Canon EF-S 15-55 mmm f/2.8 IS USM defect

[Lerley]

Hello good people,

Before I state my question I must express my delight in the tutorials on this site: simply superb!
Now my question. I purchased a used Canon 17-55 zoom lens a couple of years ago (using a Canon 40D). It has turned out to be my primary lens (I am shooting a lot of landscape pictures) but has caused me a lot of frustration because it has a defect, I believe: under certain light angles it produces spots, in the upper half of the frame. At first I thought that spots were simply stains on the glass, but after numerous thorough cleanings, I concluded that the problem must be inside the lens. Needless to say, I become very good at using the spot removal and healing tools in Adobe PE-7. I attached a photo showing an example of this nuisance. Has anyone encountered such a defect? Any guess on the cause or location?
Best regards to all.

Paul

[jeeperman]

Paul, have you tried having your sensor cleaned? Just a guess but I am thinking it more likely to be dust and/or debri in the body rather than a len defect. I have experienced these spots and a local shop cleared up the problem in 15 min for 45$

Paul

[Lerley]

Paul,

Thanks for your thoughts. (the ink of the message was not even dry! ). I will take a look at the sensor. Since the spots are not present all the time, I concluded that it must be the light through the lens.
Nice to meet you. I live in Augusta, ME. The picture was taken in Alsace, France, where I am from.

Paul

[Snarkbyte]

Paul, have you tried having your sensor cleaned? Just a guess but I am thinking it more likely to be dust and/or debri in the body rather than a len defect. I have experienced these spots and a local shop cleared up the problem in 15 min for 45$

Paul

I agree. Definitely looks like dust to me, and good cleaning should fix it right up. Do these spots show up with any other lens? (Take some test shots with another lens, and make sure some bright sky is in the area where the spots are located). If not, it's probably just some sticky dust you've missed, so you might consider having a shop clean the lens for you... it can be stubborn sometimes, so let them know where the spots appear in the images. It really doesn't look like a defect.

[pwnage101]

Paul,

Thanks for your thoughts. (the ink of the message was not even dry! ). I will take a look at the sensor. Since the spots are not present all the time, I concluded that it must be the light through the lens.
Nice to meet you. I live in Augusta, ME. The picture was taken in Alsace, France, where I am from.

Paul

They are only visible sometimes because they come into focus with small apertures. With such a wide aperture lens, you probably rarely see them.

[jbillitteri]

I've had that problem also. Take your lens off and look through at some light or sky, and I think you'll find they are on your sensor, or mirror.

[Black Pearl]

It's dust on the sensor and yes it will show up more the further you stop your lens down. Don't bother taking the lens off and having a look - thats the viewfinder you're looking through just as it is with the lens on - you won't see them.

Switch the camera to manual focus
Stop the lens down to f22
Point it at a bit of white paper.
Take a shot - doesn't matter how long the exposure is or camera shake

When you've recovered from your heart attack at seeing how filthy a sensor can get - go get it cleaned.

By the way you can put a pea sized lump of muck on the front element of your lens and not be able to see it, same goes for the mirror. You are not looking at these when using your camera, you are looking through them. Hold every lens you own up to the light and have a look at the glass inside - I'll guaranty they will all have dust in them, some of the cheaper ones are likely to have bubbles in the glass - it don't really matter.

[pwnage101]

Stop down to f22, hold he viewfinder up to your eye and press your DOF preview button. With the press of a button you will see all that dirty filthy muck instantly materialize. Let go, and they will all disappear. Press it again but try not to gag. Keep doing this, it's like watching a horror movie!

[Black Pearl]

Stop down to f22, hold he viewfinder up to your eye and press your DOF preview button. With the press of a button you will see all that dirty filthy muck instantly materialize. Let go, and they will all disappear. Press it again but try not to gag. Keep doing this, it's like watching a horror movie!

