Iso 25600 ?

[ajohnw]

I think part of the difference may simply be the reduction in size. John wrote that his is a 50% reduction, but I think it is more. The image to which you linked is approximately 95 cm on the vertical dimension on my screen. John's original as posted is 32 cm. Compressing to 1/3 of the original size should reduce the impression of noise quite a bit. However, I don't use Raw Therapee, so I have no idea what other processing it is doing in its default rendering.

The original images are crops but still max resolution. Sure I mentioned that. Cropped as the entire image is a rather large. The 50% reduction in the following images helps with the residue left from noise filtering and also has a bit of a sharpening effect enhanced with more sharpening.

Rawtherapee - nothing other than sharpening and auto levels. The later is why the images are a little brighter. I was curious to see what that did to highlight clipping. As expected on the knight it's just smoothed them over but any colour is more or less absent in them. Unless asked to rawtherapee does nothing by default.

One more edit. I didn't use rawtherapee to develop the jpg's from raw. I used Ufraw as that way I can make sure it is set to defaults - linear tone curve and in this case VNG 4 colour debayering and zero denoise. Output intent perceptual etc.

John
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[xpatUSA]

I can't post a picture as the clipped areas flash but I can assure you that they are clipped. On 2nd thoughts I can as flashing is optional in Rawtherapee. The white dot's have a channel at less than 2 bits. Some are in odd places. I used ufraw to develop the raw. Goin on other work I have done with this it does show true clipping. There was white clipping as well. Overall I feel it's usable for images that don't have a large dynamic range.

The only problem with Rawtherapee really is that some work has to be exported to the GIMP. Dodging, burning and cloning with it are easy. Some techniques need layers and masks - more than Colin uses on PS in some cases to do the same thing. As I learn more about it I find layers can be used to make it none destructive as well. I never alter the original image anyway and what ever is done can be saved in GIMP style files. I assume there is also a macro recording type plugin for it as well so that many images can be batch processed.

John
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I like this post: not one mention of ACR, LR, PS, etc. entirely Adobe-free as a madderafak

[revi]

it was

[ajohnw]

I only used Rawtherapee because some one made some 2nd hand disparaging comments about it. On the other hand I am glad I did. The noise reduction in it resulted in very little blur. I just found out loosely what 2 of the sliders did. Unlike the rest of it the terminology is unusual. There is even a gamma setting which apparently biases it's colour behaviour. As to the rest it's defaults are usually sane.

It also has a few other nice features. Detail windows - resizeable 100% views of specific part of an image, anti halo sharpening - done by restricting sharpening in lighter tones, it's adjustable and on top of that LAB adjustments. Those aren't buried in some filter but presented via various curves. They have also added the same sort of the usual curve adjustments in the same fashion that Darktable does where the bounds are shown. There are also a number of adjustment based on detail level. The only thing I am not keen on is how it presents tone mapping but that may be due to having it presented in another way in Fotoxx.

In my view the other OS package that crops up Lightzone is much more difficult to use effectively than Rawtherapee. On the other hand it does some things quickly and easily. An ideal companion package but tread carefully.

Go a little further and run linux plus Fotoxx and Rawtherapee is just another plugin.

The GIMP - There has been a lot of work done in the background on that for some years now. One day it will hit the streets - watch out PS when it does. I get the impression that it will be very very different but still probably largely aimed at professionals.

John
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[MrB]

Although it seems fair to conclude that the E-M5 controls noise well at very high ISOs (which some other Four Thirds cameras don't even have), some of this thread might possibly be confusing or misleading to anyone casually browsing here.

Just to clarify - the link in the following quote is to a full resolution crop (3005x3148) to show the noise in the Raw image shot with the Olympus E-M5 at ISO 25600:

...This is the uncropped one Edit LOL I thought it was but it's actually the cropped one. I don't have the original full sized one...

http://www.23hq.com/ajohnw/photo/14725541/original

John

All the images in posts #1, #8 and #10 are similar crops downsized 50% (approx. 1500x1500), so they are not only affected by any in-camera or post processing noise reduction applied to them, but also by the effects of the algorithms of re-sampling and those of Jpeg conversion and compression.

Again to clarify the noise performance of the camera, here is a link to a different full-size, full-res controlled test image, this time from Digital Photography Review (DPR), shot at ISO 25600 in low light studio conditions. It shows noise levels similar to that in the Image Resource (IR) test image linked in post #18:

https://s3.amazonaws.com/masters.gal...F4HeQZRHKCE%3D

(The IR and DPR images were both camera Jpegs, with its noise reduction filter turned off.)

It is also fair to conclude that several of the images in this thread show how very good results can now be achieved by using noise reduction software in the post processing of high ISO image files.

Philip