Photogtaphy Forums

Photography Forums > Camera Manufacturers > Panasonic Lumix > Long exposure, processing time on Lumix

Reply
Thread Tools Display Modes

Long exposure, processing time on Lumix

 
 
Wills
Guest
Posts: n/a

 
      09-13-2005, 10:14 AM
I have a Panasonic Lumix DMC-FZ20 camera and have been taking some long
exposure shots of 8 second (lightning).

The camera take another 8 seconds to process the pictures (at which time the
lightning strikes!)

Can anyone explain why this is, and do all digital cameras behave the same?
If not then which are the fatest.

Ta
 
Reply With Quote
 
 
 
 
Aad
Guest
Posts: n/a

 
      09-13-2005, 10:17 AM

"Wills" <(E-Mail Removed)> schreef in bericht
news:(E-Mail Removed). ..
>I have a Panasonic Lumix DMC-FZ20 camera and have been taking some long
> exposure shots of 8 second (lightning).
>
> The camera take another 8 seconds to process the pictures (at which time
> the
> lightning strikes!)
>
> Can anyone explain why this is, and do all digital cameras behave the
> same?
> If not then which are the fatest.
>
> Ta


It's prob. to do with (in camera) long exposure noise reduction.
Turn it off and look at the differences.
Aad


 
Reply With Quote
 
 
 
 
John Bean
Guest
Posts: n/a

 
      09-13-2005, 10:25 AM
On Tue, 13 Sep 2005 11:14:13 +0100, Wills
<(E-Mail Removed)> wrote:

>I have a Panasonic Lumix DMC-FZ20 camera and have been taking some long
>exposure shots of 8 second (lightning).
>
>The camera take another 8 seconds to process the pictures (at which time the
>lightning strikes!)
>
>Can anyone explain why this is, and do all digital cameras behave the same?
>If not then which are the fatest.


It's a technique called "dark frame subtraction", and most
cameras do this for long exposures. The noise generated by
the sensor builds up as the time increases in a way that's
consistent for the particular sensor in the particular
situation in which it's being used. After the "real"
exposure finishes the camera makes another identical
exposure but with the shutter closed - the "dark frame" -
which has the same noise pattern as the real exposure. This
is then subtracted from the original, cancelling most of the
noise without hurting the image detail.


--
Regards

John Bean
 
Reply With Quote
 
News Will
Guest
Posts: n/a

 
      09-15-2005, 04:06 PM
Thanks. That's something on the lines I was thinking.
Unfortunaly it's not possible to switch off noise reduction, reducing it
does nothing.

I have a friend who has a Nikon D100, which gives control back 'immediately
it finishes saving, but there's no way I can afford a D100 and the selection
of lenses of 35 -400mm equiv!

However I do have a wide selection of Pentax lens, so if some kind reader
has a Pentax *ist DS, perhaps they could let know if there is a considerable
recoverey time on on of these cameras.

Thanks
> > I have a Panasonic Lumix DMC-FZ20 camera and have been taking some long
> > exposure shots of 8 second (lightning).
> >
> > The camera take another 8 seconds to process the pictures (at which time
> > the lightning strikes!)
> >
> > Can anyone explain why this is, and do all digital cameras behave the
> > same? If not then which are the fatest.

>
> It's a technique called "dark frame subtraction", and most cameras do this
> for long exposures. The noise generated by the sensor builds up as the
> time increases in a way that's consistent for the particular sensor in the
> particular situation in which it's being used. After the "real" exposure
> finishes the camera makes another identical exposure but with the shutter
> closed - the "dark frame" - which has the same noise pattern as the real
> exposure. This is then subtracted from the original, cancelling most of
> the noise without hurting the image detail.
>
>

 
Reply With Quote
 
John Bean
Guest
Posts: n/a

 
      09-15-2005, 04:14 PM
On Thu, 15 Sep 2005 17:06:14 +0100, News Will
<(E-Mail Removed)> wrote:
>However I do have a wide selection of Pentax lens, so if some kind reader
>has a Pentax *ist DS, perhaps they could let know if there is a considerable
>recoverey time on on of these cameras.


I also have a DS :-)

Dark frame subtraction is done by default for exposures
longer than a second but it can be turned off if you so
desire - first item in the Custom Menu: "Noise rediction"
on/off.


--
Regards

John Bean
 
Reply With Quote
 
News Will
Guest
Posts: n/a

 
      09-15-2005, 05:42 PM
John Bean <(E-Mail Removed)> wrote:

> I also have a DS :-)


I DON'T have a DS, but am considering getting one.

