General information

The widest lens attachment for the E-10/E-20 made by Olympus provides the equivalent focal length of 28 mm. Close but no cigar: for many applications something shorter would come very handy.

Here comes Raynox of Japan with their DCR-FE180PRO attachment. It turns your zoom (at the widest setting) into a full-frame fisheye lens, with the diagonally measured view angle of 180 degrees. Wow.

After salivating for a couple of months, I decided to part with $400 of my hard-earned money, and ordered one from the Digital Distributors. (I have never dealt with them before, but the Web site is well-operated, and the order arrived promptly, well packaged, and as advertised.)

Note: the lens can be also used with cameras other than E-10 or E-20, although you'll need a step-up ring or adapter. I've tried it with success on the Olympus C-5050Z.

To keep things short, I will refer to the Raynox lens as just "FE180" in the remainder of this article.

Size and weight

Mounting on the camera; filters and hoods

With the rear thread of 62 mm, the attachment just screws directly on the front of the camera lens (remove any filters before that); no adapters are needed.

Obviously, with this kind of lens filters and hoods are out of question. As always with fisheye lenses, let us just hope that the flare will be under control.

I don't like the included rear push-on cap, and have replaced it with a metal, screw-on one of the proper thread diameter. Much better.

Optical

The lens has five elements in four groups, multicoated. It does not seem to affect the effective aperture of the lens, which remains at F/2 or close (this is based on my through-the-lens light reading).

According to Raynox, the attachment is computed to cover the full frame at the equivalent focal length of the main lens equal to 37 mm. True enough: at the equivalent focal length (EFL) of 35 mm, there is a slight image cut-off in the corners. If you are bothered by this, zoom in by just a little bit (less than a third between the two first values on the zoom scale).

The manufacturer also claims that the FE180 "works over the whole range of the camera zoom". I'm not sure how to understand this, as there are three aspects here:

• Vignetting: zooming in, even to EFL=140 mm, does not create any significant effect; from this point the statement is true;
• Image sharpness: lens attachments usually work best at a given focal length of the main lens. For this one, this means the wide end. My quick comparison (below) clearly shows a loss of sharpness when the main zoom is above mid-way into its focal length range.
• Image distortion: wide-angle lenses usually have image magnification varying with the distance from the center; this results in barrel- or pincushion-like distortion of straight lines. More, fisheye lenses by definition do not even attempt to correct for distortion, which therefore becomes an intrinsic feature.

The last point is of more than academic interest. While a super-wide, fisheye lens is useful only occasionally, most of the time as a novelty item, the equivalent focal length of, say, 20 mm can be immensely useful in architectural and landscape photography. I'm checking this further down in this article.

Image distortion (barrel type) is something you have to have in fisheye lenses (without it the 180-degree coverage cannot be achieved). Still, it remains to be seen how much distortion there is at settings corresponding to longer focal lengths of the lens+attachment combination.

Focusing

The focusing, as usually with this kind of accessories, is done by the main lens. The camera's macro/focus setting should show the non-blinking lens attachment symbol (this switches the infrared prefocusing off).

At the widest zoom setting, the closest focusing distance becomes less than 1 cm from the lens front. Care should be taken not to bang the lens surface against the photographed object.

Image samples

Here are examples showing the effect of using the FE180 attachment on the Olympus E-20. The difference in image angle is astounding, but that's what you would expect.

At the shortest focal length some image cut-off in the corners is visible with the FE-180. The effect is, however, very slight. (If you crop your pictures to the 3:2 aspect ratio, the corners go away at all.)

A casual inspection of full-size, original images shows that the image quality holds nicely in the frame center and, generally, in the central 60% of the frame width. It deteriorates in the furthest 20% on each side, becoming quite bad just at the borders, where both loss of sharpness and chromatic aberration (not to be confused with "purple fringing") are visible on high-contrast boundaries.

This behavior is quite typical for fisheye lenses in general, so I don't hold it against the FE180. On the contrary, I was expecting something worse.

Here is one more picture of the same scene, shot on a sunny January afternoon. The reduced, full-frame image is accompanied by three 1:1 samples. Please remember that when enlarged to 8x11" (20x27 cm) size, each sample will be just 1.14" (29 mm) tall, significantly smaller than what you see on the screen.

Overall, a respectable behavior. I have used a brand-name fisheye on a 35-mm SLR and the performance was not better.

Performance at various focal lengths

Having a full-frame fisheye lens is nice, but how often will you use it? After a while the novelty wears off and then you realize you've spent $400 for a conversation item.

Therefore I was very anxious to verify the manufacturer's claim of usability at any focal length of the main lens within a 1:4 range. If this is true, then the FE180 would provide us with the focal lengths from 9mm to 35mm or so, including the most useful, as far as I see it, value of 20 or 24 mm.

It is below freezing now in Maryland (January, 2003), so you have to understand that if I'm making the sacrifice of spending half an hour outside, in my company's parking lot, it better be important. Here are the samples, all taken in the aperture priority mode at F/4, with a -0.3EV exposure compensation. No, I wasn't using a tripod, no way.

All pictures were taken so that the car's trunk fills, approximately at least, the frame horizontally. This is to show the differences in perspective at various, especially shortest, focal lengths.

Well, I'm quite pleased with the results. The central sharpness at the widest setting (9mm) is very good, and it does not deteriorate visibly up to 25mm, although contrast falls a bit. There is a marked decrease in contrast at F=36mm (plus some additional loss of sharpness), although the lens still remains usable at this setting. (To make sure that this is not just a fluctuation in weather conditions, I took three series of tests, spaced three hours apart, and all results are quite consistent.)

A careful inspection of some of my original, full-size images shows that there is a slight vignetting in the corners at apertures of F/5.6 and above at all focal lengths. It is not as strong as the clear image cut-off at 9mm, but it shows as a slight darkening of the corners (covering the same area, or less, than the cut-off at 9mm). The effect is, however, quite unobtrusive if you are not looking for it, and it goes away at F/4.0. I can live with it.

Image distortion

The following examples show the distortion in images produced my the main lens + attachment combination at combined focal lengths which can also be achieved without the FE180.

To close the subject of distortion: before buying this lens, ask yourself the question: are you willing to accept the fisheye distortion, or maybe even use it creatively in your pictures?

If yes, then the FE180 will make you happy, both at is widest setting and at intermediate focal lengths.

The bottom line

The FE180 is a nicely-built and well-performing lens providing an exotic focal length to our digital cameras. Importantly, it also gives us the use of the very desirable focal lengths up to 28 mm (equivalent), although with image distortion much higher than that provided by non-fisheye, wide-angle lenses designed for these lengths. The FE180 has its flaws and limitations, but these are inherent to this type of lens in general.

$400 for an auxiliary lens is a lot of money, but the focal length range it opens for us, and the good optical quality may justify the expense — if you can't live without a real wide angle (i.e., below EFL=28mm).

The major setback I suffered when retiring my film SLRs was the loss of wide-angle capability: the 20-35mm zoom was one of my favorite lenses in scenics and architecture. With the Raynox lens I'm almost back in business. And what would I do with this money, anyway?

Still, if Raynox (or anyone else) comes up with a rectilinear, 20mm EFL lens attachment for the E-20, I'll be first in line. (The current 0.6x attachment by Raynox does not count, as it has a 55mm rear thread and causes unacceptable vignetting when used on the E-20 or E-10.)