Inspecting The Sensor
We have a complete web site devoted to covering this subject www.sensorinspection.com, I will include a summary here.
Using a sensor inspection device over having to shoot test images and inspect, will save you an enormous amount of time when cleaning your D-SLR Sensor. If you don't have one yet, I highly recommend that you go out and buy one now, you won't regret it.
The original method of shooting a test image is very time consuming, taking 3-15 minutes for each inspection. Lets take a look at the original method.
- Take your camera out of it's cleaning mode
- Re-attach the lens
- Re-insert the media
- Set the camera settings for shooting shoot a test image
- Shoot the test image
- Pull the media out of the camera
- Insert the media into your computer
- Open the file just shot with PhotoShop
- Change the settings of the image (levels) with Photoshop to be able to see the dust spots
- Remove the lens from the camera
- Put the camera in it's cleaning mode
- Now clean (hopefully you remembered that the image in Photoshop is vertically flipped from when you are looking at your sensor).
Now we do it with the sensor inspection device.
- Pick it up and turn the lamp on
- Place it over the lens mount and look at the sensor
Yes there is a BIG difference in time, 5 seconds versus 3-15 minutes. Don't forget that you will more then likely have to do this many times over during just 1 cleaning session. The sensor inspection devices also give you the freedom to be able to clean your sensor on location without having a computer. Inspecting your sensor after any cleaning is a requirement if you want to ensure dust free photography.
How To Create A Test Image
To Check For Dust
To make a test image, you can use about any lens you want but a non-wide angle lens works better then a wide angle just because of the normal falloff found in most wide angle lenses. You want as much of an even exposure as possible from corner to center. The second consideration is minimum aperture opening; we suggest a lens that will stop down to f/22 or greater. We have found that a great subject to shoot for the test, is your monitor. Seeing that you already have to use a computer to view your test, there is no need to go elsewhere to make the test. You already have a willing and qualified subject right in front of you, why not use it. Prepare your monitor for shooting the test:
- Create a new image in Photoshop
- Fill it with white (most any solid color will do, but we prefer a lighter one)
- Set the camera to the following:
- Mode - Aperture Priority
- Setting - Aperture to minimum f/22-f/45
- Lens - Manual Focus set to closest focus setting (if shooting the blue sky, then infinity)
- Features - Turn "OFF" all special function like "sharpening"
- Zoom in until it fills your screen
- Take Picture - shoot camera facing your monitor. Depending how bright your monitor is, your exposure may be a couple seconds. During this exposure, move your camera back and fourth being careful to not to point the lens outside of your white box. Moving the camera during the exposure insures that you are not taking a picture of dirt on your monitor. This should be done within a matter of an inch or two from your monitor.
- Photoshop - Take the image into Photoshop and do a "<CTRL><SHIFT>L" for "auto level" You can lighten or darken if needed.
- Inspect Image - You can now see where you do or do not have dust. Remember that what you are looking at is an image that is flipped 180° vertically (top to bottom) from when you're looking straight in on your sensor. What shows on the bottom of the image will be towards the top of the camera and visa versa...
Before Converting in Photoshop
Converting in Photoshop
After Photoshop and Before Cleaning