Strange circular rings on Focusing Screen - 5Dmiii

[_RD]

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!

[_RD]

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.

[wq9nsc]

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

[_RD]

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

[wq9nsc]

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

[ebiggs1]

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

[ebiggs1]

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

[_RD]

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

[jrhoffman75]

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.