Canon 5D viewfinder defect

[ThomasPatrick]

Hello, I have a Canon 5D whereby I look thru the viewfinder & all that visible is a clear hole. The remaining parts of the viewfinder are "blacked out"  I put the same lens on a different camera and the issue went away. So my auumption is that the issue/defect is on the Canon Body.  Has anyone had this experience & if so, how did you you repair your 5D?  I'd send it to Canon but because so many upgrades came out after the original 5D, the repair price might be as high as the cameras value.  I sure would appreciate any step by step instructions as I've tried other lenses on the 5D, than put those leneses on one of my other Canon's, so it has to be the body, perhaps the mirror elements.  Please help.  Kindly,

Gary

[wq9nsc]

I have never owned an EF-S lens (designed for "crop sensor" Canon cameras) but that sounds much like what would happen if you tried to install a crop sensor lens on a full frame camera.  What is the lens model that you tried?

Rodger

[JasonR]

The 5D is designed for EF lenses, putting an EFs lens on a full frame camera such as the 5D can cause damage to the shutter and or adapter. The EFs lens is a crop frame lens and that would be why you are seeing what you are when you put it on the 5D. Also, I spoke with Canon just yesterday on an unrelated 5D repair issue and the 5D can no longer be sent in for repair as they do not have parts stock for these cameras any longer.

[RobertTheFat]

---

@JasonR wrote:

The 5D is designed for EF lenses, putting an EFs lens on a full frame camera such as the 5D can cause damage to the shutter and or adapter. The EFs lens is a crop frame lens and that would be why you are seeing what you are when you put it on the 5D. Also, I spoke with Canon just yesterday on an unrelated 5D repair issue and the 5D can no longer be sent in for repair as they do not have parts stock for these cameras any longer.

---

I'm pretty sure that by the time the 5D came out, Canon had already modified the EF mount to physically refuse to accept an EF-S lens. So I'm dubious about that proposed explanation of the OP's problem.

[Waddizzle]

---

@RobertTheFat wrote:

---

@JasonR wrote:

The 5D is designed for EF lenses, putting an EFs lens on a full frame camera such as the 5D can cause damage to the shutter and or adapter. The EFs lens is a crop frame lens and that would be why you are seeing what you are when you put it on the 5D. Also, I spoke with Canon just yesterday on an unrelated 5D repair issue and the 5D can no longer be sent in for repair as they do not have parts stock for these cameras any longer.

---

I'm pretty sure that by the time the 5D came out, Canon had already modified the EF mount to physically refuse to accept an EF-S lens. So I'm dubious about that proposed explanation of the OP's problem.

---

Why do you say that?  Most third party lenses for APS-C bodies use the standard EF mount.  Why should they design two different mounts when one works just fine?

[RobertTheFat]

---

@Waddizzle wrote:

---

@RobertTheFat wrote:

---

@JasonR wrote:

The 5D is designed for EF lenses, putting an EFs lens on a full frame camera such as the 5D can cause damage to the shutter and or adapter. The EFs lens is a crop frame lens and that would be why you are seeing what you are when you put it on the 5D. Also, I spoke with Canon just yesterday on an unrelated 5D repair issue and the 5D can no longer be sent in for repair as they do not have parts stock for these cameras any longer.

---

I'm pretty sure that by the time the 5D came out, Canon had already modified the EF mount to physically refuse to accept an EF-S lens. So I'm dubious about that proposed explanation of the OP's problem.

---

Why do you say that?  Most third party lenses for APS-C bodies use the standard EF mount.  Why should they design two different mounts when one works just fine?

---

Let's be clear. The reason an EF-S lens can't be used on a full-frame Canon camera is that it takes advantage of an APS-C camera's smaller mirror, which allows the lens to extend further into the camera body, A 3rd-party APS-C lens that didn't do that could presumably be mounted on a full-frame camera. But a (Canon) EF-S lens cannot, because it would interfere with the camera's mirror. So Jason's surmise that the OP was using an EF-S lens on his 5D could hardly be true, because the camera's EF mount would block an EF-S lens from being inserted.

[Waddizzle]

---

@RobertTheFat wrote:

---

@Waddizzle wrote:

---

@RobertTheFat wrote:

---

@JasonR wrote:

The 5D is designed for EF lenses, putting an EFs lens on a full frame camera such as the 5D can cause damage to the shutter and or adapter. The EFs lens is a crop frame lens and that would be why you are seeing what you are when you put it on the 5D. Also, I spoke with Canon just yesterday on an unrelated 5D repair issue and the 5D can no longer be sent in for repair as they do not have parts stock for these cameras any longer.

---

I'm pretty sure that by the time the 5D came out, Canon had already modified the EF mount to physically refuse to accept an EF-S lens. So I'm dubious about that proposed explanation of the OP's problem.

---

Why do you say that?  Most third party lenses for APS-C bodies use the standard EF mount.  Why should they design two different mounts when one works just fine?

---

Let's be clear. The reason an EF-S lens can't be used on a full-frame Canon camera is that it takes advantage of an APS-C camera's smaller mirror, which allows the lens to extend further into the camera body, A 3rd-party APS-C lens that didn't do that could presumably be mounted on a full-frame camera. But a (Canon) EF-S lens cannot, because it would interfere with the camera's mirror. So Jason's surmise that the OP was using an EF-S lens on his 5D could hardly be true, because the camera's EF mount would block an EF-S lens from being inserted.

---

I understand that with Canon EF-S mounts.  I do not think the OP said what lens model was causing the issue.  I am just pointing out that the symptoms are consistent with some third party lenses made for Canon APS-C bodies.

[wq9nsc]

Bob,

The actual Canon EF-S lens is built so that it is physically blocked from mounting to a full frame Canon DSLR body to prevent damage to the lens and/or mirror mechanism BUT that isn't true of all third party "crop" lenses some of which will mount to a full frame Canon DSLR body. 

Depending upon the design of the particular lens, it may have sufficient clearance to avoid damage but I wouldn't chance it unless the manufacturer has tested that it will work (other than not illuminating the entire sensor area).  Be particularly cautious if trying to use a zoom lens and or a rear focusing setup because the problematic protrusion will only occur under certain optical settings.

If you search on youtube, you will find a video of how to use crop sensor Canon glass on full frame bodies by removing the "blocking" piece.  I strongly advise against this experiment because damage could be very expensive if your lens protrudes too far into the sensor box, sort of like what happens when a timing chain breaks on an "interference" car engine and the valve train becomes intimate with the piston faces.

Rodger

[Ray-uk]

It would be interesting to hear from the OP with a bit more information on this fault, although everyone is blaming the lens you can get this effect if the focus screen is missing.

[huskyC]

Check if the mirror is still there. Some early batches of 5D had the problem of mirror detached from the mount.

There has been some discussions about this issue. The following is one of them.

https://petapixel.com/2015/05/13/canon-warns-the-original-5d-may-suffer-from-mirror-separation/