topic Re: Strange circular rings on Focusing Screen - 5Dmiii in EOS DSLR & Mirrorless Cameras

Strange circular rings on Focusing Screen - 5Dmiii

_RD — Sat, 12 Oct 2019 19:16:52 GMT

Hi Everyone

I recently purchased a second hand 5Diii. It appears to be in absolute mint condition. The only thing I find strange is, when I look through my VF, there appear to be very thin black circles across the whole VF.

I have tried using a blower to clean the VF, which made no difference. When I take the lens off and I look within the camera, I can notice these lines on what I believe to be the focus screen. Can anyone shed any light as to what these marks are?

For the record;

- The lines do not seem to affect the images being taken, and don't show up in Live View Mode

- The lines can be seen when there is a lens attached, and when there is not a lens attached

- The lines are of course far more obvious when shooting in high light. But definitely noticeable no matter the situation.

- The circular lines are sperated from one another perfectly (same space between each one, which suggests they are supposed to be there..)

- I am also not referring to the focus ring that you are supposed to see in the VF. These lines start from the centre and go all the way to the edge.

- One section of the black lines seems to be ever so slightly thicker than all the others, which suggests dirt maybe?

I've attached images so you can see what I mean.

Thanks in advance!

Re: Strange circular rings on Focusing Screen - 5Dmiii

Waddizzle — Sat, 12 Oct 2019 19:34:07 GMT

That sort of looks like a manual focusing screen.

Except, I am not aware of one made by Canon for that camera.

Re: Strange circular rings on Focusing Screen - 5Dmiii

_RD — Sat, 12 Oct 2019 20:05:17 GMT

The photo I included was taken with the camera turned off, so none of the usual focus metering displays are shown. These of course do display when the camera is on.

But these black lines stay there constantly. They also go in and out of focus when I adjust the focus of the VF, which to me is a clear indication that this circular pattern in embedded within either the focus screen or some other form of glass that's located near it.

Re: Strange circular rings on Focusing Screen - 5Dmiii

Waddizzle — Sun, 13 Oct 2019 14:40:17 GMT

@_RD wrote:
The photo I included was taken with the camera turned off, so none of the usual focus metering displays are shown. These of course do display when the camera is on.
But these black lines stay there constantly. They also go in and out of focus when I adjust the focus of the VF, which to me is a clear indication that this circular pattern in embedded within either the focus screen or some other form of glass that's located near it.

Go into the camera menus, find the setting that resets the camera back to Factory Defaults.

I have a pretty good idea what it is that you are seeing. If you have not downloaded a copy of the full Instruction Manual from Canon Support, then I suggest that you do so. Make it your newest best friend.

Re: Strange circular rings on Focusing Screen - 5Dmiii

_RD — Sun, 13 Oct 2019 17:19:24 GMT

I have factory resetted as you advised and still seeing the marks.

If you have a pretty good idea of what it is i'm seeing, then it would be most helpful if you could share that information!

Thanks

Re: Strange circular rings on Focusing Screen - 5Dmiii

Waddizzle — Sun, 13 Oct 2019 17:41:37 GMT

@_RD wrote:
I have factory resetted as you advised and still seeing the marks.
If you have a pretty good idea of what it is i'm seeing, then it would be most helpful if you could share that information!

Thanks

Grid ines. it would be more helpful if you downloaded the instruction manual and educated yourself about the camera.

Re: Strange circular rings on Focusing Screen - 5Dmiii

_RD — Sun, 13 Oct 2019 20:27:22 GMT

As much I appreciate your attempts to aid me, but do you really think i'd waste my time creating this account to ask this kind of question if I didn't know what grid lines where?! I have been using Canon cameras for over 7 years and am accustomed to many variations of VF styles. But as I said in my very first message, I am not referring to the focus ring, or indeed any grid lines. These marks are irregular in width - which suggest some kind of dirt trap, and are evidently seen on the actual focus screen itself (when looking up into the inside of the camera). I can assure you these are not grid lines. I also own a downloaded copy of the instruction manual, where I found no reference to these lines - hence why i'm here!

Best.

Re: Strange circular rings on Focusing Screen - 5Dmiii

Waddizzle — Sun, 13 Oct 2019 21:03:47 GMT

@_RD wrote:
As much I appreciate your attempts to aid me, but do you really think i'd waste my time creating this account to ask this kind of question if I didn't know what grid lines where?! I have been using Canon cameras for over 7 years and am accustomed to many variations of VF styles. But as I said in my very first message, I am not referring to the focus ring, or indeed any grid lines. These marks are irregular in width - which suggest some kind of dirt trap, and are evidently seen on the actual focus screen itself (when looking up into the inside of the camera). I can assure you these are not grid lines. I also own a downloaded copy of the instruction manual, where I found no reference to these lines - hence why i'm here!

Best.

