lucasledge
Active member
Thanks for that, I did read that about an hour ago, but the thing is I'm not after 10 minute exposures or anything like that, I'm after exposures lasting at least 45 minutes.
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Long exposures/ Amp Glow
- Thread starter lucasledge
- Start date
Kluso
Senior Member
Ok, I am curious, what is it that requires 2+ hour exposure?
If humidity is low in the place you are trying to do 2 hour exposures, you could place a D300 in a cool box [one of those small car refrigerators for example, you would need a very big battery or the car engine running] with just the front of the lens poking out, of course if there is humidity present then you will get condensation on the lens or filter surface.
I notice you want a shutter speed longer than 30 minutes, just buy a corded remote and time it, 2 hours can be timed on the cheapest alarm clock, your cell phone etc, corded remotes can be locked in bulb mode until you are ready to release them.
There is a corded remote for the D300 that has a built in timer with an LCD display.
--
Inspector Kluso
lucasledge
Active member
Thanks.Just keep in mind that you will get noise in warm weather, like maybeOk that's good, cheers, I'm going to Jordan next week, I hope theThe D300 has no Amp Glow, period. When taking long exposures (several
minutes long, during warm weather the chroma noise start to get up
there. If you take pictures during cold weather 40 deg. F you should
not have problems, the low noise is amazing. Once you hit room
temperature it takes a turn, not so nice but you can use LENR or NR
software to cut it down, The alternative is to stack images of
shorter exposure, which should yeild excellent results. You can do
this in layers or in free or inexpensive astronomical imaging
software. See the below links.
http://www.astrosurf.com/buil/us/iris/iris.htm
http://www.astrostack.com/
--
Stan ;o()
In the spirit of Occam’s Razor one should embrace the less
complicated formulation or simply put, less is more.
nights aren't too warm.
So the D300 has no amp glow at all and the exposure can be several
hours long if I want it to be? Great.
in Jordan. Is there a reason that you will need to take exposures
that are several minutes long? Remember that stacking solution. Enjoy
the trip
--
Stan ;o()
In the spirit of Occam’s Razor one should embrace the less
complicated formulation or simply put, less is more.
Yeah the exposures will be long because the stars will be so much brighter in the desert than in the UK where there is A LOT light polution. So I could do the stacking thing, but without LENR, I'll have to do it every 15 minutes or soemthing though because the D80 is very prone to amp glow.I'll be in the desert in Jordan and it get's cold at night in the desert so it should..... be ok.
Thomas Comerford
Veteran Member
Some of the samples in this thread were 110 minutes:
http://forums.dpreview.com/forums/read.asp?forum=1039&message=27093023
You may also want to invest in a vertical grip, so that you have enough battery power for an exposure that long.
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http://www.pixelfixer.org
lucasledge
Active member
I want to get the light trails of the stars as the Earth rotates.
Is it impossible to have an exposure longer than 30 minutes on the D80 even with a corded remote? (I have a wireless one currently)
Or are you saying if I get a D300 I should get a corded remote with that so I can have very long exposures?
Kluso
Senior Member
The 30 minute limitation is caused by the wireless remote, there is no limitation with a corded remote on D80.
Yes if you get a D300
By the way stacking D80 photos to avoid amp glow is NOT going to work as the amp glow with be added up in the resulting final image, doing a lens cap on exposure of the same exposure time [after allowing the sensor and camera to cool down] then subtracting that lens cap photo from your real photo should solve the problem.
--
Inspector Kluso
lucasledge
Active member
Sorry mate could you explain what you mean here please.
'doing a les cap on exposire'? Not something I've heard before.
Kluso
Senior Member
D80 with NR on for say 30 minutes.
Exposure = 30 minutes.
Dark frame taken by NR is only about 15 minutes
that is half the time of the actual exposure so it does not fully compensate for amp glow.
A dark frame exposure of equal time, 30 minutes in this example would be better.
Way to achieve that is
Take a 30 minute exposure with no NR
wait for the D80 and sensor to cool down.
Place the lens cap on the camera and take a 30 minute exposure.
Use the iris astro software links to which have been supplied in replies to your questions, use that software to subtract the 30 minute lens cap on [dark frame] exposure form your 30 minute exposure, that should remove all noise caused by the sensor including amp glow.
You only need to do one 30 minute exposure with lens cap on and you can use it for all photos shot with 30 minutes exposure at that particular ambient temperarure.
If ambient temperature changes you will need another lens cap on image to do the subtraction with.
