Is this what a dirty sensor would look like!?

Nimai · October 12, 2007

A bunch of dark splotches showed up when I was just playing around with the f-stop. See the shots below. Any ideas!? Sensor? Lens? Filter? And why would it only show up (or at least be so prominent) at the high f-stop?:dunno

f/22
ISO 200
1/400th

f/4.5
ISO 200
1/1250th

hgernhardtjr · October 12, 2007

Looks like sensor dust to me. And it usually shows up at higher f-stops on a blue sky. Over the past several years of using dSLRs I have only had to clean my sensors twice. I went into sensor-clean mode (mirror lock-up), then I used a blower similar to a Rocket blower while holding my camera's lens mount down toward the ground. Cleaned it right up.

You can also buy all sorts of sensor cleaning kits. This has become a "religion" of sorts for many, with different sects proselytizing different methods, so you will get some fairly adamant opinions.

BTW, if you see the spots in the viewfinder and not on the prints, you need to clean your mirror or focusing screen the same way (gently blowing air from a rocket blower or similar on the screen while the lens opening is pointed down).

Phyxius · October 12, 2007

Yes, you have a dust bunny infestation!

The farther you stop down the easier they are to see. You can usually start to notice the around F10. At F22, like in your first shot, they're practically begging you to blast them away.

Justiceiro · October 12, 2007

this is absolutely dust on the sensor. It looks pretty bad, but DO NOT DESPAIR! This is an issue that all DSLR users face eventually, if they ever change lenses.

The dust spots are visible at higher f stops because they increase the depth of field, bringing the spots into visible focus. Wide open, only a serious dust bunny is visible.

What I would do is buy an air rocket blower thing. That's the technical term for it "air rocket blower thing." I have one from Giotto's just liek the link indicates.

If you are shooting Canon, which you ought to be regardless, because not shootin Canon is an early indicator of tendencies towards satanism, communism, anti-social behavior, and lack of personal hygiene, then this is how you take care of it.

1. Go to the "menu" of the camera.

2. Select "sensor clean".

3. At this point the mirror should flip up, exposing the sensor.

4. Take the lens off, hold the camera upside down, with the open aperture facing down, and blow vigourously onto the sensor with the air rocket. Make sure the red nozzle of the air rocket does not enter the body of the camera, or if so, does so only very slightly. You do not want to scratch your sensor.

5. Once this is done, replace the lens and turn the camera off (this will return the mirror to the normal position.

6. Take a shot against a well lit plain white surface (like an interior wall) with no images or designs at thew highest possible f stop (f22+). Exposure time doesn't matter, as long as you don't have anything non white in your frame.

7. Chimp the pic in camera, or look at it on a computer. If dust spots remain there, then repeat the previous steps.

If 3 repititions of this does not remove the significant dust particles, you will actually have to clean your sensor with a brush. You can:

a) find one of the many threads here describing how it is done and do it yourself, thereby voiding your warranty, or

b) Send it to Canon.

I myself have never needed anything more than the dust blower.

Good luck!

Richard · October 12, 2007

Yep, it's dust on the sensor. I'm not altogether clear on why a high f stop makes it more visible, but I suppose it has something to do with the increased depth of field. You are supposed to shoot test shots at f/22 or higher when looking for spots. Anyway, time for a cleaning. There are many threads on Dgrin discussing the merits of different methods.

Cheers,

dangin · October 12, 2007

as everyone else has alluded to, yes, you do have dust in front of the sensor. hopefully most of it can be easily removed by simply blowing air onto it. if not, you could always send it back to canon for the priciest, but probably best sensor cleaning or take it to your local reputable camera shop. if you're nearby a calumet camera, they offer on-site cleanings on a first come, first serve basis.

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StevenV · October 12, 2007

how much does Canon normally charge?

Terrence · October 12, 2007

StevenV wrote:

how much does Canon normally charge?

I sent my 30D in for cleaning and calibration and paid $218 (inlcuding shipping). I am happy with the calibration, but my sensor came back dirty and they were unwilling to help me correct the problem. YMMV, but I am not pleased with my first use of Canon service.

Another good way to spot the dust is shoot a clear blue sky at f/22, take the RAW file into Photoshop and apply "auto levels". That really makes the dust spots stand out.

kisi · October 12, 2007

i'm a recent convert to the copper hill method. it was easy (though nerve wracking the first time

) and worked very well

wxwax · October 12, 2007

The simplest way is to fill a bucket with warm, soapy water, and very quickly dunk your camera in it.

Two or three dunks should do the trick.

Then hang it from a line to dry. You can get special camera clothes line clips from B&H.

Easy peasy. I don't know what all the fuss is about.

:hide

LiquidAir · October 12, 2007

rsinmadrid wrote:

Yep, it's dust on the sensor. I'm not altogether clear on why a high f stop makes it more visible, but I suppose it has something to do with the increased depth of field. You are supposed to shoot test shots at f/22 or higher when looking for spots.

What you are seeing is shadows of the dust on the sensor. With a large apeture you get soft shadows. With a small aperture you get hard shadows. Its just like the difference between a bare strobe and a softbox.

The way I check my sensor for dust is to set ISO 100, stop down to f/22 and take a shot of a white ceiling (or wall) the EC set to +2. That usually gives me a long shutter speed and I deliberatly move the camera to blur out any detail in the wall.

