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Sigma Lens Doesn't Fit on EOS DSLR


hi i just bought a canon eos dslr body and i also bought a sigma lens that is for canon. the lens doent fit at all. it doesnt even have the pins that connect with the camera.. and my camera isnt turn on and i tried everything , and i read that my canon wont turn on without the lens on. Can u help me and reply to ant of this??



Hi and welcome to the forum:

Sorry to learn are having issues.  Can you please advise what camera model you have purchased?  It would also help to know the model of Sigma lens you have.
Normally, a camera will turn on without a lens attached, so I am not sure why your one does not do so... Was this a new camera, or did you purchase is second-hand.

If you bought a Sigma lens for Canon, it is almost certainly an EF mount lens - and that will work with all current DSLRs.  So, as long as the camera IS a DSLR and not a mirrorless one, it should fit and work.

cheers, TREVOR

"The Amount of Misery expands to fill the space available"
"All the variety, all the charm, all the beauty of life is made up of light and shadow", Leo Tolstoy;
"Skill in photography is acquired by practice and not by purchase" Percy W. Harris


What model camera did you buy. Please give us the full name. Canon makes DSLRs and Mirrorless cameras. Your camera WILL turn on without a lens no such limitation exists.


Current Gear: EOS 5D Mark IV, EF 16-35mm F/2.8L III USM, EF 24-70mm F/2.8L II USM, EF 50 F/1.8 STM, EF 85mm F/1.8 USM, EF 70-200mm F/2.8L IS III USM, 430EX III-RT, 470EX-AI & 600EX II-RT

Retired Gear: EOS 40D, Sigma 17-50mm F/2.8 EX DC OS HSM & EF 28-135mm F/3.5-5.6 IS USM


Current Gear: EOS 5D Mark IV, EF F/2.8 Trinity, EF 50mm F/1.8 STM, EF 85mm F/1.8 USM, 470EX-AI & 600EX II-RT

Retired Gear: EOS 40D


If the lens doesn't have pins/contacts that connect to the camera, you have an old lens for manual-focus film cameras, not for Canon EOS autofocus cameras. What is the exact name on the lens?


Unfortunately, saying that a lens "is for canon" is nowhere enough.  Canon (like all camera manufacturers) has multiple lens mounts, and to get a lens that works on your camera, you need to know the actual lens mount of the camera, and of the lens, and make sure they match.

It's not possible to get more specific until you actually tell us what lens and camera you have.  But you say that the lens doesn't have electronic contacts, so you may have an old FD-mount lens.  If your camera is EF-mount, then that won't work, and as far as I know there is no adapter.  On the other hand Sigma does make all-mechanical EF-mount lenses.

As for the camera not turning on -- is it broken?  Is the battery charged?  It should certainly turn on without a lens, and depending on the camera, there should be a menu option to set it to take pictures with no lens attached (this is for when you use an all-mechanical lens).

I wrote an article which explains lens compatibilitiy issues, if you're interested:

Just so you know, There ARE readily-available and cheap FD-to-EF adapters, requiring full-manual control.


Since FD's flange distance is shorter than EF, I think those are all diopter adapters (i.e. they have a lens in them).   I kind of discount them 'cos what I've heard is that diopter adapters are pretty poor quality.  Do you have other info?  I'd love to hear it.

I didn't RECOMMEND them, and you sure can dismiss them entirely. But you said you were unaware of their existence. That was my only point.


It's possible that you have purchased a Sigma lens that is not compatible with your Canon DSLR body. The pins on the lens are necessary to connect with the camera and allow for proper communication and functionality. If your camera isn't turning on, it could be because it's not detecting a compatible lens attached.

To resolve this issue, you should double-check that the Sigma lens you purchased is specifically designed for Canon DSLR bodies. You can do this by checking the lens mount type and comparing it to the mount type on your camera body.

If you find that the lens is not compatible, you will need to return it and purchase a lens that is compatible with your camera body. If you're unsure which lens to choose, you can consult with a knowledgeable salesperson or do some research online to find a lens that meets your needs and is compatible with your camera.

If your camera still doesn't turn on even when a compatible lens is attached, there may be another issue at play. In that case, it's best to contact Canon customer support or take your camera to a professional camera repair shop for further assistance.

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