Even though we ARE Nikon lovers,we are NOT affiliated with Nikon Corp. in any way.

English German French

Sign up Login
Home Forums Articles Galleries Recent Photos Contest Help Search News Workshops Shop Upgrade Membership Recommended
members
All members Wiki Contests Vouchers Apps Newsletter THE NIKONIAN™ Magazines Podcasts Fundraising

Long Exposure Noise Reduction

helmdr

Houston, US
297 posts

Click to send email to this author Click to send private message to this author
helmdr Registered since 08th Nov 2012
Tue 25-Jun-13 05:32 PM

I primarily do landscape and some night photography (skylines,etc). On the night exposures I have anywehere from 2 to 30 second exposures. I currently have my D800 Long Exposure NR set to off and take care of any noise in PP.

Is this how most do it, or does anyone use the camera noise reduction?

Would appreciate your opinions on this. thanks

Visit my Nikonians gallery.

danshep

Olympia, US
1629 posts

Click to send email to this author Click to send private message to this author

#1. "RE: Long Exposure Noise Reduction" | In response to Reply # 0

danshep Gold Member Charter Member
Tue 25-Jun-13 06:06 PM


I've read somewhere, that it is better NOT to use NR on the camera.

I do mine thru Lightroom 5, or Photoshop.



"Today is the tomorrow that yesterday you spent money like there was no"

Visit my Nikonians gallery.

JosephK

Seattle, WA, US
7108 posts

Click to send email to this author Click to send private message to this author

#2. "RE: Long Exposure Noise Reduction" | In response to Reply # 0

JosephK Silver Member Fellow Ribbon awarded for his excellent and frequent contributions and sharing his in-depth knowledge and experience with the community in the Nikonians spirit. Nikonian since 17th Apr 2006
Tue 25-Jun-13 06:33 PM

Standard noise reduction and Long-Exposure Noise Reduction are two different things.

Standard noise reduction (fixing shadow discoloration) is often best done in post-processing with your bigger computer and better software.

Long-exposure noise reduction is about removing hot pixels and removing sensor bloom or other discoloration due to sensor heat caused by long exposures. The camera does this by taking a "black" image of the same time duration and comparing this supposedly black result with your original picture. This is not easily fixed in post-processing.

---------+---------+---------+---------+---------+
Joseph K
Seattle, WA, USA

D700, D200, D70S, 24-70mm f/2.8, VR 70-200mm f/2.8 II,
50mm f/1.4 D, 70-300mm f/4.5-5.6 VR, 18-70mm f/3.5-4.5 DX

K64drb

Blacksburg, US
324 posts

Click to send email to this author Click to send private message to this author

#3. "RE: Long Exposure Noise Reduction" | In response to Reply # 0

K64drb Silver Member Nikonian since 18th Feb 2012
Tue 25-Jun-13 07:05 PM

Joseph is correct - two different things. I keep LENR set to On all the time. Also, keeping the ISO as low as possible is is very helpful in minimizing the amount of general noise you will have with night skies, even though that forces longer exposures. I try to keep it at 100 if possible.

Dave Badger
Blacksburg, VA
My Nikonians gallery, or visit www.AlternateViewsPhotography.com .

"You don't quit playing because you grow old; you grow old because you quit playing."

helmdr

Houston, US
297 posts

Click to send email to this author Click to send private message to this author

#4. "RE: Long Exposure Noise Reduction" | In response to Reply # 3

helmdr Registered since 08th Nov 2012
Wed 26-Jun-13 03:53 AM

Ok Makes sense and thanks. My question is now, when does LENR kick in? 10 sec, 20 sec, ? I see in the recmrnded settings by Moose Peterson, he keeps the LENR off. Are there consequenses of keeping LENR on for all exposures?

Visit my Nikonians gallery.

JosephK

Seattle, WA, US
7108 posts

Click to send email to this author Click to send private message to this author

#5. "RE: Long Exposure Noise Reduction" | In response to Reply # 4

JosephK Silver Member Fellow Ribbon awarded for his excellent and frequent contributions and sharing his in-depth knowledge and experience with the community in the Nikonians spirit. Nikonian since 17th Apr 2006
Wed 26-Jun-13 05:19 AM

Page 277 of the D800 manual says LENR starts at 1 second when on.

