by Klaus Schroiff, published August 2019
Introduction
It’s awesome … and it’s hell! There you go – the verdict is straight in the first sentence! 🙂
Most of you who have used fisheye lenses will probably agree that fisheye lenses are a love-hate relationship more so than with any other lens type. You love them because they deliver the unexpected and extreme and you hate them pretty much for the same reasons. And if you sell one because it fell into disuse, you will regret the decision a year later again – because, well, “that shot would be awesome with a fisheye”.
Fisheye lenses come in two flavors – full-frame and circular. Full frame lenses are pretty mainstream and available both from Olympus/Panasonic as well as from numerous more or less dubious third-party manufacturers. Circular fisheye lenses are far more exotic with less than a handful of “native” micro-four-thirds options. One of them is the Laowa 4mm f/2.8 Circular Fisheye and I was thrilled to hear about it when the first rumors about it started to emerge. And the best news is … that it won’t cost you can an arm and a leg at just 199USD!
In terms of build quality, it is aligned with what we have seen from Laowa lately. Thus it’s an all-metal construction and fully manual – thus it has a manual aperture as well as a manual focus ring. Some may not like this but in real-life, you set the aperture to f/5.6 and the focus to 1m and that’ll be good enough for the vast majority of shots. The lack of EXIF data may be more annoying. An aspect that is important in our book is the size and weight of the lens. Once the initial romance is over, you’ll probably rarely use the lens and you just won’t pack a brick thus losing opportunities when they emerge. The Laowa thought of that and at just 120g, you’ll barely notice it in your bag. In the product images, you will notice that it is impossible to use conventional lens caps on it due to the protruding front element. Instead, Laowa is providing a full body cover (made of metal) that aligns with the slightly protruding focus ring lever – an efficient solution.
| Specifications | |
|---|---|
| Optical construction | 7 elements in 6 groups |
| Number of aperture blades | 7 |
| min. focus distance | 0.08m (max. magnification ratio 1:9) |
| Dimensions | 45×25mm |
| Weight | 120g |
| Filter size | – |
| Hood | Tube-style |
| Other features | What more do you expect? |
| Mount | Micro-Four-Thirds (non-coupled) |
So what does it mean visually? The lens offers a field-of-view of 210 degrees (180 degrees horizontally). Just to illustrate this – below is yours truly visible on all image sides with the camera sitting on his belly.
Is it truly a circular fisheye lens?
Yesno. In terms of optical design, it is but it has one bug – its image circle is slightly bigger than the MFT image frame resulting in slight cropping at the top and bottom of the image. If it is a requirement for you to have a flawless circle out-of-the-box, this will be a showstopper.
However, if you have minimum skills in post-processing images, it’s really not that hard to correct this really. Most popular imaging tools (Photoshop, even Paint.NET) offer an elliptical marquee tool that you can easily use to fix the issue. In Photoshop you can even create an action for this to automate the procedure. By doing so you also crop the bluish fringes at the edge as well as freak reflections that made it beyond the image circle into the black part of the image frame. Below is the sample image from above but with the procedure applied. If you’d like to go the extra mile you could also soften the transition from black to the actual image zone a bit for making it less harsh.
Note: The bluish zone is in fact pretty common. The Canon EF 8-15mm f/4 USM L Fisheye shows it as well.
Crazy Shit happens … a lot …
While it is, of course, a feature to have that much field-of-view at hand, it is also downright painful for at least two reasons.
Reason 1: Even if you don’t want to, your body parts will often make it into the image. I’ve to admit that my belly isn’t that small but even if you are slim, you will have your feet (or your tripod legs) ending up in the image fairly often.
Reason 2: and that’s really the worse aspect, you can’t really use your camera grip. I’ve used the Olympus E-M5 II for this review – a camera with a very small grip. When using the grip, my hand was in the image frame! Or in other words – you’ll look a bit silly to others because you have to hold the camera at the top & bottom plate … as well as far away from your body. Honestly, I’m not sure whether the extreme field of view is an issue on MFT cameras with a deep grip (e.g. the Panasonic G9) where the grip itself may already be in the image field (but keep in mind that you’ll usually crop your image anyway)!
Keeping all that in mind, let’s head to the more formal aspects.
Distortions
Are you kidding me? 😉
Vignetting
Yeah, right …
MTF (resolution)
It’s quite a nightmare to test the resolution of a full-frame fisheye and the setup problems increase dramatically with a circular fisheye lens. Thus please consider the following results as experimental.
