Re: Can digital capture do TIME exposures?
...or approaching On Topic: From A guide for the use of CCD's: #1 Where to start, found by google at: http://www.starchaser-obs.com/Ot_art_1.htm Cooling is extremely important. If you use a CCD at room temperature, thermal noise will add about 150 electrons per second per pixel. A typical pixel has the capacity for around 150,000 electrons. This means that in 17 minutes the CCD would be saturated by noise. For each decrease in 13 degrees F. the production of thermal electrons decreases by half. Therefore the cooler the unit, the longer the CCD can be exposed before saturation by thermal noise. Most CCD's have ThermoElectric cooling (TE). The best is liquid cooling, usually liquid nitrogen. Jostein :-) - Original Message - From: T Rittenhouse [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Saturday, January 11, 2003 2:35 AM Subject: Re: Can digital capture do TIME exposures? http://www.skinsite.com/info_liquid_nitrogen.htm You could have done the google search yourself you know. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto - Original Message - From: Feroze Kistan [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 10, 2003 6:28 AM Subject: Re: Can digital capture do TIME exposures? What is the purpose of liquid nitrogen and where is it used? Feroze - Original Message - From: T Rittenhouse [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 10, 2003 1:50 AM Subject: Re: Can digital capture do TIME exposures? Yep, a little liquid nitrogen will do wonders. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto - Original Message - From: Jostein [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 09, 2003 11:40 AM Subject: Re: Can digital capture do TIME exposures? I think the ability to do long exposures depends on how much thermal noise the chip produces, and how well it can separate noise from signal. Dunno the current tech on any particular camera, but I know astro photographers have long embraced digital. However, I think their devices have some serious cooling systems.
Re: Can digital capture do TIME exposures?
On Saturday, January 11, 2003, at 09:57 AM, Jostein wrote: ...or approaching On Topic: From A guide for the use of CCD's: #1 Where to start, found by google at: http://www.starchaser-obs.com/Ot_art_1.htm Cooling is extremely important. If you use a CCD at room temperature, thermal noise will add about 150 electrons per second per pixel. A typical pixel has the capacity for around 150,000 electrons. This means that in 17 minutes the CCD would be saturated by noise. For each decrease in 13 degrees F. the production of thermal electrons decreases by half. Therefore the cooler the unit, the longer the CCD can be exposed before saturation by thermal noise. Most CCD's have ThermoElectric cooling (TE). The best is liquid cooling, usually liquid nitrogen. Jostein :-) But you wouldn't have to cool your digicam to liquid nitrogen or liquid helium extremes to see an improvement would you? Wouldn't CO2 be sufficient for non-astrophotograpy uses? Dan Scott (just guessing)
Re: Can digital capture do TIME exposures?
Dan Sco But you wouldn't have to cool your digicam to liquid nitrogen or liquid helium extremes to see an improvement would you? Wouldn't CO2 be sufficient for non-astrophotograpy uses? Dan Scott (just guessing) I think someone else posted this too, but basically we use a electronic cooler to bring the temp down. Not to liquid nitrogen or even CO2 levels, just a nice 30 deg delta or so. Makes a huge difference. -Ryan
Re: Can digital capture do TIME exposures?
On 11 Jan 2003 at 13:05, Dan Scott wrote: But you wouldn't have to cool your digicam to liquid nitrogen or liquid helium extremes to see an improvement would you? Wouldn't CO2 be sufficient for non-astrophotograpy uses? Hi Dan, Unfortunately not even tiny Peltier devices (thermo-electric coolers) are appropriate for use with battery powered cameras since they are very inefficient and produce more heat than they sink. Any gas solution would be unwieldy to the extreme as the gas would need to be used as a refrigerant. I have heard of some portable image sensors (astro orientated) being configured to be cooled using dry ice. What some digicam manufacturers have done is to provide a thermally conductive path from the image sensor to the chassis (alloy) in an effort to reduce thermal noise. The Olympus E series digicams are configured in this manner. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html
Re: Can digital capture do TIME exposures?
On Saturday, January 11, 2003, at 04:39 PM, Rob Studdert wrote: What some digicam manufacturers have done is to provide a thermally conductive path from the image sensor to the chassis (alloy) in an effort to reduce thermal noise. The Olympus E series digicams are configured in this manner. Cheers, Rob Studdert Hi Rob, Considering how hot Australia gets, additional cooling might make an improvement at high ISO. Have you tried sitting your E-10 on bag of dry ice to see if there is a noticeable improvement? Dan Scott
Re: Can digital capture do TIME exposures?
Thanks guys Feroze - Original Message - From: Jostein [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Saturday, January 11, 2003 5:57 PM Subject: Re: Can digital capture do TIME exposures? ...or approaching On Topic: From A guide for the use of CCD's: #1 Where to start, found by google at: http://www.starchaser-obs.com/Ot_art_1.htm Cooling is extremely important. If you use a CCD at room temperature, thermal noise will add about 150 electrons per second per pixel. A typical pixel has the capacity for around 150,000 electrons. This means that in 17 minutes the CCD would be saturated by noise. For each decrease in 13 degrees F. the production of thermal electrons decreases by half. Therefore the cooler the unit, the longer the CCD can be exposed before saturation by thermal noise. Most CCD's have ThermoElectric cooling (TE). The best is liquid cooling, usually liquid nitrogen. Jostein :-) - Original Message - From: T Rittenhouse [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Saturday, January 11, 2003 2:35 AM Subject: Re: Can digital capture do TIME exposures? http://www.skinsite.com/info_liquid_nitrogen.htm You could have done the google search yourself you know. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto - Original Message - From: Feroze Kistan [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 10, 2003 6:28 AM Subject: Re: Can digital capture do TIME exposures? What is the purpose of liquid nitrogen and where is it used? Feroze - Original Message - From: T Rittenhouse [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 10, 2003 1:50 AM Subject: Re: Can digital capture do TIME exposures? Yep, a little liquid nitrogen will do wonders. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto - Original Message - From: Jostein [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 09, 2003 11:40 AM Subject: Re: Can digital capture do TIME exposures? I think the ability to do long exposures depends on how much thermal noise the chip produces, and how well it can separate noise from signal. Dunno the current tech on any particular camera, but I know astro photographers have long embraced digital. However, I think their devices have some serious cooling systems.
Re: Can digital capture do TIME exposures?
I was being somewhat tongue in cheek there. While LN can cool a semi-conductor down to almost no noise, it is kind of bulky and inconvenient. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto - Original Message - From: Rob Studdert [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 09, 2003 10:26 PM Subject: Re: Can digital capture do TIME exposures? On 9 Jan 2003 at 18:50, T Rittenhouse wrote: Yep, a little liquid nitrogen will do wonders. A lot of scientific imaging devices seem to utilize semiconductor Peltier effect devices rather than gas cryogenics for noise reduction through cooling. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html
Re: Can digital capture do TIME exposures?
Liquid Nitrogen Plus Photon lube(tm). Bob - Original Message - From: T Rittenhouse [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 10, 2003 10:50 AM Subject: Re: Can digital capture do TIME exposures? Yep, a little liquid nitrogen will do wonders. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto - Original Message - From: Jostein [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 09, 2003 11:40 AM Subject: Re: Can digital capture do TIME exposures? I think the ability to do long exposures depends on how much thermal noise the chip produces, and how well it can separate noise from signal. Dunno the current tech on any particular camera, but I know astro photographers have long embraced digital. However, I think their devices have some serious cooling systems.
Re: Can digital capture do TIME exposures?
What is the purpose of liquid nitrogen and where is it used? Feroze - Original Message - From: T Rittenhouse [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 10, 2003 1:50 AM Subject: Re: Can digital capture do TIME exposures? Yep, a little liquid nitrogen will do wonders. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto - Original Message - From: Jostein [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 09, 2003 11:40 AM Subject: Re: Can digital capture do TIME exposures? I think the ability to do long exposures depends on how much thermal noise the chip produces, and how well it can separate noise from signal. Dunno the current tech on any particular camera, but I know astro photographers have long embraced digital. However, I think their devices have some serious cooling systems.
Re: Re: Can digital capture do TIME exposures?
Really I meant to ask what it had to do with photography, last time i heard they use it to break into safes and locks, and cut warts off too - Original Message - From: Peter Alling [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 10, 2003 9:12 PM Subject: Re: Re: Can digital capture do TIME exposures? Very fluffy ice cream? Except that Still vigorously until you can't might happen way to fast. At 08:05 PM 1/10/2003 +0100, you wrote: === At 2003-01-10, 13:28:00 Feroze wrote: === What is the purpose of liquid nitrogen and where is it used? = = = = = = = = = = = = = = = = = = = = Take a bowl. Mix a pint of rich cream with 5 tablespoons of sugar and two teaspoons of vanilla sugar. Whip in an egg or two, and then add liquid nitrogen to fit. Stir vigorously until you can't. Guess what you get! :-) Best regards. Jostein http://oksne.net 2003-01-10 Outside of a dog, a book is man's best friend. Inside of a dog, it's too dark to read. --Groucho Marx
Re: Re: Can digital capture do TIME exposures?
Message text written by INTERNET:[EMAIL PROTECTED] Really I meant to ask what it had to do with photography, last time i heard they use it to break into safes and locks, and cut warts off too oh, all right. they refrigerate the digital sensor and the amplifiers to lower thermal noise. works best on a 6m telescope, however, those are the people able to afford liquid helium instead. Herb
Re: Can digital capture do TIME exposures?
http://www.skinsite.com/info_liquid_nitrogen.htm You could have done the google search yourself you know. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto - Original Message - From: Feroze Kistan [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 10, 2003 6:28 AM Subject: Re: Can digital capture do TIME exposures? What is the purpose of liquid nitrogen and where is it used? Feroze - Original Message - From: T Rittenhouse [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 10, 2003 1:50 AM Subject: Re: Can digital capture do TIME exposures? Yep, a little liquid nitrogen will do wonders. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto - Original Message - From: Jostein [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 09, 2003 11:40 AM Subject: Re: Can digital capture do TIME exposures? I think the ability to do long exposures depends on how much thermal noise the chip produces, and how well it can separate noise from signal. Dunno the current tech on any particular camera, but I know astro photographers have long embraced digital. However, I think their devices have some serious cooling systems.
Re: Re: Can digital capture do TIME exposures?
Oh, liguid helium, that's fun stuff. Hard to keep around though. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto - Original Message - From: Herb Chong [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 10, 2003 5:44 PM Subject: Re: Re: Can digital capture do TIME exposures? Message text written by INTERNET:[EMAIL PROTECTED] Really I meant to ask what it had to do with photography, last time i heard they use it to break into safes and locks, and cut warts off too oh, all right. they refrigerate the digital sensor and the amplifiers to lower thermal noise. works best on a 6m telescope, however, those are the people able to afford liquid helium instead. Herb
Re: Re: Can digital capture do TIME exposures?
It's used as a coolant in image capture devices. At 12:07 AM 1/11/2003 +0200, you wrote: Really I meant to ask what it had to do with photography, last time i heard they use it to break into safes and locks, and cut warts off too - Original Message - From: Peter Alling [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 10, 2003 9:12 PM Subject: Re: Re: Can digital capture do TIME exposures? Very fluffy ice cream? Except that Still vigorously until you can't might happen way to fast. At 08:05 PM 1/10/2003 +0100, you wrote: === At 2003-01-10, 13:28:00 Feroze wrote: === What is the purpose of liquid nitrogen and where is it used? = = = = = = = = = = = = = = = = = = = = Take a bowl. Mix a pint of rich cream with 5 tablespoons of sugar and two teaspoons of vanilla sugar. Whip in an egg or two, and then add liquid nitrogen to fit. Stir vigorously until you can't. Guess what you get! :-) Best regards. Jostein http://oksne.net 2003-01-10 Outside of a dog, a book is man's best friend. Inside of a dog, it's too dark to read. --Groucho Marx Outside of a dog, a book is man's best friend. Inside of a dog, it's too dark to read. --Groucho Marx
Re: Can digital capture do TIME exposures?
