Using a sensor inspection device instead of shooting and inspecting test images will save you an enormous amount of time when cleaning your D-SLR Sensor. If you don't yet have an inspection device, I highly recommend that you go out and buy one now.
The original method of shooting a test image is very time consuming, taking anywhere from 3-15 minutes for each inspection. The steps for the original method are listed below.
Now we do it with the sensor inspection device.
As you can see, there is a BIG difference in time: five seconds versus 3-15 minutes. Don't forget that you will more than likely have to do this many times during just one cleaning session. The sensor inspection devices also give you the freedom to be able to clean your sensor on location without a computer. Inspecting your sensor after any cleaning is a requirement if you want to ensure dust-free photography.
I strongly feel that owning a sensor inspecting device is as important as having a blower because even with a blower you need to inspect your sensor. The list of devices below are in order of recommended devices, the most favorable being at the top of the list. I rated these based on the fact that I have full frame cameras as do many others. The image above is to scale so you can tell how the size of one compares to another. Any of these are better than none at all. When selecting a sensor inspection device, magnification isn’t everything, not to mention that many manufacturers claim higher magnification than their devices actually are.
The second factor that is just as important as magnification, if not more, is field of view. Field of view is even more critical with full frame cameras than others. Think of your eye as being 1X. Now stick an empty toilet paper roll tube in front of your eye and look through it. You are still at 1X but you just restricted your field of view. Now grab an empty tube from a roll of paper towels and do the same. You just restricted your field of view even more. To improve your field of view you can do two things: use a short tube and/or use a larger diameter tube. To see the far corners and edges of a full frame camera’s sensor without moving your head all over the place, you want a sensor inspection device that has a good field of view.
When it comes to using a sensor inspection device, there actually is a trick to be able to see the smaller dust particles. If the dust particles are large, it will be easy for you to focus your eyes on them. If you don’t have any large particles to focus on, it may be hard to see the small ones. It’s kind of like when people walk into sliding glass doors. The reason they walked into that door was because the glass was clean and they were focusing past/through the glass and never saw it. Those big chunks of dust on your sensor work just like decorations we may put on a sliding glass door and we can focus on them easily. When we don’t have those big focusing aids on the sensor, you may find it easier to focus your eyes on the edge of the sensor on the frame that is holding the filter in. After being able to focus on the edge, use focus lock with your eye and scan the surface of the sensor for dust.
MQ-7X Sensor Inspection Scope by Micnova - Six Ultra-bright LEDs, Multicoated high definition optical glass, 7x Magnification, Powered by two CR2032 lithium ion batteries (included). With a street price of $29.95 this is our #1 pick for sensor inspection devices.
Mini Quasar Sensor Loupe by VisibleDust - Four Ultra-bright LEDs, 7x Magnification, Powered by two CR2032 lithium ion batteries (included). With a street price of $80 this is our #2 pick for sensor inspection devices.
Quasar Plus Sensor Loupe by VisibleDust - Six Ultra-bright LEDs, 7x Magnification, powered by two CR2032 lithium ion batteries (included) and has a 52mm filer ring mount so that you can mount filters or a hood if you so desire. With a street price of $119.95, this is our #3 pick for sensor inspection devices. This price tag is what's keeping it from being our second choice of insepction devices.
Sensor Scope by Delkin - This was the very first commercially available sensor inspection device available to the consumer. Unfortunately, this was developed before full frame cameras came onto the market and you have to move your head around a bit to see the corners of a full frame sensor. Four Ultra-bright LEDs, 5x Magnification, Powered by two CR2032 lithium ion batteries (included). With a street price of $46.95, this is our #4 pick for sensor inspection devices.
DSLR Sensor Loupe by GGS - (DLC SensorVu Loupe) This loupe comes with a rig that mounts to the hot shoe of the camera to allow for its 2X function of seeing while you are cleaning. I found it to be way too cumbersome and too weak to use. Due to distortion in the lens, this is difficult to use. Four LEDs, 5x & 2x Magnification, powered by two AAA batteries (not included). With a street price of $44.95, this is our #5 pick for sensor inspection devices.
SensorMag by Carson Optical - (Sensor Check by Photographic Solutions) This 4.5x loupe has six bright LED's. It has the ability to swing 45deg while still resting on the lens mount. Powered by two CR2032 lithium ion batteries (included). With a street price of $19.95 this is the cheapest loupe on the market but it our #6 pick for sensor inspection devices.
SensorKlear Loupe by LensPen - This 6x loupe has six bright LED's and was designed with a cutout in its side to allow for access for the SensorKlear II pen. This gives you the ability to see while cleaning with the SensorKlear II pen. Powered by two AAA batteries (included). With a street price of $56, it's our #7 pick for sensor inspection devices.
To create a test image, you can use any lens you want, however a non-wide angle lens works better then a wide angle 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: