Author Topic: Any ideas  (Read 2821 times)

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Offline Fud

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Any ideas
« on: November 13, 2010, 11:02:23 PM »
This evening I was up in London and photographed the Lord Mayors Fireworks along the Thames.  I set the camera to Manual with speed set to 0.6 second and F8 as at that speed St Pauls was correctly exposed in the background.  However when I reviewed the photos this evening St Pauls seemed to vary in light so I checked the settings and whilst the speed remained constant the aperture varied which being in manual it shouldn't have - anybody got any ideas (I've checked the camera settings since I got home and it is definitely in M mode) ???
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Offline REX (aka TG)

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Re: Any ideas
« Reply #1 on: November 13, 2010, 11:12:57 PM »
Very strange something similar happent to a friend with Canon and until now no explanation
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Offline chappo1

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Re: Any ideas
« Reply #2 on: November 14, 2010, 12:00:44 AM »
My only contribution would be hobgobblins, fairies or such like so I had better refrain from commenting... ;) john
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Offline AScot

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Re: Any ideas
« Reply #3 on: November 14, 2010, 12:11:34 AM »
Your correct Fud, that should not happen. Even if you turn off the camera and change the lens, the settings will remain the same unless the new lens has a lower minimum f stop, in which case it will keep the speed and change the fstop to the minimum (maximum diaphragm opening size I mean). Even if you change the setting to S or A and half press the shutter, changing the exposure, it will revert to your original settings when you reset the camera to M.

The exposure meter still works when in M but does not change the settings, it only flashes what exposure compensation is required for a correct exposure, on the LCD panel.

I am sure you already know all this, I don't have to tell you, right. So I can only conclude that there is something wrong with the camera.
« Last Edit: November 14, 2010, 10:07:13 PM by AScot »
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Offline Rob aka [minolta mad]

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Re: Any ideas
« Reply #4 on: November 14, 2010, 05:12:15 PM »
I cant add anything other than what AScot has said, only have you tried it again since last night to see if the settings remained the same ???


Rob

Offline lothian

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Re: Any ideas
« Reply #5 on: November 15, 2010, 08:59:29 AM »
Hi

I'm wondering if this may have been caused by one of the following factors outwith the camera settings:

1.  If the fireworks were being set off in front and above the cathedral,  maybe they reflected a significant amount of light off the surface of the building (or via the surface of the river).  I'm thinking that 0.6 sec is quite short for a firework display and the difference in light from one shot to the next could be quite significant (e.g. height, and number of bursts).
2.  If the building uses modern floodlights, maybe they took a while to reach their full brightness.

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Offline Fud

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Re: Any ideas
« Reply #6 on: November 15, 2010, 12:34:48 PM »
Hi

I'm wondering if this may have been caused by one of the following factors outwith the camera settings:

1.  If the fireworks were being set off in front and above the cathedral,  maybe they reflected a significant amount of light off the surface of the building (or via the surface of the river).  I'm thinking that 0.6 sec is quite short for a firework display and the difference in light from one shot to the next could be quite significant (e.g. height, and number of bursts).
2.  If the building uses modern floodlights, maybe they took a while to reach their full brightness.

Steve
I exposed for the dome of St Pauls before the fireworks started and it was definitely dimmer in some of the photos. I checked the exif data and the aperture varied form F8 to F22 but what is interesting is that the exposures for the fireworks were about right.  I was shooting in low speed continous mode so if I had in fact shot them in speed mode I would have been quite impressed with the job the camera did on metering
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Offline d7d (aka Ronin, aka Shot by scott)

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Re: Any ideas
« Reply #7 on: November 15, 2010, 12:45:46 PM »
All I can imagine the dial wasn't 100% the M position. Or for some reason the camera didn't correctly use M mode but the mode on the dial before it S. That would explain the correct exposure @0.6 seconds with different f/