Full frame fisheye lenses fill the whole sensor area, and often have a 180° field of view along the diagonal. Circular fisheye lenses, though, only fill a circle in the middle of the sensor, and often have a 180° field of view.
This is illustrated below with the two fisheye types being used to photograph the same subject:
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| Samyang 8mm f/3.5 (Full frame fisheye) | Meike 6.5mm f/2 (Circular fisheye) |
Recently, the Meike 6.5mm f/2 circular fisheye lens was released, with a reasonable price level of around USD150. So, how does it perform?
See it compared with other circular fisheye lenses below, all designed for APS-C sensor size:
From left to right: Meike 6.5mm f/2 (for Sony E), Yasuhara Madoka 180, 7.3mm f/4 (for Sony E), and Lensbaby 5.8mm f/3.5 (for Nikon F).
Meike 6.5mm f/2
This lens has a quite impressive maximum aperture of f/2, and the field of view is a whopping 190°, meaning that the lens even sees slightly behind you.
Yasuhara Madoka 180, 7.3mm f/4
The lens is very compact, comes in a cool box with Japanese symbols on it, and has a nice metal design. The focus ring is quite loose, not well dampened, so you need to check it now and then, to see that it hasn't rotated off from where you set it. It only comes with a Sony E mount.
See my review.
Lensbaby 5.8mm f/3.5
Designed for SLR cameras, this is a rather large lens. The longer register distance of SLRs compared with mirrorless, mean that this lens needs a bigger retrofocal design.
It covers 185°, however, the image quality is rather poor. Also, the build quality does not impress anyone, with a plastic lens barrel and plastic bayonet mount. Finally, it is overpriced, in my opinion. I would not recommend this lens.
To see the size disadvantage of designing a circular fisheye lens for SLR, rather than mirrorless, consider this comparison of the Meike 6.5mm f/2 mounted on the Sony A5100 (left), and the Lensbaby 5.8mm f/3.5 on the Nikon D7200 (right):
Both cameras have pretty much the same 24MP sensor at APS-C size.
See my review.
Meike 6.5mm f/2
Back to the subject for this review, the Meike 6.5mm circular fisheye lens. Physically, it seems well designed, with a metal lens barrel, nicely dampened, ribbed and rubberized focus ring:
The focus ring appears to be slightly misaligned, in the sense that I must set it somewhat beyond infinity to focus on distant objects. This is quite common with this type of lenses. They are typically not calibrated individually, that would have been much too expensive.
The focus scale still works quite well in practice. Mostly you'll set the aperture to f/4-5.6, in which case you can just guess the distance and set it according to the scale, even if it is slightly misaligned. So don't worry about it.
The aperture ring is smooth, with no click stops at all. It is also well dampened, and feels good in use. The aperture scale has markings only for every second stop. However, it is easy to set it between f/2 and f/4 for f/2.8, and so on.
From the rear, notice the metal bayonet mount. The rear exit pupil looks small, but this is quite common for circular fisheye lenses. Keep in mind that the lens only covers a circle in the centre of the frame, far from the corners of the sensor area.
The lens comes with a metal lens hood, which is kept in place by friction. Again, it works well, and feels like a high quality item.
Image quality
I have compared the image quality with the Yasuhara Madoka 180 by photographing the same subject at different apertures:
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From the centre of the image:
And from the left edge:
In the centre of the image, both lenses appear to be more than sharp enough even wide open. In the edge, though, I think the Meike 6.5mm f/2 is the better lens.
Flare
As it is hard to avoid having the sun in the field of view with a circular fisheye lens, the flare resistance of the lens is very important. Let's see how they compare. Here, I have a dark night landscape, with a strong light source, a street light. Both images are taken at f/5.6, ISO 100. Click to enlarge them:
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As you see, the Yasuhara Madoka to the right has much more ghosting and other flare artefacts. The Meike lens, though, is rather impressive in this respect, as it handles the flare really well.
You can also see that the Meike lens has a wider field of view compared with the Yasuhara Madoka.
Conclusion
The Meike 6.5mm f/2 circular fisheye is a fantastic lens considering the price. It is well made, gives very good image quality, and is compact.
From the images, you will see that the image circle is slightly cropped on the top of the image frame. One might think that the lens is misaligned. However, as both lenses tested feature this offset, and rotating the lens in the mount does not change the image circle, my conclusion is that this is due to the image sensor being slightly offset. I have seen the same on other images posted online as well, supporting this conclusion.
| File of view | 190° | 180° |
| Length | 51.5mm | 43mm |
| Diameter | 61mm | 61mm |
| Weight | 300g | 200g |
| Lens elements/groups | 6/5 | 7/6 |
| Pros | Very good optical properties. Inexpensive | Very compact |
| Cons | No click stops on the aperture ring might be a disadvantage for some | Some CA effects in the edges, does not handle flare well. Focus ring is very loose |
Example images
These images are straight out of the camera, unprocessed. Click for larger versions:
