Topaz filters and low light photography

Updated to include an example using the latest version of Topaz Denoise (version 5).  Also updated to make the crops more detailed and to be precisely the same selection.  My first effort using version 5 was actually a lot worse than the previous examples posted here.  I don’t think this is a fault of Denoise 5, but rather that all of these filters require practice and experience to use them well.   By definition one is trying to recover a photograph that is underexposed and using a high ISO setting and so well outside of the bounds of what is reasonable.

Owning a relatively old Canon EOS 300D (the original Digital Rebel), the low light performance is not particularly good.   I generally prefer to use just the ISO 100 setting, and at most ISO 400 although it will go up to ISO 1600 but the latter is very noisy.  I tend to prefer to shoot raw and underexpose by a stop or more rather than upping the ISO setting.  However, sometimes, one cannot do anything about it and one has to underexpose and use a high ISO setting.  The following example is a single photograph, taken in the Louvre, showing a section of detail and the whole photograph in three forms: the original RAW from the camera processed to a JPG by iPhoto but no adjustments made.  It is around 1⅔ stops underexposed.  Secondly there is a version processed by iPhoto adjusting the exposure, levels and using iPhotos noise reduction.   Finally versions using the DeNoise filter from Topaz and also the Adjust filter.  The first one uses the old Denoise 4 and the second the recently released Denoise 5.   Topaz appears to give better noise reduction than iPhoto’s built in capability, although I find that using Topaz does tend to strain my various machines, although Denoise 5 seems to be better in this regard.   I seem to only be able to use Topaz on the processed JPG files from iPhoto rather than the raw files in iPhoto despite fiddling with the iPhoto settings.

Here is the original and a detail:

Original Image (reduced in size)


Crop Original.jpg


Now the images processed by iPhoto:



Crop iPhoto .jpg


The image processed by Topaz using the old Denoise4 filter:


Crop Denoise 4.jpg


Finally, the image processed with the latest Denoise5 filter.   I adjusted the exposure separately after applying the Denoise filter.  (Doing it the other way around produced an awful result, which I presume is because the noise was already amplified and then rather more difficult to remove).

Denoise 5.jpg

crop denoise 5.jpg

The comparison may be somewhat difficult because of the exposure adjustments not being quite the same and I probably should have made the details somewhat larger. The noise reduction from Topaz is much better with both Denoise4 and Denoise 5.    This is apparent both in the background where there are definitely far fewer “noisy pixels” and also on the stone of the statues.  It is really amazing what can be recovered from an under exposed high ISO image.

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