I normally have it turned off, so I cannot speak to leaving it on all the time.

---------+---------+---------+---------+---------+
Joseph K
Seattle, WA, USA

D700, D200, D70S, 24-70mm f/2.8, VR 70-200mm f/2.8 II,
50mm f/1.4 D, 70-300mm f/4.5-5.6 VR, 18-70mm f/3.5-4.5 DX

Gromit44

UK
730 posts

Click to send email to this author Click to send private message to this author

#6. "RE: Long Exposure Noise Reduction" | In response to Reply # 4

Gromit44 Registered since 04th Jan 2012
Wed 26-Jun-13 09:31 AM

>I see in the recmrnded settings by Moose Peterson, he keeps the LENR off.

Does he say why he keeps it off?

gpoole

Farmington Hills, US
4130 posts

Click to send email to this author Click to send private message to this author

#7. "RE: Long Exposure Noise Reduction" | In response to Reply # 4

gpoole Platinum Member Fellow Ribbon awarded for his excellent and frequent contributions and sharing his in-depth knowledge and experience with the community in the Nikonians spirit. Awarded for his very generous support to the Fundrasing Campaing 2014 Writer Ribbon awarded for his article contributions for the Articles library and the eZine Nikonian since 14th Feb 2004
Wed 26-Jun-13 11:34 AM

IMO the only negative consequence of leaving LENR on is the effective doubling of exposure time, If you can tolerate the extra time for the dark frame then leave it on. On the positive side, it could improve your image.

Gary in SE Michigan, USA.
Nikonians membership - My most important photographic investment, after the camera.
D4, D810, D300 (720nm IR conversion), D90, F6, FM3a (black), FM2n (chrome)
YashicaMat 124, Graflex Speed Graphic 4x5
My Nikonians Gallery & Our Chapter Gallery

Ferguson

Cape Coral, US
5751 posts

Click to send email to this author Click to send private message to this author

#8. "RE: Long Exposure Noise Reduction" | In response to Reply # 0

Ferguson Silver Member Fellow Ribbon awarded for the generous sharing of his high level expertise in the spirit of Nikonians Nikonian since 19th Aug 2004
Wed 26-Jun-13 12:41 PM

My suggestion - leave Long Exposure Noise Reduction on. Other than the delay (as mentioned), there's no downside, all upside.

And contrary to a lot of notes elsewhere -- it DOES affect raw image data. High ISO Noise reduction does not affect raw image data.

The one oddball case where you would not is if you, yourself, are going to take a dark frame and subtract. You might do that (for example) if you were going to make 10 long exposures of the same duration in a row, and didn't want to wait between them. You would then make a single dark frame (lens covered) first, shoot the 10, and subtract in post processing. That's 11 exposures as opposed to the equivalent of 20 (one for each light) the camera would do. But this only works if the one frame is at the same settings, and same temperature, as the rest.

Dark frames are a normal part of astrophotography. They can be VERY effective in removing light haze from thermal noise and hot pixels. There are also bias and flat frames used there, which are not exactly used in DSLR (though a bias frame and the dust-off reference photo are not all that different).

Here's a good discussion from the astro viewpoint: http://www.astrophotography.id.au/lights-darks-and-other-frames/



Linwood

Comments welcomed on pictures: Http://www.captivephotons.com

dm1dave

Lowden, US
13741 posts

Click to send email to this author Click to send private message to this author

#9. "RE: Long Exposure Noise Reduction" | In response to Reply # 4

dm1dave Administrator Awarded for high level knowledge and skills in various areas, most notably in Wildlife and Landscape Writer Ribbon awarded for his excellent article contributions to the Nikonians community Donor Ribbon awarded for his very generous support to the Fundraising Campaign 2015 Nikonian since 12th Sep 2006
Wed 26-Jun-13 06:19 PM

If you shoot in CH mode and need to maximize your FPS rate Long Exposure Noise Reduction should be turned off.

