Anamorphic lenses, what are they? whats the point of building your own?
Well…the answer is because it looks cool, really cool. Anamorphic lenses allow you to achieve true widescreen on your digital SLR by squashing the image onto the camera sensor, which you then have to stretch back out again in Photoshop. Essentially everything looks cinematic in style and you can also achieve some really cool lense flair which is unique to anamorphic lenses.
They are a bit of a nightmare to work with and take alot of practice to master, an added nightmare in my case is that the lens has to be focused with an alan key, which isn’t exactly convenient. But in the pursuit of all things cool sometimes we have to do things the hard way. This is the setup that I used for my images, the Canon 5D (note: this didn’t work well so don’t rush out and buy a 5D, keep reading) I already had because its a classic and my go to travel camera. The rest of the gear from left to right is a Helios 55mm f/2 lens (£26 ebay) with Canon EOS adaptor, Schneider Kreuznach 2x Anamorphic (£73 ebay), Lens clamp from Vid-Atlantic (£36 ebay) and a 58mm to 72mm step up ring (£4 ebay) £140ish total.
The nightmare that comes from working with this lens in particular, is that you have to focus it with an alan key. Yes, an alan key. It’s a projector lens that has been adapted to fit a camera, so compromises were going to be made somewhere. Anamorphic lenses that focus in a conventional fashion are available, but are much more expensive, I wanted to keep costs to a minimum. When using two lenses bolted together like this you encounter a double focussing problem. Fortunately with the Helios lens it has the focus distances set on the side of the lens in metres as does the Schneider lens, if you’re shooting landscapes you can set both lenses to infinity and be certain that anything on the horizon is going to be sharp. I found that achieving accurate focus when shooting portraits requires smoe more accurate measurements. Setting both lenses to a focus distance of three metres and then using a laser measuring device to check that I am the correct distance from the subject. Straight out of camera the image looks like this.
As you can see the image has been squashed to fit onto the camera sensor, so we upload the image into Photoshop and stretch out the long edge by 160%
What is immediately obvious as a problem is with the 5D, which is a full frame camera, you can see the edges of the lens, which is what the black areas at the edge of the frame are.
This enters us into the realm of camera sensor size. A piece of 35mm film is the standard to which film slr’s are made of, in the digital world, this size of sensor is referred to as Full Frame, a Canon 5D is a full frame camera.The principal is if you put a 50mm lens onto a full frame camera, you will see exactly what the manufacturer intended, a standard 50mm view of the world. However, if you put a 50mm lens on camera that has a smaller sensor, the image is effectively cropped or zoomed in. This is called a crop factor, an APS-H sensor has a crop factor of 1.3 and an APS-C sensor has a crop factor of 1.6. This means that if you put a 50mm lens onto one of these cameras you need to multiply the focal length of the lens by the crop factor to get the true focal length. 50mm x 1.6 = 80mm so we get an equivalent focal length of 80mm from a 50mm lens. So to develop the project I switched to a Canon 7D which has a much smaller sensor size.
We can see with this overlay of the photograph that with a cropped sensor camera, we can effectively crop out the edge of the lens when taking the shot. This will result in an equivalent 80mm anamorphic lens, but for the added benefit of cutting out the distortion from the edge of the frame, the trade off will be worth it.