Introduction to Lens Mounts and Lens Adapters


You may be thinking, "What a boring subject for an article," and you would be right. However, as boring as the interface between your camera and lens might be, the significance of your camera's specific mount, along with which lenses can be used on your camera, which lenses can be adapted to your camera, and why some lenses work and others do not, can prove to be a more interesting subject that may even inform which camera or lens system you eventually buy.

What Does a Lens Mount Do?

A lens mount is a standard or proprietary interface used by camera and lens manufacturers to ensure a secure and accurate means for attaching a lens to a camera body. Each camera system nowadays uses its own unique mount that limits compatibility between lenses and other manufacturers’ cameras, and also enables electronic communication between the lens and camera to achieve accurate focus and exposure.

Left to right: Canon EF, Nikon F, and Sony E bayonet-style lens mounts

Most lens mounts in current use are bayonet style, in which a lens is attached to the camera body by registering the lens in proper orientation with the camera body, then giving a slight twist of about 45-90° to lock the lens in place. Prior to the bayonet mount, a couple of other mounting styles were commonly used, namely thread and breech-lock mounts. Thread mounts, or screw mounts, are self-referential and describe the action of threading your lens onto the camera body, much in the same way you thread a nut onto a bolt. Breech-lock mounts are more closely related to bayonet mounts; however, they use a self-contained rotating ring on the lens itself to tighten the lens onto the camera body with friction.

Bayonet mounts are the most favored of these three mounting types, due to the ease and speed of installing and removing lenses from camera bodies, the ability to incorporate electronic contacts using this attachment method, and the repeatable precision afforded by a simpler design.

Left to right: Breech-lock mount on a Mamiya RB lens and an M39 screw mount on a Leica lens

What’s in a Lens Mount?

Besides connecting a lens to a camera and sporting a certain design style, lens mounts also have a number of distinctions from manufacturer to manufacturer. Size is the main differentiator between the various mounts, and is a slightly more complex measurement than you may imagine. The number of tabs in a specific bayonet can vary from one manufacturer to another (although most use three tabs), the direction in which you rotate the lens to connect with the camera body varies among brands, and the incorporation of electronic contacts will also be unique to the camera and lens manufacturer. Furthermore, each mount corresponds, arguably, to the most important element of this article, a specific flange focal distance (FFD). This measurement, which describes the length from the mounting flange (the edge of the lens mount on the camera body) to the image sensor or film plane, varies from manufacturer to manufacturer, and is one of the true limiters of the interchangeability of lenses with specific cameras.

Left to right: Canon FD breech-lock mount and a Mamiya 7 bayonet mount

The flange focal distance of each camera system is factored into subsequent lens designs, and is a constant length used by each manufacturer to ensure accurate focus from a specific lens’s minimum focusing distance to infinity. Using a lens with a specific FFD on a camera system with a shorter flange distance, you will not be able to achieve infinity focus. This distinction is the key element in which lenses can be used on camera systems other than the original one the lens was designed for, via a lens adapter.

Current Lens Mounts Popular Historic Lens Mounts
Lens Mount Flange Focal
Mount Type Lens Mount Flange Focal
Mount Type
Nikon Z 16.0mm Bayonet Pentax Q 9.2mm Bayonet
Nikon 1 17.0mm Bayonet Samsung NX 25.5mm Bayonet
FUJIFILM X 17.7mm Bayonet M39 (26tpi) 28.8mm Screw
Canon EF-M 18.0mm Bayonet Contax G 29.0mm Bayonet
Sony E 18.0mm Bayonet Nikon S 34.85mm Bayonet
Hasselblad X 18.14mm Bayonet Four Thirds 38.67mm Bayonet
Micro Four Thirds 19.25mm Bayonet Canon FD 42.0mm Bayonet or breech-lock
Leica L 20.0mm Bayonet Minolta SR 43.5mm Bayonet
Canon RF 20.0mm Bayonet Exakta 44.7mm Bayonet
FUJIFILM G 26.7mm Bayonet M42 (x1) 45.46mm Screw
Leica M 27.8mm Bayonet Contax C/Y 45.5mm Bayonet
Canon EF 44.0mm Bayonet DKL 45.7mm Bayonet
Sigma SA 44.0mm Bayonet Olympus OM 46.0mm Bayonet
Minolta/Sony A 44.5mm Bayonet Leica R 64.0mm Bayonet
Pentax K 45.46mm Bayonet Contax 645 64.0mm Bayonet
Nikon F 46.5mm Bayonet Bronica ETRS 69.0mm Bayonet
Leica S 50.0mm Bayonet Pentacon Six/Exakta 66 74.1mm Breech-lock
ARRI PL 52.0mm Breech-lock (cine) Hasselblad V 74.9mm Bayonet
T Mount 55.0mm Screw (M42 x 0.75) Pentax 6 x 7 84.95mm Bayonet
Hasselblad H 61.63mm Bayonet Bronica SQ 85.0mm Bayonet
Mamiya 645 63.3mm Bayonet Mamiya RZ67 108.0mm Bayonet
Pentax 645 70.87mm Bayonet Mamiya RB67 111.0mm Bayonet or breech-lock