Dave Summers
Nikonians Photo Contest Director
My Nikonians Gallery | Current Nikonians Contests

Click on image to view larger version

Ferguson

Cape Coral, US
5751 posts

Click to send email to this author Click to send private message to this author

#10. "RE: Long Exposure Noise Reduction" | In response to Reply # 9

Ferguson Silver Member Fellow Ribbon awarded for the generous sharing of his high level expertise in the spirit of Nikonians Nikonian since 19th Aug 2004
Wed 26-Jun-13 06:26 PM

>If you shoot in CH mode and need to maximize your FPS rate
>Long Exposure Noise Reduction should be turned off.

I thought it didn't kick in for under 1s exposures?

Linwood

Comments welcomed on pictures: Http://www.captivephotons.com

cpopescu

BUcharest, RO
120 posts

Click to send email to this author Click to send private message to this author

#11. "RE: Long Exposure Noise Reduction" | In response to Reply # 8

cpopescu Gold Member Nikonian since 14th Apr 2011
Wed 26-Jun-13 06:38 PM

Very interesting and educative discussion.

Is it a way to bookmark/tag the topics that are of interest for an user in his profile so that she/he can easily go back to them?

I've noticed that one can subscribe to a topic once you write something, but subscription is different from tagging.

Thanks,

Catalin

Visit my Nikonians gallery.

dm1dave

Lowden, US
13741 posts

Click to send email to this author Click to send private message to this author

#12. "RE: Long Exposure Noise Reduction" | In response to Reply # 10

dm1dave Administrator Awarded for high level knowledge and skills in various areas, most notably in Wildlife and Landscape Writer Ribbon awarded for his excellent article contributions to the Nikonians community Donor Ribbon awarded for his very generous support to the Fundraising Campaign 2015 Nikonian since 12th Sep 2006
Wed 26-Jun-13 07:23 PM

You are correct but for some reason it is one of the settings that can cause the frame rate to slow below the maximum. Active D-Lighting has the same affect.

Now, I haven’t tested this with my D800 but I have on earlier Nikon bodies.

Dave Summers
Nikonians Photo Contest Director
My Nikonians Gallery | Current Nikonians Contests

Click on image to view larger version

Ferguson

Cape Coral, US
5751 posts

Click to send email to this author Click to send private message to this author

#13. "RE: Long Exposure Noise Reduction" | In response to Reply # 12

Ferguson Silver Member Fellow Ribbon awarded for the generous sharing of his high level expertise in the spirit of Nikonians Nikonian since 19th Aug 2004
Wed 26-Jun-13 08:09 PM

>You are correct but for some reason it is one of the settings
>that can cause the frame rate to slow below the maximum.
>Active D-Lighting has the same affect.
>
>Now, I haven’t tested this with my D800 but I have on earlier
>Nikon bodies.

I'm travelling for a week so I cannot either. I know High ISO noise reduction is reported to slow things down, I had never heard that for low.

Speaking of older bodies, the D300 had an oddity as well, it's dark exposure was not the same length as the light, so you might do a 20 second exposure, and the NR job ran for maybe 10 (I made that up -- but shorter; strange; when I tried the D800 it was the same length).

And Auto-ISO is suppose to potentially affect frame rate, though I've never understood why, as it is supposed to shoot at full speed with auto-exposure, and that to me are auto-exposure also.

Someone try it!


Linwood

Comments welcomed on pictures: Http://www.captivephotons.com

jamesvoortman

Durban, ZA
1479 posts

Click to send email to this author Click to send private message to this author

#14. "RE: Long Exposure Noise Reduction" | In response to Reply # 2

jamesvoortman Silver Member Nikonian since 06th Sep 2004
Thu 27-Jun-13 02:21 PM

LENR basically takes a second exposure of same length with the shutter closed to pick up any small inaccuracies in the sensor under dark conditions. These are then "subtracted" from the original exposure.

