Sigma 15mm F1.4 DG DN Diagonal Fisheye Art Lens Review

As I start the Sigma 15mm F1.4 DG DN Fisheye Art Lens review, there are 310 fisheye lenses available at B&H. This count includes multiple mount versions of the same lens, but that is still a high number. However, only 29 of those lenses cover a full-frame imaging sensor, and none have an aperture wider than f/2.8, which is two full stops narrower than this lens's f/1.4.

Not long after releasing the 14mm F1.4 DG DN Art Lens, the world's first 14mm full-frame interchangeable lens with an f/1.4 aperture, Sigma followed up with the 15mm f/1.4 fisheye lens carrying a similar claim. This lens is the first 15mm 180° diagonal fisheye interchangeable full-frame model with an f/1.4 aperture.

The record-setting claim is not the only attribute shared by these lenses. They appear and function nearly identically.

While it appears excessive to offer two nearly identical lenses varying by only 1mm, the Fisheye designation is a huge differentiator, and these lenses produce dramatically different results.

Those familiar with fisheye lenses may be wondering why an f/1.4 aperture is needed in a lens featuring such an extraordinarily wide angle of view. Fisheye lenses are often used to photograph close action (and the night sky), the magnification in the middle of the optical circle is similarly strong as a rectilinear lens of this focal length, and the f/1.4 aperture permits a 2-stop lower ISO setting, another significant differentiator. In addition, the background blur difference between f/1.4 and f/2.8 is substantial, even with this ultra-wide angle of view.

The well-built, high-performing Sigma 15mm F1.4 DG DN Fisheye Art Lens is large, heavy, and expensive, but its capabilities can set a photographer's work apart from the crowd.

Focal Length

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While "15mm" does not sound extreme, the "Diagonal Fisheye" part of the name changes everything. The absolute center of this lens's image circle magnifies comparably to a normal 15mm lens. However, extreme barrel distortion rapidly diminishes magnification as the image circle radius is increased until the corners show considerably less magnification than even a 10mm rectilinear lens — and without the normal stretching seen in ultra-wide-angle corners.

A picture showing this lens's crazy geometric distortion should clarify any remaining ambiguity. The image below is a straight-on closeup of a normal brick wall.

Vertical and horizontal lines perfectly centered in the frame remain straight, but they become increasingly curved as the distance from center is increased. The center bricks appear large, but the peripheral bricks are tiny. Use that effect to emphasize centered subjects while keeping a large amount of background, the sense of place, in the frame.

The skateboarder example was captured with a different lens, but it illustrates the point along with a frequent use for fisheye lenses — close action sports photography and especially extreme sports photography. This fisheye lens's overall angle of view with strong subject emphasis creates exciting action photos, and this lens may become your #1 choice for such.

Landscape photography is a popular use for fisheye lenses.

The 15mm fisheye focal length, and this lens in particular, is a great choice for nightscapes.

The unique look this lens creates invites creativity.

Buildings are large subjects, and fisheye lenses are often used to creatively photograph them.

How does the 15mm fisheye angle of view compare to rectilinear focal lengths?

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As mentioned, the subject in the center of a 15mm fisheye image circle is magnified about the same as in a 15mm rectilinear frame. The fisheye lens's magnification decreases dramatically by the periphery, where details are considerably smaller than even those in a 10mm rectilinear lens frame. Also, as mentioned, a fisheye lens does not stretch corner details as the rectilinear options do.

The 15mm fisheye is not an alternative or replacement for the rectilinear lenses, but it is a valuable complement.

APS-C sensor format cameras utilize a smaller portion of the image circle than full-frame models, and that fact means a scene is framed tighter, with 1.5x being the angle of view multiplier for Sony's lineup. The 22.5mm angle of view is noticeably narrower, and the strongest distorted portion of the image circle is discarded. While the uses for this angle of view are similar, the results are less dramatic.

Max Aperture

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Never before has a full frame 15mm fisheye lens provided a massive f/1.4 aperture, enabling this lens to send 4x as much light to the imaging sensor vs an f/2.8 alternative.

The additional light provided by wider aperture lenses permits sharp images of subjects in motion and with a handheld camera in lower light levels and with lower (less noisy) ISO settings. A wide aperture also aids low-light AF performance.

