Dust my sensor!
What’s the best way to clean the sensor of my Nikon D2x? Are there tricks for changing lenses in extreme conditions to prevent dust from getting on the sensor?
Carlos Carvajal
Via e-mail
To blow dust off the optical low pass filter (OLPF) that covers the D2x’s sensor: In a clean, dust-free location, hold the camera horizontally, lens facing down.Remove the lens, and, using the D2x’s Mirror Lock Up function (see Custom Settings in your manual), quickly open the shutter using the camera’s bulb setting.
Blow off the OLPF with a few rapid bursts from a simple air bladder and then turn off the camera to close the shutter. Without changing camera orientation, quickly replace the lens.
To remove dust spots after the fact, go to the D2x’s Custom Settings menu and follow the instructions to take a Dust Reference Photo in the camera’s RAW (NEF) mode—this is like a topographical map of the OLPF surface. In post-production, open your images in Nikon’s Capture software, and select the Image Dust Off option.
Select the photos you want “dusted” and follow a few screen prompts. The software will compare the images taken to the Dust Reference Photo and automatically remove any evidence of dust. It’s quicker and easier than it might sound. You might want to take a Dust Reference Photo before each important shoot.
To change lenses in extremely dusty or gritty places, we recommend trying a film changing bag like those used to load film onto developing reels in darkrooms (prices start at $13, street). For best results, vacuum the bag out before each use.
Like lenses?
I bought a digital superzoom camera with a lens focal length of 6–72mm (35mm equivalent 36–432mm). If I take a picture with the digital camera at 6mm and the same scene with my 35mm camera at 36mm, will the two be identical? Will they have the same angle of view, depth of field and perspective?
Paul Kem
Yorktown, IN
Answers: No, yes, no, it depends. Pictures identical: No. The 35mm frame has a 2:3 aspect ratio (which allows it to enlarge just about exactly to 4x6 and 8x12), whereas the sensor in your superzoom is a 3:4 aspect ratio (which enlarges to a sloppy 4x5.3 or 4.5x6, which is why 4x6 prints from digital compacts sometimes have areas cut out). Simply, they’re a different shape.
Angle of view: Pretty much the same, within a variation of a few degrees.
Depth of field: No. The digital picture will have greater depth of field, given the same aperture and distance from the subject. Shorter focal lengths provide greater depth of field—but we’re certainly not getting into why that is, because major wars have been started on this topic.
Perspective: The relative sizes of objects in the picture (that’s what perspective means) is determined by distance to the subject, not focal length.
If you stand in the same place with your digital superzoom and your 35mm camera and take pictures at every focal length with both cameras, all the pictures will have the same perspective. Move closer or farther from your subject, and that will change the perspective.
|
