a7rii long exposure color noise - quick rudimentary test

[itsskin]

Thank you for the files! I personally think it's not that bad actually. Files are heavily underexposed. Try pushing histogram to the right.

Yes, there is thermal noise, but we are pushing files to extreme. It will definitely work for 4K timelapses of stars I'm planing to do.

[itsskin]

Remaping before\after http://www.dpreview.com/forums/post/56284987

[bdp]

Capture One handles hot pixels much better than Lightroom. There is a 'single pixel' slider in the NR tab that cleans up your raw file nicely, although it may remove real stars from the sky if it was in focus, not sure.

 

 

Ben

 

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[bbphoto]

Someone on dpreview had mentioned successfully ridding of hot pixels by forcing the camera to re-map pixels with a forward date change. I tried doing so (and could hear the re-mapping occurring with shut off exposure) to no avail. BDP, looks like Capture 1 has a pretty nice feature there for removing. I just had hoped that I would be able to get away with using LR only. Not to mention I still am not completely convinced this issue is widespread across all copies of the camera, nor do I know whether it will be addressable in some fashion by Sony. Nikon addressed it on the D810, which is great, but I can't speak for Sony.

[stephenv2]

I can confirm on 30 second dark frame exposure regardless of ISO, ACR/Lightroom needs an update as Capture One opens the files much cleaner than ACR both hot pixels and regular sensor noise. Date change does kick off remap but does not affect the ACR issue.  It may just need an ACR update but it's quite a difference. And Long Exposure NR works very well and other than time lag for timelapse shooting seems to give good results into the 6400 ISO and greater range. But the bottom line right now is A7rii + ACR is not a great combo right now and wonder if this affects some of the noise complaints in general beyond Long Exposure shooting.

[bbphoto]

@stephenv2 - I agree with your consensus here. I've found all of that to be true. Curious, did you use your own a7rii files or ones provided by myself or another user? I'm hoping this will all be in the past with an update to ACR and/or camera firmware!

[EDBR]

Big problem indeed, 

If you would like to use this for astrophotography you get a second Milky Way

Have a A7s and A7r as well. Did some tests and the A7r seems producing the pictures the best clean images, with less noise (6400, 30sec).

A7s isn't clean as well but my new A7r2 is useless for night photography;

Like also to use the big stopper, seems not possible with this camera, a lot of wasted money...?

Will try to give it back and continue to use my "second hand" A7r

Don't know how they will solve this with an update ?

Since I'm a also a Canon user I don't know if it's a good idea to go for the new 5series ( seems that they have also noise problems) but with the A7r2 it's huge !!!!

Af on the other hand seems much better with the Canon lenses

Hope they will solve this problem

[barrakj]

Guys forgive my ignorance but I don't shoot long exposure shots however I wanted to test this. All I did was set the shutter to 30 and took these shots. Again if this is not what this topic is about please correct me. I do not see anything wrong with the photos and here are links to the RAW files on drop box.

 

Both were taken with shutter speed on "30.

 

https://www.dropbox.com/s/wifrmp9xb4vifi8/DSC00178.ARW?dl=0

https://www.dropbox.com/s/nhng3gbqd26bb1a/DSC00180.ARW?dl=0

[bdp]

Hi Barrakj, 

 

Did you have Long Exposure NR turned on or off?

[barrakj]

Hi Barrakj, 

 

Did you have Long Exposure NR turned on or off?

I just checked and its on.

[bdp]

That seems to be the solution.

 

Are people turning it off because it shoots in 12-bit with it on?

 

Is there a noticeable reduction in DR with LE NR turned on?

[Singingsnapper]

I turn it off on all my cameras because the usual reason I shoot long exposures is because it's twilight or predawn.  If I had to wait for the dark slide, then the light will have changed too much.  My files were clean on successive long exposures - 10 in total.