Increasing the aperture opening provides a shallower DOF (Depth of Field) that creates a stronger, better subject-isolating background blur (at equivalent focal lengths). 15mm may be the wrong focal length choice for those with a primary goal of creating a diffusely blurred background. However, no full frame 15mm fisheye lens before this one is as capable of that task.

These examples illustrate the maximum blur this lens can create at the specified aperture.

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The background is impressively blurred at f/1.4, and the difference at f/2.8 is significant.

A wide aperture's disadvantages are related to (often significantly) increased lens element size, including larger overall size, heavier weight, and increased cost, and this lens bears those traits, but in moderation. Many of the uses for a 15mm fisheye require a narrower aperture, such as f/8 or f/11, to keep everything in the frame sharp, and photographers concentrating on landscape, architecture, real estate, etc. may seldom use the f/1.4 option. Only a 1/60 second shutter speed (twice the framerate) is needed for 30 fps video capture, and wide apertures are not often required to get 1/60 in normally encountered ambient lighting.

This lens features an aperture ring, permitting a manually selected aperture. The camera controls the aperture setting with the ring in the A (Auto) position. All other settings electronically force the aperture to the chosen opening. A 2-position switch on the bottom left side of the lens toggles the aperture ring between 1/3 stop clicks and smooth, quiet, non-clicked adjustments, ideal for video recording.

Aside from a slightly more complicated design, inadvertent aperture changes the primary disadvantage of an aperture ring (especially when photographing in the dark). An iris lock switch solves that problem, preventing switching between A and the manual selection range while allowing changes within the manual range.

Image Stabilization

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The longer the focal length, the larger the subject details (captured at the same distance) are rendered, and the more still the camera must be held to avoid subject details crossing imaging sensor pixels, the cause of motion blur. Sigma has omitted image stabilization in their recent wide-aperture prime lenses, and with this lens having a low magnification, it is not surprising is that the 15mm Fisheye Art Lens also lacks this feature.

Sony addresses that omission with Steady Shot IBIS (In-Body Image Stabilization) in their mirrorless cameras. In addition to reducing camera shake, the stabilized imaging sensor provides a still viewfinder image, enabling careful composition. Furthermore, sensor-based AF takes advantage of the stabilized view for improved accuracy.

With no IS switch on the lens, the camera menu must be used to enable or disable IBIS or check the current settings. This extra step is a slight impediment to working quickly, going from tripod mounted to handholding, for example.

Image Quality

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Owning a world record title leaves a lens's design suspect for what's been sacrificed to achieve that accomplishment. In this case, it was not image quality.

Sorry, but 180° fisheye lenses are not compatible with the site's standard testing, so this lens's test results are not included in the comparison tools. Still, good image quality is critical.

Wide open at f/1.4, this lens produces extremely sharp center-of-the-frame results. Stopping down produces only minor contrast and resolution improvement, and none is needed.

Lenses typically show decreased sharpness in the periphery of the image circle, where light rays are refracted to a stronger angle than in the center. This lens's mid- and peripheral image quality performance varies based on subject distance. At a close distance, as illustrated in the brick wall image above, the mid- and periphery image circle details are strongly blurred at f/1.4 and improve modestly as the aperture is narrowed. Still, the f/11 corners remain soft.

At mid and long focus distances, the results are quite different — extraordinary would be an accurate descriptor. Corners are remarkably sharp at f/1.4 and improve only modestly at narrower apertures, primarily due to reduced peripheral shading. As you will see in some of the comparisons below, a tiny area of the extreme corners is slightly blurred at f/1.4 and shows improvement through f/2.8.

Taking the testing outdoors, we next look at a series of center-of-the-frame 100% resolution crop examples. These images were captured in RAW format using a Sony Alpha 1 and processed in Capture One using the Natural Clarity method. The sharpening amount was set to only "30" on a 0-1000 scale. Note that images from most cameras require some level of sharpening, but too-high sharpness settings are destructive to image details and hide the deficiencies of a lens.

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These results are outstanding. There was no need to include the f/2 samples.

