I Made the "Next-Level" Camera and I love it

Table of Contents

This is one of my favorite lenses: the Helios 44. It has an "aperture" of 29mm, meaning that if you look straight through it, the circle that you see has a diameter of 29 millimiters. Why do we care, you might ask?

You probably know that pictures can be out of focus. But why does "out of focus exist"?

Well, without getting too technical, the lens takes the rays of light emitted by an object and then converges them into a single point; if you place the camera sensor in that point, you'll be able to see the object. However, if you place the sensor closer or further away from where the rays of light intersect, then you'll get a circle and the image will be out of focus.

Now, here's the kicker: the bigger the focusing lens is, the larger the cone of light rays is, meaning the the out of focus parts of the image will be more out of focus:

This is (partly) why phone cameras can't naturally reach the same levels of background-out-of-focus that camera can reach: they have such small lenses!

This is the camera lens that I do most of my work in. As you can see, this lens is much bigger; indeed, its (maximum) aperture is more than 53mm, almost double what the Helios can offer, which allows for a very strong separation between the subjects and the background.

The question now is: how big can we go? How much blurriness can we get out of a lens?

Well, assuming we're okay with carrying around a lot of weight, we can go pretty big. As an example, take the Sigma 135mm f1.4; this lovely lens (which I sadly don't own, yet) has a majestic aperture of 96mm,

and it can deliver pictures like the following one. There's a catch, though: due to physical constraints, all of these large lenses are also always very "zoomed in"! Take your phone camera and set the zoom to 4x: that's roughly what you're going to get with this Sigma lens. This can be great for some scenarios (and it's my favorite focal length indeed) but what if we want to keep the same giant aperture but with a wider field of view too?

Well, we can't.

The reason is: remember the cone of light rays above? The bigger the lens is, the bigger the cone of light is too. But also: the wider the field of view of a lens, the bigger the cone of light too.

And, the combination of wide-angle-view and super-high-aperture would literally require light to pass through the metal of the camera in order to reach the sensor:

In order to work around this, you'd have to quite literally tear your camera apart in order to expose the sensor. Somebody has done it, namely some "Stanley Kubrik" guy, and - of course - the lovely folks at Media Division:

But even so, Kubrik only reached ~71mm of aperture, and that's still on a 50mm focal length lens, which is 2.7x wider than the 135mm mentioned above, but also not exactly a wide angle lens either. Media Division instead went for 136mm of aperture, but on a focal length of 100mm, awfully close to the 135mm. Also, I'm not taking my camera apart. And, finally, all of these solutions require these giant pieces of lenses that are extremely rare and pricey.

Luckily, there's a solution to all of these problems. Meet the Charles Beseler 18" Series III:

As you can see, it's absolutely huge. It's also really cheap to get: I bought to for around 200€, including shipping costs. These lenses were produced a lot of time ago and they were used as projector lenses, in machines like these:

They are no longer used nowadays, and can be bought for cheap. And, as one can see by naked eye, they have a giant aperture. I can only provide an estimate for it, since there's no specs sheet for it, but it should be around 125mm.

So, you might ask, is this a wide angle lens? Well, the 18" in the name is telling us its focal length, and - converted to metric - that's ... 457mm. Which is roughly a 13x zoom in your normal camera, and so much more than we were looking for. Oh, no. Well, we knew it was physically impossible anyway.

Also, look how crazy of a contraption you have to build in order to connect this giant lens to a camera:

Though, it would produce some pictures, and indeed we can see a lot of out-of-focus (but also a lot of zoom...):

Fear not, though, the Charles gives us an extra tool to work with. So far, we've always assumed that we were working with a camera like mine, with a "standard"-sized sensor (it's called "full frame").

Suppose instead that we have a sensor that's double the size of mine. That would make for a pretty big camera, but still: a bigger sensor is able to capture a bigger image, effectively "zooming out": thus, our 457mm lens would become a 228mm lens. That's still not enough.

Let's double the size again. We're zooming out by a factor of 2 again, reaching a focal length of 114mm. That's still too much zoom. Let's double the size of the sensor again. We're now at 57mm. This is better already, though we should probably make the sensor just a bit bigger still, so that we can be around 40mm.

This means that the size of the sensor needs to be: the original size, times two, times two, times two, times one point five; that is, we need to increase the sensor size by a factor of 12.

My camera sensor size is 35mm by 24mm. Multiplied by 12, we get 420mm by 288mm. That's, uh, 42cm by 29cm. It's, like, pretty big. That's the size of a painting you'd hang on your wall. This gives us two issues:

Firstly, such a sensor simply doesn't exist. Films shot on IMAX use very big "sensor" (it's film) areas and we're talking about ~7cm by 5cm. It's not even "it's expensive" territory, it simply... does not exist.

Secondly, lenses usually can't project an image big enough to cover such a large area. Most lenses are designed to be used with Full Frame sensors nowadays, or slightly bigger ones (such as "Medium Size" – look, I don't make the names).

The good news here is that the Charles was not built "nowadays". Maybe back then they didn't get the memo about future sensor sizes. How can we check how big of an area our lenses can cover?

It's thankfully pretty easy. If you simply put a lens near a white surface, you'll be able to see what the sensor would see. The Helios projects a rather small image on my white wall, but that's just enough to cover the similarly-small full frame sensor in my camera.

I do also have lenses that project bigger images. As an example, this weird lens that found in some used market gives us a pretty big image circle. It certainly covers a camera sensor, even a "Medium Size" one, but not a the 43cm by 29cm area we need.

The Charles produces a giant image. It's tough to see it exactly because the lens has to be very far from the wall now, thus the image is very faint, but it's there. I'm not sure how big it is, but it's bigger than 43cm by 29cm. This is it.

Now we have to deal with the incompetence of the human mind and quickly invent a new giant sensor, bigger than anyone has ever seen. It should only take a few minutes.

Jokes aside, what we need to make this work was invented a long time ago for camcorders. Back then, we were dealing with a similar problem: we had these consumer video cameras with very small sensor, and we had "pro" camera lenses that were designed to handle much bigger sensors. We needed some kind of "adapter" that would allow to connect the two.

This adapter is called a Depth-of-field adapter, and here's how weird it looks.

The idea is the following: we build a big "fake sensor" that's actually just semi-trasparent paper, and we focus the camera lens onto that "fake sensor". Of course paper by itself is not going to "capture" any image, but we can then go on the other side and take a picture of the resulting image, like this:

This is a rather weird two-step process, if you think about it. It needs to have a first lens that supports a bigger sensor area, then you project to a big "fake sensor", and then you need another (smaller) lens that captures the image coming out of the "fake sensor" onto the act