Kaili Optronics Kelda 6.5mm f/3.5 Fisheye Lens Review

Handling and Features
Performance
Verdict
Specification

 

This 6.5mm fisheye lens provides a diagonal field of view of 180 degrees on a 1.5x crop APS-C DSLR, sports f/3.5 maximum aperture and is available for around £170 from Kauser International. It is available to fit Canon, Four Thirds, Nikon, Pentax and Sony cameras and is more common with Opteka branding than Kelda, although both are the same lens. In this review we’ll take a look at how it performs.

Kelda 6.5mm f/3.5 Fisheye Handling and Features

The build quality of this 6.5mm fisheye lens is good, with high quality plastics used for much of the lens barrel and metal for the lens mount. As a result, it balances well on the Nikon D300 used for testing.

Focusing is manual, and the action of the focus ring is smooth. Focus distances are marked on focusing ring, although there is no hyperfocal scale, which is a shame as this can make setting a focus distance dependant on the selected aperture much easier.

Taking images of subjects from two to three metres or further away is quite straightforward, as the lens can simply be left set on or close to infinity. For closer distances it is recommended to use the electronic focus confirmation feature of your DSLR, if it has one, or a dedicated focusing screen for manual focus lenses if taking stills using the viewfinder. Otherwise, a magnified section using live view will serve you well. If recording video, viewing a magnified section of the frame will ensure accurate focusing.

Kelda 6.5mm f/3.5 Fisheye Performance

At maximum aperture, sharpness is very good in the centre of the frame, and good towards the edges of the frame. Stopping down improves across the frame, reaching outstanding levels in the centre by f/5.6 and excellent levels towards the edges of the frame by f/8.

 

MTF
 

How to read our charts

The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges. Averaging them out gives the red weighted column.

The scale on the left side is an indication of actual image resolution. The taller the column, the better the lens performance. Simple.

For this review, the lens was tested on a Nikon D300 using Imatest.

Levels of chromatic aberrations are typical for a fisheye, just exceeding 1.25 pixel widths between f/3.5 and f/4 and falling as the lens is stopped down to between f/8 and f/11. Diffraction causes fringing to become more prevalent again at smaller apertures, exceeding 1.25 pixel widths at f/22.

CA
 

How to read our charts

Chromatic aberration is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software.

Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimize the problem, hence they usually cost more.

For this review, the lens was tested on a Nikon D300 using Imatest.

As you might expect from a fisheye optic, straight lines placed towards the edges of the frame curve wildly, due to the extreme field of view. However, this lens produces images with stereographic projection, which means that images are more natural looking than typically found with fisheye lenses that produce images with equal-area projection. Objects placed near the edges of the frame appear less squashed than those taken with a lens that produces orthographic or equal-area projection.

Testing of illumination falloff towards the corners formally isn't possible, due to the extreme angle of view. In use, at f/3.5 and f/4 a noticeable, but gradual falloff in brightness can be seen appearing towards the corners, but this disappears by f/8.

Flare can be an issue with this lens, with contrast being reduced by harsh sources of light in the frame and flare being quite prominent. Although it may be possible to exploit this to great effect, it is best to be mindful of images taken with the sun, or other bright sources of light in the frame.

Kaili Optronics Kelda 6.5mm f/3.5 Sample Photos

Value For Money

Being priced at around £170, this lens falls well and truly into bargain basement territory and represents excellent value for money.

Canon only offer an 8-16mm f/4L fisheye zoom for covering the APS-C format with a 180 degree diagonal field of view. This lens is quite expensive, retailing for around £900.

Nikon's 10.5mm DX fisheye has an enviable reputation for optical quality, plus it sports a faster f/2.8 maximum aperture and  autofocus. However, you do pay quite a bit for these features, with this lens retailing for around £550.

Sigma also offer a fisheye lens for APS-C sensor DSLRs. Their 10mm f/2.8 fisheye has silent autofocus and a fast f/2.8 maximum aperture, but costs around £480.

Finally, Tokina's 10-17mm DX zoom fisheye is another alternative. As this lens offers zoom, it should afford greater flexibility, but at a price, as it costs around £430.

Kelda 6.5mm f/3.5 Fisheye Verdict

For many people, the cost of a fisheye lens makes purchasing one difficult to justify, as the curved effect isn't something you'd want to feature in every image you take. With this lens, you have a very reasonably priced alternative to the offerings from camera manufacturers and the better-established third-party lens makers, that is more than capable of delivering outstanding sharpness. If you can live with this optic's propensity for flare and a few other minor handling niggles, such as the lack of a hyperfocal scale, then this lens offers a perfect introduction to fisheye photography, for not a lot of money.

Kelda 6.5mm f/3.5 Fisheye Pros

Outstanding sharpness in the centre when stopped down
Good Build Quality
Very inexpensive
Stereographic projection
 

Kelda 6.5mm f/3.5 Fisheye Cons

Susceptible to flare
No hyperfocal scale

FEATURES
HANDLING
PERFORMANCE
VALUE FOR MONEY
VERDICT

The Kelda 6.5mm f/3.5 Fisheye lens delivers outstanding sharpness and offers excellent value for money.

Kaili Optronics Kelda 6.5mm f/3.5 Specifications

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