Next, we'll look at a series of comparisons showing 100% resolution extreme top left corner crops captured and processed identically to the above center-of-the-frame images. The lens was manually focused in the corner of the frame to capture these images.

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Count on samples taken from the outer extreme of the image circle, full-frame corners, to show a lens's weakest performance. There are very few lenses that rival the corner performance of this one. The stopped-down aperture results were primarily included to show the effects of vignetting, which is not testable in the site's standard method.

Circling back to the close distance mid and periphery softness, many close-focus scenarios benefit from this increased background blur that improves subject separation.

Lateral (or transverse) CA (Chromatic Aberration) refers to the unequal magnification of all colors in the spectrum. Lateral CA shows as color fringing along lines of strong contrast running tangential (meridional, right angles to radii), with the mid and especially the periphery of the image circle showing the most significant amount as this is where the most significant difference in the magnification of wavelengths typically exists.

With the right lens profile and software, lateral CA is often easily correctable (often in the camera) by radially shifting the colors to coincide. However, it is always better to avoid this aberration in the first place.

The white tree branches against the blue sky, along with the other corner sample images shared above, indicate that lateral CA is not a problem for this lens.

A relatively common lens aberration is axial (longitudinal, bokeh) CA, which causes non-coinciding focal planes of the various wavelengths of light. More simply, different colors of light are focused to different depths. Spherical aberration, along with spherochromatism, or a change in the amount of spherical aberration with respect to color (looks quite similar to axial chromatic aberration but is hazier) are other common lens aberrations to observe. Axial CA remains somewhat persistent when stopping down, with the color misalignment effect increasing with defocusing. The spherical aberration color halo shows little size change as the lens is defocused, and stopping down one to two stops generally removes this aberration.

In the real world, lens defects do not exist in isolation, with spherical aberration and spherochromatism generally found, at least to some degree, along with axial CA. These combine to create a less sharp, hazy-appearing image quality at the widest apertures.

This lens produces only minor color blur at f/1.4.

Bright light reflecting off lens elements' surfaces may cause flare and ghosting, resulting in reduced contrast and sometimes interesting, usually destructive visual artifacts, and it is difficult to keep those bright lights out of the 180° angle of view. The shape, intensity, and position of the flare and ghosting effects in an image are variable, dependent on the position and nature of the light source (or sources), selected aperture, shape of the aperture blades, and quantity and quality of the lens elements and their coatings. Additionally, flare and ghosting can impact AF performance.

This lens features Sigma's Super Multi-Layer Coating to avoid flare and ghosting, but the high 21 lens element count increases the challenge in this regard. Still, at most, this lens produced only minor flare effects even at narrow apertures in our standard sun in the corner of the frame flare test, reflecting excellent performance. This is an f/16 test image:

I was not able to get a 180° clear view of the sky, and some distractions were removed from the periphery of this sample, but the flare performance was unaffected.

Flare effects can be embraced or avoided, or removal can be attempted, though removal is sometimes challenging. Thus, high flare resistance is a welcomed trait.

Two lens aberrations are particularly evident in images of stars, mainly because bright points of light against a dark background make them easier to see. Coma occurs when light rays from a point of light spread out from that point instead of being refocused as a point on the sensor. Coma is absent in the center of the frame, gets worse toward the edges/corners, and generally appears as a comet-like or triangular tail of light that can be oriented either away from the center of the frame (external coma) or toward the center of the frame (internal coma). The coma clears as the aperture is narrowed. Astigmatism is seen as points of light spreading into a line, either sagittal (radiating from the center of the image) or meridional (tangential, perpendicular to sagittal). This aberration can produce stars appearing to have wings. Remember that Lateral CA is another aberration apparent in the corners.

The image below is a 100% crop taken from the top-left corner of an Alpha 1 image captured at f/1.4.

That performance is remarkable.

Add "fisheye" to the lens name, and the standards are changed. This lens has extreme barrel distortion, and in this case, that is welcomed. The look is both expected and desired for effect.

Fisheye images can be de-fished using strong distortion correction.

It is easy to illustrate the strongest blur a lens can create, and wide-angle lenses are inherently disadvantaged in this regard. Due to the infinite number of variables present among available scenes, assessing the blur quality, bokeh, is considerably more challenging. Here are some f/11 (for diaphragm blade interaction) 100% crop examples from near the center of the frame.

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These examples appear especially nice for the focal length.

An 11-blade count diaphragm will create 22-point sunstars (diffraction spikes) from point light sources captured with a narrow aperture. Generally, the more a lens diaphragm is stopped down, the larger and better shaped the sunstars tend to be. Wide aperture lenses tend to have an advantage in this regard, and this lens can produce beautiful stars, as illustrated below.

The example above was captured at f/16.

The design of this lens is illustrated above. While a couple of mid sections appear shared with the 14mm f/1.4 Art lens, the overall designs are vastly different.

The Sigma 15mm F1.4 DG DN Diagonal Fisheye Art Lens optically impresses, leaving little to complain about. The corners are not sharp at close distances, but that may be an advantage.

Focusing

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Powered by Sigma's HLA (High-response Linear Actuator), the 15mm F1.4 DG DN Art Lens internally focuses fast and quietly, with barely audible clicks.

While the focus speed is relatively fast, Sony cameras' normal defocusing prior to focusing increases lock time significantly in AF-S (single shot) mode.

This lens autofocuses in crazy-low light levels. The Sony a1 and this lens easily locked AF on good contrast at f/16, ISO 100, and 30 seconds still indicating strong underexposure.

FTM (Full Time Manual) focusing is supported in Sony's DMF (Direct Manual Focus) mode with the shutter release half-pressed or the AF-ON button pressed.

Sigma provides a customizable AFL (AF Lock) button. While in continuous focus mode, this button can be pressed to lock focus at the currently selected focus distance, facilitating a focus and recompose technique. This button also acts as a custom button, programmable to another function using the camera's menu.

Night sky photographers often want an established focus distance locked for an entire shoot, and gaffer-taping the focus ring is the conventional method of ensuring that happens. More elegant is this lens's MFL (Manual Focus Lock) Switch, which prevents manual focus adjustment when in MF mode.

The rubber-coated, sharp-ribbed focus ring is large, and being raised from the lens barrel behind it, it is easy to find. This ring rotates smoothly, has an optimal amount of resistance, and the long MF 430° of slow rotation MF adjusts focusing at a rate that facilitates precise manual focusing even at close distances. Turn the ring fast to go the full extent range in about 180° of rotation. The transition from slow to fast happens slightly too quickly, modestly impeding rocking the MF ring back and forth to precisely focus.

It is normal for the scene to change size in the frame as the focus is pulled from one extent to the other. This effect is focus breathing, a change in focal length resulting from a change in focus distance. Focus breathing impacts photographers intending to use focus stacking techniques, videographers pulling focus (without movement to camouflage the effect), and anyone critically framing while adjusting focus.

This lens produces a modest change in subject size through a full-extent (worst-case) focus distance adjustment.

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The 15mm fisheye has a minimum focus distance of 15.2" (385mm), where it generates a low 0.06x maximum magnification spec. Out of 496 lenses having maximum magnification specs in the site's database, only the Canon RF 5.2mm F2.8 L Dual Fisheye Lens has a lower number (0.03x). That said, this lens's tested minimum focus distance is about 9.7" (246mm), but only the center of the frame focuses sharply at very close distances, including at the spec distance.

Model	Min Focus Distance		Max Magnification
Canon EF 8-15mm f/4L USM Fisheye Lens	5.9"	(150mm)	0.39x
Canon RF 10-20mm F4 L IS STM Lens	9.8"	(250mm)	0.12x
Canon EF 15mm f/2.8 Fisheye Lens	7.9"	(200mm)	0.14x
Sigma 14-24mm f/2.8 DG DN Art Lens	11.0"	(280mm)	0.14x
Sigma 14mm F1.4 DG DN Art Lens	11.8"	(300mm)	0.08x
Sigma 14mm f/1.8 DG HSM Art Lens	10.6"	(270mm)	0.10x
Sigma 15mm F1.4 DG DN Fisheye Art Lens	15.2"	(385mm)	0.06x
Sigma 20mm F1.4 DG DN Art Lens	9.1"	(230mm)	0.16x
Sigma 24mm F1.4 DG DN Art Lens	9.8"	(250mm)	0.14x
Sony FE 12-24mm F2.8 GM Lens	11.0"	(280mm)	0.14x
Sony FE 14mm F1.8 GM Lens	9.8"	(250mm)	0.10x
Venus Optics Laowa 10mm f/2.8 Zero-D FF Lens	4.7"	(120mm)	0.24x

