The best way with any camera to take full advantage of ETTR is to calibrate your exposure meter to the RAW data. I calibrate the in camera meter as well as my external spot meter for all my cameras.
I'll get to the how in a moment but the why deserves an explanation.
By calibrating the RAW data against your exposure meter (in camera or external) you can guarantee that the brightest highlight that you wish to retain data in will have no clipping. All in camera Histograms display the jpeg data (0-255) with a WB applied which multiplies the red and blue chanel data to balance against the green (remember there are always more green phtosites than red or blue except foveon and monochrome sensors) which has the effect of throwing off the histogram. So even if you follow the histogram and expose to the right you are not getting the most ideal data capture for RAW (which is devoid of WB data except a value assigned by the camera in exif). For the best RAW capture requires something other than a histogram.
This is why it's best to calibrate your RAW data against the light meter. Let's say you are taking a landscape with your camera and it's critical to increase your exposure as much as possible to ensure good dark tone detail but you do not want to loose the cloud detail. Following the histogram and exposing to the right you will save the highlights but you could be missing lots of dark tone detail. If you knew exactly how much over exposure you can give to a spot metered highlight value and retain detail there you can at the same time maximize the dark tone data. So in this scenario you could use the spot meter in your camera or better yet external handheld spot meter to read your brightest tone that you need to have detail in and from that reading increase the exposure by the amount you determined (by calibration) that your RAW highlight data will be preserved. This is in practice quicker than watching and adjusting against a histogram (as long as the lighting isn't too variable otherwise it takes the same time) and ultimately yields better data.
The easiest way to calibrate your RAW data is with the free software called
RAWDIGGER. You'll also find step by step instructions on how to do the
calibration on the site.
I used to try and use the in camera histogram (reviewing) on my Nikon bodies and found the jpeg data wasn't accurate enough to the RAW data. Then I explored
UNIWB which worked beautifully it required shooting a WB target (in the same lighting as your subject) to get the best color results in the end since the image is in essence free of WB adjustment in order to get a more accurate histogram (still off jpeg data) that will approximate RAW data better. I found UNIWB effective but cumbersome.
Since I began calibrating RAW data to exposure meter my data captures have been perfectly controlled. I've calibrated the meters of D3S, D800, X100, X-Pro 1, RX100 and I saw an improvement in quality of RAW data (in dark tones) by doing this with every camera.
Just don't take my word for it visit the sites and read up and try it for yourself. If you care about the best RAW capture you owe it to yourself.
**life would be better if camera makers would get out of the film mindset and create exposure modes that best capture RAW data. Imagine an ETTR exposure mode where the photog in the menu specifies an amount of allowable highlight clipping (0.5-99% etc) and the camera automatically increases exposure above metered value to the specified clipping amount. Simple effective. They could even go a step further and tag in exif the amount over baseline exposure and RAW converters could automatically normalize exposure on import. See this
article.
Cheers
-Mark