DSPographer

DSPographer

Lives in United States United States
Works as a digital signal processing engineer
Joined on Jan 10, 2005
About me:

Canon 5D mark II camera.

Canon 28-135/3.5-5.6_IS_USM, 24/2.8, 50/1.8II, 100/2.8_USM_macro, 200/2.8L lenses.

Sigma EF-500_DG_Super flash.

DSPographer's recent activity

  • Sony's algorithm is worse than what you are explaining. They use a lossy algorithm that introduces what looks like jpeg mosquito noise in the low level bits. It is possible to create a lossy ...
  • Digital sensors, with their high QE, have *lower* reflectivity than standard film. This is why off-sensor automatic flash exposure estimation doesn't work- necessitating the pre-flash seen with ...
  • A frequency at 64 units of a 256 point fft corresponds to a cycle length of 4 pixels in the spatial dimension, so that looks like the 4 channel amplifier effect.
  • You may want to Google orthophotography. You would want to capture overlapped images from a constant, not too low, elevation with the camera pointed straight down. The elevation requirement means ...
  • Replied in 5 Axis IBIS
    Pitch and yaw are the normal 2-axis corrections of all IS systems (5 axis adds roll and x and y translation). The amount of pitch and yaw that is corrected is small enough so that the dominant ...
  • First of all consider the mechanical shutter: The first curtain sweeps across the sensor to start the exposure, this takes something like 3 milliseconds. After the exposure time the second curtain ...
  • This must be the post I missed that you are thinking of: http://www.dpreview.com/forums/post/54580543 This does show an uncorrected conversion but only in B&W since the software didn't yet support ...
  • One situation that seems to give my G7-X trouble is focusing on a moving subject in indoor lighting. So if you will be photographing speeding toddlers or pets indoors you might not like the ...
  • The OP is probably interested in a review using the accessory waterproof case. I don't think it is shipping yet.
  • We should put a link here to the previous posts on DPreview that have example images showing the distortion. Unfortunately, when I searched the forum I didn't find any. Do you have a link to the ...
  • Sorry that I missed the previous posts. I didn't realize examples of the distortion had already been discussed.
  • If you only look at jpegs or raw files converted with DPP or Adobe Camera-Raw/Lightroom then you can't see how much lens corrections have been automatically applied. Using a raw converter like ...
  • You could just point them to the imaging-resource files. They have down-loadable raw files with color checkers in them: http://www.imaging-resource.com/PRODS/canon-g7x/canon-g7xTHMB.HTM Note that ...
  • Samsung has made statements about the NX1 being able to read the sensor very fast: as in 1/240 second. It is not clear if this is in a mode where it is reading all pixels of the full sensor for 4k ...
  • Bill, I think fitting a pixel and ADC noise value to the read noise versus ISO curves will work okay for some cameras but not others. For instance, the Sony A7S has a step change in the read noise ...
  • Some photographers have also been known to take photos with the camera supported so that it doesn't move, which also negates any IBIS advantage.
  • Replied in Kapla!
    Aarrggh. No, he already said that the time for the sum of all the exposures is set to not have a problem with motion blue- just the same as a single exposure for your hypothetical ISO 25 sensor.
  • Replied in Kapla!
    If all we do is accumulate the exposures then we don't need a fast write speed to storage. Samsung has demonstrated some trick modes of the NX1 (automatic ball on bat) even though the storage card ...
  • Replied in Kapla!
    If you could use a single ISO 25 exposure, then you could use 4 gapless ISO 100 exposures accumulated without motion adjustment just as well. That you could perform motion compensation on the 4 ...
  • Replied in Kapla!
    As I pointed out in my post that I wrote as you were posting yours, with a fast electronic shutter there is no penalty in stacking. The read-reset time is a small fraction of the read-out time for ...
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