Message text written by INTERNET:[EMAIL PROTECTED] This is interesting! Since the silver halides respond to the cumulative effect of light, it is unlikely that the digital sensor would behave in a similar manner. I could be wrong, (and I have been before) but I believe that the different ISO speeds are achieved by processing the received signal/light. This result in ordinary images at higher ISO settings. Bob higher ISOs are achieved mostly by increasing the analog gain of the amplifiers. this leads to a lot of thermal noise. at least for consumer cameras, that also means hot spots as individual pixels may go very nonlinear. i have been thinking about writing a Photoshop filter to handle this type of noise where you get pure R, G, or B hot spots. they can be found because there is near no response in the other two channels at that position. Herb
Re: Can digital capture do TIME exposures?
On 9 Jan 2003 at 7:06, Herb Chong wrote: higher ISOs are achieved mostly by increasing the analog gain of the amplifiers. this leads to a lot of thermal noise. at least for consumer cameras, that also means hot spots as individual pixels may go very nonlinear. i have been thinking about writing a Photoshop filter to handle this type of noise where you get pure R, G, or B hot spots. they can be found because there is near no response in the other two channels at that position. The Oly E-20 provides for time exposures on bulb of up to 8 minutes however the results aren't too impressive if test sites are to be believed. See the following article for an interesting dissection of image noise vs ISO exposure time: http://www.wrotniak.net/photo/e10/e10-dark.html Also the following link is to a good utility for logging hot/dead pixels in images generated with any digital camera, the test text logs can be filed for later comparison in order to determine if the response of the sensor has changed over time, see: http://www.starzen.com/imaging/deadpixeltest.htm Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html
Re: Can digital capture do TIME exposures?
Rob Studdert wrote: = snipped = Also the following link is to a good utility for logging hot/dead pixels in images generated with any digital camera, the test text logs can be filed for later comparison in order to determine if the response of the sensor has changed over time, see: http://www.starzen.com/imaging/deadpixeltest.htm Thanks, Rob, however... for those to whom it matters, this utility is only good for Windows machines. ~ keith whaley Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html
Re: Can digital capture do TIME exposures?
I think the ability to do long exposures depends on how much thermal noise the chip produces, and how well it can separate noise from signal. Dunno the current tech on any particular camera, but I know astro photographers have long embraced digital. However, I think their devices have some serious cooling systems. -- Not that they need it much here, though... :-) Jostein (happy about the last two days' whiff of mild air; only minus ten now) - Original Message - From: J. C. O'Connell [EMAIL PROTECTED] To: Pentax Discuss Mailing List [EMAIL PROTECTED] Sent: Thursday, January 09, 2003 2:36 AM Subject: Can digital capture do TIME exposures? I was wondering, do any of the digital cameras on the market do time exposures? i.e. if the correct exposure is like 2 minutes at F11 ? If they can't, it seems like there will alway be niche for film no matter how good digital gets. JCO J.C. O'Connell mailto:[EMAIL PROTECTED] My Business references Websites: http://members.ebay.com/aboutme/jco/
Re: Can digital capture do TIME exposures?
Message text written by INTERNET:[EMAIL PROTECTED] Dunno the current tech on any particular camera, but I know astro photographers have long embraced digital. However, I think their devices have some serious cooling systems. -- Not that they need it much here, though... :-) Jostein liquid nitrogen is normal for astro photography. Herb
Re: Can digital capture do TIME exposures?
