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Wide Angle Converters for Compacts

by Gisle Hannemyr

Recently, I wanted to get a wide angle converter for a Canon Powershot G5 and a Olympus Camedia 2020Z digital compact cameras.

Cheap 0.42x-0.5x "fisheye" converters

My quest initially lead me look at to various 0.42x, 0.45x and 0.5x wide angle converters. Adorama sells one for $40. They're frequently found at eBay between $20 and $80. Some webshops sell them for more than $100. I don't know whether all the examples I've seen advertised are the same item. They are labeled with miscellaneous brands (e.g. Bower, Cokin, Crystal Vision, Deitz, Digital Optics, Hi Tech Optics, Pro Optic Deluxe, Phoenix, Platinium, Sakar, Titanium, TopBrand) - but they all share the characteristic of being "Made in Japan" by an obscure company, suffer from a bad case of barrel distortion (so they are called "fisheye"), attach to the prime via a Series VII thread, and come with a rear element labeled "macro" that can be detached and used seperately as a close-up diopter adjustment.

The Adorama product sheet for the Pro Optic 0.42x quotes extensively from a review in Popular Photography Jan. 2002, which gives the impression that the converter is half decent. The truth is that when attached to a prime stopped down to its optimum aperture, the resulting images are still as soft as a baby's bottom, and there is a lot of vignetting, CA and barrel distortion.

Here is links some user reports found at various websites, blogs and boards:

More useful converters

After deciding that those brand X converters was not worth the money, I started looking for other solutions.

All the leading camera manufacturers make quality wide angle converters for their non-DSLR cameras, but they're expensive. For the Canon Powershot G3/G5, there is the Canon WC-DC58N (0.7X) converter with 58mm thread ($150), and for the Olympus C-2020Z, there is Olympus WCON-07 (0.7X) ($130) and WCON-08 (0.8X) ($140), both with 55 mm thread.

In addition to the converters from the major camera manufacturers, the following manufacturers have a reputation for making useful converters that can be attached to most digital compacts with a suitable adapter: Kenko, Raynox, Tiffen and Hakuba.

Most of the third party converters come with a 52 mm thread. Since I both own a Canon G5, and an Olympus C-2020Z (I still use it for infrared work), I decided to go for third party adapter tubes with 52mm threads. For the G5, I use the G3/G5 Lensmate 52 adapter ($25), and for the Olympus C-2020Z, I use the Kenko 41mm-52mm adapter tube ($16). Using 52mm adapter tubes also let me use the filter collection I built up for my Nikon SLR film body and my Kodak DCS-460.

I ended up buying a Raynox DCR-720 (0.72x) wide angle converter ($55), and, on a whim, I bought a vintage Kenko fisheye (0.18X) at an action on eBay ($68). Click on the links to fast forward to see the samples from the Raynox DCR-720 and from the Kenko.

My tests

Raynox DCR-720 (52 mm thread)

The Raynox DCR-720 multiplies the focal length of the prime with approximately 0.72, so a 35 mm becomes a 25 mm lens. Sharpness is good, with just a little softness at the edges, even at wide apertures. Barrel distortion is pretty bad, but can be corrected with Panorama Tools.

Sample 7.2 mm Sample DCR-720
Model:Canon G5Model:Canon G5
Date:2004-08-12 12:26Date:2004-08-12 11:34
Shutter speed:1/1250 sec.Shutter speed:1/1000 sec.
Aperture:f/3.2Aperture:f/4.0
Focal length:7.2 mm (~ 35 mm)Focal length:7.2 mm (~35 mm)
 Focal length 2:5.18 mm (~ 25 mm)

A peculiar quirk is that when you stick an adapter and an wide angle attachement on a Powershot G5, they block the G5's focus assist beam. This means that you lose the autofocus if the ambient light is so low that the focus assist beam is needed.

Kenko 0.16x Fish-eye Converter (52 mm thread)

This Kenko attachment is most famous for being used as the "eye" of Hal in Stanley Kubricks: 2001 – a Space Odyssey. It has a huge, bulging, front element.

