Dirt in the D50 viewing system

[Ian Rance]

<p>As a rule I am very careful what lenses I put on my D50 camera as I know dust gets onto the sensor but somehow I have two blobs that are not on the outside of the focus screen. With my F100 or F3 film camera I would whip out the screen and give the prism a clean, however I don't think the D50 is so straightforward as it has pentamirrors.</p>

<p>So, is there any way of getting these two distracting blobs out without major dis-assembly or is the pentamirror system too awkward to even think about cleaning myself? I know dust isn't important to the image but I have no visible dust in any of my cameras due to careful cleaning after dusty assignments so it would be nice to have a clear view. Image of blobs is below.</p>

<p> </p><div></div>

[Matthew Brennan]

<p>I've have a pair of dust bunnies chasing each other around under the viewer screen for a couple of years inside my D700. I happened to send the body off for a chronically needed sensor clean about a month after these dust spots appeared. The techo said it would cost another $70 for the labour to remove the screen, clean the cavity+screen and re-fit - he also said there is no other way of removing them aside from the same random fluke which forced them into the cavity in the first place.</p>

<p>I have managed to ignore these two for just over 2 years and won't be forcing the issue unless they multiply rapidly. If you can ignore them I'd live with them before delving into screen removal and associated costs if you want someone else to perform the task.</p>

[pete_s.]

<p>I believe the D50 has the same LCD overlay as the D70 over the focusing screen (#1046 in the image below). The screen (#G3) itself is easy to remove. Blow off any dust and then also blow in the mirrorbox. Be careful blowing compressed air on the shutter though as it is delicate.</p>

<p>I don't think you could see dust in the viewfinder prism because it is not in focus. So it's probably on the top side of the focusing screen or under the LCD overlay.</p><div></div>

[Ian Rance]

<p>Thank you for the help. Is item #297 the LCD overlay or a shim? If anything were to fall out when the screen was released then it may not go back as it was.</p>

[pete_s.]

<p>#297 is a shim and it's not 100% sure that there is one in yours. It will come out whan you take out the screen and it will have to go back in the same place.</p>

<p>There are a couple of third party focusing screens with split-images and such avaliable. They usually have instructions online for all popular models and how to replace the focusing screen.</p>

[Michael R Freeman]

<p>Here is the D50 diagram...</p><div></div>

[iso200]

<p>If it's anything like a D700, the wire retainer [#284] can be released with your thumbnail [DO NOT USE ANY TOOLS, the plastic screen [#3] is softer than you'd expect and easily marked/scratched]. Hold your camera upside down when you release the retainer, and then tilt it backwards, and the wire, screen and shim will all pivot free and end up lying against the mirror. You can then use a dust blower to get anything off the screen and/or bottom of the prism. You don't actually have to take anything out of the camera. Gently bring the camera upright and the shim, screen and retainer should all fall back into place, and just use your thumb to re-attach the retainer.</p>

<p>You may also be able to get the tip of a dust blower against the screen and blow air under it - I'd try that before attempting any disassembly. If you're not comfortable with this any competent camera shop should be able to do it for you.</p>

[Ian Rance]

<p>Thanks again. I managed to clean off the blobs (they were sticky pollen I think) and did as you discribed Dave. I also did the same for my F70 and that was easier as the wire retainer was accessable through a notch in the mirror buffer foam.</p>