Fish species diversity and its consequences | Articles

The first question that might spring to mind here is: Why use a fisheye lens at all? The trend for this type of lens comes and goes like a boomerang; it’s like salt in the kitchen – for a few years it’s deadly, then for the next few it’s essential for life, only to come back and kill us all over again. I’ll deal with that another time. Personally, I love fish in every form – fried, boiled, and those attached to the camera body.

We have diagonal, circular and – let’s call them – ‘incomplete’ fish-eye lenses. We sometimes come across the term ‘portrait fish-eye’, which refers to a circular lens with cropped edges. This is an effect that we’ll also see when using fish-eye zoom lenses, naturally to a greater or lesser extent between the diagonal and circular ends. Therefore, by the term ‘incomplete’, I mean here a lens that produces noticeable and severe distortion but does not achieve, nor come close to, a field of view of 180 degrees or more diagonally across the frame.

I will demonstrate the differences in the images captured by three different MFT system lenses. The photographs were taken with an OM-1 camera using a tripod. I used the tripod so that I could compare photographs taken from the same vantage point but with different angles of view. Consequently, the compositions may not seem entirely logical, as images captured in a rectangular or circular format may require the camera to be oriented differently to look its best. Furthermore, using a tripod with a circular fish-eye lens results in the tripod being visible in the photograph, as this type of lens partially looks backwards.

Let’s move on to discussing the lenses used to take the photos being compared.

Standing, from the left: Olympus M.Zuiko 8/1.8 AF, Brightin Star 10/5.6 II MF, 7Artisans 4/2.8 MF. A few words about them.

Olympus M.Zuiko 8/1.8 AF – the most expensive in the list. The manufacturer’s official price is around 1,100 euros / 1,300 US dollars. The market price is sometimes much lower, but it’s not cheap either way. It has an autofocus. And don’t believe those who say that autofocus doesn’t matter with a fisheye lens. They simply don’t use lenses like this. You very often have subjects very close to the camera in your frame. The minimum focusing distance here is 0.12m/0.39ft. And at the widest aperture of f/1.8, the depth of field is by no means great. And with such wide angles, it’s not at all easy to focus by eye. The lens is from the PRO series, superbly built, rugged and splash-proof. And, crucially, when used in conjunction with the manufacturer’s higher-end camera models, it enables automatic de-fishing. Yes, just one press of a button (provided you’ve assigned that function to one) or selecting the option from the menu, and the image is transformed and cropped to a rectilinear ultra-wide format. There are three possible settings, ranging from the widest to a slightly narrower angle. The transformed image is saved as a JPG, whilst the original can remain unchanged in its native RAW (ORF) format. So, just in case, we don’t lose anything. We can also perform the rectification process in post-production using the manufacturer’s OM Workspace software. Here, there are even slightly more adjustment options. Given this lens’s superb resolution, we can successfully use it as a rectilinear ultra-wide-angle lens at the touch of a button. For me, it’s brilliant.

Brightin Star 10/5.6 MF - it costs just 75 USD. It weighs 120 grams (MFT version). One of these lenses, alongside, for example, the 7Artisans 18/6.3 ‘micro-pancake’, with which you can put together an almost non-visible discreet kit. Get an older PEN E-PL7 and a few ‘feather-light’ lenses, and you’ve got a complete travel kit in your pocket for very little money and weighing less than about 1kg / 2lb. Sounds good, and it’s doable. I’ll tell you more about that later. This is one of those lenses. The manufacturer states that the field of view is 173 degrees. It has a single, fixed aperture of f/5.6 and, as with the other two lenses described here, it is not possible to attach a filter, including a rear filter. 7 elements in 5 groups. The image quality is surprisingly good for such a simple and compact design. As is often the case with Brightin Star lenses, it’s simply a lovely good looking thing and you get a pleasure from owning it.

7Artisans 4/2.8 MF – costs 149 USD. Another reasonable price lens. Circular, 225 angle of view. You take photos with your arms straight and held out in front of you. I’m not joking. Otherwise, your feet and forehead will always end up in the shot. This problem is illustrated in the examples. The OM-1 body grip is visible on the right-hand side of the image. Taking photos with the PEN does not cause this problem. The aesthetics of circular forms are distinctive, different. For me, what happens outside the frame itself is incredibly important – the luminous circles, the flares, the flashes, all that magic born of chance. I have come across the claim that, with this type of manual lens – which has no image stabilisation – you should switch on the in-body image stabilisation. Anyone who writes such things has probably never taken a single photograph in this configuration. You must absolutely NOT switch on image stabilisation. The image circle fits precisely within the sensor frame, and using stabilisation – which involves sensor movement – will cause the image to move out of the frame. This can have a particularly dramatic effect in a video when literally half the image ends up out of frame and then proudly swings back into the centre. Back to the specification… 201 grams, fastest aperture f/2.8, 0.085m focusing distance. You can get very, very close (be careful not to scratch the lens).