Lens Adapters

Spurred by the somewhat recent advent of mirrorless camera systems, a renewed interest in the ability to use a wide array of third-party lenses has also occurred. Due to the self-referential design of these cameras, the lack of having a mirror in a camera body design affords, besides a more compact overall design, a shorter FFD. By having this shorter registration distance, you can theoretically mount any lens with a longer FFD on a camera with shorter FFD through the use of a lens adapter

The lens adapter effectively serves to make up the difference in focal flange distance between the camera and lens—for example, a Nikon F lens to Sony E adapter makes up the difference of 28.5mm to provide the proper total 46.5mm of focal flange distance for a Nikon F-mount lens to achieve infinity focus. While this is the ideal situation, to mount lenses with a longer FFD on cameras with a shorter FFD, adapters do exist that allow you to physically attach lenses with shorter FFD measurements to camera bodies with a longer FFD. The caveat with these adapters is that you will not be able to achieve infinity focus without the inclusion of a corrective element in the adapter itself, and it is unlikely the quality of this corrective element will match the quality of the lens being mounted. However, without the corrective lens in place, this combination will afford the ability to work at focusing distances less than infinity, since the lens adapter is now functioning as an extension tube.

Top left to bottom right: Metabones Speed Booster for Canon EF to Sony E, Metabones Nikon F to Sony E adapter, Fotodiox Nikon F to Canon EF adapter with Dandelion Focus Chip, and Fotodiox M39 to Leica M adapter

With this basic concept in mind, lens adapters can also be substantially more sophisticated and maintain electronic communication between the adapted lens and body through the use of dandelion chips, with some adapters even capable of retaining a lens’s autofocus and image-stabilization capabilities. On the other hand, completely manual adapters will not convey any information between the camera and adapted lens, forcing you to manually focus and adjust the aperture settings on a lens, and work in manual or aperture-priority mode on the camera.

One additional type of adapter that has gained tremendous attention over the past few years is a style designed exclusively for APS-C and smaller format mirrorless cameras, most commonly Sony E, Fujifilm X, and Micro Four Thirds systems, that has been popularized by Metabones and Mitakon Zhongyi. With the exception of Sony E-mount now being featured on full-frame cameras, these mounts typically correspond to crop-sensor sizes and, as such, are associated with terms like “crop factor” and “equivalent focal length.” This batch of lens adapters strives to make these terms somewhat moot by incorporating a condensing lens into their design to minimize, or in some cases eliminate, the crop factor and increase the amount of light reaching the sensor. This is accomplished by projecting all of the light gathered by the lens onto the image sensor, rather than just simply losing the light that would typically be cropped out by the smaller sensor dimensions.


I have just replaced my old Pentax ME super wind-on with a Sony alpha 65 SLT A65V.  Can you supply an adapter.  I understand I will lose lots of functionality but the Sony should cope with my longer FFD lenses. 

Pentax K mount lenses that originally worked on your Pentax ME can be adapted to your Sony A65 using the Fotodiox Pro Lens Mount Adapter for Pentax K Lens to Sony A Mount Camera, BH # FOPSAAPK.


I have a Nikon D3400 camera and 2 old lenses that might be interesting to use on it, if they can be adapted to fit. The lenses are a Soligor Auto Wide 1:2.8 f=28 mm (No 9851433) and a Vivitar 80-200 mm 1:4.5 MC Zoom (No 28241117 ) 58mm. Any advice?

If you can send us a photo of each lens mount to, we can have a look and make a suggestion on a suitable adapter. 

May son has a Fuji XT30 and requires some lenses for a degree course - Fuji 400 zoom is very expensive ! What sigma or other  options do we have and our local camera store Orms recommends an adaptor BH sells? 
Please advise.

thanks Andrew

To save a bit more, you can use the Sigma 100-400mm f/5-6.3 DG OS HSM Comtemporary Lens for Canon EF along with an adapter to fit onto the X-T30 such as the Fotodiox Pro Fusion Smart Auto Focus Adapter for Canon EF Mount Lens to Fujifilm X-Mount Camera, BH # FOEOSFXRFPF.


