How Lens Adapters Work & Why You Should Try Them

Published November 4, 2021

With both Nikon and Canon switching out their DSLR markets for mirrorless platforms and offering up new lens mounts as a result, and with Sony and Fuji both developing great lenses for their platforms, a common question we get asked is about lens adapters. And lens adapters are no new thing, dating back at least a few decades now; I wasn’t able to get an exact creation date. But as more time goes on, lens adapters have become an increasingly common thing for photographers and videographers alike – so let’s talk about them.

What Are Lens Adapters?

When you first buy your camera, whether it’s a DSLR or mirrorless camera, you’ll have a lens mount system on the front of it. This mount is designed to easily change lenses on your camera, switching focal length, aperture speed, and much more with a quick button press and turn. These lens mounts are almost exclusively made of metal, and are simple in design, with a few contact pins on them for the camera to communicate with the lens. While these lens mounts can’t really be changed (though it has been done before), but they can be adapted to work with a larger variety of lenses, through the use of a lens adapter.


This means you’re able to convert Canon EF lenses to Sony E-mount cameras, Nikon F-mount lenses to their latest Z series cameras, and in some cases, even change out lenses and cameras that have different sensor sizes, like converting EF mount lenses to work on the Fuji GFX platform. With lens adapters, you’re able to switch camera platforms much easier, and even take some of your grandpa’s old lenses found in a box in the attic for a spin.

How Lens Adapters Work

Fundamentally, the concept of lens adapters is simple. You know those pins and contact plates found on lenses and lens mounts? All a lens mount does is reroute the data sent from those pins and ‘translates’ it so that your camera body reads the information delivered from the lens. This will (usually) allow you to use autofocus, give you correct f-stop readouts, and use the lens as if it was intended for the camera.

Those are electronic adapters, which have become far more popular in recent years that maintain the communication of the lens and camera, and certainly the future of lens adapters – but there are mechanical adapters as well. These adapters are essentially just a metal plate, where you mount your lens to one end, and camera to the other. There is no communication between the two, so your EXIF data will be blank when shooting. You’ll also need lenses that allow you to adjust the aperture manually, in order to maintain the functionality and control of the lens.

SpeedBoosters & Specialty Lens Adapters

However, not all lens adapters are created equal, and some of them offer different features that can add interesting effects to your image quality and lens sharpness. For example, there are lens adapters that can adapt lenses designed for smaller sensors that work on larger sensor platforms, like an adapter that converts Canon EF lenses to an m4/3rd sensor. The reverse is true too, so let’s talk about how these work.

Lens Adapter Examples

Shot using the Fuji GFX 100s w/ a Canon 85mm f/1.2L II
Adapted using the Vizelex Cine ND Throttle Fusion Smart AF Adapter

How ‘Speed Booster’ Adapters work

When converting a specific lens to a larger sensor size than it was designed for, the term commonly associated with these adapters is called ‘Speed Booster’ adapters, because they end up shortening the focal length, and giving you a larger f-stop. Think of it as the opposite of a teleconverter adapter. A teleconverter will use a convex lens (or magnifying lens) to increase the focal length of a lens by a magnification of 1.4x, 2x, or even 4x. As a result, these lenses will gather less light when shooting, and cause you to lose a stop of light or more – depending on the magnification level. Speed Boosters flip that idea on its head – putting a concave lens between the sensor and lens, offering you a reduced focal length (to better fill the sensor frame), and bringing in more light to the lens – giving you an additional stop of light.

Lens Adapter Tutorial

Shot using the Fuji GFX 100s w/ a Canon 85mm f/1.2L II
Adapted using the Vizelex Cine ND Throttle Fusion Smart AF Adapter

The result allows you to drastically expand your lens availability, while also giving you some really unique effects. For example, I recently purchased an adapter that converts Canon EF lenses (designed for a 35mm full-frame camera), onto my Fujifilm GFX medium format camera. Meaning I’m able to use incredibly low aperture lenses like the Canon 85mm f/1.2L II of a medium format – giving me something along the lines of a 66mm f/0.95 lens.

Lens Adapter Example

Shot using the Fuji GFX 100s w/ a Canon 85mm f/1.2L II
Adapted using the Vizelex Cine ND Throttle Fusion Smart AF Adapter

Other Speciality Lens Adapters

In addition to teleconverters and speed booster adapters, there are also a few other adapters that will give you specialty properties that your lens or camera mount might not already have. Among the most popular of these adapters are the ones with built-in filters – with variable neutral density filters being the most common. I’ve talked about Neutral Density (ND) filters extensively in the past on this blog, but essentially they limit the amount of light being entered into your lens, allowing you to blur movement, or even help lower your shutter speed so that you can use flashes more effectively on location. Having a filter at the base of the lens (resulting in a much smaller filter) is inherently a more affordable process, as it works as a one size fits all solution, and is smaller than most traditional filters. This is why it’s common to see drop-in filter systems for large telephoto lenses, like the Canon EF 200-400mm f/4L IS USM Extender 1.4x Lens.