Case one – the tomato.

Understandably, correcting distortions results in some loss of image detail. The corrected image from the Olympus no longer shows any trace of the sky. The details in the corners have disappeared. However, the image has become uniformly rectilinear without losing much in the way of sharpness or detail reproduction. The image captured by the Brightin Star 10mm appears to have a field of view similar to that of the Olympus’s standard lens, but exhibits the distortion typical of a fisheye lens. It may not be excessively pronounced, but it is clearly visible. The 7Artisans is a circular fisheye, so everything looks quite different here. It has a 225-degree field of view, no matter which way you look. Standing in front of a wall, you can see the whole of it, a bit to the sides, and even a little bit behind you. The image looks particularly interesting when you’re standing in a square opening (such as a window or door), as it then turns into a circle. It’s worth having an element in the image that really catches the eye, and it’s worth remembering that the line dividing the image horizontally in half will remain straight. In this particular case, the two green tomatoes positioned right in the centre mean that there is actually something to catch the eye.

Olympus

Olympus – in body defishing

Brightin Star

7Artisans

Case two – rudbeckia.

Here, the situation is somewhat different in that the Olympus M.Zuiko, with its f/1.8 aperture, allows us to effectively blur the background. As a result, the centrally positioned rudbeckia flower seems to leap out towards the viewer. With the Brightin Star 10/5.6, this isn’t possible, and with the 7Artisans 4/2.8, it doesn’t make much sense, as in that case the tiny flower would almost disappear from the frame and escape our attention. What matters more here is its yellow colour, which differs from its surroundings.

Another thing that stands out is the difference in bokeh. With the M.Zuiko, the bokeh looks interesting both before and after straightening, and the light circles are quite striking. With the Brightin Star, the bokeh is, generally speaking, rather mediocre – but then again, it is f/5.6. As for the 7Artisans, given its circularity, it isn’t the sort of lens you’d turn to for beautiful bokeh…

Olympus ![image](files/P8250164 1.jpg) Olympus – in body defishing

Brightin Star

7Artisans

Case three – the bench.

The focus is set on the little plant at the bottom centre of the frame. Even at an aperture of f/1.8, the subject isn’t particularly well separated from the background; however, in the case of the image taken with the M.Zuiko – which has not been geometrically modified either in-camera or in post-production – the shape of the little plant seems to harmonise better with the vertical rhythm of the trees in the background. This example shows that the Brightin Star’s angle of view is narrower than that of a straight image from the M.Zuiko, whilst producing an image with very distorted lines. This is why I classify it as an ‘incomplete’ fish-eye. It gives us the full fish-eye experience whilst not covering quite such wide angles of view. We’ll check at some point whether it really is as wide as the manufacturer claims. Nevertheless, given its tiny size and low price, it’s an excellent addition to our camera bag, provided we don’t regard the fish-eye aesthetic as the main focus of our project, but merely as a possible complement. As I’m shooting into the sun here, the 7Artisans produces strong and distinct flare. The luminous halos around the image circle are impossible to miss. And then there’s the visible tripod and the visible camera body grip. It’s not the best setup or way to shoot with this lens, but once again – the same camera body and tripod were used to maintain consistent angles for comparison purposes.

Olympus

Olympus – OM Workspace defishing

Brightin Star

7Artisans

Case four – mirabelle plums.

Looking at the elements diagonally across the images, one might assume that the 173-degree viewing angle claimed by Brightin Star applies only to the version with an APS-C mount; on MFT, this angle is noticeably smaller. So, once again, without taking anything away from it, ‘incomplete’. You get more of an impression than a range.

Olympus

Olympus – in body defishing

Brightin Star

7Artisans

When to fillet a fish and when not to (correcting distortion) is a matter of personal aesthetic preference as well as the subject of the photograph. However, it is good to have this option. The type of lens used will also determine the subsequent post-processing required. Whilst I think it makes sense in some cases to go for black and white with the Brightin Star, I wouldn’t really do that with the 7Artisans, except perhaps in some extreme situations. Similarly, I find it baffling when some people crop everything outside the circular field of view from an image taken with a circular fish-eye lens. For me, these flares, highlights, rings, or other artifacts are inextricably linked to the lens’s character. Using any kind of fisheye lens requires you to use your imagination. Not everything is quite so obvious anymore. For example the three-way split and all that… The angle at which you raise or lower the camera now has a different significance. The joy of photography remains the same.

Hope the fish are biting!