3/20/2023 0 Comments Sensor dust big aperture![]() Banding usually manifests itself as a black-and-white shadow, which made my colorized encounter a bit curious. But anyone who’s ever tried to photograph a television is familiar with refresh rates and how it can affect an image. But while shooting in April, I noticed that many of the overhead wash lights were LED-based.įlicker from various light sources is a well-known problem in video, and less known in still photography. Many years ago when I worked in the theater, it was outfitted with halogen-based lighting instruments. The G (and G2) channels have no visible banding, while the red and blue channels have heavy banding. Red channel in RAW Digger Green channel in RAW Digger G2 channel in RAW Digger Here are the individual RGB channels as seen in RAW Digger. Here’s unretouched RAW from the DNG generated in Photoshop. Of the first 1,000 images that I shot with the Q2, thirteen of the images contained significant banding. I put the camera through the paces while photographing some dance rehearsals at my high school’s theater. But the dust reappeared in a matter of a few days. A temporary remedy was to gently knock the side of the unit with my palm, which seemed to dislodge the dust temporarily. ![]() The Q2 addresses the problem with IP52 weather sealing which provides “Protection against solid bodies larger than 1mm” and “Protection against condensation.” The engineers reportedly went to great lengths to add weather sealing while maintaining essentially the same small body size.īut as others have noted, the EVF is prone to dust accumulation, and my unit had dust inside the EVF out of the box. I used black tape to cover up the microphone ports on top of the camera. Since the Q employs a fixed lens, there’s no way to clean the sensor without sending the unit back to Leica’s notoriously slow service center. My major complaint with the Leica Q was the lack of dust sealing, which eventually caused me to tape up the microphone and speaker ports to avoid dust on the sensor. Magnify the image and check every section of the image to find dust.While I hope to do a full review of the unit in the future, I had two problems that caused me to send the unit to Leica’s service center within the first month. Over expose the image by 1 or 2 stops by turning your exposure compensation to plus 1 or plus 2.Ħ. Switch to aperture priority mode and set to f/22Ĥ. Point your camera at a plain surface like a white wall or blue sky without clouds.ģ. If you are looking for dust on your image then you need to shoot at the smallest f/stop possible. In conclusion, this is physics not a "phenomena”. So the dust did not disappear, it just became more visible.” f/22) shadows appear sharper and darker and thus dust particles are now more visible on your image. ![]() On the other hand when the light is focused with a small f/stop (eg. With a wide aperture opening the scattered light reduces the shadow areas of the dust particles therefore it can become nearly invisible on the image. And although dust particles are small and sit directly on the surface of the sensor, it is still sitting on top of the sensor. “When light is transmitted through glass the light is scattered about. Theilmann explained our test results this way. Theilmann’s Ph.D thesis was in Optical Sciences. Rebecca Theilmann at the University of California (San Diego). So we set out to photograph a plain blue sky with focus set to the middle of the lens w/ three different f-stops and voila! As you can see the participant was correct (see images below)!Īlthough the results are clear it didn’t make any sense, so we checked in with Dr. So we ran a test! Cause our motto is “When in doubt, test”. The argument for stopping down would be to increase depth of field and therefore make the dust appear sharper, thus helping to identify whether or not there is actually dust on the sensor and where that dust is! But again this seemed wholly preposterous as depth of field has to do with things in front of the lens not on the sensor! Or does it? This seemed a little bit peculiar as we were discussing dust particles on the sensor and not on any of the lens elements. A while back a safari participant noted that the best way to check for dust on your sensor was to take a photo with the lens stopped all the way down (eg f/22 or greater, Eg. ![]() This is not a depth of field discussion, but it kind of is.
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