Canon 7D Sensor Dust


I bought a brand spanking new Canon 7D and the very first pictures I took were to check for any sensor dust. It's difficult to see the dust particles with your naked eye, but it's trivial to find 'em by taking a picture of the sky or white LCD screen at a very small F-Stop. So after unwrapping the Canon 7D, I (quickly) attached a 55-250 lens, and then took pictures at various apertures at ISO 100. Dust on the camera sensor (it's actually on the glass filter) is unavoidable, but I was curious how clean the camera would come as shipped from Canon. Plus I wanted to establish a baseline to compare down the road - lets hope the built-in sensor cleaning keeps it clean!

Click on the Image you'd like to see, what View, and what F-Stop. I used "auto tone" in Photoshop to (grossly) exaggerate what the dust bunnies look like on the sensor ... but then you can go back to the original image and see where to look. Javascript is used to "flip" to the selected image. Give it a second the first time as the browser caches the image - after that, you can go back-n-forth to quickly see the dust change with F-Stop. Conclusions below.

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Choose Image: White LCD Screen as shot or enhanced via PS auto-tone
Choose View: original resized (can't see much) ... or actual pixels cropped showing dust bunny!
Choose F-Stop: 5.6 - 8.0 - 10 - 16 - 22 - 32

LCD Image auto-toned at F/32 - actual pixels




Conclusion: Dust on the camera sensor looks scary, especially in the enhanced images. It would have been nice if the brand new Canon 7D had shipped with no dust ... but looks like there are a couple of 'em there - there's another similar "large" one at another spot. However, if you flip to the as-shot images, they are barely visible, even at extremely small apertures. So for most real-life shooting, they aren't significant, so I'm not going to worry about it for now ... and HECK, over time, they might just go away!

BTW, one thing that is quite noticeable is how much vigenetting the 55-250 lens has, even at F/8.0 and especially wide-open at F/5.6. This is a very light/small $250 lens, so you get what you pay for, and while it's a great bargain, keep this in mind when shooting with it.

Hulk'in picture of Devil's Tower - note sensor dust at middle left



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