Downfalls to Lens Adapters

Obviously, having lens adapters isn’t all good news with none of the bad. With each new element added to the equation, you’re adding more variables for what could go wrong. The biggest shortfall of using lens adapters is that you may see some communication issues with your lens and the camera body. Apertures not changing, autofocusing cutting out, and incorrect data displayed on the camera and EXIF data are all more frequent when using an adapter (though they have gotten much much better in recent years). If you’re using an adapter with a piece of glass in it, you will also suffer image quality issues, but that may be minimal. Lens adapter brands don’t have the team of optic specialists that Canon, Nikon, Sony, and Fuji do, so you’re likely getting a mass-manufactured piece of glass in these adapters – though you’re likely to see more image quality issues at the longer focal lengths. 

Additionally, adding a lens adapter to your system is going to add size to your lens kit. While this may be marginal, if you’re using something like the Canon 200mm f/2L with a lens adapter, it will be far more noticeable when using a small 50mm lens. The size change of the system is very much user-dependent, if you’re already bringing a full camera bag of lenses to the event you’re shooting, an adapter or two won’t make that big of a difference to your process – but if you’re using the Fuji X-T3 because you love its small form factor, an added adapter is going to change the dynamics of the camera pretty significantly.

Lens Adapter Tutorial

Shot using the Fuji GFX 100s w/ a Canon 85mm f/1.2L II
Adapted using the Vizelex Cine ND Throttle Fusion Smart AF Adapter

In the past, I’ve called lens adapters a transition product – something you might buy to support your new Canon R5, while they develop more lenses for the RF series. However, as time has gone on, lens adapters have become way more robust in design, and offer a lot of features that you might not see on traditional lenses. Do you have some examples of creative photos you’ve taken with the use of an adapter? Share some of your favorites in the comments below.



Author: Zach Sutton

I’m Zach and I’m the editor and a frequent writer here at I’m also a commercial beauty photographer in Los Angeles, CA, and offer educational workshops on photography and lighting all over North America.

Posted in Equipment
  • Cheap And Cheerful

    Exactly, the article lacks detail and therefore is misleading.

    A more explanatory answer lies in how adaptors are designed and constructed, and also how lenses are designed and constructed for their target sensor/film plane dimensions.
    Micro Four Thirds users are well adapted to comprehending focal length, focal ratio and angle-of-view equivalence, as do the engineers at the MFT manufacturers. That’s where I go for my information.

  • I’ve also seen affordable tilt/shift adapters on eBay that except full frame lenses on crop sensor bodies.

  • Franz Graphstill

    The example doesn’t match the rest of the sentence:

    “For example, there are lens adapters that can adapt lenses designed for smaller sensors that work on larger sensor platforms, like an adapter that converts Canon EF lenses to an m4/3rd sensor”

    The EF lenses are not designed for a sensor smaller than m4/3…

  • Mikelodeon

    I have been using the Fringer EF-FX Pro adapter for about 18 months with very acceptable results. I had a collection of Canon legacy glass after I moved to Fujifilm mirrorless cameras in 2013. On the older Canon lenses – 85 1.8, 100 2.0, 135 2.8, 50 1.8 – autofocus hunted to the point where it wasn’t a usable set up. However on two newer lenses the results were very reliable. The Canon 70-200 f4 produces faultless results in autofocus, IS, EXIF data and anything else I checked. I use it for sports regularly. I sold my Fuji 55-200 as I much prefer the Canon lens colours and contrast. The real win was with the 24-105 4.0. So much so that I leave it permanently attached to one of my XT2s. It produces about 36 – 160 range on the crop sensor and I find that a great walk about range. IS on this lens was a bit hit or miss to start with but after upgrading to Fringer firmware 3.5 it has become just as reliable as the 70-200. Unless Fuji produces a lens in this zoom range I intend to stick with this arrangement for the foreseeable future.

  • eggplant

    I think this diagram would help to understand what the adapters are actually doing.
    Both teleconverters and focal reducers use a mixture of convex and concave elements, so it’s not useful wording.

    Rather, a rear teleconverter has an overall negative power- required to disperse the light cone of a lens.
    A focal reducer has an overall positive power- required to focus the light cone of a lens onto a smaller sensor/area.

    As this is how their optical designs are configured, I find it helpful to start from that language- rather than mixing in ‘magnification’ and such.

  • Tracy Bosworth Page

    Check out my Instagram @tracybosworthpage, I have photos that are captured with both the 55 and 100 Otus lenses and they should all be noted. 🙂 And I’d love to have you see the work!

  • The_Incomparable_Douche

    Eh, the part about the Fotodiox Canon EF to Fuji GFX adapter is confused or confusing. By mentioning it in the section on speed boosters, you give the impression that this adapter is a speed booster. It’s not: it has no optics. This adapter doesn’t change the focal length of the lens. When you say that it turns your 85mm f/1.2 into something like a 66mm f/0.95, you’re just applying the crop factor of the larger sensor to the lens. But the combination of this lens and the adapter behaves the same as a native GFX-mount 85mm f/1.2 would (in terms of angle of view and depth of field).

  • Oh wow, I’d love to see photos from that combo.

  • Tracy Bosworth Page

    I use one daily to adapt my Zeiss Otus 100 1.4/100 ef mount to a Sony e so I depend on them. I appreciate the information and perspective Zach!

  • Thanks for the read, Tracy!
    I was admittedly skeptical of adapters for a long time, but now that I know I can convert various formfactor lenses to different bodies, I’m excited to experiment with it a bit more.

  • Tracy Bosworth Page

    Great article Zach! I get questioned about adaptors all the time and will share this!

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