In my last post, I explored some ways of reducing long exposure noise (LEN) but made only modest progress: Long Exposure Noise - Parameter That Improve the E-M5 I started this because I enjoy making night landscapes & those sometimes require exposures >1 min. But OMD cameras produce significant noise at ISO=>1600. Here's a capture I did at the Grand Canyon w/ a histogram of just the red rock walls to illustrate what min. exposure is needed for star light only work. RedRockhistogram.jpg by tradesmith45, on Flickr So ISO 3200, f2 & 2 min. is what's needed but for my Kowa f2.8 that would be 4 min. There is substantial noise in this image that will limit print size to something rather small. Certainly the rumored f1.2 WA lenses will help this problem if they are sharp enough. But even those lenses will leave OMD cameras at a distinct disadvantage to Fuji & a few Canon & Nikon DSLRs. See the stunning photo Roger Clark has on his home page made w/ a 6D for example: Clarkvision.com home I wanted to try several options for reducing this noise. To test, I created a simple "scene" in my office that I could light w/ an adjustable LED head lamp placed in black nylon cloth. This gave me dim & somewhat reproducible light - except when stray light came past the window curtain from say a passing car. (All the following images are 100% crops w/ typical LR adjustments: modest increases in Noise Reduction, Contrast, Clarity, Vibrance & Sharpening - the kinds of modest adjustments I'd be likely to make to an image I'd like to print.) First I tried stacking 9 images in PS & then dark frame subtraction in post processing. As you can see, neither worked very well. 9xStack 3200.jpg by tradesmith45, on Flickr DFS Post 400.jpg by tradesmith45, on Flickr Then I tried using very high ISO to shorten the exposure time needed: ISO5000.jpg by tradesmith45, on Flickr This too failed. And post processing noise reduction software worsens the visibility of LEN by turing color pixels to white. LR vs OV3.jpg by tradesmith45, on Flickr As mentioned in my first post, the E-M5mII has more long exposure noise than the mkI: And the E-M5mi get really bad if you have to use 4 min. to accommodate an f2.8 lens. EM5_Mk1_vs_2_ISO_3200.jpg by tradesmith45, on Flickr M5II_NR0ff3200.jpg by tradesmith45, on Flickr But I had found that turning on in camera Noise Reduction for the Mark I would significantly reduce long exposure noise: EM5NrOn3200.jpg by tradesmith45, on Flickr Having just bought a markII, I did extensive testing to see what is possible with this camera. Generally, turning on in camera Noise Reduction significantly reduces LEN but leaves some fine black grain in the picture- more for higher ISO &/or longer exposure durations. Haven't printed anything yet but the grain at ISO 3200 for 2 min. looks acceptable. Not sure ISO 3200 & 4 min. is acceptable however. Here's result for equal exposures @ ISO 3200 @ 4 min & 1600 for 8. Not sure you'll be able to see this but ISO 1600 is better but to use it, the camera will be tied up for 16 min-ugh. NRon3200vs1600.jpg by tradesmith45, on Flickr So I also tried ISO1600 & 8 min. but w/ NR off. NR3200vsOff1600.jpg by tradesmith45, on Flickr Not even close. But ISO1600 @ 4 min.w/ camera NR off isn't too bad but longer exposures even at ISO 800 have more noise. NRoff1600800.jpg by tradesmith45, on Flickr So reducing ISO by a stop (& doubling the exposure time) does NOT substitute for using in camera Noise Reduction, its still needed. As mentioned, this problem applies to star light only night shooting. So can the E-M5mII do well if there is supplemental lighting? Yes, here's results for exposures needed is the scene is lit by a quarter moon (50%) & in camera NR turned off. Virtually no LEN visible: ShortSSEM5II.jpg by tradesmith45, on Flickr One last thing regarding pixel mapping. All the OMDs have this function. Its basically a test so the camera can ID the stuck/hot/bad pixels on the sensor & create a map of their locations. This is different from LEN however. The camera then interpolates a signal for these bad pixels by sampling from surrounding good pixels. Roger Clark says for at least Canon, interpolation done during RAW development (probably by placing the bad pixel map into the EXIF data) so in camera noise reduction isn't needed. Sure wish Oly did that. From these tests, I've concluded that the only way the bad pixels map gets used in an OMD is is in Camera NR is turned on & this function is much more than just simple DFS. Where this leaves us is needing big lens apertures & really long exposure times to keep exposures below ISO 3200 for 2 min. Fuji is so much better at this! I'm still thinking about the MZ 8mm f1.8 too.