Surprisingly the resolution is actually quite impressive. The image center is tack sharp at f/2.8 already and the image borders are pretty good as well. The corners aren’t great at this setting but it’s not bad either. Stopping down lifts the corner quality and the quality is very good around the f/5.6 mark. There is, of course, a further drop in resolution on the last couple of pixels near the black zone.
Please note that the MTF results are not directly comparable across the different systems!
Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations
Chromatic Aberrations (CAs)
Chromatic aberrations are a bit on the high side albeit that’s hardly surprising. An average CA pixel-width of 1.8px is visible in the “borders”. This is visible albeit not terrible. However, if you plan to “de-fish” your images (more on this later) you should correct the issue beforehand – most modern RAW converters can do that for you these days.
Flare
So yes, it does flare a lot when placing the sun or other strong light-sources near the edges. Glare can also be an issue when having extreme contrast transitions.
Sample Images
Beyond native Fisheye Images
There are at least two post-processing opportunities with such a lens:
- De-Fishing images to a normal perspective
- Creating a 360 degree scene
As “post-processing” implies, you will need some software to make it happen. For 360 degree images, you will have to take some images from distinct angles and stitch those images together. I will leave this exercise to the reader … 🙂 … also because the freeware options are rather limited and evaluating options simply takes quite a while.
However, let’s look a bit deeper into the de-fishing. In essence, this is about creating distortion-corrected, ultra-wide images based on the fisheye image. This also works for full-frame fisheyes, BTW. In terms of quality, you shouldn’t expect wonders because some image portions are extreme stretched to make it happen but it’s an easy option if you are on a budget or simply for having some fun.
For the following images, we used Hugin (Freeware) which can be downloaded from HERE. A commerical option is e.g. Panoweaver
In Hugin, you can load the base image into the tool and specify the lens (=circular fisheye), it’s focal-length (=4mm) and focal-length magnification factor (=2x for Micro-Four-Thirds). From there, you move on to the perspective tool, select “rectilinear” and adjust the image until it fits your goal.
Below are two corrected images that you will also find in the sample image section above.
Competition
While full-frame fisheye lenses are commonplace with almost a dozen options for MFT alone, circular fisheye lenses are true exotics. The Laowa 4mm f/2.8 may already be hard to find on the vendor map for some but have you ever heard of iZugar? They are actually also offering a “native” micro-four-thirds lens – the iZugar MKX22 (center below). It is a 3.25mm f/2.5 – and it has a fixed aperture albeit it seems as if it does offer manual focusing at least. The performance is unknown. It’s even smaller than the Laowa but we’ve never seen this lens in shops and it goes for a hefty 499USD. Another exotic option – albeit not from a brand name perspective – is the Sigma 4.5mm f/2.8 EX SD HSM … for Canon EOS … which you could use via an (electronic) EOS-MFT adapter. It is an APS-C format lens but the fisheye circle is small enough to reside within the MFT image field (thus no cropping). However, the lens alone costs 799USD and, as you can see to the right below, it’s quite a brick on a micro-four-thirds camera. Thus while it is probably a better lens (based on the sample images that we have seen), it is not really an option for most users. It does have one advantage though – you can actually use the camera grip with your hand.
Visual comparison courtesy of camerasize.com.
The Laowa 4mm f/2.8 circular fisheye is both difficult as well as fun to use. Due to its immense image field, it will create lots of frustration because very often it's just too much really and staying out of the image is actually not as trivial as you might think. Conversely, if you find the right subject, the results are very rewarding indeed. It's also just awesome to explore this strange new extreme fisheye world. The image quality is almost secondary but technically it is still surprisingly high. The center quality is great and the image borders are pretty nice when stopped down a little. Chromatic aberrations are fairly high but that's rather typical for most lenses in this class. As mentioned there's also a zone with heavy fringing albeit you would/SHOULD apply a circular crop anyway. If this is no option for you, it's best to stay away. Flare and also glare can be an issue in difficut lighting.
In terms of mechanical quality, Laowa did a good job. Thus the lens body is made of metal down to the mount. This also applies to the lens "cap" - a tube really. There is no electronic coupling, thus you'll have to live without EXIF data as well as a manually controlled aperture and focus. Focusing is rarely an issue though. Unless you try your luck with closeups, most of the world will be in focus anyway - just set it to 1m and you are good to go.
So do you have to own a lens like the Laowa 4mm f/2.8 Circular Fisheye? No. But you should and at just 199USD, it is a steal really. Highly recommended!
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Optical Quality
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Build Quality
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Price / Performance