I want to adapt Nikon F Manual lenses to a Nikon Z6 & Dfmirrorless camera, using the Nikon Z adapter,  but from reviews I've read the lens is NOT stopped down by the camera when you press the shutter.  Is this true?  

If true then I don't know what to do, since manual F lenses I have do NOT have a press-to-minimize-aperture since that was done by a button on the camera.  Even if the Df body or some other body does have it, it is way way too much of a slowdown to have to press the shutter close button/lever before every shutter release.  

So what am I facing with a Z6 or DF Nikon body and aperture use?.

If using a Nikon AI or AI-s Lens on the Nikon FTZ adapter along with the Z6, you would have to adjust the aperture manually. The same applies if mounting these lenses on a Nikon Df body, where an adapter would not be needed. As you click the aperture, you will see the exposure change accordingly. 

i can’t find any cheap fisheye lens that are 58mm so i am getting a 43mm fisheye would i also need to get a 58mm lens adapter ?

If you are referring to an add-on lens that is designed to screw into the front filter threads of your lens, the Dot Line 58mm 0.25x Wide-Angle Conversion Lens​B&H # DODLV2558, would be the most economical option in our inventory which may work for your usage needs.  The Opteka 58mm 0.3X HD Ultra Fisheye Lens AdapterB&H # OPTSC58FE, is higher in price, but is the second-most economical option compatible for your usage needs.
If you already own a add-on lens adapter with a smaller 43mm rear filter thread mount, you would need to purchase both the Sensei 58-46mm Step-Down Ring​B&H # SESDR5846, along with the Sensei 46-43mm Step-Down RingB&H # SESDR4643, for your usage needs.  However, do note that the using an add-on lens with a smaller diameter than the lens onto which the lens adapter will be connected may result in vignetting.

Is there any modern mount that can be used on a Russian A/H mount Lens ?

There may be some adapters you can try. If you can, please e-mail some photos of your lens mounts to so can look into this for you. 

Hi I have a Panasonic DMC-gF3 I understand that I can interchange Lens what do I need to do this please

many thanks 


The Panasonic FMC-GF3 uses the Micro 4/3 mount, so you just need to get an adapter that will fit this mount. Below are some options in this case.


 I have a couple of Samyang manual lenses that I want to to use with my new Leica SL
Does it exist any adapter from E-mount to other mount?
To LM for example?

Adapting Sony E lenses to anything else is pretty tricky since the flange focal distance is so short (just 18mm). We don't have a Sony E to L-mount adapter; I'm not sure if there is one somewhere else, but it would require a correction lens for use, which would likely degrade the image quality of the lens pretty significantly. That's one of the potential "downsides" of mirrorless, is that the lenses aren't interchangeable like how SLR lenses are on mirrorless cameras.

I was given a Vivatar Wideangle for Mamiya 528TL - is there a way to adapt this lens to my Sony A7R3?

From my understanding, the Mamiya 528TL had a fixed lens, so if your Vivitar wide angle lens just screws into the front, the fitment would depend on which lens you have mounted on the A7R III. To assist further, please e-mail us to along with some photos of the lens and its mount. 

I want to attach my a6000 to a 23mm microscope eye piece. What adapters do I need..?

To assist you with your inquiry, we would need to know the brand/model of the microscope you own to see if we have an adapter that would be compatible for use with your 23mm eyepiece.  If you may e-mail the brand/model of your microscope, along with your above inquiry, to, we may then assist you with your inquiry.

I just bought a 5 dollar lens, 5 Star 500mm in pretty OK shape. The problem is the lens adapter, I have never seen one like it. The lens itself has a tapered end, no threads or bayonet, just an out-taper. The adapter it came with slips over this taper and locks with 3 set screws onto the taper, I looked on line and found info about T mounts but those seem to be threaded, this has no threads. Is this a different style of T mount?

We would like to help figure out the right adapter for you. If you can, please send us an e-mail with your questions and a few photos of the lens mount to


This has helped me understand a little bit more now, i need a lens adapter to fit my canon eos 750d camera. I have a screw type lens and need an adaptor that will fit  but also need to have a manual aparture (iris) control. Is there an adaptor out there for me please ?    

If the lenses you would like to adapt have a screw mount, they are most likely an M42 type lens which was used on Pentax cameras in the past. Those lenses should already have a built in aperture ring, so the Vello M42 Lens to Canon EF/EF-S-Mount Camera Lens Adapter would be an option to consider.


