The information presented here is for informational purposes only. Use at your own risk
Dirty Sensor
Ok - it isn't that dirty, but there's a couple of pesky specs in the upper-left that were annoying when shooting open skies.
Ok - it isn't that dirty, but there's a couple of pesky specs in the upper-left that were annoying when shooting open skies.
Look for 'em
Here's a close-up of the dust, circled. They don't look like much but at wider apertures they'd show up as slightly darker spots in open blue skies. Small enough to "clone out", but let's try to get rid of them.
To really make dust show up you need to shoot a couple frames of an open area lacking detail - and all at a very small f-stop (f16, f22, f32, etc).
Hint!
Don't have a nice clear blue sky to shoot? Sometimes a white wall or ceiling will work, or an overcast sky with the lens out of focus.
Here's what I do: find an old filter and replace the glass with a piece of white frosted mylar. A layer of good quality paper will work too. This new opaque white "filter" can be carried in your bag to check for spots just about anywhere.
Here's a close-up of the dust, circled. They don't look like much but at wider apertures they'd show up as slightly darker spots in open blue skies. Small enough to "clone out", but let's try to get rid of them.
To really make dust show up you need to shoot a couple frames of an open area lacking detail - and all at a very small f-stop (f16, f22, f32, etc).
Hint!
Don't have a nice clear blue sky to shoot? Sometimes a white wall or ceiling will work, or an overcast sky with the lens out of focus.
Here's what I do: find an old filter and replace the glass with a piece of white frosted mylar. A layer of good quality paper will work too. This new opaque white "filter" can be carried in your bag to check for spots just about anywhere.
Test for dust using your new "filter" on your favorite medium to long focal length lens (on a DX-format camera a 50mm or higher lens will work great).
* Manually focus the lens to infinity, get the lens up close to a light source if possible (light bulb, tube, looking up to the sky, whatever)
* Set the len's aperture to a high number, the higher the better. Using Manual mode would be easiest for the rest of this chore.
* Set the camera to over-expose by 1-2 stops by adjusting the shutter speed. Don't worry about getting too slow. You're using an opaque filter, camera shake doesn't enter into the equation.
* Shoot a test frame
* Look at the test in the LCD. Lengthen the shutter speed if the image looks a little dark. Go ahead and increase the ISO if the shutter speed is getting outrageously long. Reshoot if necessary
See the dust? Any dust will show up as vivid dark spots. Extremely blurred, soft, grayish spots may be dust on or in the lens. If you don't see any dust then you have a clean sensor.
* Manually focus the lens to infinity, get the lens up close to a light source if possible (light bulb, tube, looking up to the sky, whatever)
* Set the len's aperture to a high number, the higher the better. Using Manual mode would be easiest for the rest of this chore.
* Set the camera to over-expose by 1-2 stops by adjusting the shutter speed. Don't worry about getting too slow. You're using an opaque filter, camera shake doesn't enter into the equation.
* Shoot a test frame
* Look at the test in the LCD. Lengthen the shutter speed if the image looks a little dark. Go ahead and increase the ISO if the shutter speed is getting outrageously long. Reshoot if necessary
See the dust? Any dust will show up as vivid dark spots. Extremely blurred, soft, grayish spots may be dust on or in the lens. If you don't see any dust then you have a clean sensor.
Where's the dust?
So you see dust in your test, but where is it on the sensor?
The lenses on our cameras invert the image scenes. From our perspective behind the camera, the upper-left corner of the scene (1) gets projected on the lower-right corner of the sensor (2). We'll be working on the sensor from the front of the camera, thereby flipping the projected image horizontally (3).
That's a great bit of jibberish, isn't it? Ok, let's simplify a little: our dust appears in the upper-left corner of the frame (1) as we view it on the LCD or screen. Just imagine a mirror image of the LCD/Screen from top to bottom. When we go to clean the sensor the dust will actually be in the lower-left (3) corner of the sensor, and that's where we'll concentrate our cleaning efforts.
So you see dust in your test, but where is it on the sensor?
The lenses on our cameras invert the image scenes. From our perspective behind the camera, the upper-left corner of the scene (1) gets projected on the lower-right corner of the sensor (2). We'll be working on the sensor from the front of the camera, thereby flipping the projected image horizontally (3).
