# 5D Mark III--What is this? Dust, smearing, fibers, . . . ?



## notapro (Jan 1, 2014)

Hello, Everyone.

I thought I noticed a dust spot in a photo. I did a wet cleaning with one swab (VisibleDust green swab, VDust Plus liquid), then took a shot at f/16 with a 50mm f/1.2. Threw it into Photoshop, brought the levels to where "dust stuff" could be seen, and this is what I got. Maybe follow-up cleaning could take care of this? Is shipment to Canon advised?


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## Jim Saunders (Jan 1, 2014)

notapro said:


> Hello, Everyone.
> 
> I thought I noticed a dust spot in a photo. I did a wet cleaning with one swab (VisibleDust green swab, VDust Plus liquid), then took a shot at f/16 with a 50mm f/1.2. Threw it into Photoshop, brought the levels to where "dust stuff" could be seen, and this is what I got. Maybe follow-up cleaning could take care of this? Is shipment to Canon advised?



It might be crap on your focusing screen. That has been an issue on my 5D2. If you're willing to open it the lid on it and blow some air in you might get crap out, you might make static and end up with more crap in.

Jim


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## privatebydesign (Jan 1, 2014)

It can't be anything on the focusing screen the image is not recorded through it!

A simple DIY clean should be fine.


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## neuroanatomist (Jan 1, 2014)

notapro said:


> I thought I noticed a dust spot in a photo. I did a wet cleaning...



I thought I noticed a nail on the side deck sticking up just a little bit. I pounded on it with a sledgehammer... 

Point is, first test to make sure it's dust on the sensor. Then use a rocket blower, test again. Then try dry cleaning, test again. Only then do a wet cleaning. Personally, I've never needed to wet clean a sensor. 

http://www.lensrentals.com/blog/2010/04/how-to-clean-a-camera-sensor


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## Mt Spokane Photography (Jan 1, 2014)

Doing a wet cleaning can do this if not done right. You can pickup dust from the edges of a sensor and pull it across the sensor. I also had that happen to be with a brand of pre-moistened swabs, so I bought some solution and moistened my own using eclipse solution.
It does look like the debris came from your swab.

There are also some gotchas to using a swab. 
1. Only swipe a swab once, using it a 2nd time will often make things worse.
2. Be prepared to use up to 5 swabs to get things reasonably clean, depending on how dirty it was to start.
I'd try more swabs, and if it does not come clean, toss them or return them.
Wet cleaning is for situations where oil or grease have stuck particles to the sensor, and is a last resort, best done by experienced technicians or those willing to pay to have someone fix the mess if it comes to that.


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## notapro (Jan 1, 2014)

I agree with your idea completely, Neuro. I wasn't complete in the description of what I did before the wet cleaning. I took a shot at f/16 and saw an image similar to what I posted. I used a rocket blower, took a shot, and noticed no difference. Then I did a wet cleaning (I don't have a brush).

I'm attaching an image of the previous image. Now that I look at both of them, it seems like I have two versions of "not good". I'll take some calming breaths and do subsequent cleaning. I can't help wondering whether some of what I see might be smearing from lubricant, but that's just pure conjecture.

In the meantime, I need to wean myself off the sledgehammer, as it can be just too tempting at times to do more than what is necessary.


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## Sporgon (Jan 1, 2014)

Great 'before and after' shots. You've made a really good job of smearing the contaminants across the sensor. If I took an f16 shot of any of my sensors against a White background there would be 'dust' spots all over them. Dust on sensors (and film) is a fact of life, and generally nothing to worry about, being simple to spot out. 

Also bear in mind that the 'dust' is often things such as pollen that can be sticky, and smear beautifully. I wasn't adverse to giving the sensor a gentle blow with a suitable blower but now don't bother. When the dust builds to a serious level I get the sensor cleaned by a Canon service sensor. 

Given that you have now smeared your contaminants I'd strongly recommend you do the same.


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## Jim Saunders (Jan 2, 2014)

privatebydesign said:


> It can't be anything on the focusing screen the image is not recorded through it!
> 
> A simple DIY clean should be fine.



Yes, this; Note to self, quit posting late at night!

Jim


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## privatebydesign (Jan 2, 2014)

Hey Jim, no worries, most of us do it. So far this week have forgotten the naming structure on hundreds of thousands of my own images, and said I had a 50 foot Apollo, not a 50 inch one. I think a 50 foot Apollo would be like the third stage of a Saturn V!


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## MovingViolations (Jan 3, 2014)

Sporgon said:


> Great 'before and after' shots. You've made a really good job of smearing the contaminants across the sensor. If I took an f16 shot of any of my sensors against a White background there would be 'dust' spots all over them. Dust on sensors (and film) is a fact of life, and generally nothing to worry about, being simple to spot out.
> 
> Also bear in mind that the 'dust' is often things such as pollen that can be sticky, and smear beautifully. I wasn't adverse to giving the sensor a gentle blow with a suitable blower but now don't bother. When the dust builds to a serious level I get the sensor cleaned by a Canon service sensor.
> 
> Given that you have now smeared your contaminants I'd strongly recommend you do the same.


I second this emotion.


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## East Wind Photography (Jan 3, 2014)

Hmmm at f16 you may be picking up some rear element lens dust as well. Better to use wide open aperture or no lens at all against a white wall. The parallele light rays at small aperture can project lens particles onto the sensor. Any dust or grease on the sensor will show up without a lens attached.

If the particles continue to show up, I would recommend sending off to Canon for a factory cleaning. They will clean more than just the sensor so less likely other particles in the mirror box will recontaminate the sensor.


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## notapro (Jan 4, 2014)

I finally got around to having another go at cleaning my sensor. I think I'll leave well enough alone at this point. The current condition seems much improved. I see three obvious spots, and I feel comfortable ignoring them since they do not show up in "normal" (i.e., non-dust-detecting) photographs, whether the images are processed or unprocessed. Only though choosing deliberately close levels in Photoshop to look for/find/show dust do these three spots appear. This will do for now. It happens to be that the sensor is now cleaner than it was when the camera was new. That helps take the sting out of the frustration of a few days ago.

To give more information on the cleaning, I cleaned the sensor today with a Visibledust VSwab (green) moistened with VDust Plus. After taking a test shot, the smears and fibers of before were gone, though there remained a section of droplets on the right side of the image--something along the lines of what an inefficient wiper blade might leave on your windshield (windscreen). 

I then wiped the sensor with a second swab moistened with Visible Dust's Sensor Clean, and that got me to what you see in the attached image. Before and after each swabbing, a Giottos Rocket Air Blower was used, and I insepcted the sensor with a VisibleDust Quasar Sensor Loupe 7x.

In the past, I was able to get a T3i Rebel sensor cleaner than what you see here, and it was when shooting the test image at f/32. Only one faint spot would show up in the photo.

For the images I've posted, I photographed an overcast daytime sky. Part of my interest in having dust-free images at f/16 is because I photograph aircraft from time to time, and the shots are taken often in the f/10 to f/16 range. With the sky as a background, dust spots are easily seen, and when there are upwards of 17 of them (which was the case with the then new T3i), removing them in post is can be a "PITA".

Practice and proper technique are important in sensor cleaning. As VisibleDust cleaning swabs are somewhat expensive (over US $40 for 12 of the green 1.0x size), there is incentive learning good technique quickly. In the meantime, I am waiting for delivery of a Lenspen SensorKlear II so that I have another option for future cleanings.

I give my sincere thanks to those who replied with their helpful comments and suggestions. I also stand with Neuro in his caution against doing more than is warranted under given contexts or circumstances.


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