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Inspector Kluso
Kluso
Senior Member
Read the information at the links supplied in this reply to your question earlier
http://forums.dpreview.com/forums/read.asp?forum=1034&message=24224112
which was this link
http://www.fotocanada.ca/Articles/By%20Andrew.html
do read part 1 and part 2
--
Inspector Kluso
You could always take your own darkframe (with lens cap on) before your sequence of images as long as the exposure times are the same and subtract it manually (layers) or use a stacker. Unfortunately LENR and stacking star trails just isn't going to work, besides you don't want to be freezing yhour butt off in the desert for every darkframe exposure.Thanks.Just keep in mind that you will get noise in warm weather, like maybeOk that's good, cheers, I'm going to Jordan next week, I hope theThe D300 has no Amp Glow, period. When taking long exposures (several
minutes long, during warm weather the chroma noise start to get up
there. If you take pictures during cold weather 40 deg. F you should
not have problems, the low noise is amazing. Once you hit room
temperature it takes a turn, not so nice but you can use LENR or NR
software to cut it down, The alternative is to stack images of
shorter exposure, which should yeild excellent results. You can do
this in layers or in free or inexpensive astronomical imaging
software. See the below links.
http://www.astrosurf.com/buil/us/iris/iris.htm
http://www.astrostack.com/
--
Stan ;o()
In the spirit of Occam’s Razor one should embrace the less
complicated formulation or simply put, less is more.
nights aren't too warm.
So the D300 has no amp glow at all and the exposure can be several
hours long if I want it to be? Great.
in Jordan. Is there a reason that you will need to take exposures
that are several minutes long? Remember that stacking solution. Enjoy
the trip
--
Stan ;o()
In the spirit of Occam’s Razor one should embrace the less
complicated formulation or simply put, less is more.
so much brighter in the desert than in the UK where there is A LOT
light polution. So I could do the stacking thing, but without LENR,
I'll have to do it every 15 minutes or soemthing though because the
D80 is very prone to amp glow.
I'll be in the desert in Jordan and it get's cold at night in the
desert so it should..... be ok.
--
Stan ;o()
In the spirit of Occam’s Razor one should embrace the less complicated formulation or simply put, less is more.
Daniel
Senior Member
...that amp noise generated during a 10 minute exposure would diminish during a 45 minute exposure! In other words, if Thom finds that there is a problem with 10 minute exposures, I wouldn't trust those who say that there is none at 45 minutes.
Daniel
Daniel
Jake Loves Good Glass
Senior Member
But what are you shooting that requires these long exposures?
--
Wow...that's a pretty killer camera! Are you any good?
-Jake-
--
Wow...that's a pretty killer camera! Are you any good?
-Jake-
I'm not a D80 expert, but I can't believe that the D80 would have a 30-minute limit on bulb! There must be something that YOU are doing wrong. Perhaps that remote (not remote release) thingie is confusing you?
You probably used the NR instead of the LENR. LENR makes a BIG difference. But you have to understand a few things. If you figure out how to keep the shutter open for 2+ hours, you will ALSO have to go away and let the camera do the dark-frame-subtraction, which will take another 2+ hours. If you interupt the camera during this LENR phase, it doesn't do any NR!
The bulb works just like your D80...it will stay open as long as it has battery left! The D300 has great battery life. The D80 might run out?
I have never seen amp glow in my D300 pix. There WAS a firmware boo-boo, that got fixed...it produced vertical colored stripes with specific camera settings. Unless you either cool the camera below 0 degrees F or use LENR, you WILL see some chroma noise.
Since I don't have any amp glow, I may be wrong about this, but I believe that ANYTHING that is NOT in the scene photographed AND that is constant, will be subtracted by LENR.
--
Charlie Davis
Nikon 5700, Sony R1, Nikon D300
HomePage: http://www.1derful.info
Bridge Blog: http://www.here-ugo.com/BridgeBlog/
'Experience: Discovering that a claw hammer will bend nails.
Epiphany: Discovering that a claw hammer is two tools...'
There is no discernable amp glow on my D300 up to 30 minutes.
Chroma noise becomes unbearable beyond that at cold temperatures, and considerably worse at warmer temperatures.
LENR removes a lot of that noise, but it removes faint stars, too. Dark frame subtraction is a better way to deal with the noise.
Shorter exposures, stacked is the way to go.
Trust me, I am struggling to make a decent astro-camera out of the D300, but I think I'll be ending up with a used 20D, modded for better IR. The Nikons just don't see what the Canon sensors do, and a lab in Japan claims that at ISOs above 800, that even in RAW the D300 applies some noise reduction, otherwise known as star reduction even when all NR is turned OFF.
I love my D300 and my collection of Nikon glass, but astro photography is not its strong point.
Jeff
Chroma noise becomes unbearable beyond that at cold temperatures, and considerably worse at warmer temperatures.
LENR removes a lot of that noise, but it removes faint stars, too. Dark frame subtraction is a better way to deal with the noise.
Shorter exposures, stacked is the way to go.
Trust me, I am struggling to make a decent astro-camera out of the D300, but I think I'll be ending up with a used 20D, modded for better IR. The Nikons just don't see what the Canon sensors do, and a lab in Japan claims that at ISOs above 800, that even in RAW the D300 applies some noise reduction, otherwise known as star reduction even when all NR is turned OFF.
I love my D300 and my collection of Nikon glass, but astro photography is not its strong point.
Jeff
Timkat
Leading Member
My D300 was a bad one. So my comments until the new body arrives are obviously skewed.
What we did find out was how poorly the D300 performs at temperatures above 10 degrees C in exposures longer than 10 minutes. Below zero and its excellent!
