Focusing screen issue...

Raphy

Hey guys and gals, maybe comeone came across a similar issue. I was cleaning the sensor last night as i noticed some dust in pics with higher f numbers... after cleaning I also noticed that I have, what seems to me, a blob or a black spot on the focusing screen. THis only shows up thru the viewfinder, with or without lens attached.

But not only does it seem like a piece of dirt (perhaps?) but it almost seems like the opaque-ish screen has a tiny hole, where you can actually see throught it - i'm not sure if that makes sense. When i move the D40 around the blob goes from black to white depending on where i point the camera and what the background it..... just plain wierd.

THis blob is not seen in photos, just thru viewfinder.

Should i clean the focusing screen with the lens liquid and microfibre cloth ? is my focusing screen defective and should it go back to nikon ? its hard to believe that there would be a hole in the screen.....

ziggy53

Raphy,

I doubt that it's a hole. It sounds like a droplet of some sort. If it doesn't change at all over time, potentially some oil.

If it is tiny and does not affect anything, I would not mess with it. If it is large enough to cause problems with sighting or viewing through the viewfinder then yes, you might try cleaning the viewfinder screen.

Do be careful that you don't touch the mirror during the process.

Sensor swabs would probably be the best tool for the job, but I "Do Not" suggest using the sensor cleaning fluid. Use only distilled water unless that does not cut the material and then use an extremely mild and weak dish detergent and water solution, followed with distilled water rinse.

Let me repeat that the sensor cleaning solution should probably not be used. The screen is usually plastic, unlike the sensor which has a glass filter on it.

Practice with a plain, rear surface (cheap) mirror (like a common "hand mirror") first to learn the process. The swab should not drip within the camera, or you could have bigger problems.

Raphy

Thanks for your input ziggy. I'll see what happens over the next few days... i'll try the blower again...

I found it to be more annoying than anything... but like i mentioned it doesn't show up in the photos, so i MAY be able to live with it... i'll wait and see,

thanks agian !

pathfinder

Raphy,

Dust and fibres are not uncommonly seen on the ground glass when looking though the viewfinder. Although annoying, they are harmless, are not seen in the final images, and are best ignored unless they are really disturbing.

When my viewfinder gets to the point when I can't stand it anymore, I use a Rocket blower bulb first and try to just stop there. If it has not helped, then I would consider using a clean camel's hair brush, or a sensor brush that I no longer planned to use on my sensor. I might consider a keyboard vacuum cleaner brush very carefully also. I would not try liquids cleaners on the ground glass except under the direst of circumstances. I would prefer to replace the ground glass screen if possible. I agree with ziggy, no alcohol used on the ground glass whatsoever.

The mirror, directly in the front of the sensor, is a front surface mirror, and is not to be touched. A camel's hair brush could be used if absolutely needed. Do not try to clean the surface of the mirror - it will scratch very easily as it is a front surface mirror.