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
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Feb
26
comment Why can't the ISO level on most digital cameras be set below 80?
"if the base ISO was lower, them you would need to use more gain to achieve higher sensitivities and you would get more noise" this is not necessarily true - there are two ways to decrease the native sensitivity of a sensor, one is to reduce efficiency (so fewer photons get through, essentially the same as always having an ND filter) the other is to increase the capacity of each pixel, allowing more light to come in before the signal clips and overexposure happens. Comment continued below...
Feb
26
awarded  Nice Answer
Feb
25
revised GoPro Hero HD field of view is larger at lower resolutions, how is that?
added 39 characters in body
Feb
25
answered GoPro Hero HD field of view is larger at lower resolutions, how is that?
Feb
24
answered Why do compact digital cameras not have the aperture range of DSLRs?
Feb
24
comment How can I get maximum DoF with no distance markers?
Having a chart doesn't really help in the absence of a distance scale on the lens. Auto hyperfocal focussing would be easy to implement in the body but noone does this...
Feb
24
revised How to improve quality of pictures that are already taken (if possible in GIMP)?
added 252 characters in body
Feb
24
comment How to improve quality of pictures that are already taken (if possible in GIMP)?
@mattdm I'm pretty sure the questioner is talking about upsampling images, doesn't seem too vauge to me
Feb
24
comment Why do DSLRs in movie mode have a rolling shutter instead of a global shutter?
@Nick, no worries, I'll leave my post there as there will just be more confusion if I delete it! Basically the camera can't capture the whole frame at once in any mode, it's just in stills mode after the shutter has closed the camera has all the time in the world (relatively speaking) to read the pixels in any order it chooses as there's no extra light coming in to alter the result!
Feb
24
comment How to improve quality of pictures that are already taken (if possible in GIMP)?
Yeah I just realised that and had to edit!
Feb
24
revised How to improve quality of pictures that are already taken (if possible in GIMP)?
deleted 40 characters in body
Feb
24
comment Why do DSLRs in movie mode have a rolling shutter instead of a global shutter?
@Andres, when shooting stills the frame is scanned after the shutter is closed, so with a 1 second exposure, the shutter is open for 1 second, then it closes and then the whole frame is scanned in approx 1/25s
Feb
24
comment Why do DSLRs in movie mode have a rolling shutter instead of a global shutter?
@Nick it's only at speeds faster than 1/250s that the shutter scans the frame, at 1/200s there's a moment when the whole sensor is exposed, thus enabling flash at this speed
Feb
24
answered How to improve quality of pictures that are already taken (if possible in GIMP)?
Feb
24
revised Why do DSLRs in movie mode have a rolling shutter instead of a global shutter?
added 196 characters in body; added 311 characters in body; added 8 characters in body
Feb
24
comment Why do DSLRs in movie mode have a rolling shutter instead of a global shutter?
@Andres, the image is still read line by line in photo mode, you just don't notice it!
Feb
24
answered Why do DSLRs in movie mode have a rolling shutter instead of a global shutter?
Feb
23
answered Alternative media for printing photos
Feb
23
awarded  Nice Answer
Feb
22
answered Maximum focusing distance when using Canon FD to EF adapter?