Mist

by Jakub

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101,454 reputation
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bio website mattgrum.com
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visits member for 4 years, 10 months
seen 6 hours ago

May
21
answered Distance measuring
May
20
answered Why is my Sony A57 creating low res JPGs?
May
19
comment What determines the fastest shutter speed for an electronic shutter?
Yes there are CMOS sensors with global shutters, e.g. the one in the Blackmagic Production camera. It's more difficult to implement than in a CCD but it's perfectly possible.
May
19
comment What determines the fastest shutter speed for an electronic shutter?
That's only true for non global shutter CMOS sensors. CCDs or CMOS sensors aren't constrained by how fast data can be read out (in a global shutter architecture charge is transferred from the pixel to a buffer until the camera is ready to read it out). The first generation digital cameras with CCDs would often shoot at 1/1600s, faster than the fastest mechanical shutters available. They could have been made faster if the manufacturers desired (they're only limited by the switching speed of the sensor).
May
18
comment HDR and RAW dynamic range clipping, mapping, and compression
@feetwet The camera's JPEG engine probably clips the shadows a bit, as for lightroom it depends on what settings you apply - if you crank the exposure slider all the way up then it's going to clip the highlights!
May
17
answered HDR and RAW dynamic range clipping, mapping, and compression
May
17
comment Why is it called “macrofocus” and not “microfocus”?
@Skaperen you can attach a microscope to a camera just like you can attach a macro lens. It is not true that microscope refers to the intended subject and macro refers to what the lens does! They both refer to the size of the subject, which is larger with macro lenses. Please remove your original comment, which implies you're summarising my answer but instead says something completely different. You may leave your own answer if you wish!
May
15
awarded  Enlightened
May
15
awarded  Nice Answer
May
15
comment Sony a7: Is there more noise for ISO <100?
@inkista only if you're shooting JPEG, if you're shooting RAW you can just keep the camera at ISO100 and overexpose if you're in dire need of a slower shutter speed, and get the same result.
May
15
comment Why is it called “macrofocus” and not “microfocus”?
@Skaperen not really, microscopes make even smaller subjects into big images. Macro lenses simply deal with larger subjects than microscopes.
May
15
answered Why is it called “macrofocus” and not “microfocus”?
May
14
awarded  Guru
May
14
revised Why did I get blurry star trails?
added 9 characters in body
May
14
comment Which has a faster write time: RAW or JPEG?
@RomeoNinov Of course (Canon's RAW compression uses JPEG and then does simple entropy encoding on the difference between the JPEG compressed version and the original), my point was that compression/processing are generally not the bottlenecks, writing data to the card almost always is.
May
14
comment Sony a7: Is there more noise for ISO <100?
Looking at the graph on Bill's page, the only anomaly appears to be the ISO80 result, the others are all very close to 10.5 EV. I don't think this can be the result of compression (I've been studying their algorithm a lot recently) all that happens in the shadows is that values are shifted a bit to the right (i.e. they go from 14 -> 13 bits). My guess is that there's some sort of systematic error in how the RAW values are corrected digitally for for ISO 80.
May
14
comment Which has a faster write time: RAW or JPEG?
JPEG compression is done in hardware and is very very fast.
May
14
answered Why did I get blurry star trails?
May
14
comment Sony a7: Is there more noise for ISO <100?
@theJollySin it's important to note that you're unlikely to actually be able to see a difference of 0.3EV in DR, so the results are not exactly unpredictable, DR will appear to be pretty much the same at all settings between ISO50 and ISO200. As to why the feature exists, it's to allow for longer shutter speeds for people shooting JPEG, who would otherwise not be able to benefit from the extra headroom available.
May
14
revised Sony a7: Is there more noise for ISO <100?
added 7 characters in body