Perhaps you can tell me, how long after a 8+second exposure, before you can
take another picture.

> Dark frame subtraction is done by default for exposures longer than a
> second but it can be turned off if you so desire - first item in the
> Custom Menu: "Noise rediction" on/off.

Unfortunately this is not available on the Lumix

Ta
 
Reply With Quote
 
John Bean
Guest
Posts: n/a

 
      09-15-2005, 06:09 PM
On Thu, 15 Sep 2005 18:42:56 +0100, News Will
<(E-Mail Removed)> wrote:

>John Bean <(E-Mail Removed)> wrote:
>
>> I also have a DS :-)

>
>I DON'T have a DS, but am considering getting one.


I used "also" because I have a DS as well as a Panasonic,
not because I thought you had a DS.

>
>Perhaps you can tell me, how long after a 8+second exposure, before you can
>take another picture.


I thought I already had. I already explained that the delay
is caused by the dark frame subtraction (noise reduction)
process, so ...

>
>> Dark frame subtraction is done by default for exposures longer than a
>> second but it can be turned off if you so desire - first item in the
>> Custom Menu: "Noise rediction" on/off.


.... if you turn it off there's no delay. Hope that's
clearer.

>Unfortunately this is not available on the Lumix


Yes, but you asked about the DS...

--
Regards

John Bean
 
Reply With Quote
 
News Will
Guest
Posts: n/a

 
      09-15-2005, 06:24 PM
[Posted and mailed]

John Bean <(E-Mail Removed)> wrote:

> On Thu, 15 Sep 2005 18:42:56 +0100, News Will <(E-Mail Removed)>
> wrote:
>
> > John Bean <(E-Mail Removed)> wrote:
> >
> > > I also have a DS :-)

> >
> > I DON'T have a DS, but am considering getting one.

>
> I used "also" because I have a DS as well as a Panasonic, not because I
> thought you had a DS.
>
> >
> > Perhaps you can tell me, how long after a 8+second exposure, before you
> > can take another picture.

>
> I thought I already had. I already explained that the delay is caused by
> the dark frame subtraction (noise reduction) process, so ...
>
> >
> > > Dark frame subtraction is done by default for exposures longer than a
> > > second but it can be turned off if you so desire - first item in the
> > > Custom Menu: "Noise rediction" on/off.

>
> ... if you turn it off there's no delay. Hope that's clearer.
>
> > Unfortunately this is not available on the Lumix

>
> Yes, but you asked about the DS...


It's been a long hot sticky day!
Thanks very much, I hope to have a DS soon :-)

Willie
 
Reply With Quote
 
News Will
Guest
Posts: n/a

 
      09-15-2005, 06:27 PM
John Bean <(E-Mail Removed)> wrote:

> On Thu, 15 Sep 2005 18:42:56 +0100, News Will <(E-Mail Removed)>
> wrote:
>
> > John Bean <(E-Mail Removed)> wrote:
> >
> > > I also have a DS :-)

> >
> > I DON'T have a DS, but am considering getting one.

>
> I used "also" because I have a DS as well as a Panasonic, not because I
> thought you had a DS.
>
> >
> > Perhaps you can tell me, how long after a 8+second exposure, before you
> > can take another picture.

>
> I thought I already had. I already explained that the delay is caused by
> the dark frame subtraction (noise reduction) process, so ...
>
> >
> > > Dark frame subtraction is done by default for exposures longer than a
> > > second but it can be turned off if you so desire - first item in the
> > > Custom Menu: "Noise rediction" on/off.

>
> ... if you turn it off there's no delay. Hope that's clearer.
>
> > Unfortunately this is not available on the Lumix

>
> Yes, but you asked about the DS...


It's been a long hot sticky day!
Thanks very much, I hope to have a DS soon :-)

Willie
 
Reply With Quote
 
John Bean
Guest
Posts: n/a

 
      09-15-2005, 06:32 PM
On Thu, 15 Sep 2005 19:27:20 +0100, News Will
<(E-Mail Removed)> wrote:
>It's been a long hot sticky day!


I blame age when I do it :-)

>Thanks very much, I hope to have a DS soon :-)


It's a nice camera, you'll like it - especially if you
already have some nice Pentax lenses.


--
Regards

John Bean
 
Reply With Quote
 
 
 
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Kodak CX4230 - slow processing time Sean Kodak 2 01-02-2004 07:20 PM
how long is too long? Mark C Digital Cameras 8 07-23-2003 08:38 PM