Help with scratching issue.

[Ferdinand]

I think I have scratched the piece of glass on top of the mirror while trying to clean it cause I was seeing dust in my viewfinger, any suggestion as to what cause of action should I take? It doesn't seem to affect my picture quality nor can I see it once I have my lens on, its only when the lens is off. :(

Regards,
Ferdinand

[EoSD30fReAk]

It doesn't effect you picture because the mirror is only there to see through your viewfinder.
so keep your lenses on and don't think about it i would say :D

[CyberDyneSystems]

Sound advice... :wink:

[Guillermo Freige]

Ferd:
First, nothing seen in the viewfinder with the lens removed will affect AT ALL the picture image, because you are looking at the mirror, focusing screen, pentamirror optical path only, a none of those elemens are in the CMOS optical path. A REALLY REALLY dirty mirror can affect AF/AE, at least in theory, but that's all.
Second, if all you see are concentric circular lines, don´t worry. That is the normal focusing screen finish, and usually can be seen only with the lens removed. Any other line can be only dust. The focusing screen and mirror are even more prone to collect dust than the sensor itself, as they are always exposed, and not only during shutter release as the CMOS sensor. The same cleaning techniques (blower, swabs) can be used to clean the mirror and the focusing screen.

[KennyG]

Ferd: The same cleaning techniques (blower, swabs) can be used to clean the mirror and the focusing screen.

I would beg to differ. The mirror coating is on the surface and should not be touched as it is easily damaged. The focus screen has very fine groves and is very easily damaged/marked. Both should only be cleaned with a blower.

[Ferdinand]

Eeek ok don't touch the mirror, so far I have used those cleaning tissue on them, no scratches that I can see yet. So I am going to stop doing it from now on. As for the focusing screen, that is not that one on top of the mirror with the concentric circle when you look thru the viewfinder without the lens on is it? <prays hard, fingers cross>

Regards,
Ferdinand

[KennyG]

As for the focusing screen, that is not that one on top of the mirror with the concentric circle when you look thru the viewfinder without the lens on is it? <prays hard, fingers cross>

Regards,
Ferdinand

That is the one. It is very delicate and marks very easily. The only way to clean it is with a good quality blower. I only clean mine, along with the mirror, if I see any dust in the viewfinder, which is not very often. They do not hold onto the dust like the CMOS does as they are not as statically charged.

[Ferdinand]

Ouch Kenny,

I have scatches on mine but only visible when I don't have the lens on, is that an issue? What does the concentric circle do? And does it affect focusing if its slightly scratch? Should I push for a warranty repair? Thou I doubt they would cover something I did while cleaning. So far I have used the optical cleaning paper and lens cleaning fluid on them. Please advice.

Regards,
Ferdinand

[KennyG]

It won't effect focus, it will just be very annoying when you have to look at it every time. I would live with it until it really bugs you then get the screen replaced. As a spare part they are quite cheap, but unless you know what you are doing you will have to pay to have it fitted.

I am lucky enough to have a special tool to remove the focus screens in my cameras as you can get dust/hair behind them. Not for the feint hearted.

Keep on top of the dust problem by using a blower after every shooting session. Blow the dust off your lenses (particularly the camera end) before you put them away. Use a microfibre cloth to clean the outside of the camera before you open it to use a blower. It is all about getting into a simple housekeeping routine.

Finally, pads and fluids are the last resort to clean a really dirty sensor. They should not be used on a regular basis.

[Ferdinand]

Thanks Kenny,

And yes its kinda annoying having this nagging behind the back of your mind that its scratch, but I can live with it as long as I don't keep peeking into the viewfinder without my lens on! :shock:

Do you have an idea on roughly how much a replacement would cost at a dealer? And would you recommend regular blower or compress air? If so what brand? I am sorry for all these questions but I am new to photography.

Best regards,
Ferdinand