This article was very helpful - thank you! I came across it while searching for a DSLR camera that would allow me to use my Minolta lenses, etc. It's been many years since I used anything other than my phone for pictures, but I used to work in pretty much M or A mode with my Minolta X700. Which digital camera would give me a similar experience? From reading this article, it would seem I will need an adapter in order to use my existing lenses? I am a recreational photographer, but I do want to grow in my skills - probably will aim for the middle where price is concerned. Thanks for any advice as I decide what to purchase!

To keep the same image format as your Minolta X700, a full frame DSLR like the Nikon D610 DSLR Camera with 50mm f/1.8 Lens Kit, B&H # NID61050K would be the most affordable option.  You can add the Vello Minolta MD Lens to Nikon F-Mount Camera Lens Adapter, B&H # VELANFMD which will allow for manual control of your Minolta MD lenses.

Thanks so much, Kirk! 

Hi, I bought some lenses from ebay and seller can not name their mounts. Can you help me? If there is an option, I could upload pictures.

Kind regards

Hi there, is there any way to find out whether the compact camera AMKOV R2 can use mounts to use interchangeable lenses?

Thanks, M. 

That's a great question. We ask if you can e-mail to so we can look into this for you. 

Hi there! Great read, thank you. I have acquired a pk 135mm 1:2.8 lens and an Auto Sears with the same numbers... they came with a film camera but I would like to find a digital camera that I can adapt these lenses to. I’d like to keep the price down and would love input on what camera to be looking for? 

The most economical Pentax DSLR camera that would work for your usage needs would be the Pentax K-70 DSLR Camera Body with Accessory Kit (Black), B&H # PEK70BAK.  It would be compatible for use with a manual Pentax K-mount lens.  However, do note that you will have to go to the [Custom Setting (Tab 3)] tab in the camera's menu, go to [16. Using Aperture Ring] and select [Enable] so you may use your manual lens on the digital camera. 

I am thinking about purchasing a Lumix DC-GH5 M43 camera and have Canon EFS and EF lens. What adapter do I need to maintain the quality of images on the Lumix?

Hi Teresa,

The Metabones T Smart Adapter for Canon EF or Canon EF-S Mount Lens to Select Micro Four Thirds-Mount Cameras, B&H # MEEFM43BT2 would be your safest bet to maintain good image quality on your GH5 with your Canon lenses.


Thank you for this! I teach high school photography and I have a question. Most of my students use Nikon cameras and I have a range of Nikon lenses and Sigma lenses for Nikons. If a student with a Canon Rebel T6 wants to use one of our lenses, would the Fotodiox PRO adapter work? I have one and tried it, but can't get the lens to autofocus. Would this be solved by purchasing the Fotodiox PRO with Focus Chip?

The FotodioX Pro Lens Mount Adapter with Generation v10 Focus Confirmation Chip for Nikon F-Mount, G-Type Lens to Canon EF or EF-S Mount Camera, B&H # FONIKGEPFC10, would allow you to connect a Nikon F-mount lens onto the Canon EF lens mount.  However, it will not autofocus on a Canon camera; the Canon lens mount controls lenses electronically, while Nikon lenses are controlled mechanically.  A Nikon lens cannot focus on a Canon camera.  The addition of the Focus Confirmation Chip allows the focus confirmation LED in the camera’s viewfinder to illuminate to assist/inform you when the image is in focus when you are focusing the lens manually. This feature allows focus to be quickly and accurately achieved through a compatible camera's viewfinder or live view feature.   However, it will not let you use autofocus when using a Nikon lens on the Canon camera body.

I have a C-mount video camera.
Can I use adapters that will accept 37mm, 42mm, 52, and 58mm lenses, or does that not work in the real world?

This will depend on the mount on the lenses and if there is an adapter that allows you to use them on C-Mount cameras.  For additional assistance with this question feel free to email us at


what do i buy if i have a Sony A7 and a Mayfair Crystar 35mm f3.5 lens?

The Vello T-Mount Lens to Sony E-Mount Camera Lens Adapter, B&H # VELANEXT would be appropriate for your Sony A7 and your Mayfair Crystar 35mm f/3.5 lens.

I have an old screw mount I'd like to find an adapter for to fit my Nikon D7000. I have a Solinar Tele-Auto 1:63 f=400mm 72 No.17518266. Is there any way possible to use this lens again?

If the lens has an M42 type screw mount, then you may use the FotodioX Pro Lens Mount Adapter for M42 Lens to Nikon F Mount Camera, B&H # FOPNFAM42I.

I was thinking about buying a Lumix DC-GH5 M43 camera soon and was thinking of using an adapter to put my old Nikkor 35mm lens on it. If I do that, will the image still look the same? Or will the M43 "zoom" the lens in and make it look like a 70mm?

