Sunday 21 October 2007

Low noise images at high ISO with the Foveon?! Heresy!!!

..not! It is possible to get some low noise images at high ISO with the Foveon, regardless of many of the reviewers say, I came to find. The problem is that not that many people are willing to put the time in processing the images in its proprietary software, nor do they know how to do it properly (and also not willing to learn how to). Granted, RAW processing can take time, but once you have mastered the process and you bare some basic principles of photography in mind at the picture taking moment, you can get the results. I currently have both SPP2.1 and 3.0 as I like to experiment with both as sometimes I get different results that suit different things.
The problem with the Foveon it seems, is mostly to do with artificial light. I like a photographic challenge so I set myself to one (more of a quest really).

I had done a test with ISO1600 and a flash, yielding very very low noise for the setting but according to many it wasn't a fair test as there was plenty of light provided by the flash. Not only that, it produced very sharp images, another point going against what most reviewers state; that the Foveon produces very soft images at high ISOs.

I came to find that it is more a case of bad processing (as the SD10 only produces RAW files that have to be processed in the software. The camera does not do any in camera processing).
Most of the times, by setting highlight, shadow and it's unique X3 fill features to negative values, increasing contrast as needed along with sharpness settings at maximum or near maximum I managed to produce consistently similar results and very acceptable ones too. Another point to be raised is that the Foveon sensor requires extreme care with White Balancing. As for exposure, I found that most of the times at high ISO one needs to overexpose by 2 stops or so (in some cases more) and work with that in the SPP software. Of note as well is that the lens used was the very average Sigma 18-50mm DC lens.

Here is one example, taken at ISO1600 at ambient light (incandescent) and processed as above in SPP:

(Click on the image above for a bigger size)

As far as I can see, the photo is very sharp, relatively low noise for the ISO setting (1600) even though colour was toned down a little. Also bare in mind, that this camera is 4 years old. There is no in camera sofisticated processing or noise reduction methods.

In conclusion, careful processing of images produced by Foveon sensor cameras is all that is needed as well as some solid basic knowledge in photography and mastery of SPP, something that perhaps most reviewers perhaps felt it was too time consuming.


Until next time,



Luis

Update: Some have asked why don't I expose at ISO400 since I am doing that by overexposing by two stops at ISO1600. The reason is simple: with digital, results are not as predictable as with film and in the case of the Foveon, if I exposed at ISO400 the noise that the sensor produces would have been more difficult to clean as by the time I used the method above, the image shadow detail would have been lost as the shadows would be too dark. Remember we are simply talking here of using the system on its own, not with 3rd party software. The above method holds detail well, noise levels down and good sharpness.

After months of waiting...

...I have a Sigma SD10 to work with. I missed those tack sharp photos, so off I went with it to the streets. One of things I love about this camera as well is the ability to produce very good results even with average lenses (such as the Sigma 24-70HF used for this shot).





So, The Viewfinder's Foveon Factor section is once again open.



Until next time,



Luis