It does seem to perform quite reasonably at no more than 5 minutes at ISO100 around the 24 degree c mark. (NOT using LENR) No good at ISO 200 unless LENR is used.
Amp glow can be pulled out of the image using severe post processing. But in real world images amp glow is no issue.
Its an extraordinary camera, of that there is no doubt at all. But an astro camera it is not.
I am itching to get my new body and will report back when it arrives.
What we did find out was how poorly the D300 performs at temperatures above 10 degrees C in exposures longer than 10 minutes. Below zero and its excellent!
It does seem to perform quite reasonably at no more than 5 minutes at ISO100 around the 24 degree c mark. (NOT using LENR) No good at ISO 200 unless LENR is used.
Amp glow can be pulled out of the image using severe post processing. But in real world images amp glow is no issue.
Its an extraordinary camera, of that there is no doubt at all. But an astro camera it is not.
I am itching to get my new body and will report back when it arrives.
DuncanM1
Leading Member
The D40/40x/50/70/70s/80 have a 30min limit with the IR remote;
The D80 LENR only does a dark frame of 1/2 the exposure duration, which naturally will not remove all the amp glow.
UFRAW has a dark frame subtraction feature, which makes subtracting a dark frame (2nd image of same duration as the first, but with the lens capped), quite easy. UFRAW is free, and you can get it here:
http://ufraw.sourceforge.net/Install.html
If you have a D80 make sure you are using the lastest firmware, as some D80s will benefit greatly with the latest firmware, which has a fix for excessive ampglow.
DuncanM1 wrote:
:
--
Stan ;o()
In the spirit of Occam’s Razor one should embrace the less complicated formulation or simply put, less is more.
:
You should check up, but the darkframe exposure time should be the same as the image exposure time which is shown on the shutterspeed indicator.
--
Stan ;o()
In the spirit of Occam’s Razor one should embrace the less complicated formulation or simply put, less is more.
Good information. I said that I didn't know diddly about a D80. Both those "features" of the D80 make me glad I didn't get one. ;-)
The OP should get a proper Phottix Cleon wireless remote that supports long bulb exposures.
Charlie Davis
Nikon 5700, Sony R1, Nikon D300
HomePage: http://www.1derful.info
Bridge Blog: http://www.here-ugo.com/BridgeBlog/
'Experience: Discovering that a claw hammer will bend nails.
Epiphany: Discovering that a claw hammer is two tools...'
The OP should get a proper Phottix Cleon wireless remote that supports long bulb exposures.
--
Charlie Davis
Nikon 5700, Sony R1, Nikon D300
HomePage: http://www.1derful.info
Bridge Blog: http://www.here-ugo.com/BridgeBlog/
'Experience: Discovering that a claw hammer will bend nails.
Epiphany: Discovering that a claw hammer is two tools...'
Hmmm... LENR is DFS. Perhaps you meant something else?
Yes, I think that's true.
True.
--
Charlie Davis
Nikon 5700, Sony R1, Nikon D300
HomePage: http://www.1derful.info
Bridge Blog: http://www.here-ugo.com/BridgeBlog/
'Experience: Discovering that a claw hammer will bend nails.
Epiphany: Discovering that a claw hammer is two tools...'
Trond N
Veteran Member
One of the reasons (among others) I bought the D300 is the capability for long (past 30 min) exposures (guess we're in the same game ). My previous D70 had the same 30 minutes limit which I found, well, limiting ;-) The D70 had terrible amp glow and hot pixel noise, but the LENR (long exposure noise reduction) did a great job at neutralizing it.
After a few attempts at long exposures with the D300 I'm very impressed. I've made a few shots at about an hour, and with LENR on there no visible amp glow. I have yet to try really long exposures without LENR so can't say whether amp glow is an issue or not. Reviews I've read say it is better than the D200 though.
Hopefully I get around to try REALLY long exposures (twho hours or more)sometimes during Easter, if weather permit ;-) Also I'll try without LENR to see how good it really is.
I should mention I'll use a battery grip or AC-adapter for the extremely long shots to avoid running out of power.
--
TrondN 'The Frozen Viking'
Equipment list in profile.
http://www.home.no/trond-nordland
Comments, criticism and suggestions always appreciated.
). My previous D70 had the same 30 minutes limit which I found, well, limiting ;-) The D70 had terrible amp glow and hot pixel noise, but the LENR (long exposure noise reduction) did a great job at neutralizing it.After a few attempts at long exposures with the D300 I'm very impressed. I've made a few shots at about an hour, and with LENR on there no visible amp glow. I have yet to try really long exposures without LENR so can't say whether amp glow is an issue or not. Reviews I've read say it is better than the D200 though.
Hopefully I get around to try REALLY long exposures (twho hours or more)sometimes during Easter, if weather permit ;-) Also I'll try without LENR to see how good it really is.
I should mention I'll use a battery grip or AC-adapter for the extremely long shots to avoid running out of power.
--
TrondN 'The Frozen Viking'
Equipment list in profile.
http://www.home.no/trond-nordland
Comments, criticism and suggestions always appreciated.
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