This is a sequel to an earlier post, entitled Why Do I Swim in Blood - I was listening to Stereolab at the time - in which I take my Kodak DCS 560 out into the sunshine with its infrared filter removed, and a visible light blocking filter mounted on the front of the lens, which in this case is a super-sharp Olympus 24mm f/2.8. More technical details in the earlier post.
I ended up with far more images than I could fit into a single post, and so here are some more. They were shot in Freshford, Somerset, a posh village with its own train line. If you want to be buried in a plot in its cemetery, and you are not a resident, it will cost you £780.
This is a follow-up to a couple of earlier posts. In the first, Machines Worked by Fire, I used the power of software to stretch out and "defish" images shot with a fisheye lens, and in the second, which does not have a name but I will call him Klarc Kumquat, I applied the same magic to video. This was a laborious process that involved transforming the video into a series of still frames, applying software correction to each frame, and then assembling the frames into a video again. It took an age, but the end result was an extremely wide field of view, impossible to achieve otherwise.
I've since found a better way to do things. Have a look at this:
It's part of my daily bicycle commute, shot with a Canon 5D MkII and a Zenitar 16mm fisheye lens, mounted on the handlebars of my bike with a Gorillapod, although it's not much use without the ball head). The camera wobbled up and down a lot, although this is much less apparent when the video is run at ten times normal speed. I suspect something like a Panasonic GH1 or a Canon 550D would be more practical for bike-mounted filming - or for that matter a motorbike! The music is by myself.
Previously I worked on individual frames, because I wasn't aware of a VirtualDub plugin or standalone piece of software that could stretch out video. Defishing fisheye images is a computationally intensive task, and the technique is very esoteric. Fortunately at least one other person in the world has had the same idea, and a handy chap called David Horman has written a bang-up-to-the-minute plugin for AVISynth that will defish images (I found it in this forum thread at Doom9, which is full of people who are experts on ripping, fiddling with, and then reconstituting digital video into new forms). It appears to date from February 2010 and is available here.
The tricky thing is that it only works with AVISynth, a free, command-line video editor which can be run independently, or invoked as part of VirtualDubMod, an older version of VirtualDub with some novel features. Being a command-line editor, there isn't a graphical user interface. None of that girly point-and-click with the mouse nonsense. In order to defish the bike ride above I had to type:
The "fov" parameter stretches out the video, and the "scaling" parameter scales it so that the edges aren't cropped off. The end result looked like this:
And so I cropped off the top and bottom, and added a border so that the image was an even number of pixels. Several video compressors require the pixel dimensions to be a multiple of a whole number, and I chose 800x400 because they are good whole numbers, and I like the colours. Eight is yellow and four is blue and zero is water. 800x400 looks like a field of sunflowers underneath a bright blue sky, turned on its side, with water.
You'll notice that it's blurry around the edges - this is a consequence of the defishing process, but in the context of a fast-moving point-of-view shot it just looks like motion blur, as in the famous "trench run" sequence from the first Star Wars film. In fact it adds to the effect.
Of course on the day that I write this post it is overcast again. England continually fails me. I dream of a land where there is sunshine.
From back to front, a Canon 24mm f/2.8, a Canon 50mm f/1.8 MkII, and right at the front a tiny tiny Olympus 21mm f/3.5. Like the rest of the OM range, the 21mm is very small and well-made. It is shorter and less girthsome than Canon's 50mm f/1.8, and as far as I can tell it is smaller than any other full-frame 21mm SLR lens before or since. Mine is number 116869. It has a production code of G16, which means that it was made in June 1981, according to a post by OM expert John Hermanson on this forum thread at Photo.net. I was intrigued to see whether it would be any good on my full-frame Canon 5D.
According to the ever-handy Mir.com, the 21mm f/3.5 is one of the oldest OM lenses, and dates from the mid-70s. There isn't much about it on the internet apart from this article in which it is used for night-time photography on a tripod. The lens is also overshadowed by the later Olympus 21mm f/2, which was for many years the fastest ultrawide SLR lens. Even today the f/2 model fetches a steep price on the used market. The modern Sigma 20mm f/1.8 is slightly wider and faster, but based on the tests I have seen on the internet it is unusably soft at wider apertures. Leica nowadays sells an extraordinary 21mm f/1.4 for a typically extraordinary Leica price tag of around $6,000, but it is Leica M-Mount only and thus belongs to another world.
