Hi Aperture, Grainy Viewfinder

[bluewaker]

I have a 20D, got it used.

I notice when I set the aperture to something really high and I hit the aperture preview button close to the lens mount, the picture darkens (as expected). When I hold it to the light, I notice alot of little grainy marks that resemble a fingerprint that is REALLY disconnected. My pictures dont show up bad though. Does anyone know why this happens?

thanks

[sfu_engineer]

I have a 20D, got it used.

I notice when I set the aperture to something really high and I hit the aperture preview button close to the lens mount, the picture darkens (as expected). When I hold it to the light, I notice alot of little grainy marks that resemble a fingerprint that is REALLY disconnected. My pictures dont show up bad though. Does anyone know why this happens?

thanks

Well the aperture is so high (the lens is stopped down so much), you can begin to see dust/dirt/grime on the sensor and the lens. Perhaps you have a finger print or two on your lens or sensor?

[bluewaker]

Hmm, I just checked the front element and based on that, I am sure it's not the filter or the lens at the front (I rotated it, but the grim didn't rotate with it.).

My photos, in the >>post your best picture<< or something thread don't look so grainy =\. I only notice it when I put my aperture super high. It's either the inside of the lens or the mirror or the sensor and I don't think anyone stuck their finger inside to the sensor. The guy who owned the camera before me was a professional.

[eelfliw]

Check your pentaprism. Chances are, it's on the focusing screen.

[bluewaker]

Checked it. There seemed to be no traces. The thing that really disturbs me is that the lens looks 100% covered in these tiny tiny specks. You don't really notice them, they seem almost microscopic, but they're everywhere. The average piece of dust on the viewfinder's mirror or pentaprism is bigger than one of these marks. And there are hundreds on this one. I'm basically making a big deal out of nothing, but I just don't understand why/how this happened.

[sfu_engineer]

It could be diffraction caused by such a small aperture.

http://www.bobatkins.com/photography...ffraction.html

[bluewaker]

Hmm...this is probably one of those issues that can't be solved over the net. I'll probably take it to a henry's or something and see what they say.

Perhaps diffraction, but I notice the same spots on f5.6 as I do on f32, it's just that the darkness of the higher aperture value makes the dots more visible.

EDIT:
Well I've gone and f*d myself now. I went in to try and blow out the "dots" but it turns out that they seem to be irremovable. They aren't really visible, they're like...imprinted into the view finder. Anyways, in the process of using the blower and opening the camera, I allowed dust in. My use of Q-tips, etc brought more dust into the system. What I'm left with is a nightmare. I've cleaned up most of the dust from the viewfinder screens and mirror but I have 8 specks of dust on my sensor now. I want to kill myself.

[bluewaker]

bump, don't want to make new thread.

[KorruptioN]

You used Q-tips on the sensor??

[CSAgent]

20D is quite old, doesn't matter who owned it pro or not. Dust irrevocably gets in one way or another. Consider buying new factory fresh if you're going to be very nitpicky about things. For a used 20D, you get what you paid for.

Take it to a Canon Service Center, they might be able to do a better job than you did in cleaning it up?

[bluewaker]

Nope, never used q tips on the sensor. That would be asking to get pwnt. =(

Used em on the pentaprism, and super lightly on the mirror. I left the sensor as it was.

How much is it to get Canon to service it in comparison to getting a sensor cleaning kit?

[sungfra]

Use an Arctic butterfly instead of Q tip next time. Here is a video clip in case you are not familiar with the butterfly.

http://tinyurl.com/2h8mcz

[bluewaker]

I didn't use anything on my sensor yet.

I don't want to pay for a butterfly considering the negative reviews I've heard about them smearing sensors. =\

[skyline518]

I personally used sensorklear lens pen. I thought they worked alright for getting rid of dust on sensor. I used a blower blowing the sensor while holding the camera facing downward, then use the sensorklear pen to clean the sensor. Repeated few times, and finally cleaned.

If you want to save some time, get one of those magnifying glass with lights so that you can see easily where the dusts are on the sensor.

[bluewaker]

I got the sensorklear pen today, went to the website, looked at the instructions and started at it. I am no hamfist in anyway, and I've dealt with little electronics my whole life, from when I was a little kid working with my busted rc cars to soldering a cell phone camera's wires back in place.

On my first two cleans, I got progressivley more and more dust off. I used very very short stroke motions as the dust would not come off otherwise. Here's the twist.
At one point, I don't see any dust at all, but I know there is dust in that general region according to the latest photo taken of a white wall. I try to dab / shortstroke it off. I hear a very high pitched screech, my heart drops and I swear. I knew I was using very little pressure, probably less than the people who use sensorwipes. I look on the sensor in the light and sure enough, there is a small scratch. I don't have much to say other than the lenspen experience was good then turned incredibly sour. I' have owned my camera for a week and a day and this happens to me all because of my want to fix the grainy viewfinder. I am so full of self pity and crap...this is ********. I don't ssee how I could've applied enough pressure to scratch it. I know it's not oil as I went over the scratch later with the lenspen and it wouldn't budge.

ARRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR GHHHHHHH