While modern wide angle attachements usually have no controls, this Kenko model (long since discontinued) has two control rings. The first displays a series of f-stops, going from f/3.5 up to f/90. The second is a series of focal lengths for 35 mm camera lenses - starting at 200 and going down to 30.

F-stops: 3.5  4 . 5.6 . 8 . 11 . 16 . 22 . 32 . 44 . 64 . 90
Focal lengths: 200 . 135 . 100 . 85 70 58 50 40 35 30

After asking for help on Usenet on putting it to best use, I received the following replies:

From Nostrobino: It is recommended to always shoot with the prime lens wide open. Aperture adjustments should be applied to the attachement. This of course will mean putting the camera into aperture-priority (or manual) mode. The focal length ring should be adjusted to the 35 mm equivalent of the focal length (but I have no idea what happens if you lie - its only purpose seem to be to limit the range of available apertures.).

From Apteryx: I have only used it with 50 mm and 135 mm fixed focal length lenses on a 35 mm film camera. (I think I may have fitted it in the distant past to a 75-150 mm zoom and a 24 mm, but found those combinations unsuitable.) At 50 mm it gives a full 180 degree angle of view horizontally, and bit less vertically. With a 135 mm lens, it is a full frame fisheye, with little or no vignetting.

DSLR experience: On a Sigma SD10 (1.7x crop), I got the best results by putting the attachement with 35 mm f/2.0 (~60 mm equivalent) fixed focal length lens. A 30 mm (~50 mm equivalent) would probably work even better. I opened the prime fully up to f/2.0, and stopped the attachement down to f/13. The image on the left below show the angle of view afforded by the 35 mm prime, and at the image on the right shows the result when the Kenko attachment is put in front of the prime. It is a typical fisheye "look" with near circular vignetting. It provides a full 180 degree angle of view horizontally, and bit less vertically. After adjusting for the 0.16x fisheye factor, the resulting focal length is 10 mm. Sharpness is decent in the center, but the edges are somewhat soft.

Sample 5.6 mm Sample 5.6 mm
Model:Sigma SD10Model:Sigma SD10
Date:2006-03-12 11:23Date:2006-03-12 10:45
Shutter speed:1/1250 sec.Shutter speed:1/640 sec.
Aperture:f/4.0Aperture:f/2.0 + f/13
Focal length:35 mm (~ 60 mm)Focal length:35 mm (~60 mm)
 Focal length 2:5.6 mm (~ 10 mm)

For comparison, I've also included an image (left, below) of the same scene taken with the Sigma 10-20 mm f/4.0-5.6 EX DC HSN at 10 mm (~ 17 mm) at f=10 mm. This is a rectilinear lens that at its widest setting gives a 103 degrees field of view on the SD10 body.

Compact experience: Putting the Kenko attachement on a Canon Powershot G5 with a 4x zoom was a disappointment. Best results with the attachement was achieved with the G5's prime was zoomed to its tele end - 28.8 mm (~139 mm) - which means that after adjusting for the 0.16x fisheye factor, the resulting focal length is 22 mm. This results in a fisheye "look" - sort-off, but with an angle of view of no more than about 120 degrees. Zooming the G5 out to wider focal lengths just results in a smaller image circle with no increase in angle of view. The adapter necessary to mount the attachement probably puts too much distance between the prime and the attachement, so the angle of view is never more than about 120 degrees, and the vignette is gradual rather than a distinct circle. Sharpness is decent in the center, but the edges are very soft, as are the edges of the image circle.

Sample 7.2 mm Sample FE
Model:Sigma SD10Model:Canon G5
Date:2006-03-12 11:20Date:2004-08-12 11:29
Shutter speed:1/2500 sec.Shutter speed:1/640 sec.
Aperture:f/4.0Aperture:f/3.0 + f/11
Focal length:10 mm (~ 17 mm)Focal length:28.8 mm (~139 mm)
 Focal length 2:4.6 mm (~ 22 mm)

Link farm

I've registered a couple of webpages that publishes reviews of various converters:

These sites has full size sample shots of some of the converters:

If you want to comment, use the blog!

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