What lens adapters do and why
There have been endless amounts of cameras over the years varying greatly in style and function. One thing that is true for all of them is that the lens is either built-in or removable. Cameras that allow you to remove lenses are often called interchangeable lens cameras. These cameras have a lens mount allowing you to mount and unmount different lenses to the body. This is called the lens mount, mount, lens system, or sometimes just system.
Each mount has a name so you know which lenses fit and operate on which body. If you have a Sony E mount camera you will need a Sony E mount lens to use on it. If you have a Pentax K mount lens, it would work on any Pentax K mount body.
This is, at least, the standard way of doing things. But what if you want to use a lens not originally made for your camera? This is where lens adapters come in! They allow you to use a lens and on a camera even when the mounts don’t match, and in many cases, there are no almost no restrictions as to what can be adapted.
When film photography was being replaced by digital photography in the 2000s, many new lens systems were developed and analog gear gradually became less desirable and less valuable.
Thus, adapting these old lenses to digital cameras was a great way for people to capture the images they wanted at a lower cost. Using vintage lenses to digital cameras was one of the main reasons for using lens adapters, but today there are just as many options for adapting digital to digital.
There are many reasons why people use lens adapters, here are a few:
- I found some old lenses in my attic and want to try them on my camera.
- I want to switch to a Sony camera but I already invested in Canon lenses.
- I want a new lens but the ones made for my camera are too expensive.
- I own different systems already, I want to mix and match!
- I need a specific lens for a specific purpose, but it’s not made for my camera.
- I want to use my expensive lenses on my cheaper back-up body.
- I want to get creative and do some weird stuff!
The size of an adapter depends on the model of the camera body and the lens you want to attach to it.
Lens adapters give you an opportunity to use old lenses from film cameras on your new digital system camera. Especially if you have a mirrorless camera body it’s a fun way to experiment with various manual focus lenses and their unique optical qualities. Many digital camera bodies have functions that assist manual focusing, making it easier than it used to be with film cameras. Some of the optical features and characteristics are even impossible to achieve with brand new lenses. Old ‘legacy’ lenses get a lot of use with cinematographers and in other video work. Many TV series, music videos, commercials and even feature films get shot with lenses that were made for film camera bodies.
In our webstore you can find a wide selection of lens adapters for different purposes.
How a standard lens system works
There are two things that allow a given lens to work with a given camera body: The physical connection (attaching the lens), and a matching flange distance (allowing the lens to focus and intended).
The flange distance is the distance between the mounting flange (where the lens attaches to the body) and the camera sensor or film plane. Roughly speaking it’s the distance between the back area of the lens and the surface of the camera sensor. If this distance is not equal to what the lens was designed for, focus will not be accurate or even impossible.
A “lens system” or “lens mount” is defined by these two things. A camera and lens with a matching lens mount means they were made for each other. The lens will physically attach securely to the camera and the flange distance will be exactly what the lens was designed to function with.
How lens adapters work
You have seen that using a lens from one system on a camera with a different system means it will not fit or focus. This is where lens adapters come in to solve both these problems at once.
In most cases, a lens adapter is a seemingly simple metal ring or short tube, where the front of the ring is designed to attach to a lens of one mounting system, and the back is designed to attach to a camera with another mounting system. At the same time, the length of the adapter is designed to match the flange distance (distance between the lens and the sensor) to the lenses originally intended system’s flange distance. In short, adapters allow many incompatible lenses and camera bodies to become compatible – like magic!
However, not every adaptation is this simple.
You may already be wondering how can a lens with electronic functions communicate with the camera if there is a metal tube between them? Or “I don’t have a full frame sensor, how will that affect my images if the lens is made for full frame?”
We will answer that below, but first let’s see some examples of what we have already covered.
The thickness of the camera body will give you an indication of the flange distance of the system. The difference is obvious when comparing an SLR and mirrorless digital camera side by side.
A SLR camera with its native lens mounted on. In order to put the lens on the mirrorless camera you will need an adapter which fits the lens physically and also gives the same distance to the image sensor as the lens had on the camera system it was made for.
Successfully adapted legacy lens!
Most film cameras, and many digital cameras are of the SLR (single-lens reflex) design, which have a mirror box between the shutter, film or sensor, and the lens.
Mirrorless cameras do not have this and therefore the flange distance is usually much shorter. This means that the adaption to mirrorless is almost always possible since an adapter can be made longer.
In general, the only obstacles would be the availability of the adapter itself and the size of the image circle the lens can produce. Mirrorless camera systems are, for example Sony E, Sony FE, Micro Four Thirds, Fuji X, Fuji GFX, Canon M, Canon R, Nikon Z, L-mount, Nikon 1, Samsung NX and Pentax Q. If you have a camera using one of these lens systems you are in the easiest position to begin adapting lenses to your camera.