That's a great bit of jibberish, isn't it? Ok, let's simplify a little: our dust appears in the upper-left corner of the frame (1) as we view it on the LCD or screen. Just imagine a mirror image of the LCD/Screen from top to bottom. When we go to clean the sensor the dust will actually be in the lower-left (3) corner of the sensor, and that's where we'll concentrate our cleaning efforts.
Prepping the SpeckGrabber
The Speck Grabber wand needs to be clean before using. Say that 100 times and remember it well. The Grabber's blue nub is capable of lifting fingerprints right off of glass and it's equally capable of lifting grease and oils off your skin and depositing it on the sensor, requiring more cleaning.
Fortunately the grabber is easily cleaned. Use pre-moistened isopropyl cloths to gently wipe the nub clean then let it dry. A can of compressed air can help speed drying.
Important: Be careful not to let the nub touch anything after you clean it.
The Speck Grabber wand needs to be clean before using. Say that 100 times and remember it well. The Grabber's blue nub is capable of lifting fingerprints right off of glass and it's equally capable of lifting grease and oils off your skin and depositing it on the sensor, requiring more cleaning.
Fortunately the grabber is easily cleaned. Use pre-moistened isopropyl cloths to gently wipe the nub clean then let it dry. A can of compressed air can help speed drying.
Dab the blue nub on a clean filter to clear it of any additional residue. Hold the filter at an angle to the light and dab until the grabber leaves no mark. I usually have to dab 2-3 times before working on the sensor.
This cleaning process may need to be repeated during a heavy sensor-cleaning session, but usually just one pass with the isopropyl cloth is needed.
This cleaning process may need to be repeated during a heavy sensor-cleaning session, but usually just one pass with the isopropyl cloth is needed.
Get into the camera
Warning -- Read the instructions for locking the mirror on your dSLR. Most manuals will suggest using a power-supply or a fresh battery. Heed the warnings! A weak battery may let the mirror and shutter slam down onto your Speck Grabber while you're cleaning, causing serious damage.
Look closely at the sensor. If you're really lucky you'll be able to attack the dust directly with the grabber, otherwise just concentrate on the suspected contaminated area. Either way, just gently dab the grabber on the sensor a few times. The grabber's nub isn't an eraserso just use soft dabs, not rubbing motions.
Stubborn dust or grunge from using a wet-cleaning process may take more effort.
Reshoot the test and repeat as necessary until all the dust is gone.
Warning -- Read the instructions for locking the mirror on your dSLR. Most manuals will suggest using a power-supply or a fresh battery. Heed the warnings! A weak battery may let the mirror and shutter slam down onto your Speck Grabber while you're cleaning, causing serious damage.
Look closely at the sensor. If you're really lucky you'll be able to attack the dust directly with the grabber, otherwise just concentrate on the suspected contaminated area. Either way, just gently dab the grabber on the sensor a few times. The grabber's nub isn't an eraserso just use soft dabs, not rubbing motions.
Stubborn dust or grunge from using a wet-cleaning process may take more effort.
Reshoot the test and repeat as necessary until all the dust is gone.
Is it clean?
Your sensor should produce a clean test after cleaning. No marks, dots, or smears.
This is the result after a quick cleaning. Including cleaning the wand the whole process took about 3 minutes. Major cleanings take a couple of repeat "tests" and usually take me 10 minutes to complete.
I've been cleaning my sensors with Speck Grabbers for years. I do a cleaning at home in controlled conditions when I need to, but I also carry a Speck Grabber in my bag. I had to clean major spots from my sensor outdoors "in the field" once, and very successfully.
This gadget works well for me, but use whatever method you're most comfortable with - and most importantly one that works for you
Your sensor should produce a clean test after cleaning. No marks, dots, or smears.
This is the result after a quick cleaning. Including cleaning the wand the whole process took about 3 minutes. Major cleanings take a couple of repeat "tests" and usually take me 10 minutes to complete.
I've been cleaning my sensors with Speck Grabbers for years. I do a cleaning at home in controlled conditions when I need to, but I also carry a Speck Grabber in my bag. I had to clean major spots from my sensor outdoors "in the field" once, and very successfully.
This gadget works well for me, but use whatever method you're most comfortable with - and most importantly one that works for you
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| All images Copyright © Scott Keating unless otherwise noted - Unauthorized use is prohibited by international law
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