Do I need Long Exposure NR to be On?

Started Jun 1, 2014 | Questions thread
Luke Kaven Veteran Member • Posts: 5,705
Re: Do I need Long Exposure NR to be On?

WIMorrison wrote:

Luke Kaven wrote:

WIMorrison wrote:

Luke Kaven wrote:

brony etr wrote:

no, I've done exposures of over 20mins on the DF without any noise reduction. getting a clean exposure is the key

You can kind of get away with that on the Df, but not with the D800.

Rubbish - even when presented with images that show NR in camera is not required you make silly (and incorrect) comments about tinge and colour shift which has nothing to do with NR.

The D800 does not require LENR for normal use, all it will do is double the exposure time and flatten you battery

Ian, you're a good photographer, but you were wrong on this one (and a little insulting).

Thermal noise produces spurious signal manifest as bluish-magenta cast with local hotspots (around the column amplifiers). LENR uses a dark frame subtraction to mitigate this, along with other sources of noise, such as hot pixels. So yes, it has everything to do with NR.

Where the D800 needs the most help is at high gain settings, even at handheld shutter speeds.

I did mention that the newest Exmor 33x44mm cameras (e.g., the IQ 250) do a mandatory dark frame subtraction on every single shot.

And there was me thinking that the blueness of the London Eye was down to the lighting that they used and all the time it was because I hadn't used LENR on my camera

You have London eyes, but you do not see! 

Seriously.  Try doing just a dark frame to see what the contribution from the sensor is.  Use a couple of minutes of live view before you do it and see how that contributes more to the effect.

In the kind of shots you're doing, which include multicolored blue, fluorescent, and amber (sodium) lighting and lots of spill from everywhere, you can get away without using a dark-frame subtraction.  A little added blue and magenta here and there might even look good.  But in other situations, the issue will be more obvious.

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