If you use, for example, a 30 sec exposure time then the camera takes a second "black" 30 sec exposure after the shutter closes to capture the background inaccuracies. your camera will appear to be non-responsive during this time. so be aware that when shooting a series of shots or using time lapse, the period of time between successive exposures needs to be more than twice the actual exposure time.

I have LENR enabled only in the long exposure/tripod menu bank of my settings. It is pointless to use it in normal shooting. As far as I know it is only activated when the shutter speed exceeds a certain time threshold - the manual will detail any restrictions.

Normal noise reduction carried out in-camera is different. It can be replaced with aftermarket software or enhanced and adjusted by using the "high quality" NR options in Nikon's Capture NX2 software (my preferred option because it gives a lot of options and fits seamlessly into my normal NX2 workflow.

Visit my Nikonians gallery.

Visit

richardd300

Dyserth, UK
4560 posts

Click to send email to this author Click to send private message to this author

#15. "RE: Long Exposure Noise Reduction" | In response to Reply # 11

richardd300 Silver Member Nikonian since 19th Apr 2009
Thu 27-Jun-13 07:50 PM

I take exposures between 30 and 120 seconds with ND 10 and 6 stop filters. I certainly do use the long exposure noise reduction, especially important on really long exposures. Mind you I get very bored of waiting for the routine to run

Richard

Visit my Nikonians gallery

Visit my website www.pixels4u.co.uk
The important thing is not to stop questioning. Curiosity has its own reason for existing. Einstein

helmdr

Houston, US
297 posts

Click to send email to this author Click to send private message to this author

#16. "RE: Long Exposure Noise Reduction" | In response to Reply # 15

helmdr Registered since 08th Nov 2012
Wed 03-Jul-13 11:27 AM

I want to thank everyone for their comments. I have turned LENR back on.

thanks again

Dennis

Visit my Nikonians gallery.

ajdooley

Waterloo, US
3378 posts

Click to send email to this author Click to send private message to this author

#17. "RE: Long Exposure Noise Reduction" | In response to Reply # 0

ajdooley Gold Member Nikonian since 25th May 2006
Wed 03-Jul-13 09:17 PM

This thread and others of its ilk are top reasons to be part of Nikonians and to support the group. I know of nowhere else to find similar fully supported opinions that have no profit motive nor ego connected with them. My advice to new Nikon users is to buy a camera and to join Nikonians -- simultaneously. It's cheap tuition!

Alan
Waterloo, IL, USA
www.proimagingmidamerica.com

Visit my Nikonians gallery.

Ferguson

Cape Coral, US
5751 posts

Click to send email to this author Click to send private message to this author

#18. "RE: Long Exposure Noise Reduction" | In response to Reply # 0

Ferguson Silver Member Fellow Ribbon awarded for the generous sharing of his high level expertise in the spirit of Nikonians Nikonian since 19th Aug 2004
Thu 04-Jul-13 04:14 PM | edited Thu 04-Jul-13 04:16 PM by Ferguson

Well, I found the first place I needed to turn off LENR. Fireworks. The displays are too short to let each shot be separated by a gap of the same length.

I was shooting at 5 seconds before turning it off, and went back to see if I could tell the difference. I found two shots with the same exposure and same area. I zeroed the post processing, then added 2 stops of exposure noise, and looked on the upwind size (no smoke haze) for dark sky.

There's NO visible difference when the fireworks are properly exposed, but by highlighting the exposure you can see a background glow that is a bit brighter on the right. Just a bit.

That's only 5 seconds. I would definitely say the LENR is doing little good in this case, especially for something like fireworks where the bright is so overwhelming. But it's there.

Thought it may be worth mentioning since tonight is the 4th -- I'd suggest OFF for the fireworks then if you want to get twice as many shots!

Click on image to view larger version



Linwood

PS/EDIT: Don't look at the foreground and colors, the light from the fireworks in the two shots are very different. The black sky is behind and there was no visible haze, so that's pretty much not affected by the rockets at that moment.


