E-M5 and low iso noise with long exposures.

WeaselWily

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Oct 9, 2014
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Hello,

I recently bought E-M5 with a grip and 12-40/2.8 and have been using it for a while now as travel camera. Last summer I visited Cyprus and took a few long exposure photos with E-M5 attached to a gorillapod. The resulting images were surprinsingly noisy even at the lowest base iso. I'm wondering if my copy of the camera has some sort of defect or if it's supposed to be like this.

One example of the color noise can be found from here http://vkphoto.sunlevy.com/forum/base-iso-kohina-1.jpg. You can find the color noise by looking at the sky.

This seemed to only affect exposure times over 10 seconds and not anything below that. The temperature outside was somewhere around 25 to 30 degrees celcius. What do you think?

Thank you in advance!
 

barry13

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Hi,

If the E-M5 has a setting called NOISE REDUCTION, set it to Auto. This enables 'Dark Frame Subtraction' for shots over 1 second.

Also make sure you have the 'noise filter' setting enabled.

If you are looking at the RAW/ORF files, the above settings will have no effect; they only affect the JPEGs.

Barry
 

barry13

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If you're using RAW, you can put the lens cap on and shoot a couple of dark frames yourself in between your shots.

Then, you can use the dark frames in post-processing to map out some of the noise.
I don't know if Lightroom can do it, but there are some free progams that can, iirc.

Barry
 

RDM

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If you're using RAW, you can put the lens cap on and shoot a couple of dark frames yourself in between your shots.

Then, you can use the dark frames in post-processing to map out some of the noise.
I don't know if Lightroom can do it, but there are some free programs that can, iirc.

Barry
I have never heard of that possibility .. that's cool.. Do you remember the name of any program that can ?
 

kwalsh

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Dark frame subtraction does work with RAWs from the camera, the other noise filter settings do not of course but most RAW converters can do at least as good a job.
 

christofp

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Jul 21, 2012
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261
Yes, as I have done it many times:

- pixel mapping,
- shading compensation
- and darkframe subtraction

are applied to the RAW file. Both, EM1 and EM5 do it.

All other settings are JPG only.


While pixel mapping and darkframe are quite useful, especially with my EM1 which has more long exposure issues, the shading compensation can give very ugly results in night shots.
If you see an ugly noise vignette/frame around your night shot, try the same shot with shading compensation=off.


Christof
 

wjiang

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Christchurch, New Zealand
Dark frame subtraction ('Noise Reduction') is only engaged in AUTO for exposures longer than 4 seconds. If you want it on for shorter exposures you have to force it to ON. Nice thing is that it's applied to RAWs, so if you're lazy (like me) you don't have to take a separate dark frame and apply it in post.

'Noise Filter', on the other hand, is just a normal smoothing noise filter that gets applied to JPEGs, so if you shoot RAW it's not much use.
 

Wisertime

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I've done noise reduction (dark frame subtraction) in Raw with the 12-50 at ISO 100 and get very clean files...12-40 should be even slightly better.
 

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