Can you always see dirt/dust on a sensor?

[goinggreynow]

Hi everyone
Have had my Canon 450D for about a year and I change lenses very rarely.
Am having a bit of a panic because I've spotted a "dirty mark" on some of my recent photos (particularly noticeable against a plain blue sky).
Checked my 2 lenses - both look OK. Have had a quick look at the sensor and it looks spotless.
Never having had to attempt a sensor clean before, my question is should I expect to be seeing something or is it possible/probable that there is either dirt or dust on the sensor which is not visible to the naked eye?
From other posts, I'm guessing that my first port of call should be a rocket blower?
Thanks for any help.

 

[Davec223]

Nope, you will not always see the dust on the sensor, I presume you have looked at the sensor and not just the mirror inside the shutter box, I am sure you have but just checking. Rocket blower is the first port of call.

 

[mmcp42]

shows up best when taking a plain picture (white wall) at high f/number
go -on try it and post!:nuts:

 

[goinggreynow]

Hi Dave
Thanks for your speedy reply.
I am totally inexperienced when it comes to the inside of my camera. I am not sure if this is the right way of doing things, but I took off the lens, pressed the shutter button (with a 10 sec shutter time), the mirror flipped up and I am assuming that what I saw behind the mirror was the sensor (sort of greenish colour??)

 

[Davec223]

Hi Dave
Thanks for your speedy reply.
I am totally inexperienced when it comes to the inside of my camera. I am not sure if this is the right way of doing things, but I took off the lens, pressed the shutter button (with a 10 sec shutter time), the mirror flipped up and I am assuming that what I saw behind the mirror was the sensor (sort of greenish colour??)

Yes that is the sensor. Unless it is a large piece if dust you really will not see it. What aperture were you shooting at when it became visible, I had a similar problem last year, but is was only visible IIRC at f16+ and in all reality I did not need to shoot that wide, so it was a lesson learnt for me.

 

[Davec223]

shows up best when taking a plain picture (white wall) at high f/number
go -on try it and post!:nuts:

Thats naughty:nono:, you know that just scares everyone who does it for the first time.

 

[goinggreynow]

Dave
I noticed it first a couple of days ago when I took 2 shots of aircraft (both F 5.6). I then went back through previous photos and have noticed a mark on a particular photo from September, shot at F7.1.
Should it be of more concern to me that I am seeing these blemishes at those sort of aperture settings?

 

[Davec223]

Nothing to worry about, sensor just needs cleaning, it something that everyone has to do/ get done.

 

[lawrenceots]

I always get the camera into sensor clean mode with mirror/shutter up, and then turn on the vac and keep the hose about 5 inches away from the camera. Seems to do just fine for me.

 

[A.Gibson]

I always get the camera into sensor clean mode with mirror/shutter up, and then turn on the vac and keep the hose about 5 inches away from the camera. Seems to do just fine for me.

i wouldnt dare do that with our new dyson it would suck the sensor out of the camera.lol just check its on suck and not blow.lol i like your thinking though.

 

[lawrenceots]

i wouldnt dare do that with our new dyson it would suck the sensor out of the camera.lol just check its on suck and not blow.lol i like your thinking though.

Oh aye, tis a very old one, recycled from the skip by my mum, so not very powerful. I'd be ULTRA careful if using a Henry, they have mean power! Seriously though, it is very good for it, and gets those nasty bits out of the viewfinder area great.

 

[A.Gibson]

oooooooooo i need to clean my viewfinder i may give that a go i will make sure i stay about 20 meters away with the nozzle though.lol

 

[trencheel303]

EDIT: Nevermind, misread the post I quoted...

 

[martyp]

The sensor in my camera looks gleaming but there is still one bit of dust left on the filter that the SensorPen just can't get rid of...

 

[mickhall]

have tried cleaning mine several times put still spots!