A mirrorless digital camera adapter can function with almost any lens when using the correct adapter. In the picture, the Sony camera is using a fast semi wide-angle lens originally intended for Nikon cameras. A Voigtländer wide-angle lens made for Leica M cameras is mounted on an Olympus here as well. The Panasonic camera is using an Olympus telephoto lens. All of these are mirrorless systems.
Adapting SLR lenses to other SLR bodies is not always possible, but it is the easiest with the EOS mount camera body. The Canon EOS system with its EF/EF-S lenses has one of the shortest flange distances of any SLR. Sony A and Pentax K mount cameras can also handle old M42 screw mount lenses, for example. If at all possible, cases of SLR to SLR adaptation, the difference in flange distance will be very small. Therefore, adapters typically look more like a ring than a short tube.
In the picture we can see a Leica R lens on a Canon EOS and a M42 lens on a Sony. Both cameras and lenses are from different SLR systems.
What kind of adapters can be found?
Most of the adapters are pretty affordable in the 20€-40€ price range. These being those made with no electronics, no glass, and little or no moving parts. They don’t transmit mechanical or electronic functions between the lens and the camera body. Your digital camera will not understand that there is a lens attached, and focusing and setting the aperture must be done manually. Some cameras also have a setting that stops you from shooting when no lens is attached – this has to be turned off. For some shooters this can be seen as a downside but others enjoy the straightforward feel of the mechanical parts. In general, those using cameras for filmmaking have less concern about manual focus only and may prefer it.
Even though the lenses are fully manual the current digital camera bodies can still measure the light passing through, so the camera can be used in aperture priority mode (A or Av) and it will select the correct shutter speed automatically without any problem.
Many mirrorless digital cameras often have focus peaking and other assisting functions which help you to use manual lenses correctly. It’s not nearly as difficult as you may think!
Adapting Lenses with Autofocus (or other Electronics Functions)
Many lenses from the 1990s and 2000s have electronic parts to render them incompatible with cameras from other manufacturers. If they could be fitted, only some of the basic functionality would be available. However, there are currently many adapters that also convert the electronic signals between the lens and the body. These are often a bit more expensive.
Adapters with electronic contacts make it possible to use motorized lenses on other camera systems. In the picture a Mamiya 645AF lens is mounted on a Sony mirrorless body and a Canon EF lens is on a tiny Canon M body.
Depending on the model, these adapters keep functions such as auto focus, optical stabilization, and aperture settings intact and operational. This means that you can control the lens with the camera, just as if you were using a lens the camera was made for. For limited use with certain cameras and lenses there’s even an adapter that turns a manual focus lens into an autofocus lens.
Switching to another camera brand does not always mean replacing your entire lens arsenal in the process. For example, adapters with electronic contacts for Canon EF / EF-S lenses exist for almost any current mirrorless camera system. Since the major camera companies, Canon, Sony, Olympus and Nikon, all started making mirrorless digital cameras we have seen many adapter makers offering solutions to put old SLR lenses to these new mirrorless systems.
Major camera brands also make their own adapters, note that usually the lens mount is mentioned first when describing an adapter. Here are some examples available:
Canon EF – Canon M AF adapter:
Canon EF – Canon R AF adapter:
Sony A – Sony E / FE AF adapter:
Nikon F – Nikon Z AF adapter:
Olympus 4/3 – M4/3 AF adapter:
Third party electronic adapters are available from manufacturers such as:
Limits of adapting lenses
Even when there’s an adapter available that can fit your old lens to your new camera, it’s not always even a sensible thing to do. A lens that was designed for a film camera might have some issues with optical resolution and overall rendering of the image when mounted in front of a digital sensor.
Furthermore, the image circle of the lens might be too small, meaning the lens was designed to capture an image on a frame of film much smaller than the size of many current digital sensors. In the worst-case scenario, the vintage lens will leave the camera physically damaged. Damaging your camera is only possible by a small number of lenses that fit with an adapter but have an incompatible design compared to the other lenses in that system. This is rare and it is known which lenses cause problems on which bodies. If you are nervous about this you can always ask us or search the internet for the exact combination you want to make to see if any issues arise.
Often the adapted lens is bigger than the native lenses of the mirrorless camera, but sometimes it can be significantly smaller, too. It’s common that the size of the lens itself will indicate the size of the image circle it can produce. For example, many C-mount lenses were designed for movie cameras using narrow 8mm or 16mm film. When mounted on a full-frame digital body they produce a circular image in the middle of the frame. On a camera with a smaller sensor, the circle will cover most of the sensor area or even the entire frame.
Som Berthiot 25mm f1.4 Cinor Paris is a C-mount lens and a pretty small one when compared to current photography lenses. It was made for 16mm movie cameras.
