Any Ideas On How To Remove Dust From An Image??

Hello everyone...


As I was prepping my gear for our vacation trip tomorrow, I noticed that my Siggy 10-20 has a speck of dust or something deep within the lens. The dust is noticeable in the images if the aperture is dialed into f/16 and above. I tried everything in my power to rid my lens of such critter, but alas it seems that I have an unwelcome guest in my lens.


The idea of using a vacuum hose to forcibly remove said speck has come to mind, but I'm worried that the aperture blades may get damaged or worse, I'll suck out all the glass elements!


I guess I can manually remove the particle from the photos using software, but I'm wondering if there is some other option that is avail to me.


I performed the Dust Delete function against a white sheet of paper but I assume that would only help if I had dust on the sensor and not in the lens.


Any ideas???


Here is a sample of what I need to deal with (not the best I know - shot at 10mm at f/22, please mind the other so called dots and the blue thing is my blower - I SAY PARDON!)


[img]/resized-image.ashx/__size/550x0/__key/CommunityServer-Discussions-Components-Files/13/4846._5F00_MG_5F00_4717.jpg[/img]


Thanks

I have to ask - are you certain the dust is in the lens? Generally speaking, a piece of dust in the lens will have no effect on the image, because of the repeated refraction of the light as it passes through the lens.


Sorry for the basic question, but have you tried shooting with a different lens (stopped down shooting a clean, white surface or a clear blue sky)? I suspect you're looking at dust on the sensor (there may be dust in the lens, but that's not causing the spot on the image).

If the spot shows up when that specific lens is mounted, but not when using other lenses, then it must be dust in the lens and not the sensor. Not many people realize this, but dust in the lens *can* show up on the image, depending on where it is located in the optical path, the focal length of the lens, the chosen f-number, and other factors. Essentially, when the DOF is very large, dust in the lens may be visible. Diffraction can even cause the spot to appear in the blur disks of the lens when taken wide open (but this is not what is happening in this case).


Do not attempt to vacuum the dust out. Not only will it fail to work, it may introduce more dust into the lens than you are trying to remove.


As for the Dust Delete function, it doesn

Hi Neuro..

Quote:

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Originally Posted by neuroanatomist

I have to ask - are you certain the dust is in the lens? Generally speaking, a piece of dust in the lens will have no effect on the image, because of the repeated refraction of the light as it passes through the lens.


Sorry for the basic question, but have you tried shooting with a different lens (stopped down shooting a clean, white surface or a clear blue sky)? I suspect you're looking at dust on the sensor (there may be dust in the lens, but that's not causing the spot on the image).

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The particle is definitely somewhere under the outer element and I can also see it from the inner side (the mounting side). I now a while back I got drenched by sea water so I'm thinking what I have here is a genuine sea salt crystal. As for my other lenses, no presence of dust only with the Siggy 10-20.

Bummer. [:(]


Thanks for the explanation, wickerprints! It does make sense that with a deep DoF and a reasonably-sized particle under the front element (optically furthest principal focal point, similar to but opposite to where the image plane is projected), especially with a retrofocus lens, would show up in the image.

Hi wickerprints...

Quote:

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Originally Posted by wickerprints

If the spot shows up when that specific lens is mounted, but not when using other lenses, then it must be dust in the lens and not the sensor.

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It does, this is the only lens that displays this *particle*. The image output and the location of the particle matches where I can see the object within the lens.

Quote:

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Finally, if it is truly bothersome to you, you can always have the lens disassembled and cleaned. But be aware that even if you do this, dust will eventually find its way back inside. So, unless the particle is exceptionally large (easily visible without the use of a flashlight), I doubt it is worthwhile to have it cleaned.

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I can actually see the particle without the use of a flashlight but I prefer not to send it in especially as we leave tomorrow - [;)]

Update...


After further testing, it is in fact a dusty sensor. I tried with both the 24-105 and 70-200 and the particle shows up all in the same region. To make things worse, I attempted to manually clean via the blower, and now I

Short of the blower, I wouldn't recommend trying to clean your sensor with anything but a product specifically designed for sensor cleaning. Is there a major photo store anywhere near you (Henry's, Vistek)? They will likely have something to rescue you. Or, depending on when you leave tomorrow, you can possibly have something overnight shipped? I've gotten great results with theVisible Dust Arctic Butterfly 724 Super Bright..


Or, use the Dust Delete function. Or clone out the spots in post.


Good luck, and have a great trip!

Henry

Quote:

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Originally Posted by elmo_2006

Henry's has the solution that you have mentioned, so I'll check them out tomorrow as I'll be in their *neck of the woods* for some last minute shopping - the flight is @ 22:30 pm have plenty-o-time to kill.

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You know it seems to create fear when you start talking about cleaning a sensor. I stuck with the blower for a long time before I finaly graduated to somthing else. Alot of people like the brushes, and I have talked to alot of people that do not. The local camera shop does not use the brush. It is my understanding if you use a brush, the idea is to generate static that attrackts dust, not sweep the sensor. Any one can correct me here if I am wrong, because I do not use the brush.


So about 6 months ago when the sensor got really dirty on the 5D II I decided it was time I took the plunge. I used these with some cleaning sensor solution:


[View:http://www.bhphotovideo.com/c/product/308405-REG/Photographic_Solutions_SS3BOX_Sensor_Swab_Type_3.h tml]


It took me about 7 of them to get the sensor clean. You use these with a bit of sensor cleaning solution. Use them only one swipe and discard. Make sure you have the right size swab for your camera.Use a fluid motion from one side to the other firm but gently stroke. After you finish use the blower and blow it off, then check it again. Most common is it will leave a little resude in the corners. It may leave small pieces of lint that easily blows out. Put the lens on, and retest. Sometimes it takes a few trys before you finaly get it all.


That was a short explanation, there are several videos on the net that tell you how to do this. Watch a few of them, make sure you have a full battery charge, go slow and be carefull.


When I bought my 1D IV it was dirty as heck right out of the box. I had to clean it first thing, kind of disapointing that Canon wouldn't QC there top camera for cleanliness.


Don't take this as my recomenation to try or not. It is your camera and sensor, take what risk you feel acceptable with your skill level and abilities.


Good Luck


Rick

You might also consider taking a swab/q-tip and rolling it around it the bottom of the box first before using your blower. Most dust gets shook down there after every use and blowing it out first will send a plum of junk all over the place.

Manually cleaning the sensor is not to be feared. The swab method works very well. Usually, they provide a solvent (methanol) that is dropped onto the swab, just before cleaning the sensor. This will dislodge stubborn particles.


I think I remember reading that you're not actually touching the sensor, but an IR filter that covers it. Just follow the instructions on how to wipe the slightly damp swab across the sensor area.


Be sure NOT to touch the mirror with the swab.

After yesterday's results, I decided to look at some other photos taken in the past where I had the aperture dialed up high. Boy was I surprised.
Check out this ugliness of a photo rendered in HDR, can you count the number of dust spots??


http://farm6.static.flickr.com/5021/...cd8fec34_z.jpg


Canon EOS Digital Rebel XSi, 0.004 sec (1/250), f/14.0, 10 mm, ISO 200, 2009.


And to think that all this time I thought it was all lens related - I should just return my gear and stick with a point and shot!


I may very well use my gear as is and upon my return send it out to Canon for a complete cleaning. Just need to keep that aperture wide open as possible!


Also, Adobe Lightroom does a great job of removing the specks.


Thanks for all your input!


Your embarrassed forum member,


Emilio