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View Full Version : Focusing issue. Canon "Bulb" setting (Pics incl)


dancewithethan
03/23/2009, 01:30 AM
Camera: Cannon EOS 40D
Lenses: SIGMA 150mm 1:2.8 APO Macro DG HSM

Mode: M
settings: ISO 200, "bulb" feature setting

What I did: camera was mounted on the tripod with a remote.

What I didn't do: turn off power heads and main pump (I know this help and will try it next time).

All of these pictures are taken under moon light. I took about 20 plus pictures and almost all of them are not focus, any input greatly appreciated.

Pic 1
http://i380.photobucket.com/albums/oo244/emanisone/IMG_0254640x480.jpg
Pic 2
http://i380.photobucket.com/albums/oo244/emanisone/IMG_0245640x480.jpg
Pic 3
http://i380.photobucket.com/albums/oo244/emanisone/IMG_0242640x480.jpg
Pic 4
http://i380.photobucket.com/albums/oo244/emanisone/IMG_0243640x480.jpg
Pic 5
http://i380.photobucket.com/albums/oo244/emanisone/IMG_0253640x480.jpg

IPT
03/23/2009, 02:10 AM
The first and last just look like a shallow DOF from a wide aperature. If you are using the bulb setting the exposure is relatively long and turing off all the pumps, and waiting while for any flow to stop will be imperative to get sharp images.

TitusvileSurfer
03/23/2009, 02:10 PM
But the exposure is NOT relatively long. The first 3 are all 1 second and the last 2 are both 2 seconds. Why were you using bulb mode on these? I would have just set the shutter speed to "1 second" or "2 seconds". Bulb mode is usually reserved for exposures longer than 30 seconds. It is also useful for subjects such as fireworks where the brightness of the exposure is a moot point, but how long the firework will last is debatable. My guess is that the movement caused by the flow is the culprit.

glparr
03/23/2009, 02:13 PM
I would vote for flow movement, too.
Gary