Comments welcomed on pictures: Http://www.captivephotons.com


Attachment#1 (jpg file)

K64drb

Blacksburg, US
324 posts

Click to send email to this author Click to send private message to this author

#19. "RE: Long Exposure Noise Reduction" | In response to Reply # 0

K64drb Silver Member Nikonian since 18th Feb 2012
Fri 05-Jul-13 12:37 AM | edited Fri 05-Jul-13 12:39 AM by K64drb

Well, I can echo what Linwood said to definitely turn OFF LENR when shooting fireworks. No time to wait on that thing when you're trying to grab as many shots as you can in such a short time-frame.

Dave Badger
Blacksburg, VA
My Nikonians gallery, or visit www.AlternateViewsPhotography.com .

"You don't quit playing because you grow old; you grow old because you quit playing."

helmdr

Houston, US
297 posts

Click to send email to this author Click to send private message to this author

#20. "RE: Long Exposure Noise Reduction" | In response to Reply # 19

helmdr Registered since 08th Nov 2012
Fri 05-Jul-13 11:32 AM

I can echo what Alan has stated. I joined Nikonians while waiting for my D800 which was my first full frame DSLR and first Nikon. I have learned a lot from these great forums. Probably the most important is that I take time to contemplate and prepare each time I go our for a shoot. I think about the type of shooting that I will be doing and trying to prepare and make some settings prior to every leaving the house. I also try to make a note of what to check before every snaping the picture.

Visit my Nikonians gallery.

Mako

US
75 posts

Click to send email to this author Click to send private message to this author

#21. "RE: Long Exposure Noise Reduction" | In response to Reply # 20

Mako Registered since 02nd Apr 2009
Fri 12-Jul-13 05:00 PM | edited Fri 12-Jul-13 05:28 PM by Mako

Mastering the Nikon D800 written by fellow Nikonian Darrell Young addresses this topic quite well. I highly recommend his book.

Darrell likes to keep LENR set to ON, unless shooting "action" or "sports" because LENR can effect continuous shooting frame rate. I consider fireworks action so I think his recommendation corroborates the other posts.

His book also covers High ISO NR and its' three settings: Low/Med/High.

I echo, echo helmer and Alan, regarding the value of the Nikonian forum AND add to that Darrell Young's Mastering the Nikon D800, which I found more useful than the orginal manual.

Geo

ericbowles

Atlanta, US
10633 posts

Click to send email to this author Click to send private message to this author

#22. "RE: Long Exposure Noise Reduction" | In response to Reply # 0

ericbowles Moderator Awarded for his in-depth knowledge and high level skills in various areas, especially Landscape and Wildlife Photoghraphy Writer Ribbon awarded for for his article contributions to the community Donor Ribbon awarded for his very generous support to the Fundraising Campaign 2015 Nikonian since 25th Nov 2005
Fri 12-Jul-13 06:49 PM

Great comments here - right on target about the value of LENR.

I had the same experience with fireworks. I like an 8 second exposure timed with launch, and LENR caused me to miss some nice cycles of fireworks. LENR does not work when you need short duration between images.

Another place to be careful about LENR is with multiple exposure images. I often use multiple exposures in lieu of long exposures. For example, with moving water I might use a series of 5-7 two second exposures rather than one 30 second exposure. The time between exposures for LENR to work can reduce the smoothness of the multi-exposure image.

This also applies to interval imaging of any type when the exposure is more than 1 second.

Another place to avoid LENR is with star trails. There are two types of star images - short images to capture stars as dots (typically under 30 seconds using the 500 divided by focal length formula), and long star trails with an exposure of an hour or more. With the former, LENR is fine. But with star trails, you would have to wait an hour or more for the LENR black frame image. In some cases you might have 3 hour images - completely unacceptable for a second frame as battery life becomes an issue.



