Debris behind lens?

leonardotmnt · 09-15-2017, 02:32 PM

I've had a piece of dust in the lower corner of the viewfinder on my K-3 for a few months now. It bothered me intermittently and I finally decided to use a Rocket Blower to try to get the dust off of the mirror. It worked but I got a smaller piece of dust on the mirror in the mean time. When I tried to dislodge that one with the blower I seem to have gotten an even larger piece of debris in there. This one is much bigger than the original and much closer to the middle of the viewfinder so it's bothering me quite a bit.

I know the general advice is to just leave it be. It's not showing up on pictures so that part's good. When I take the lens off and look inside I can see the debris but it looks like it might be behind the mirror? You can see it but it's not sharp so it looks like it's behind something you can see through. I've tried quite a bit to use the blower to get the debris out but haven't had any luck. Is there anything else I can try or am I just stuck with it? Thanks.

Adam · 09-15-2017, 03:04 PM

Originally posted by leonardotmnt

I've had a piece of dust in the lower corner of the viewfinder on my K-3 for a few months now. It bothered me intermittently and I finally decided to use a Rocket Blower to try to get the dust off of the mirror. It worked but I got a smaller piece of dust on the mirror in the mean time. When I tried to dislodge that one with the blower I seem to have gotten an even larger piece of debris in there. This one is much bigger than the original and much closer to the middle of the viewfinder so it's bothering me quite a bit.

I know the general advice is to just leave it be. It's not showing up on pictures so that part's good. When I take the lens off and look inside I can see the debris but it looks like it might be behind the mirror? You can see it but it's not sharp so it looks like it's behind something you can see through. I've tried quite a bit to use the blower to get the debris out but haven't had any luck. Is there anything else I can try or am I just stuck with it? Thanks.

Have you targeted the focusing screen? That's where you should be blowing as it's where the dust tends to settle.

leonardotmnt · 09-15-2017, 04:21 PM

How exactly do I target it? Is it on the top or is that just the reflection? I've been trying to blow at where I see the dust but from what I can tell I don't think the air directly hits it.

When I look directly into the camera the contaminant is straight ahead. I can see what's behind the camera like I'm looking through the viewfinder only through the lens and the debris is part of that picture. I don't see it if I look up above if that's where the screen is.

When I'm looking straight into the camera is that the mirror? Would I be able to see through it at all?

MarkJerling · 09-15-2017, 08:50 PM

Originally posted by leonardotmnt

I've had a piece of dust in the lower corner of the viewfinder on my K-3 for a few months now. It bothered me intermittently and I finally decided to use a Rocket Blower to try to get the dust off of the mirror. It worked but I got a smaller piece of dust on the mirror in the mean time. When I tried to dislodge that one with the blower I seem to have gotten an even larger piece of debris in there. This one is much bigger than the original and much closer to the middle of the viewfinder so it's bothering me quite a bit.

I know the general advice is to just leave it be. It's not showing up on pictures so that part's good. When I take the lens off and look inside I can see the debris but it looks like it might be behind the mirror? You can see it but it's not sharp so it looks like it's behind something you can see through. I've tried quite a bit to use the blower to get the debris out but haven't had any luck. Is there anything else I can try or am I just stuck with it? Thanks.

Based upon you post, the debris is either on the underside of the focus screen or on the top surface of the focus screen.

The focus screen is a soft plastic removable item underneath the prism. There are other threads in the forum that explains focus screen removal and replacement. This does carry some risk as the focus screen can easily be damaged. If the piece of debris is clearly visible when you look in the viewfinder, you can remove your lens and look at the focus screen and if the debris is on the underside, you'll see it quite easily. DO NOT touch the focus screen surface with anything - they are very easily scratched. But you can direct air from the Rocketblower very easily and if the debris is on the bottom, it will easily be cleaned off that way.

Where it get tricky is if the debris is on the top surface. Then you need to lower the focus screen. That's not something I'm comfortable doing myself but several others here have done it.

Here's a link to a thread and video that shows replacement of a focus screen. You would not need to take the screen out, simply flip it down and then you'd be able to blow off the debris that way. However - I will advise you that, should you attempt to do this it is, of course, at your own risk.

https://www.pentaxforums.com/forums/116-pentax-k-r/178682-s-type-screen-focu...on-review.html

I might add that I had the same problem on my K5 and the debris eventually moved of it's own accord and is not longer visible through the viewfinder. To me that seemed a good solution!

Last edited by MarkJerling; 09-15-2017 at 09:12 PM.

