ettr(expose to the right) low light photography

hi everyone per my reading of astrophotography web sites i came across a method called ettr(expose to the right)which refers to exposing on the right side of the histogram. by doing this you essentially raise the iso,open up the aperture and slow down the shutter speed to allow maximum light collection.the pictures will appear over exposed until processing is done attached are some before and after pics.on my d3100 i use manual mode,raw file, hi 1-f/3.5-30 sec ss and a +3ev.these were my first attempts.i used nikon view nx2 to process and obviously you can adjust to your own taste.photoshop and lightroom can do much more but i don't have either to play around with.

for more informationa and a video how to take astrophotos from light polluted places. i am attaching a hyperlink from youtube/ian norman's lonelyspeck.com How to Photograph the Milky Way in Really Heavy Light Pollution Using ETTR (Expose to the Right) - YouTube in which he produes some beautiful pics there is also an exposure calculator in his web site.

Interesting...I thought that astrophotography is the one place where ETTR breaks down. If you expose so that the star blips on the histogram are far to the right, what's remaining to the left is darkness amplified, ie. noise. I have always exposed nighttime sky to get the star 'blips' are to the left and thus not amplify darkness (noise).
Can anyone shed some light (sorry for the pun) on this?

High ISO decreases your DR - dynamic range. If you can, use ISO 100 and increase your exposure time.

ETTR does nothing to the ISO. What it does is to utilize the full dynamic range of the sensor. For example if you have a DR of 12EV, and you are at the extreme right, the DR will be 12. If in contrast you try to under expose by 1 EV (the histogram shifts left), your DR will be 12-1 = 11EV. In digital, you gain nothing by moving left, unless there are a few pixels (which are difficult to see in a small histogram) which will over expose the region around them. This happens when there is a bright, but small (in relation to the rest of the frame) light , say sun or street light. You expose for the average and the bright light will blow area around it. Blown highlights are not recoverable.

With a large DR of modern sensors, many scenes do not need the full range, and there, under exposing 1EV gives a safety margin against blown highlights. The best method of cheching DR is to use "spot meter" and point it at the brightest, average and darkest portions. If you use aperture priority, then the range of speeds will give you the DR of the scene.

Guess I need to listen to his youtube video.

I suggest that you download Capture NX-D beta from Nikon site. It is a full blown post processing program, and that is all I use. It is quite powerful and best part is that as long as it is beta it is free.

Nikon | Capture NX-D | Beta version download for free

In this shot
ISS - International Space Station - Nikonites Gallery
I used the expose to the left scenario.

lol. there are so many technicalities to this "hobby" at times it can be overwhelming.last night was my first experience trying this technique.clouds rolled in and kept me from "practicing" more. of course now that i know the information i.e. stars and night sky can be recovered i think i need to re-examine my other pics.in any case it may or may not be a new style but it can definitely produce some beautiful pics.

from the little guide pic on the camera the higher the ev the more sensative the sensor? vs the lower the ev the less and darker colors come through.however in the effort to stuff as much light onto the sensor higher seems better(imho) because its easier to darken a pic than to lighten it.the only reason i say that is if you attempt to lighten a pic the light and dark spots all become brighter as opposed to stripping away too much light(just a theory)

The ETTR approach comes about since there is more data available to work with the further you are to the right. There are many articles about this on the Internet and in books. As long as you don't clip highlights you can reduce the exposure in PP with better results than increasing the exposure in PP.

attached is the same photo run through the new beta nikon nx-d program again it needs further tweeking but there is definitely more info there.thanks for the program link aroy