Eric Bowles
Nikonians Team
My Gallery
Fall Workshops - Golf Photography at the Tour Championship and Fall Color in the Smokies

Nikonians membership — my most important photographic investment, after the camera

Mako

US
75 posts

Click to send email to this author Click to send private message to this author

#23. "RE: Long Exposure Noise Reduction" | In response to Reply # 22

Mako Registered since 02nd Apr 2009
Fri 12-Jul-13 07:20 PM | edited Fri 12-Jul-13 07:21 PM by Mako

>Another place to be careful about LENR is with multiple
>exposure images. I often use multiple exposures in lieu of
>long exposures. For example, with moving water I might use a
>series of 5-7 two second exposures rather than one 30 second
>exposure. The time between exposures for LENR to work can
>reduce the smoothness of the multi-exposure image.
>
>Eric Bowles

Hi Eric - I haven't heard of this very interesting technique for water. So am I correct in understanding that you are selectively blending multiple 2 sec water exposures to create one image with smooth looking water surface that also has texture (as opposed to water that looks completely smooth and almost featureless as a 30 sec exposure might produce)?

ericbowles

Atlanta, US
10633 posts

Click to send email to this author Click to send private message to this author

#24. "RE: Long Exposure Noise Reduction" | In response to Reply # 23

ericbowles Moderator Awarded for his in-depth knowledge and high level skills in various areas, especially Landscape and Wildlife Photoghraphy Writer Ribbon awarded for for his article contributions to the community Donor Ribbon awarded for his very generous support to the Fundraising Campaign 2015 Nikonian since 25th Nov 2005
Fri 12-Jul-13 07:48 PM

<So am I correct in understanding that you are selectively blending multiple 2 sec water exposures to create one image with smooth looking water surface that also has texture (as opposed to water that looks completely smooth and almost featureless as a 30 sec exposure might produce)?>

Yes - that is exactly right. It's all done in camera and produces a single NEF. It's an easy way to simulate the effect of a strong ND filter. The effect takes advantage of the fact that there is motion between frames, so the combination of multiple exposures works very well. I've used this with the D300, D800, etc.

For water, I think the better effects are with exposures of 1 second or longer. Seven exposures of 1/100 sec still look choppy. Seven exposures of 2-3 seconds looks like an exposure of 30-60 seconds - about double the cumulative actual exposure time or more.

I still prefer a ND filter and use the Vari N Duo, but this is a good workaround when I am just carrying a CP, or when the VND does not create a long enough exposure without going to an extreme.

Eric Bowles
Nikonians Team
My Gallery
Fall Workshops - Golf Photography at the Tour Championship and Fall Color in the Smokies

Nikonians membership — my most important photographic investment, after the camera

Mako

US
75 posts

Click to send email to this author Click to send private message to this author

#25. "RE: Long Exposure Noise Reduction" | In response to Reply # 24

Mako Registered since 02nd Apr 2009
Fri 12-Jul-13 08:41 PM | edited Fri 12-Jul-13 08:46 PM by Mako

><So am I correct in understanding that you are selectively
>blending multiple 2 sec water exposures to create one image
>with smooth looking water surface that also has texture (as
>opposed to water that looks completely smooth and almost
>featureless as a 30 sec exposure might produce)?>
>
>Yes - that is exactly right. It's all done in camera and
>produces a single NEF. It's an easy way to simulate the
>effect of a strong ND filter. The effect takes advantage of
>the fact that there is motion between frames, so the
>combination of multiple exposures works very well. I've used
>this with the D300, D800, etc.
>

>Eric Bowles

Whoa...you're saying it's all done "in camera"?!? I was thinking your exposure blending was done in post. Ahhh soooo you are using the "Multiple exposure" feature found in the menu...right? I never thought I had a use for this until now. I agree with your preference for the VND as that's my go-to method as well, but I can't wait to try your multi exposure technique! THANKS MUCH ERIC FOR THE TIP!

To the OP - apologies for the thread drift, but Eric got me so excited

richardd300

Dyserth, UK
4560 posts

Click to send email to this author Click to send private message to this author

#26. "RE: Long Exposure Noise Reduction" | In response to Reply # 25

richardd300 Silver Member Nikonian since 19th Apr 2009
Sat 13-Jul-13 05:22 AM

<<apologies for the thread drift, but Eric got me so excited>>

As it did me Nice one Eric, I'd never thought of doing that.

