Alley in Pisa, Italy

by Lars Kotthoff

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bio website mattgrum.com
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visits member for 3 years, 10 months
seen 32 mins ago

Jul
15
revised Why use UniWB? Doesn't apparent clipping of “final” colors matter more than actual clipping of RAW sensor values?
added 345 characters in body
Jul
15
comment Raw is larger and softer than JPG
@clabacchio I think the real reason is, as stated in the dcraw documentation: "Any algorithm that combines each pixel with its neighbors is going to have problems near the edges. C code is cheap, so dcraw applies a different algorithm to edge pixels. Hardware logic is expensive, so cameras crop off the edge pixels after processing"
Jul
15
answered repair corrupt cr2 (raw) withouth jpeg prview
Jul
15
revised Why use UniWB? Doesn't apparent clipping of “final” colors matter more than actual clipping of RAW sensor values?
added 281 characters in body
Jul
15
comment Raw is larger and softer than JPG
@clabacchio The JPEG standard allows for incomplete blocks along the bottom and/or right edges of the image, meaning image dimensions do not have to be multiples of 8. Additionally I know of no image editor that crops images to a multiple of 8 before saving. RAW converters may aim for multiples of 8 in order to produce JPEG images which can be rotated without re-encoding (a desirable property of camera generated JPEGs).
Jul
15
comment Dark zone appearing on pictures when using an external flash
Basically what @JamesSnell said. It's worth noting that with the Canon 430EX (and similar speedlights) reducing the flash power also reduces the flash duration, making it better at freezing motion (but make sure you're still able to overpower the ambient light or you'll get blur).
Jul
15
comment Dark zone appearing on pictures when using an external flash
It is a duplicate - the sync speed of the 6D is 1/180s, shoot faster than this and you'll see the shutter curtains. Case closed.
Jul
15
revised Why use UniWB? Doesn't apparent clipping of “final” colors matter more than actual clipping of RAW sensor values?
added 486 characters in body
Jul
15
answered Why use UniWB? Doesn't apparent clipping of “final” colors matter more than actual clipping of RAW sensor values?
Jul
12
awarded  resolution
Jul
11
answered Do you lose the increased sharpness of not having an AA filter if downscaling?
Jul
9
comment Foveon x3 sensor
@KendallHelmstetterGelner this isn't a discussion forum, so that's all for now I'm going to update my answer when I get a chance and provide sources for everything, I'm not making all this up - I very nearly bought a DP2M, and did a lot of research.
Jul
9
comment Foveon x3 sensor
@KendallHelmstetterGelner I meant a yellow object in an image contains red and green. Also you missed the point entirely, red and green don't measure the same spatial location, but when the red and green response increase together then you can use the green values to reliably estimate what the missing red values are and vice versa. So you get 33.75MP of red and green data, and you only need to "guess" 1 in every 4 pixels where there is a blue sensor which doesn't record useful information for yellow objects. That's a lot more than the 15MP of red and green you get from the X3.
Jul
8
comment Is there an automated way to create composites from multiple images of a moving object?
I think you might have it the wrong way round, the question was asking about a fixed camera and moving object, the object should appear many times in the final image in different positions. Pick up any snowboarding magazine for an example of this effect!
Jul
8
answered Is there an automated way to create composites from multiple images of a moving object?
Jul
8
comment Foveon x3 sensor
@KendallHelmstetterGelner With 45MP total, in the worst case (e.g. only red light) you get 11.25MP out of the Bayer and 15MP out of the X3. In the best case (e.g. a monochrome scene) you still get 15MP out of the X3 but get 45MP out of the Bayer! Yes most scenes have colour elements. A yellow object contains red & green light, when the brightness of yellow changes, red & green change by the same ammount, and demosaicing can fill in the missing red values using green of which there are 22.5MP! So it's really a case of fixed 15MP, or between 11.25MP and 45MP, averaging somewhere in the middle.
Jul
8
comment Foveon x3 sensor
@KendallHelmstetterGelner You mention Bayer sensors "topping out" in resolution in the same sentence as the Foveon Quattro - the design of which was necessary to fight a fundamental limitation in the X3 design, in that light is defocused as it penetrates deeper into the sensor! A perfectly focused image will appear out of focus if you move the sensor backwards even slightly. The same effect happens inside the X3, which is why the Quattro reduced the resolution of the lower layers. The Bayer sensor is only limited by manufactures' unwillingness to push resolution due to consumer misconceptions.
Jul
7
comment How do I take a photo like this (very bright)?
It's often repeated in answers to similar questions, but you don't generally need additional light or reflectors when shooting into a really low sun, the sun's brightness is greatly reduced and the open sky is usually bright enough to provide diffused light on your subject.
Jul
7
answered How do I take a photo like this (very bright)?
Jul
4
awarded  Nice Answer