was easily correctable in raw image processing to make the sky look uniformly illuminated.
Mechanics
Despite its low cost the TTArtisan is very well built, of all metal and glass construction. It feels dense for its size and weighs 550 grams with lens caps, about 20 grams more than the Rokinon 12mm and 200 grams more than the old 15mm Canon fish-eye. The front cap is a metal slip-on; the rear lens cap is plastic. There is no weather sealing, to be expected at this price.
The aperture ring turns from f/2.8 to f/16, with full f-stops marked, but with no click stops, a nuisance for operating at night by feel. The ribbed metal focus ring turns smoothly with a nice degree of firmness.
Conveniently, the lens focuses sharpest on stars when it is turned all the way to the stop at infinity. Unlike most auto-focus lenses, it does not turn past infinity. So there’s no fussing with focusing at night.
There is a small built-in lens hood, but a lens of this type cannot accommodate screw-on filters or filter holders. With some care, I found it was possible to hand-hold a 100mm square StarGlow filter in front of the lens to add a soft focus effect to stars.
In conclusion, I was impressed with the new TTArtisan 11mm, especially considering its price. For mirrorless shooters, it can open up some new photo opportunities at low cost, and without taking up much space in your camera bag.
If you are looking for a similar fish-eye lens for a DSLR camera, I can recommend the older Rokinon manual 12mm f/2.8 ED, through at double the price.
Plus: Compact; sharp optics, with easy infinity focus
Minus: Some off-axis aberrations; no electrical contacts with the camera
Summary: Available only for mirrorless cameras, the TTArtisan 11mm fish-eye works well for several types of astrophotos, and is affordable enough to include in the kit bag.
Who Is It For? Nightscape photographers shooting with mirrorless cameras.
Typical retail price: $215 for most lens mounts, $370 for Leica M mount.