On a full frame digital camera this lens will give just a small circle in the middle of the image area. It was never made to spread and focus the light to cover such a comparatively large area.
When mounted on a M4/3 camera with a smaller sensor, most of the image area is covered and use of a C-mount lens can be perceived as a heavy vignetting effect rather than an image in a circle.
Speed boosters / focal reducers – turning crop sensor into a full frame?
Even more specialized adapters for mirrorless cameras not only maintain electronic connectivity, but can add one or more glass elements to the adapter giving it even more features.
These specialized adapters called speed boosters can shorten the focal length of a lens and concentrate the light passing through them, casting more light onto the sensor. With more light you can capture what’s needed using faster shutter speeds – hence the name Speed Booster. These also can undo the crop factor of a non-full frame camera sensor.
Concentrating the light coming through the lens also makes the field of view appear wider compared to the same lens on the same camera with an adapter that is not a speed booster. Yet this is beneficial to most people.
A speed boosters function is similar yet opposite to that of a teleconverter. A teleconverter magnifies the field of view and loses light in the process.
Before we explain these further, let’s try to understand the issue that they solve.
Fuji X-T1 with a Metabones Speed booster for converting Minolta MD lenses to Fuji X mount.
What is a Crop Sensor Camera?
Many consumer level mirrorless system cameras (M4/3, Fuji X, Sony E) have a crop sensor. This refers to the size of the image sensor. Crop sensor sizes vary but are smaller in dimensions than a “full frame” sensor which can be found in many professional level camera bodies.
A full frame sensor is a digital image sensor that is the same size as a full single frame of 35mm film. Full frame is considered the standard even though the vast majority of digital cameras have crop sensors.
Capturing an image projected by a full-frame lens onto a crop sensor means not all of the image area is captured because the total surface area of the sensor doesn’t capture all of the light.
If you were to take a picture of a sign that said “supermarket” (filling the frame) while using a full-frame lens on a full-frame body, the image would show the supermarket sign. If you replicated the scenario with a camera using a crop sensor and the same lens, it would capture a smaller area than the lens shows. The resulting image of the sign might read “upermarke”. Due to the smaller sensor size a portion of the top, bottom, and sides disappear compared to a larger full-frame sensor.
And so taking images with a crop sensor camera will appear to be zoomed in compared to a full frame sensor. For example a camera sensor with a crop factor of 1.6x will give you images that appear 1.6 times closer than the focal length of the lens in most cases.
This is not usually a problem of course as you could just take a few steps back to capture the whole sign. In this particular case, a 50mm full-frame lens shot on a crop sensor body would give you the same image as a 81mm full-frame lens on a full-frame body. Here is an example of the simple math behind it.
50mm full-farme (FF) lens on FF body:
50mm lens x 1.0 = 50mm
Result: The image captured is equal to the field of view the lens captures.
50mm FF lens on example Crop Sensor body:
50mm lens x 1.6 = 81mm
Result: The image captured is not equal to the exact field of view the lens captures. It appears equivalent to using an 81mm lens on a full-frame sensor.
This difference is what’s known as a Crop Factor. It has been predetermined by the sensor manufacturers and is easy to find out. For example, a Canon APS-C sensor has a crop factor of 1.6x, which means due to the reduced size of the sensor, all images will appear to be zoomed 1.6x compared to what a full-frame lens was meant to show.
Some lenses are made specifically for crop sensor cameras and thats what you see when hearing about a lens that has a “full frame equivalent of 50mm”. This is different than a lens that is simply “50mm”.
As you can see this simple concept can be quite confusing in practice and can lead to wider angle lenses being unavailable to the crop-sensor camera. This is where speed boosters some in.
Speed Boosters for Crop Sensor Cameras
Speed boosters can undo the crop factor given by a camera using a crop sensor. This can result in your crop sensor camera capturing images at the exact field of view the lens was designed to capture. When this is true your picture accurately reflects the field of view written in millimetres on the lens.
In the following pictures you can see the effect. In the first picture the lens is mounted with a regular adapter, using a full frame lens on a crop sensor camera. In the second picture, the same combination is used but the adapter has been switched to the appropriate speed booster adapter. The pictures were taken from the exact same distance to the subject.
It’s possible to use this kind of adapter only when the lens can produce a bigger image circle than the sensor area of the camera, because the booster adapter will make the image circle smaller. Compatibility of the lenses might vary a lot so some of the lenses cannot be used with a speed booster. The most well known and perhaps the best speed boosters in terms of build quality are made by Metabones, but many other manufacturers have made a decent effort to offer similar products. Price range of speed boosters start from around 100€ and go all the way up to a 1000€ range. The most expensive models work as a speed booster but can also adapt the electrical functions of the lens making it fully usable just like it was mounted on its native camera body.
Examples of the speed booster manufacturers:
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