Canon 6d mirror actuation rubbing rear lens element on Rokinon 14mm f2.8 EF mount.

[NpPhotography]

Would anyone have advice on if my Canon 6D mirror might be rubbing the rear lens element on my EF mount Rokinon 14mm f.2.8? I used the lens for the first time the other day and noticed some knicks had formed after actuating the shutter. The rear lens element does protrude past the rear of the lens. 

[NpPhotography]

This is purely speculation as to why the knicks appeared on the rear lens element. Otherwise, Im at a loss as to how the damage was incurred. This was literally the first time using this lens.

[deebatman316]

Can we see a picture of the camera body too. Something is not right. The mirror should never hit the rear element of a lens under any circumstances.

-Demetrius

40D, 5D Mark IV, EF 16-35mm F/2.8L III USM, EF 24-70mm F/2.8L II USM, EF 28-135mm F/3.5-5.6 IS USM, EF 50 F/1.8 STM

430EX III-RT & 600EX II-RT

[Waddizzle]

I have no explanation for it, either.  There is a 16mm that is very similar and is actually made for APS-C bodies, even though it uses the EF mount.                  

It is more likely that it is coincidence that you noticed it now when you are using a new lens.  As you rotate the focus ring, nothing should protrude from the rear lens mount.  If that is the case, then the lens is almost certainly not to blame.

[deebatman316]

Hi Waddizzle is this lens an internal or externally focused lens. The way how the OP describes the problem. Sounds like this an EF-S lens which cannot be mounted on a FF/ 35mm Film camera. Canon is the only one who makes EF-S lenses. Due to the nature of EF-S lenses they're designed to have short back focus and protrude into the camera body. 

-Demetrius

40D, 5D Mark IV, EF 16-35mm F/2.8L III USM, EF 24-70mm F/2.8L II USM, EF 28-135mm F/3.5-5.6 IS USM, EF 50 F/1.8 STM

430EX III-RT & 600EX II-RT

[shadowsports]

Greetings,

I have the Rokinon 12mm.  Fully manual, no contacts.  It doesn't hit the mirror on my 6D2.

Rokinon 12mm f/2.8 ED AS IF NCS UMC

 12mm

14mm no chip

The 14 is basically the same with or without AE chip.  Not sure how yours might be hitting.  The flange isn't deep enough on mine.  

[deebatman316]

The way the OP describes this problem makes this lens sound like an EF-S lens. An EF-S lens cannot be mounted to a FF/ 35mm camera. An EF-S lens would cause a whole lot more damage though.

-Demetrius

40D, 5D Mark IV, EF 16-35mm F/2.8L III USM, EF 24-70mm F/2.8L II USM, EF 28-135mm F/3.5-5.6 IS USM, EF 50 F/1.8 STM

430EX III-RT & 600EX II-RT

[jrhoffman75]

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@deebatman316 wrote:

The way the OP describes this problem makes this lens sound like an EF-S lens. An EF-S lens cannot be mounted to a FF/ 35mm camera. An EF-S lens would cause a whole lot more damage though.

-Demetrius

40D, 5D Mark IV, EF 16-35mm F/2.8L III USM, EF 24-70mm F/2.8L II USM, EF 28-135mm F/3.5-5.6 IS USM, EF 50 F/1.8 STM

430EX III-RT & 600EX II-RT

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I have never seen a third-party lens with an EF-S mount. There are EF lenses with an APS-C field of coverage, but they will mount on a full-frame camera.

Quite possibly the lens 1. came with the damage and OP didn't notice it, or 2. OP may have banged lens on mount while installing.

I don't the mirror would have enough closing force to scratch a glass element. It would likely jam and initiate an error message.

[Lotus7]

Debatman316: "I know Rokinon lenses are usually completely manual lenses. They also don't have electronic contacts to communicate with the body."

FWIW:  Currently Rokinon makes 25 different auto focus lenses, including several with automatic apertures.  There are EF and RF versions of the 14 mm and 85 mm and a range of auto focus Sony cine lenses.  All have the required electronic contacts including all 12 contacts on the 14 mm RF AF version which works perfectly on the EOS R, RP and R5. The RF version even has a programmable control ring.

Canon did apparently curtail the sale of the 14 mm f/2.8 RF mount version with their cease and desist warning, but not before a number were sold.  Even though the 14 mm f/2.8 AF RF is still listed in the Rokinon catalog, and on their website, they are now listed as  "not currently available" via their factory direct sales outlet.

[NpPhotography]

Thank you all for your responses. I have determined it is not the camera. The lens should have been inspected more carefully before I used it. Fortunately, the seller has offered a full refund and paid shipping.