This lens covers a 180° angle of view diagonally, potentially to infinity on both sides. However, the middle of the frame is considerably narrower, and a subject measuring approximately 24 x 16" (610 x 407mm) fills a full-frame imaging sensor at this lens's minimum MF distance.

The fisheye effect with a close subject is great.

Design & Features

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Sigma's Art lenses are premium grade, featuring great build quality, physical performance, and aesthetics, and the Sigma 15mm F1.4 DG DN Diagonal Fisheye Art Lens maintains those positive attributes.

This lens features a TSC (Thermally Stable Composite) exterior. "TSC is a state-of-the-art polycarbonate that is designed to be both lightweight and extremely durable, and its chemical makeup means it doesn't shrink or expand with changing temperatures. This material is so high-quality that we're also incorporating it into our Art and Sports lenses to provide lightness and thermal consistency." [Sigma]

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The 15mm fisheye has a fixed size that steps to an increasingly wide diameter toward the front of the lens.

Like the Sigma 20mm F1.4 DG DN Art and Sigma 14mm F1.4 DG DN Art, this lens features a Lens Heater Retainer. The heater, used to avoid condensation when temperatures drop, wraps around the barrel, with the raised area at the hood preventing it from sliding forward and blocking the optical path.

About 1/3 of the space between the focus ring and the aperture ring is ribbed for improved grip. 3/4 of the aperture ring is ribbed, and when this ring is locked, these grooves also increase grip which is especially useful for mounting and unmounting the lens.

All four switches are easy-to-use 2-position types that firmly click into their positions, with a white background displayed when the enabled position is selected. Two of the switches, along with the autofocus lock button, are mounted on a low-profile switch bank.

This lens has weather sealing, including a rear mount gasket.

Water- and oil-repellent coating is applied to the front element to repel dust and water and facilitate cleaning.

This lens is big and heavy, yet still manageable. Here is the comparison chart:

Model	Weight oz(g)		Dimensions w/o Hood "(mm)		Filter	Year
Canon EF 8-15mm f/4L USM Fisheye Lens	19.1	(540)	3.1 x 3.3	(78.5 x 83.0)	n/a	2010
Canon RF 10-20mm F4 L IS STM Lens	20.1	(570)	3.3 x 4.4	(83.7 x 112.0)	n/a	2023
Canon EF 15mm f/2.8 Fisheye Lens	11.6	(330)	2.9 x 2.4	(73.0 x 62.0)		1987
Sigma 14-24mm f/2.8 DG DN Art Lens	28.1	(795)	3.3 x 5.2	(85.0 x 131.0)	n/a	2020
Sigma 14mm F1.4 DG DN Art Lens	41.3	(1170)	4.0 x 5.9	(101.4 x 149.9)	n/a	2023
Sigma 14mm f/1.8 DG HSM Art Lens	41.3	(1170)	3.8 x 5.0	(95.4 x 126.0)	n/a	2017
Sigma 15mm F1.4 DG DN Fisheye Art Lens	48.0	(1360)	4.1 x 6.3	(104.0 x 159.9)	n/a	2024
Sigma 20mm F1.4 DG DN Art Lens	22.2	(630)	3.5 x 4.5	(87.8 x 113.2)	82	2022
Sigma 24mm F1.4 DG DN Art Lens	18.0	(510)	3.0 x 3.8	(75.7 x 97.5)	72	2022
Sony FE 12-24mm F2.8 GM Lens	29.9	(847)	3.8 x 5.4	(97.6 x 137.0)	n/a	2020
Sony FE 14mm F1.8 GM Lens	16.2	(460)	3.3 x 3.9	(83.0 x 99.8)	n/a	2021
Venus Optics Laowa 10mm f/2.8 Zero-D FF Lens	14.8	(420)	3.2 x 2.8	(82.0 x 70.8)	77	2024

For many more comparisons, review the complete Sigma 14mm F1.4 DG DN Art Lens Specifications using the site's lens specifications tool.