[bdp]

I turn it off on all my cameras because the usual reason I shoot long exposures is because it's twilight or predawn.  If I had to wait for the dark slide, then the light will have changed too much.  My files were clean on successive long exposures - 10 in total.

 

Ah ha, understood. I forgot about people who need to shoot multiple long exposures in a row with no gap. 

[Jamooche]

Hi everyone.  I just did a test of long exposures with in camera NR turned on and off for 40 second and 2 minute exposures.  I'm seeing that with NR turned off and 30 seconds or less exposures, the images are great.  Anything above that may need the long exposure NR turned of.  See this gallery for my tests.  I did screen captures for the unedited RAWs and 100% crops of the image with Lightroom default setting with Shadows set to +100.  And the lens info is wrong.  These were taken with the Metabones IV and the Canon 24-70 2.8 II.  

 

http://www.jamilabbasy.com/Galleries/A7RII-Long-Exposure-Noise-Test/n-xP3Cc8/

 

I'm not a professional and only do this as a hobby, so this issue doesn't concern me at all.  However, it would be nice if we could clean up the colored pixels in LR or with some firmware fix.  

 

 

[bdp]

Thanks Jamil, this is a great test.

 

Ben

[stephenv2]

@stephenv2 - I agree with your consensus here. I've found all of that to be true. Curious, did you use your own a7rii files or ones provided by myself or another user? I'm hoping this will all be in the past with an update to ACR and/or camera firmware!

 

My own files - got a camera on Thursday. Going to shoot some live astrophotography of meteor show probably Thursday night if weather cooperates.

[Jamooche]

I just read about having the camera take a blank "hot pixel" photo and did another test.  Here is info about that:

 

http://www.dpreview.com/forums/post/56284904

 

I added 2 more photos to the gallery and this fix seems to truly fix the problem 99.9% of the way.  This photo is ridiculously underexposed and with shadows +100 there is barely any chroma noise.  Pics are here:

 

http://www.jamilabbasy.com/Galleries/A7RII-Long-Exposure-Noise-Test/n-xP3Cc8/

 

I plan on doing an outdoor longer exposure test again tomorrow.  It might just be part of the process to do the blank hot pixel procedure before any long exposures.  It takes only 2 seconds to do it too.  

[eric5dmark3]

The problem is identical to A7S last year but looks like it has already been kind of fixed or reduced through firmware updates. 

 

Here are the tests on A7R2 from ISO 100 to 12800. I posted it on Mobile01 (a Chinese forum), just scroll down to the end of the first post

 

http://www.mobile01.com/topicdetail.php?f=254&t=4489059&p=1#56963625

[bbphoto]

I turn it off on all my cameras because the usual reason I shoot long exposures is because it's twilight or predawn.  If I had to wait for the dark slide, then the light will have changed too much.  My files were clean on successive long exposures - 10 in total.

So you haven't been experiencing the hot pixels with LENR off under same conditions as myself and others? Even after pushing files a few stops and 100% crop?

[bbphoto]

I just read about having the camera take a blank "hot pixel" photo and did another test.  Here is info about that:

 

http://www.dpreview.com/forums/post/56284904

 

I added 2 more photos to the gallery and this fix seems to truly fix the problem 99.9% of the way.  This photo is ridiculously underexposed and with shadows +100 there is barely any chroma noise.  Pics are here:

 

http://www.jamilabbasy.com/Galleries/A7RII-Long-Exposure-Noise-Test/n-xP3Cc8/

 

I plan on doing an outdoor longer exposure test again tomorrow.  It might just be part of the process to do the blank hot pixel procedure before any long exposures.  It takes only 2 seconds to do it too.  

So you shot dark frame and edited out hot pixels on your own and it worked? Is that what you're saying? Or did you mean the forced mapping technique worked for you...?

[Jamooche]

So you shot dark frame and edited out hot pixels on your own and it worked? Is that what you're saying? Or did you mean the forced mapping technique worked for you...?