Richard

Visit my Nikonians gallery

Visit my website www.pixels4u.co.uk
The important thing is not to stop questioning. Curiosity has its own reason for existing. Einstein

Gromit44

UK
730 posts

Click to send email to this author Click to send private message to this author

#27. "RE: Long Exposure Noise Reduction" | In response to Reply # 24

Gromit44 Registered since 04th Jan 2012
Sat 13-Jul-13 08:52 AM

Eric - when you're doing multiple exposure water shots in camera, how do you work out the correct exposure for each one?

PhotoSpydie

Buckeye, US
226 posts

Click to send email to this author Click to send private message to this author

#28. "RE: Long Exposure Noise Reduction" | In response to Reply # 17

PhotoSpydie Silver Member Donor Ribbon awarded for her support to the Fundraising Campaign 2014 Nikonian since 17th Jul 2011
Sat 13-Jul-13 10:35 PM

Agreed. Agreed. I learned so much from this thread. I am not new to photography, but every time I check in I learn something.

Carol
photospydie.com

PhotoSpydie

Buckeye, US
226 posts

Click to send email to this author Click to send private message to this author

#29. "RE: Long Exposure Noise Reduction" | In response to Reply # 24

PhotoSpydie Silver Member Donor Ribbon awarded for her support to the Fundraising Campaign 2014 Nikonian since 17th Jul 2011
Sat 13-Jul-13 10:50 PM

OK Eric, so now you have a bunch of us running for water!! Love this. A new assignment!!

Carol
photospydie.com

lukaswerth

Lahore, PK
578 posts

Click to send email to this author Click to send private message to this author

#30. "RE: Long Exposure Noise Reduction" | In response to Reply # 22

lukaswerth Registered since 24th May 2012
Sun 14-Jul-13 04:22 AM

...
>Another place to avoid LENR is with star trails. There are
>two types of star images - short images to capture stars as
>dots (typically under 30 seconds using the 500 divided by
>focal length formula)...
>

Eric,

your suggestions are very much to the point, only one remark with regard to the formula to capture stars as dots: I anything but an expert here, but I recently made some initial experiments which suggested to me that for the d800, a formula of about 300 divided by focal length might be more adequate.
However, I did these trial exposures here in Lahore, Pakistan, which is about the same latitude as the Northern border of Florida. In a few weeks, if I get some clear sky, I will do some more testing in Germany.

Lukas

Trying to be a keeper of the light

http://www.flickr.com/photos/lukaswerth/

also see my Nikonians gallery:
https://images.nikonians.org/galleries/member.php/uid/444897

Ferguson

Cape Coral, US
5751 posts

Click to send email to this author Click to send private message to this author

#31. "RE: Long Exposure Noise Reduction" | In response to Reply # 22

Ferguson Silver Member Fellow Ribbon awarded for the generous sharing of his high level expertise in the spirit of Nikonians Nikonian since 19th Aug 2004
Sun 14-Jul-13 10:23 AM

>Another place to be careful about LENR is with multiple
>exposure images. I often use multiple exposures in lieu of
>long exposures. For example, with moving water I might use a
>series of 5-7 two second exposures rather than one 30 second
>exposure. The time between exposures for LENR to work can
>reduce the smoothness of the multi-exposure image.

I get why LENR would cause breaks in both of these, but I am curious why multiple exposures without reading out the sensor is better than a continuous long exposure of the same (as the cumulative) length?

Stacking separate exposures improves signal to (thermal) noise ratio by reducing the noise accumulation time in each. I would have thought that by not reading out the sensor in between, multiple exposures are the equivalent of a long exposure?

Or does the camera read it out each time and do some kind of average or addition itself?

Linwood

Comments welcomed on pictures: Http://www.captivephotons.com

JosephK

Seattle, WA, US
7108 posts

Click to send email to this author Click to send private message to this author

#32. "RE: Long Exposure Noise Reduction" | In response to Reply # 27

JosephK Silver Member Fellow Ribbon awarded for his excellent and frequent contributions and sharing his in-depth knowledge and experience with the community in the Nikonians spirit. Nikonian since 17th Apr 2006
Sun 14-Jul-13 04:00 PM

The camera does it for you. It will basically divide the exposure time by the number of frames you want to combine.

