Sensor: Scratch or water residue?

[Elissa Bogos]

Hi everyone!

Recently I've noticed a sort of row of whitish spots , always in the same location, across all of my video. I know it's an issue with my sensor, since it doesn't show up on photographs, which use the mirror.
The spots are also not always apparent, but when they're there, they're always in the exact same location and of the same size and shape.e

I've examined the sensor (during the "manual clean" mode) and found what looks like a streak, almost like an oil stain. It's possible that somehow water (condensation?) could have perhaps made its way in there while changing lenses, which I often do for work. I showed it to one person who thought it was a scratch, but another person didn't think it looked like a scratch.

I exported a still of a shot where the white spots are apparent and cropped it and zoomed in. Does anyone have any input on what this might be and how (if?) I can fix it? I think the darker spots are dust and they move around, but it's the white line that I can't get rid of.

Here is the cropped still:
http://i56.tinypic.com/346ujq0.jpg

I'm not anywhere near a Canon dealership or even a reputable place to take my camera in for a cleaning, and thus I'd be very, very appreciative of any input from the DV Info community!
Thank you!
Elissa

[Justin Molush]

I would give it a round of wet cleaning before saying that it is a scratch. Looks like it could just be residue of some kind.

Dont be scared of wet cleaning the sensor - I was paranoid about it as well, but after I did it the first time I realized its a very simple process if you buy a kit. At a local camera shop in town it was about $30.

[Elissa Bogos]

Thanks for your feedback, Justin. Do you have a particular kit in mind that worked for you? I've, of course, heard horror stories about using anything liquid on it, so would be helpful to know which kit you found to work.

Many thanks again!

[Vincent Oliver]

Originally Posted by Elissa Bogos

Hi everyone!

Recently I've noticed a sort of row of whitish spots , always in the same location, across all of my video. I know it's an issue with my sensor, since it doesn't show up on photographs, which use the mirror.
The spots are also not always apparent, but when they're there, they're always in the exact same location and of the same size and shape.e

Elissa

Not sure what the mirror has to do with anything as this moves out of the way for both stills and video.

It looks like oil residue to me, and is probably more noticeable in brightly lit scenes such as your sample. I would suggest having the sensor professionally cleaned, especially if it is oil, otherwise you could be smearing it over the sensor - (nice for soft focus effects)

Good luck

[Elissa Bogos]

Vincent, thanks so much for your feedback. It looks like some kind of oil to me, too, although I wish I knew how it got in there. Perhaps acid rain?
I'm unable to bring it to a Canon dealer, as there are no professional camera shops in the entire country, so I may have to just try my luck and see if the cleaning kits I can order will do the job.

If anyone has any recommendations about cleaning kits for the MKII sensor, would be grateful to hear them!

[Jon Fairhurst]

VisibleDust has some nice packages that include swabs and cleaning fluid. The packages I bought come with four 24mm green swabs. I bought both kinds of kits: one with an oil-based solvent and the other with a water solution. "Sensor Clean" is their water solution. "Smear Away" is their oil solvent. There is also an oil/water hybrid cleaner with orange brushes. Make sure to get 24mm for the 5D and 16mm for APS-C cams.

I had changed lenses on a windy day near a beach, so I had sand/salt/water marks on the sensor. To see the marks shoot a photo of a uniform surface with a small aperture (f/22 or so). Shoot it out of focus so you are seeing crud on the sensor, not on the lens or the "uniform" surface.

1) I started with a Rocket air bulb to clean out any lose dust. It doesn't touch the sensor, so it's the least invasive treatment. I did this a few times and got some improvement, but there were still large flaws.

2) I used an Arctic Butterfly brush on the sensor. It spins to clean the brush and give it an electrostatic charge. It didn't make much difference. I used it very lightly to avoid scratching the sensor with dried sand.

3) I used the water-based solution and swabs. Like washing a car, water and a cleaner lifts the dirt off the surface. It becomes a lubricant that avoids scratches. You wet the swab, lean it and sweep one way, then lean it and sweep it the other way. Then throw it out. It took two cycles to get the sensor reasonably clean. I still had a couple of very tiny flaws, but was satisfied with the results.

4) I didn't need the oil-based solvent. At least not yet. The "Smear Away" label should be a hint. A smear is more likely to be oil-based, while water impurities are likely to be spots. If you were around pollen, this could cause an oil-based contamination.

5) I also bought a SensorKlear II LensPen. It's for stubborn spots. I haven't used it. It's for spot scrubbing. Apparently, it leaves some small, black artifacts that need to be blown and/or brushed out. To me, this is a last resort, but some people swear by it. It is best used with a sensor loupe, so you can ensure that you are scrubbing the flaw - not just near it or in the wrong corner.

Another tip: do this work in a clean space. You can remove towels from a bathroom and wipe it down for a good, dust-free environment. You want good lighting, a uniform surface to photograph, and something soft and dust-free to set the camera on. Use a fully charged battery and make sure you have room on your CF card. Turn off your phone. Get everything organized before you take the lens off your camera so it all goes smoothly without interruption.

With these tools and good attention to detail, you can do as well as any professional. Possibly better: It's your camera, and you'll take all the care and time that you need, rather than just go through a routine. Also, you get to decide what is "good enough." You won't over or under do the cleaning.

[Elissa Bogos]

Jon, that's very helpful! Thank you for sharing your experience. I'm going to invest in the swabs...I hope that will do the trick.

Many thanks again to everyone who shared their knowledge!

[Jon Fairhurst]

Best of luck, Elissa!