Newbie: High speed photos coming as black - page 2 - Hello, I'm a NEWBIE - HELP!! (Newbies assistance, User Guides and thank you notes) - CHDK Forum
« previous next »
Pages: 1 [2]   Go Down

Newbie: High speed photos coming as black

  • 13 Replies
  • 8072 Views
*

Offline whoever

  • ****
  • 280
  • IXUS950
Re: Newbie: High speed photos coming as black
« Reply #10 on: 18 / October / 2010, 15:06:12 »
Advertisements
Quote from: Microfunguy on 18 / October / 2010, 14:51:21
'Bright day' implies the ND filter is in which means that if the ND filter were out the required shutter speed would be about 1/12,800 sec (on most cameras).
Pardon me?

I believe the ND filter is usually 2 or 3 stops (2.86 stops on my cam, for instance), which makes it 1/6400 sec at most. This is indeed a bit over the rim, but still quite safe to use, as image artifacts just start to appear at such speeds.
Logged
*

Offline Microfunguy

  • ****
  • 4037
    • StereoData Maker
Re: Newbie: High speed photos coming as black
« Reply #11 on: 18 / October / 2010, 16:06:17 »
Quote from: whoever on 18 / October / 2010, 15:06:12

I believe the ND filter is usually 2 or 3 stops (2.86 stops on my cam, for instance), which makes it 1/6400 sec at most.

No, that is two stops, or a factor of 4x.

Three stops is a factor of 8x or 1/12,800 sec.
Logged
*

Offline reyalp

  • ******
  • 14128
Re: Newbie: High speed photos coming as black
« Reply #12 on: 18 / October / 2010, 16:13:14 »
Quote from: Microfunguy on 18 / October / 2010, 14:51:21
'Bright day' implies the ND filter is in which means that if the ND filter were out the required shutter speed would be about 1/12,800 sec (on most cameras).
Example:
1/2000th is correct exposure without ND
Camera chooses 1/256th + ND instead, because Tv limit is 1/1600
-> vibration or fast movement is blurry when it doesn't need to be.

I had to work around this exact situation shooting timelapse with sd990 for a moving vehicle.

edit:
You are right, this isn't bright, direct sun. *shrug* problem still exists, solution is still to use modest override, and engage the ND later for really bright scenes.
Logged
Don't forget what the H stands for.
*

Offline whoever

  • ****
  • 280
  • IXUS950
Re: Newbie: High speed photos coming as black
« Reply #13 on: 19 / October / 2010, 12:08:07 »
Quote from: Microfunguy on 18 / October / 2010, 16:06:17
No, that is two stops, or a factor of 4x.
Three stops is a factor of 8x or 1/12,800 sec.
You're right, of course. I must've had a momentary brain blackout.

Still, the question as I perceive it is this: How far can one override the shutter speed, still enjoying predictable exposures and without image artifacts? This is obviously very much hardware-dependent -- foremost, CCD-dependent. In my case, 1/12000 will be correctly exposed, but may have visible image non-uniformity.

I now realize that I've had that override (ND filter always out) activated since I don't remember when, and never noticed ill effects. Of course, it should've been a really bright day indeed...
Logged
Pages: 1 [2]   Go Up
« previous next »
 

Related Topics


SimplePortal © 2008-2014, SimplePortal