The Olympus 21mm f/3.5 takes 49mm filters, which was the standard Olympus size. Unfortunately even the thinnest filter vignettes on the lens with a full-frame camera, and if you don't want to crop out the corners you have to use a stepping ring or a filter adapter. The vignetting isn't apparent through the viewfinder of my OM10, and perhaps in the days of machine-cut 6x4 prints it wasn't obvious. The lens focuses very closely, to whit:
The monkey was only a few centimeters from the lens. In practice this is the only way to get shallow depth of field effects; at f/8 and beyond pretty much everything is in focus.
On a conventional digital SLR it doesn't have much of a role, because it is no faster or wider or sharper than a typical kit lens. On a Four Thirds or Micro Four Thirds body it becomes a very slow normal lens that is rendered utterly obsolete by the Panasonic 20mm f/1.7. It is however interesting on a full-frame camera, which in practice means a Canon 1Ds or 5D (in common with most other vintage lenses, it will not focus to infinity on a Nikon body). Canon sells a 20mm autofocus lens, but no-one has a good word to say about it and it is bulky and expensive; the company also sells several zooms that cover the 20mm range, but they are much larger and more expensive.
Here are some tests. The lens has aperture stops for f/3.5, f/5.6, f/8, f/11, and f/16. Here's what the vignetting is like (using a large, Cokin filter mount that does not intrude on the image), at f/3.5 and then f/5.6:
Here's what the image looks like just to the left of centre, at f/3.5, f/5.6, and f/8. F/11 is just as sharp, f/16 is slightly softer due to diffraction. These are 100% crops from a 21mp original, with mild unsharp mask:
It has a slight glow at f/3.5, but is generally sharp, and then gets better one stop down and stays better. Here's a lengthy series of 50% crops from the bottom-left corner, through all the aperture stops:
In my opinion it seems to reach a plateau at f/8, beyond which it improves only slightly. In practice, at screen sizes and for A4 prints, nobody will care about the softness even at f/3.5, certainly not at f/8. There is a fly in the ointment, however: the lens has a problem with purple fringing and chromatic aberration. Here's an example, shot at f/11, with a crop of the top-left corner:
The lens is not great for shooting tree branches in the corner of the frame. To be fair, purple fringing is -as far as I can tell - a consequence more of the sensor design than the lens, and I can't fault the engineers at Olympus for designing a lens in the mid-70s that purply-fringes on a digital SLR in 2010. The CA is however visible through the viewfinder of my Olympus OM10, and so must surely be caused by the lens. Fortunately it can be corrected with software (or simply painted over, or even cropped out).
I have no problem with the colour rendition. It is not a particularly contrasty lens and does not cope well with flare, a problem exacerbated by the difficulty of finding a suitable lens hood. Olympus made a special 21mm lens hood. Good luck finding it in 2010. My copy of the lens has "MC" in the name, and so presumably is multi-coated, but I surmise that multi-coated ultrawide lenses from the early 1980s are never going to be ideal for shooting bright lights. So far I haven't mentioned distortion, the reason being that I haven't really noticed any. I'm sure it's there, it's just not particularly offensive.
It's useful for video. It's compact, and at f/8 it is pretty much focus-free. Indoors at f/3.5 it still has enough depth of field for comfort, although you'll have to bump the ISO up. Given that it is so small, it isn't a pain to carry in a camera bag. The lack of distortion is handy too; most wideangle attachments for video cameras, for example, make everything look like it was shot with a fisheye. Here's a short video shot at the Heygate Estate, south London, with the lens at infinity, f/8, Canon 5D MkII, music by myself:
There are other ultrawide lenses on the used market. Nikon seemed to have a thing for the 20mm focal range, and there was a late-70s Tokina 17mm that had a decent review at Photozone.de. Brand-new there aren't many 21mms - the Zeiss 21mm f/2.8 Distagon, which is apparently superb, and the intriguing but obscure Voigtlander 20mm f/3.5 for Nikon and Pentax and thus by adaption Canon, although I can't find any thorough reviews, and most Google returns seem to be people asking where they can find thorough reviews of the lens, or whether anybody has one.
EDIT: With the exception of Photozone.de, whose review was posted twenty-four hours after I wrote the above! The lens obviously wanted to be heard.
I ended up with far more images than I could fit into a single post, and so here are some more. They were shot in Freshford, Somerset, a posh village with its own train line. If you want to be buried in a plot in its cemetery, and you are not a resident, it will cost you £780.