---------+---------+---------+---------+---------+
Joseph K
Seattle, WA, USA

D700, D200, D70S, 24-70mm f/2.8, VR 70-200mm f/2.8 II,
50mm f/1.4 D, 70-300mm f/4.5-5.6 VR, 18-70mm f/3.5-4.5 DX

JosephK

Seattle, WA, US
7108 posts

Click to send email to this author Click to send private message to this author

#33. "RE: Long Exposure Noise Reduction" | In response to Reply # 30

JosephK Silver Member Fellow Ribbon awarded for his excellent and frequent contributions and sharing his in-depth knowledge and experience with the community in the Nikonians spirit. Nikonian since 17th Apr 2006
Sun 14-Jul-13 04:06 PM

Check out this article about moon and planet motion. It may give you some ideas of the math involved:
https://www.nikonians.org/forums/dcboard.php?az=show_topic&forum=432&topic_id=247

---------+---------+---------+---------+---------+
Joseph K
Seattle, WA, USA

D700, D200, D70S, 24-70mm f/2.8, VR 70-200mm f/2.8 II,
50mm f/1.4 D, 70-300mm f/4.5-5.6 VR, 18-70mm f/3.5-4.5 DX

Vlad_IT

US
1354 posts

Click to send email to this author Click to send private message to this author

#34. "RE: Long Exposure Noise Reduction" | In response to Reply # 8

Vlad_IT Silver Member Nikonian since 21st Sep 2011
Fri 23-Aug-13 11:06 PM


>The one oddball case where you would not is if you, yourself,
>are going to take a dark frame and subtract. You might do
>that (for example) if you were going to make 10 long exposures
>of the same duration in a row, and didn't want to wait between
>them. You would then make a single dark frame (lens covered)
>first, shoot the 10, and subtract in post processing. That's
>11 exposures as opposed to the equivalent of 20 (one for each
>light) the camera would do. But this only works if the one
>frame is at the same settings, and same temperature, as the
>rest.

Folks,

this thread is just remarkable!. Have a question of my own. would it be the same to have a "collection" dark frames for PP with different length and use the one needed for PP? or it requires to take a dark frame at the same conditions as other light frames are taken?


Best regards,
Vlad

Ferguson

Cape Coral, US
5751 posts

Click to send email to this author Click to send private message to this author

#35. "RE: Long Exposure Noise Reduction" | In response to Reply # 34

Ferguson Silver Member Fellow Ribbon awarded for the generous sharing of his high level expertise in the spirit of Nikonians Nikonian since 19th Aug 2004
Sat 24-Aug-13 01:05 AM


>this thread is just remarkable!. Have a question of my own.
>would it be the same to have a "collection" dark
>frames for PP with different length and use the one needed for
>PP? or it requires to take a dark frame at the same conditions
>as other light frames are taken?

Thermal noise is impacted by temperature, as well as the exact nature of the hardware. So it definitely needs to be at a given temperature (and it's not just ambient temperature but the temperature of the guts of the camera). This is one reason that the best way is to take it immediately before or after.

What I don't know is whether, for a given temperature, the noise changes over time (e.g. as electronics age for example). So I don't know if you built such a library of dark frames (indexed by temperature and length of exposure) whether it is still valid 6 months later at the same temperature.

So long winded way of saying "probably not but it might still be better than no dark frame at all".


Linwood

Comments welcomed on pictures: Http://www.captivephotons.com

Vlad_IT

US
1354 posts

Click to send email to this author Click to send private message to this author

#36. "RE: Long Exposure Noise Reduction" | In response to Reply # 35

Vlad_IT Silver Member Nikonian since 21st Sep 2011
Sat 24-Aug-13 02:08 AM

Thanks, Linwood
Best regards,
Vlad

G