 

 

The "hot pixel" technique puts a blank image with the known hot pixels in the cameras memory - or something...I'm not sure exactly how it works.   I did this part with the lens cap on.  I then just took a long exposure photo (54 seconds) at my desk, deliberately underexposing it to highlight any noise issues when I opened the shadows.  No other edits except Lightroom default settings and shadows +100.  

 

It seems to have worked.  

[Singingsnapper]

So you haven't been experiencing the hot pixels with LENR off under same conditions as myself and others? Even after pushing files a few stops and 100% crop?

No hot pixels at all.  I'm shooting twilight photos with and without filters, so there aren't any deep blacks, but I'd see the red ones, and notice the hot pixels I get on longer exposures with my 645Z.

[EDBR]

Did some quick tests yesterday and produced rather bad results with a lot of hot pixel noise for the A7r2. Was very late but will pick it up again this evening. Will post the crops..

Having much hope for this “blank hot pixel procedure". Hope it will solve the problem. Will perform this on my A7s & A7r as well. Maybe the A7r is clean because it just did a blank ?

If this procedure is running monthly I think Sony should better do it every week… day. And rather at start-up than when turning it off, in order to take a clean start.

Or provide a sort of menu item “clean sensor”. Must be easy…

Has anyone an idea how it maintains in time (on other A7)…days, week ?

But when looking around on the net it seems that the D810 and the new 5DS also have the same issue. Know that for the Canon 6D you just have to perform a manual clean of the sensor to fix it.

[Singingsnapper]

Did some quick tests yesterday and produced rather bad results with a lot of hot pixel noise for the A7r2. Was very late but will pick it up again this evening. Will post the crops..

Having much hope for this “blank hot pixel procedure". Hope it will solve the problem. Will perform this on my A7s & A7r as well. Maybe the A7r is clean because it just did a blank ?

If this procedure is running monthly I think Sony should better do it every week… day. And rather at start-up than when turning it off, in order to take a clean start.

Or provide a sort of menu item “clean sensor”. Must be easy…

Has anyone an idea how it maintains in time (on other A7)…days, week ?

But when looking around on the net it seems that the D810 and the new 5DS also have the same issue. Know that for the Canon 6D you just have to perform a manual clean of the sensor to fix it.

Sensor dust and hot pixels are two very different things.  All cameras without exception will get hot pixels on particularly long exposures, or many relatively long exposures in a row.  This is why there is Long exposure noise reduction in the menu.  There is less post processing to do if you have it switched off, but unless Sony brings in the feature that exists on some Olympus cameras of live bulb, you will miss shots in quickly changing light.  I find hot pixels relatively easy to sort out with the google's efex series' Dfine noise reduction by selecting hot pixels and either filling the whole layer, or if they are only in certain areas, choosing brush and selecting an optimum brush size and texture to brush them out of deep shadows...

[EDBR]

Dear Singingsnapper

1. Sensor dust and hot pixels are two very different things: INDEED but the Canon 6D performs a remove of the sensor dust + a sort of blank when manually triggered.
2. Long exposure noise reduction: Yes but not suitable for a timelapse or when shooting the Milkway or Aurora = lot of lost time: https://lightroom.adobe.com/shares/ea9037b4edac4aacbfb54e1bb6c81823/albums/3220b9570603a1438d48d4c95725c04d
3. Instead of noise reduction I think it’s better to take a black image (same exposure with lens cap on) every 30 minutes and do the rest in post processing by substracting.
4. Will definitely try Dfine = thanks for the tip but will first follow this, and post editing with brush looks not suited for let say a panorama made of 7 Images from https://lightroom.adobe.com/libraries/f2761e4524854b0ea01b1a0609fd739a/albums/c332fb86117470a0890995d5b6f43bd4/assets/53b5fc4410543677cdda50ab0195c8b7 the Milkway.   
5. Hope “blank hot pixel procedure" will help.