If you are looking for a lens adapter that would allow you to connect a Nikon F-mount lens onto the Micro Four Thirds lens mount used on the Panasonic Lumix DC-GH5 Mirrorless Micro Four Thirds Digital Camera, I would recommend the Metabones Nikon G Lens to Micro Four Thirds Lens Mount Adapter (Matte Black), B&H # MENFGM43BM1, or the Vello Nikon F-Mount G Lens to Micro Four Thirds Camera Lens Adapter with Aperture Control, B&H # VELAMFTNG, for your usage needs.  If the Nikon 35mm lens you own was originally used on a 35mm film camera or a full-frame DSLR camera, then due to the 2x crop factor of the smaller sensor, the lens used on the Micro Four Thirds sensor would be the equivalent of a 70mm lens used on the full-frame camera or 35mm film.  When compared to the 35mm full-frame sensor, all lenses used on the Micro Four Thirds lens mount will require the lens' focal length to be multiplied by 2x to find the full-frame equivalent focal length.

Like the prior person (Ilias G), my father just gave me all his vintage lenses and I am looking for an adapter to use them with my Nikon D3000, as well as any input you could offer on the viability and practicality of using these older lenses with a newer camera. The lenses I received are:

Minolta Maxxum AF 70-210/4

Minolta Maxxum AF 50mm - 1:1.7 (22)

Vivitar Wide-Angle Auto 28mm - 1:25 (No. 22230299)

Vivitar Telephoto 135mm - 1:28 (No. 282371128)

Vivitar Automatic Tele Converter - 2x-7

Konica Hexanon AR 52mm - F 1.8

Makinon MC 72MM 1A - Zoom 1:3.5 - (f = 35 - 105mm)

Peerotar 45mm - 1:18 (No. 307827)

Ernst Leitz GmBH Wetzlar - Elmar f = 9 cm - 1:4 (No. 1521087)

(The last one is considerably smaller in diameter than the rest)

Any assistance you can offer will be greatly appreciated. Thank you in advance for your help.


Being that you have quite a few lenses on your list there, we would ask that you e-mail your inquiry to us directly to so we can further assist you. Thank you. 

Hi! I took the liberty to ask you something if it's not any trouble. I have a nikon d3200 and recently my father gave me his vintage lenses from his adulthood. And I had the idea of mounting them to my camera with adapters. 1st lens is a ampex vidicon 25mm f1. 9 (c mount) and the 2nd Is a helios 44-3 (if I remember). Can you point me to the best adapters to use them effectively? And not to spend too much money :P thanks a lot in advance! 

The only adapter we carry that will allow you to connect a C-mount video lens onto the Nikon F-mount used on the Nikon D3200 DSLR camera would be either the FotodioX Mount Adapter for C-Mount Lens to Nikon F-Mount Camera, B&H # FOCNIKF.  Do note that as the C-mount lens was designed for the smaller CCTV sensor or older 16mm cine video cameras, the lens’ imaging circle will not fully cover the larger APS-C sensor used in the Nikon D3200 DSLR camera.  Also note that this lens will have to be used fully manually, as the lens has no electronic contacts and the adapter does not transmit any electronic data from the lens to the camera.  As such, you will have to set the focus, metering, and aperture all manually.  Also note that you will not have infinity focus, and the lens will operate like a macro lens or close focus lens when using the C-mount lens on the Nikon F-mount used on your camera; your focus range will be limited. 



If I am not mistaken, I believe the MC Helios 44-3 50mm f/2 lens used the M42 screw mount.  If so, the  FotodioX Pro Lens Mount Adapter for M42 Lens to Nikon F Mount Camera, B&H # FOPNFAM42I, should work for your usage needs.  You will still have to set everything manually (and the camera has to be in full “M” Manual mode when using the above lenses on your camera.)  However, it should be large enough to cover the APS-C sensor in the camera.

I am still a bit confused on my particular issue if I can ask, appreciate your help! I would like to use my old canon glass, FD mount, manual focus, bayonet lenses on an APSC Canon camera. I see that there are lens mount adapters (I realize the quality may be lowered, but the quality of the glass is high and the cost to replace one lens in particular would be about $1100 for the closest to it), but I just can't seem to figure out which one I can use? 

Hi Carla,

The FotodioX Pro Lens Mount Adapter for Canon FD Lens to Canon EF-Mount Camera B&H # FOPCEACFD is going to be your safest bet to mount your current FD lenses on a Canon EOS DSLR with an APS-C sensor.

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