Can you please explain how you will be able to see the dirt on your sensor when you look through your viewfinder when the sensor is switched off, behind a metal shutter and the mirror in your camera is down to let you see through the lens?

[Lerley]

Thanks folks. I am so impressed by so many responses! I am anxious to test your suggestions (can't this weekend: taking care of our grandson...). To Snarkbyte's point, I should have mentioned that the spots occur only with this lens. I will post my progress.

[Black Pearl]

You need thirty seconds.

Aperture priority - f22 - Manual Focus (cos it will hunt not because you need to focus it) - pale blank wall/paper - take a shot.

All but the most microscopic dust on the SENSOR will show - it is not your lens.

Not convinced - take the same shot at f2.8.....all the dust will magically vanish because of the shallow depth of field.

[pwnage101]

Can you please explain how you will be able to see the dirt on your sensor when you look through your viewfinder when the sensor is switched off, behind a metal shutter and the mirror in your camera is down to let you see through the lens?

Damn, and this is even after i read your post
Ok, just switch back and forth between the images on your computer. It should still be pretty fun!

[MiniChris]

This is why I sent my Nikon D7000 back to the factory...have had sensor dust problems with it from the start but they were somewhat intermittent until just recently...this is a small section of the second image...what a nightmare!





I never change out a lens in the wide open, and always with the camera off, and I can do a lens change in less that 15 seconds. I think it was there from the factory and just couldn't escape.

[Black Pearl]

Hells teeth mate - thats one dirty sensor, looks like a vacuum cleaner has been emptied into it.

[MiniChris]

Pretty much... be glad to get it back clean. Camera was purchased on November 14th..not old enough to be experiencing this kind of crap.

[inkista]

Two pieces of information:

On this very website: Camera Sensor Cleaning

and



I live somewhere very dry, so for me, the bulb-blower technique alone is good enough for most of my dust issues, so I'd recommend trying that first. A rocketblower costs about $10, and takes about 10 seconds to use, so you haven't lost much if it doesn't work, and since you're not touching the sensor, you haven't risked anything. The technique for using one is displayed in the video above. DO NOT USE CANNED AIR. Do not blow air in with your mouth. You do not want to get liquid gunk/spit into your chamber or on your sensor. And you want to hold the camera face down, so the dust can fall out and not settle back into the chamber.

[MiniChris]

Since it is still under warranty, I am going back to Nikon..when that warranty is gone, I'll buy the supplies and do it myself. Now, I have to go search out all those supplies.

[inkista]

I don't think using a bulb blower is going to void your warranty, as you're not touching anything in the chamber. But yeah, when it's that bad, the camera's new, and you can get a free cleaning, probably a good idea to send it in. I just hate being without my camera for any length of time. And dust happens. Might as well learn sooner than later how to deal with it. I generally use the Rocketblower on my cameras every month, because my somewhere dry is also somewhere dusty and I change lenses like a mad thing.

The one thing to know that might make you a little more comfortable with this whole process is that you're not actually cleaning the surface of the sensor: you're cleaning the surface of the glass filter that sits over the sensor both to protect it and to filter out UV/IR light so the colors aren't thrown off. And if the idea of using a lenspen on your sensor makes you nervous, it's been said that it's what the Canon Service center is using.

[MiniChris]

I did the blower thing several times and while it helped for awhile, it didn't stay...I'll do the free thing, then the other later. Do you know where I can procure the bsuh, pen and stamp?

[inkista]

d'oh! Just noticed, you're in FL. No wonder you've got the welded on dust. Yeah, a blower isn't going to be as good for you as it is for a desert dweller like me.

Most camera stores will have the Sensorklear pen (it's basically just another Lenspen, but with a triangular head instead of a circular one).

Arctic butterfly: http://www.visibledust.com/products.php (it's pricey).

The Dust-Aid: http://www.dust-aid.com/the_product.html

You could probably pick up all three on Amazon, B&H, Adorama, etc.