Actually, just the opposite. If someone didn't know what grid lines were, then I expect that type of person to ask about what they are. I suggest that you contact Canon Support, and send your camera in for an inspection.

Re: Strange circular rings on Focusing Screen - 5Dmiii

jrhoffman75 — Mon, 14 Oct 2019 00:05:02 GMT

The 5D Mark III does not have "user replaceable" focus screen, like the Mark II and other cameras where a little clip is dpressed and optional screens are installed.

There are no optional Canon screens; the system map in the manual shows no optional screens, where as the ID X does, for example.

There are third party screens available from eBay; none that I saw showed rings like you are describing. I agree that you should consider sending it in for Canon service.

Re: Strange circular rings on Focusing Screen - 5Dmiii

Ray-uk — Mon, 14 Oct 2019 10:38:22 GMT

A lot of focus screens consist of a suface which is actually a fresnel lens which has very fine circular lines engraved, these are not normally visible unless they get dirty. It is likely that this is engraved on the upper side of the screen so it is not possible to blow any dust or dirt off without removing the screen.

As the screen of your camera is user-changeable I would suggest you drop it out (wear a pair of cotton gloves because they are easily damaged) then you will be able to see if it has a problem. A dirty screen can be washed in a dish of tepid distilled water with a drop of dish soap added, dab it dry with a tissue but do not rub the surfaces with anything.

Re: Strange circular rings on Focusing Screen - 5Dmiii

_RD — Mon, 14 Oct 2019 10:49:12 GMT

Thank you for this. I have also gone into my local London Camera Exchange today and they've taken a look. From what Canon UK helpline, you and they have said, it does in fact just seem as though these are dirt marks that have got stuck within the circular engravings of the focus screen (a little worrying that the screen has been left in such a way that so must dust can get to it, but things things happen).

All of the advice i've been given has been in agreement that the issue does not have any bearing on the final images being taken, which to me is the important thing. If I buy a second hand camera, i've got to accept that it's not going to be flawless. If this is the only thing wrong with it then it sounds like it's not the end of the world.

Seems to be lots of split opinion on whether the 5Diii screen is interchangeable. Either way I think given the cost of sending cameras off, and my inexperience with taking them apart, it's probably not worth getting myself worked up about it.

I appreciate your help, thank you.

Re: Strange circular rings on Focusing Screen - 5Dmiii

wq9nsc — Mon, 14 Oct 2019 13:28:24 GMT

You can be a replacement focusing screen but the installation isn't as simple as with the Canon cameras designed for interchangeable focus screens and you have to remove some screws to release the focus screen retainer. This procedure creates more potential for damage which is why Canon considers it to be an item that needs service by a shop. A friend replaced her screen and it was pretty simple but if you aren't confident and careful then an annoyance can turn into a bigger issue.

With that amount of dust on the focus screen, I am surprised the sensor and mirror aren't also showing signs of the environment. I suspect either the lens was changed often in a dusty location or more likely the previous owner stored it without a lens or body cap in place.

Rodger

Re: Strange circular rings on Focusing Screen - 5Dmiii

_RD — Mon, 14 Oct 2019 13:38:46 GMT

Thanks for that Rodger. I agree, it's rather unusual that there's dust on the focus screen yet everywhere else is fine.

I'd love to find out the answer but the previous seller is of course just claiming he's 'looked after it'. The joys of buying second hand!

Best

Re: Strange circular rings on Focusing Screen - 5Dmiii

ebiggs1 — Mon, 14 Oct 2019 19:13:03 GMT

On a hunch, are you using third party lenses? If you they are the problem. Try a Canon branded lens, just for kicks.

Re: Strange circular rings on Focusing Screen - 5Dmiii

wq9nsc — Mon, 14 Oct 2019 21:10:54 GMT

It sounds like other than the annoying rings that your camera is working fine so in the grand scheme of things, you probably made a very good second hand purchase. That is mysterious how the focus screen became dirty without anything else attracting dust; it could have been one of those rare factory issues and the original purchaser never paid enough attention to realize it was there. I would definitely avoid any temptation to clean the focus screen which would probably lead to damage and dispersal of the dust to other places.

Rodger

Re: Strange circular rings on Focusing Screen - 5Dmiii

ebiggs1 — Mon, 14 Oct 2019 22:07:17 GMT

"I agree, it's rather unusual that there's dust on the focus screen ..." And highly unlikely! Just sayin'.

Re: Strange circular rings on Focusing Screen - 5Dmiii

_RD — Mon, 14 Oct 2019 22:13:46 GMT

I have used a variety of canon branded lenses during testing 🙂

Re: Strange circular rings on Focusing Screen - 5Dmiii

jrhoffman75 — Mon, 14 Oct 2019 22:31:40 GMT

The circular rings with third party lenses happened in the digital images and was caused when in camera lens correction was activated. I think it was with certain Sigma lenses.