Use the site's product image comparison tool to visually compare the Sigma 15mm F1.4 DG DN Diagonal Fisheye Art Lens to other lenses.

Front filter threads are not available on this lens, but a rear drop-in filter holder is provided.

A GP-11 plastic stencil is provided to aid in cutting gel filters. Neutral density filters are the type I would most utilize with this lens.

A tripod ring on a 15mm lens? We should not be surprised by the unique features of a "World's First" lens, and this lens, like the Sigma 14mm F1.4 Art Lens, comes with the robust, removable, Sigma Tripod Socket TS-141. Balancing the weight over the tripod head avoids camera mount strain and a front-heavy condition that results in sagging after lockdown. The tripod mount has a standard 1/4" threaded insert and built-in Acra Swiss dovetails compatible with screw-type clamps (specified by Sigma). Unfortunately, the Acra Swiss "standard" is not closely adhered to by all players in this space, and some lever-style clamps are not compatible.

The tripod ring is a great feature of this lens. However, note that a vertical grip extending below the lens's tripod foot readily interferes with the tripod head. Sigma's alternative would have been to extend the tripod ring outward, but that change would have unbalanced the lens when angled upward, so the right design decision was made. Take the grip off if it is in your way and the extra battery capacity is not required.

The tripod ring is removable, and the included Sigma Protective Cover PT-11 snuggly fits over the exposed rotation nubs.

A lens strap is even included.

This lens has a small integrated lens hood that adds modest protection to the front element.

Another unique feature of this lens is the cap, the Cover Lens Cap LC1040-01. This substantial (3.2 oz, 90.8g) cap locks over the hood with a thin edge of flocking adding protection against hood scratches. The deep center pinch design must be oriented with the longer petals, but the interior angles push the cap toward the proper rotation. There are no peripheral releases, but the cap doesn't release when the mounted lens is placed on a flat surface.

Store your gel filters in your lens cap?

You can with this unique design (the similar LC1014-01 is illustrated above). A pair of spring-loaded doors open to hold gel filters.

Sigma provides a nice zippered, padded nylon case, in the box.

Price, Value, Compatibility

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This lens has a rather high price, high enough to challenge purchase justification for a niche lens. Primarily, professionals and serious amateurs working in certain genres, including close action sports (such as skateboarding), landscapes, and nightscapes will have this lens in their kits.

The "DG" refers to full-frame camera compatibility, and the "DN" indicates that this lens was designed for short-flange mirrorless cameras. The Sigma 15mm F1.4 DG DN Diagonal Fisheye Art Lens is compatible with all Sony E-mount cameras, including APS-C sensor format models, and it is also available in the L mount (Sigma, Panasonic, Leica).

Made in Japan, each Art lens is tested with Sigma's proprietary MTF measuring system, ensuring a quality product. Regarding the Sony E-mount version of this lens, Sigma develops, manufactures, and sells lenses based on the specifications of the E-mount, disclosed by Sony Corporation under license agreement.

Sigma provides a 1-year limited warranty, and Sigma Corporation of America provides a limited 3-year warranty extension.

The reviewed Sigma 15mm F1.4 DG DN Diagonal Fisheye Art Lens was borrowed from Sigma Corporation of America.

Alternatives

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The Sigma 15mm F1.4 DG DN Diagonal Fisheye Art Lens's key feature is the ultra-wide angle of view with center emphasizing strong barrel distortion. Add in the f/1.4 aperture, and this lens has no close alternative.

If you prefer a rectilinear lens, those included in the above comparison tables should be on your options list.

Summary

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Welcome to the world's first 15mm 180° diagonal fisheye interchangeable full-frame lens to have an f/1.4 aperture. The Sigma 15mm F1.4 DG DN Diagonal Fisheye Art Lens, featuring excellent build quality and impressive optical performance, creates a unique ultra-wide angle of view with a center emphasis look that enables standout images, images that lift a portfolio above the crowd.