IT HAD TO HAPPEN SOMETIME !

Hi guys, I've been swopping and changing between my 28mm + 50mm lenses everytime I go taking photos. Today I took a couple of hundred photos swopping between the 2 lenses and after getting the pics up on the laptop, there they are ! 2 whopping big dust spots !!! I looked in on the mirror and there they were, the 2 culprits ! I've tried blowing them off to no avail, now what !?

DERYN

Hi Deryn, I find a rocket blower usually does the trick..but you may have already tried that as you said you already tried blowing them off.

I'm also slightly confused as to where these exactly are - it sounds like they are on the mirror, or perhaps the focusing screen, which actually will not affect the image. It's dust on the image sensor which causes these problems.

If you can provide more detail I'm sure we can offer the best advice.

Hi Bob, when I remove the lens I see a glass screen at an angle. Behind that in the camera is the mirror. The 2 dots are on the glass screen. I've blown and wiped the front of the glass but the dots remain so the dots must be behind it !

DERYN

Deryn I think you may be a wee bit confused. The glass screen at an angle is the mirror and behind that is the sensor.

You need to go into the menu and select mirror up for cleaning. Hold the camera face down and use your rocket blower to remove the spots. Just be careful you don't hit the sensor with the tip of the rocket blower.
Works for me every time.

Deryn, i'm pretty sure you are talking about the focusing screen.

The glass screen you are talking about is the mirror itself, but that gives the illusion that the focus screen is directly behind the mirror, when in fact it is at the top above the mirror (hope that makes sense).

I'd get some tweezers and take out the focusing screen and give it a blow or a very very gentle clean (it scratches very easily).

Ah, beat me to it Clarky. I'm not sure though that Deryn has locked the mirror up and noticed that the two spots are on the sensor, it does sound as if it's what he has seen by just peering inside the body after taking the lens off, in which case I bet it's dust trapped behind the focusing screen, hence why he can't get to it.

But let's wait and see...

But Deryn is saying the spots are showing up on his pics : so that must mean the spots are on the sensor.

No amount of crud on the mirror will show up on the pics.

I conceed to that highly logical conclusion. I overlooked that!

So the dust isn't on the angled mirror but on the sensor ? I've had 4 tins of cider so I think any internal surgery should be left until tomorrow

DERYN

Good call Deryn, but it is an easy fix, just go into the menu and find sensor cleaning and select mirror up. point the camera face down and give it a couple of good puffs with your blower. I would be surprised if it doesn't get it off. good luck.

Umm I think actually touching any part in the throat of the camera can lead to regrettable results - I emphasise can it's by no means certain - so I always avoid that.

Also I hope you haven't been blowing cider soaked breath in there as that's a path to grief as well. Get a proper blower and I suspect all will be well once you've mastered actually blowing the sensor but do use a proper rocket style blower!

Do you remember to turn the camera off when changing lenses? Apparently the sensor is charged while its on and that attracts dust. I'd be interested to know how quickly it loses that charge.

Mike

Mike

Better still get an Artic Butterfly brush for cleaning your sensor, or even the Pentax sensor cleaning kit. Blowers just move the muck around, if you are lucky, and don't move it at all if you are not.
Do not under any circumstances touch the mirror with anything. You could end up with a lot of grief.
In the menu you will find sensor cleaning. With a full battery on board choose that, which will put the mirror up so you can clean the sensor carefully, preferably whilst sober .
Make sure the battery is full - you don't want the battery running out whilst you are cleaning!

Hi guys, well my first action was to get a blower. I've just used the blower then took a couple of photos. The dust spot is still there !
NOW, the lens I used is a 50mm prime. So I thought just maybe the lens is at fault ? I changed to a 28mm and I can't find the dust spot !

BUT, I just wanted to clear a point up. The 50mm is a higher magnification than the 28mm. BUT, this doesn't mean dust on the sensor will be magnified more on a 50mm photo than a 28mm photo does it ? Dust on the sensor will show up the same size on a photo no matter what the lens, right ?

DERYN

Right. Could the dust have been dislodged when you changed lenses?

use the dust alert feature, thats what its for, point the camera at something white and let it do its magic, and as stated don't use nothing on the mirror at all, and myself i hate rocket blowers as i had a problem with scratching the focus screen, but also blowing dust up in the eye piece, so i always use dust aid on the sensor and never a blower, also always take a plastic bag and point the camera down when changing lenses, and put the camera in the bag whilst changing lenses,