- Original Message - From: Herb Chong [EMAIL PROTECTED] liquid nitrogen is normal for astro photography. Uh... Cheers? ... :-) There are many amateurs who use modified web-cameras on their scopes... Jostein
Re: Can digital capture do TIME exposures?
Yep, a little liquid nitrogen will do wonders. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto - Original Message - From: Jostein [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 09, 2003 11:40 AM Subject: Re: Can digital capture do TIME exposures? I think the ability to do long exposures depends on how much thermal noise the chip produces, and how well it can separate noise from signal. Dunno the current tech on any particular camera, but I know astro photographers have long embraced digital. However, I think their devices have some serious cooling systems.
Re: Can digital capture do TIME exposures?
It can certainly be used to get rid of unsightly appendages. At 06:50 PM 1/9/2003 -0500, you wrote: Yep, a little liquid nitrogen will do wonders. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto - Original Message - From: Jostein [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, January 09, 2003 11:40 AM Subject: Re: Can digital capture do TIME exposures? I think the ability to do long exposures depends on how much thermal noise the chip produces, and how well it can separate noise from signal. Dunno the current tech on any particular camera, but I know astro photographers have long embraced digital. However, I think their devices have some serious cooling systems. Outside of a dog, a book is man's best friend. Inside of a dog, it's too dark to read. --Groucho Marx
Re: Can digital capture do TIME exposures?
My Dimage 7 poops out at 30 seconds. Jeff. J. C. O'Connell wrote: I was wondering, do any of the digital cameras on the market do time exposures? i.e. if the correct exposure is like 2 minutes at F11 ? If they can't, it seems like there will alway be niche for film no matter how good digital gets. JCO J.C. O'Connell mailto:[EMAIL PROTECTED] My Business references Websites: http://members.ebay.com/aboutme/jco/
Re: Can digital capture do TIME exposures?
--- J. C. O'Connell [EMAIL PROTECTED] wrote: I was wondering, do any of the digital cameras on the market do time exposures? i.e. if the correct exposure is like 2 minutes at F11 ? Enjoy: http://www.fredmiranda.com/1Ds_review/index_longexp.html Mark __ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com
RE: Can digital capture do TIME exposures?
JCO, I believe the Nikon D100 has a Bulb setting.. therfore.. it can go for .. well.. ever I guess Dave -Original Message- From: J. C. O'Connell [mailto:[EMAIL PROTECTED]] Sent: Wednesday, January 08, 2003 8:37 PM To: Pentax Discuss Mailing List Subject: Can digital capture do TIME exposures? I was wondering, do any of the digital cameras on the market do time exposures? i.e. if the correct exposure is like 2 minutes at F11 ? If they can't, it seems like there will alway be niche for film no matter how good digital gets. JCO J.C. O'Connell mailto:[EMAIL PROTECTED] My Business references Websites: http://members.ebay.com/aboutme/jco/
RE: Can digital capture do TIME exposures?
Or until it runs out of juice. At 11:04 PM 1/8/2003 -0500, you wrote: JCO, I believe the Nikon D100 has a Bulb setting.. therfore.. it can go for .. well.. ever I guess Dave -Original Message- From: J. C. O'Connell [mailto:[EMAIL PROTECTED]] Sent: Wednesday, January 08, 2003 8:37 PM To: Pentax Discuss Mailing List Subject: Can digital capture do TIME exposures? I was wondering, do any of the digital cameras on the market do time exposures? i.e. if the correct exposure is like 2 minutes at F11 ? If they can't, it seems like there will alway be niche for film no matter how good digital gets. JCO J.C. O'Connell mailto:[EMAIL PROTECTED] My Business references Websites: http://members.ebay.com/aboutme/jco/ Outside of a dog, a book is man's best friend. Inside of a dog, it's too dark to read. --Groucho Marx