, although it's not much use without the ball head
). The camera wobbled up and down a lot, although this is much less apparent when the video is run at ten times normal speed. I suspect something like a Panasonic GH1 or a Canon 550D would be more practical for bike-mounted filming - or for that matter a motorbike! The music is by myself.
And so I cropped off the top and bottom, and added a border so that the image was an even number of pixels. Several video compressors require the pixel dimensions to be a multiple of a whole number, and I chose 800x400 because they are good whole numbers, and I like the colours. Eight is yellow and four is blue and zero is water. 800x400 looks like a field of sunflowers underneath a bright blue sky, turned on its side, with water.
From back to front, a Canon 24mm f/2.8, a Canon 50mm f/1.8 MkII, and right at the front a tiny tiny Olympus 21mm f/3.5. Like the rest of the OM range, the 21mm is very small and well-made. It is shorter and less girthsome than Canon's 50mm f/1.8, and as far as I can tell it is smaller than any other full-frame 21mm SLR lens before or since. Mine is number 116869. It has a production code of G16, which means that it was made in June 1981, according to a post by OM expert John Hermanson on this forum thread at Photo.net. I was intrigued to see whether it would be any good on my full-frame Canon 5D.
According to the ever-handy Mir.com, the 21mm f/3.5 is one of the oldest OM lenses, and dates from the mid-70s. There isn't much about it on the internet apart from this article in which it is used for night-time photography on a tripod. The lens is also overshadowed by the later Olympus 21mm f/2, which was for many years the fastest ultrawide SLR lens. Even today the f/2 model fetches a steep price on the used market. The modern Sigma 20mm f/1.8 is slightly wider and faster, but based on the tests I have seen on the internet it is unusably soft at wider apertures. Leica nowadays sells an extraordinary 21mm f/1.4 for a typically extraordinary Leica price tag of around $6,000, but it is Leica M-Mount only and thus belongs to another world.
The Olympus 21mm f/3.5 takes 49mm filters, which was the standard Olympus size. Unfortunately even the thinnest filter vignettes on the lens with a full-frame camera, and if you don't want to crop out the corners you have to use a stepping ring or a filter adapter. The vignetting isn't apparent through the viewfinder of my OM10, and perhaps in the days of machine-cut 6x4 prints it wasn't obvious. The lens focuses very closely, to whit:
The monkey was only a few centimeters from the lens. In practice this is the only way to get shallow depth of field effects; at f/8 and beyond pretty much everything is in focus.
Here are some tests. The lens has aperture stops for f/3.5, f/5.6, f/8, f/11, and f/16. Here's what the vignetting is like (using a large, Cokin filter mount that does not intrude on the image), at f/3.5 and then f/5.6:
Here's what the image looks like just to the left of centre, at f/3.5, f/5.6, and f/8. F/11 is just as sharp, f/16 is slightly softer due to diffraction. These are 100% crops from a 21mp original, with mild unsharp mask:
It has a slight glow at f/3.5, but is generally sharp, and then gets better one stop down and stays better. Here's a lengthy series of 50% crops from the bottom-left corner, through all the aperture stops:
In my opinion it seems to reach a plateau at f/8, beyond which it improves only slightly. In practice, at screen sizes and for A4 prints, nobody will care about the softness even at f/3.5, certainly not at f/8. There is a fly in the ointment, however: the lens has a problem with purple fringing and chromatic aberration. Here's an example, shot at f/11, with a crop of the top-left corner:
The lens is not great for shooting tree branches in the corner of the frame. To be fair, purple fringing is -as far as I can tell - a consequence more of the sensor design than the lens, and I can't fault the engineers at Olympus for designing a lens in the mid-70s that purply-fringes on a digital SLR in 2010. The CA is however visible through the viewfinder of my Olympus OM10, and so must surely be caused by the lens. Fortunately it can be corrected with software (or simply painted over, or even cropped out).
I have no problem with the colour rendition. It is not a particularly contrasty lens and does not cope well with flare, a problem exacerbated by the difficulty of finding a suitable lens hood. Olympus made a special 21mm lens hood. Good luck finding it in 2010. My copy of the lens has "MC" in the name, and so presumably is multi-coated, but I surmise that multi-coated ultrawide lenses from the early 1980s are never going to be ideal for shooting bright lights. So far I haven't mentioned distortion, the reason being that I haven't really noticed any. I'm sure it's there, it's just not particularly offensive.