As for cleaning, I use the Copperhill dry/wet system. Depending on what I see on my sensor, I normally start with the dry brush and only go to the wet cleaning system if I have to.

pathfinder · October 12, 2007

If you missed the memo, Sid ( wxwax) IS Joking!!:D:D

PineapplePhoto · October 12, 2007

No., that is too much trouble...

I could not afford a Rocket Blower thingy, so I just set it in cleaning mode and blow with my mouth into it... it cleaned it good!

wesleyt · October 12, 2007

PineapplePhoto wrote:

No., that is too much trouble...

I could not afford a Rocket Blower thingy, so I just set it in cleaning mode and blow with my mouth into it... it cleaned it good!

You're kidding, right?

LiquidAir wrote:

What you are seeing is shadows of the dust on the sensor. With a large apeture you get soft shadows. With a small aperture you get hard shadows. Its just like the difference between a bare strobe and a softbox.

The way I check my sensor for dust is to set ISO 100, stop down to f/22 and take a shot of a white ceiling (or wall) the EC set to +2. That usually gives me a long shutter speed and I deliberatly move the camera to blur out any detail in the wall.

As for cleaning, I use the Copperhill dry/wet system. Depending on what I see on my sensor, I normally start with the dry brush and only go to the wet cleaning system if I have to.

Nimai · October 12, 2007

Oh well, I guess the day had to come! <sniffle> And I thought it would never happen to me! :P

Thanks everyone - makes a lot of sense. FWIW I'll follow up on this thread with how my cleaning goes.

ulrikft · October 12, 2007

Did noone but me see the "dirty sensor?! DIRTY PHOTOGRAPHER!!"-phun in those two images?

jww · October 14, 2007

LiquidAir wrote:

As for cleaning, I use the Copperhill dry/wet system. Depending on what I see on my sensor, I normally start with the dry brush and only go to the wet cleaning system if I have to.

I like the Coperhill method as well, but have recently started using Dust Aid to pull bigger chunks and other loose stuff off. ..just make SURE you use the correct side of adhesive on the wand!!!

I also recently picked up a Sensor Scope system. I love the scope for inspecting the sensor. The vaccum thingy is pretty cool, but I don't really like their foam padded sensor wipes. I feel the pec pads used in the Copperhill method are much much safer.

Scott_Quier · October 15, 2007

LiquidAir wrote:

The way I check my sensor for dust is to set ISO 100, stop down to f/22 and take a shot of a white ceiling (or wall) the EC set to +2. That usually gives me a long shutter speed and I deliberatly move the camera to blur out any detail in the wall.

I startup up Notepad on my computer, maximize it to fill the screen. Set camera to JPG (it's faster than converting from RAW), Tamron 28-75, f/22 (or better), 75mm, focus on infinity. Now, shoot the screen. Inspect the resulting JPG after using Auto-Levels in PS. It'll show all those ugly dust bunnies.

But, I usually don't clean the sensor unless I see something at f/16 as I usually don't work at much above f/8.

claudermilk · October 15, 2007

We all get hit by sensor dust sooner or later. Nobody is immune.

I will add another copperhill recommendation. My process is: step 1, use a blower, step 2, use a sensor brush, step 3, use the Eclipse/Pec-Pad swab. Only go sa far as needed to get the dust bunnies off. It's not as scary as you think the first time. Before looking at Dust-Aid, run a search either here or on fredmiranda--I personally will not ever use that method. Oh, and one final thought: remember that it's not the actual sensor you will be touching, but a glass filter over it.

Zee · October 22, 2007

kisi wrote:

i'm a recent convert to the copper hill method. it was easy (though nerve wracking the first time ) and worked very well

+1

On the Copper Hill method. I use it at least 2 or 3 times a month on my D200. Now that I've gotten better at it, it only takes one pad and the dust is gone! It's very simple but it takes a little practice. It's well worth learning so you don't have to send your camera away every time you get a dust spot on your sensor.

Morbid Andrew · October 22, 2007

Justiceiro wrote:

If you are shooting Canon, which you ought to be regardless, because not shootin Canon is an early indicator of tendencies towards satanism, communism, anti-social behavior, and lack of personal hygiene

I like Canon and Satanism! What's wrong with both?

BobT · May 14, 2010

Being an Olympus user, I'm new to the world of sensor dust. However, I'm baffled by why it should appear only at high f stops. There are those that suggest it is due to DOF but I can't see how that is when the dust is presumably sitting right on the sensor. DOF is affected by the aperture setting which is way in front of both the sensor and the dust. Am I missing something here?

ziggy53 · May 14, 2010

BobT wrote: »

Being an Olympus user, I'm new to the world of sensor dust. However, I'm baffled by why it should appear only at high f stops. There are those that suggest it is due to DOF but I can't see how that is when the dust is presumably sitting right on the sensor. DOF is affected by the aperture setting which is way in front of both the sensor and the dust. Am I missing something here?

A small aperture acts similar to a pinhole and casts a sharper shadow of the dust. The dust does not sit directly on top of the sensor, rather it rests on the AA/IR cutout filter in front of the sensor.

BobT · May 14, 2010

ziggy53 wrote: »

A small aperture acts similar to a pinhole and casts a sharper shadow of the dust. The dust does not sit directly on top of the sensor, rather it rests on the AA/IR cutout filter in front of the sensor.

A good clear explanation. Thanks for that.
Bob

Is this what a dirty sensor would look like!?

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