09-15-2017, 02:32 PM	#1
leonardotmnt Forum Member Join Date: Sep 2015 Posts: 94	Debris behind lens? I've had a piece of dust in the lower corner of the viewfinder on my K-3 for a few months now. It bothered me intermittently and I finally decided to use a Rocket Blower to try to get the dust off of the mirror. It worked but I got a smaller piece of dust on the mirror in the mean time. When I tried to dislodge that one with the blower I seem to have gotten an even larger piece of debris in there. This one is much bigger than the original and much closer to the middle of the viewfinder so it's bothering me quite a bit. I know the general advice is to just leave it be. It's not showing up on pictures so that part's good. When I take the lens off and look inside I can see the debris but it looks like it might be behind the mirror? You can see it but it's not sharp so it looks like it's behind something you can see through. I've tried quite a bit to use the blower to get the debris out but haven't had any luck. Is there anything else I can try or am I just stuck with it? Thanks.

09-15-2017, 03:04 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	Originally posted by leonardotmnt I've had a piece of dust in the lower corner of the viewfinder on my K-3 for a few months now. It bothered me intermittently and I finally decided to use a Rocket Blower to try to get the dust off of the mirror. It worked but I got a smaller piece of dust on the mirror in the mean time. When I tried to dislodge that one with the blower I seem to have gotten an even larger piece of debris in there. This one is much bigger than the original and much closer to the middle of the viewfinder so it's bothering me quite a bit. I know the general advice is to just leave it be. It's not showing up on pictures so that part's good. When I take the lens off and look inside I can see the debris but it looks like it might be behind the mirror? You can see it but it's not sharp so it looks like it's behind something you can see through. I've tried quite a bit to use the blower to get the debris out but haven't had any luck. Is there anything else I can try or am I just stuck with it? Thanks. Have you targeted the focusing screen? That's where you should be blowing as it's where the dust tends to settle. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

09-15-2017, 04:21 PM	#3
leonardotmnt Forum Member Join Date: Sep 2015 Posts: 94 Original Poster	How exactly do I target it? Is it on the top or is that just the reflection? I've been trying to blow at where I see the dust but from what I can tell I don't think the air directly hits it. When I look directly into the camera the contaminant is straight ahead. I can see what's behind the camera like I'm looking through the viewfinder only through the lens and the debris is part of that picture. I don't see it if I look up above if that's where the screen is. When I'm looking straight into the camera is that the mirror? Would I be able to see through it at all? Last edited by leonardotmnt; 09-15-2017 at 04:39 PM.

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09-15-2017, 08:50 PM	#4
MarkJerling Moderator Site Supporter Join Date: May 2012 Location: Wairarapa, New Zealand Photos: Gallery \| Albums Posts: 20,422	Originally posted by leonardotmnt I've had a piece of dust in the lower corner of the viewfinder on my K-3 for a few months now. It bothered me intermittently and I finally decided to use a Rocket Blower to try to get the dust off of the mirror. It worked but I got a smaller piece of dust on the mirror in the mean time. When I tried to dislodge that one with the blower I seem to have gotten an even larger piece of debris in there. This one is much bigger than the original and much closer to the middle of the viewfinder so it's bothering me quite a bit. I know the general advice is to just leave it be. It's not showing up on pictures so that part's good. When I take the lens off and look inside I can see the debris but it looks like it might be behind the mirror? You can see it but it's not sharp so it looks like it's behind something you can see through. I've tried quite a bit to use the blower to get the debris out but haven't had any luck. Is there anything else I can try or am I just stuck with it? Thanks. Based upon you post, the debris is either on the underside of the focus screen or on the top surface of the focus screen. The focus screen is a soft plastic removable item underneath the prism. There are other threads in the forum that explains focus screen removal and replacement. This does carry some risk as the focus screen can easily be damaged. If the piece of debris is clearly visible when you look in the viewfinder, you can remove your lens and look at the focus screen and if the debris is on the underside, you'll see it quite easily. DO NOT touch the focus screen surface with anything - they are very easily scratched. But you can direct air from the Rocketblower very easily and if the debris is on the bottom, it will easily be cleaned off that way. Where it get tricky is if the debris is on the top surface. Then you need to lower the focus screen. That's not something I'm comfortable doing myself but several others here have done it. Here's a link to a thread and video that shows replacement of a focus screen. You would not need to take the screen out, simply flip it down and then you'd be able to blow off the debris that way. However - I will advise you that, should you attempt to do this it is, of course, at your own risk. https://www.pentaxforums.com/forums/116-pentax-k-r/178682-s-type-screen-focu...on-review.html I might add that I had the same problem on my K5 and the debris eventually moved of it's own accord and is not longer visible through the viewfinder. To me that seemed a good solution! Last edited by MarkJerling; 09-15-2017 at 09:12 PM.