One of the criteria that every camera review site uses in evaluating the quality of a new camera is image noise. As ISO increases noise normally increases as the sensor capture capabilities (or lack thereof) and boost processing electronics take their toll on the quality of the captured image.

There are many things that affect that noise, not the least of which is the size of the light-gathering pixels that capture the image. As discussed in detail in The Digital Sensor and The Digital Sensor Part 2, the size of the photosite is the reason the tiny sensors used in pocket point and shoot cameras are so limited in capabilities compared to the Digital SLR, which is where the major growth in the photographic market is now occurring.


The impact of photosite size is ably demonstrated in one of today's hottest DSLR cameras - the Nikon D3. This $5000 camera is a 12.2MP full-frame camera. Since it can also handle Nikon DX crop lenses and create a 5MP image at the common APS-C size seen in most of today's DSLR cameras, it is easy to understand that this 12MP full-frame has the same photosite size as a 5MP crop-sensor DSLR.

As discussed in detail in the Digital Sensor articles, the sensor is an analog light-gathering device. It is not a simple digital on-or-off digital device where size really matters very little. In a camera sensor the light gathering is analog and the larger the light gathering area, all else being equal, the better the light gathering ability.

Compared to today's 10 to 14.6MP sensors in top DSLR cameras with a 14x24 sensor, the Nikon D3 has huge photosites in its 24x36mm 12MP sensor. Combined with CMOS technology and evolved electronics the Nikon D3 has a normal ISO range to ISO 6400. As a comparison, the Canon XSI top sensitivity is 1600 and most prosumer models extend to ISO 3200.


As you can see in this dramatic ISO 6400 hockey shot produced by Dave Black for Nikon, D3 images at ISO 6400 are extremely low noise. Even more impressive is the ability to still capture usable images at ISO 12800 and all the way to ISO 25600 with much increased noise in a pinch.

Clearly noise is related to the size of pixels in analog sensors, but that is only part of the story. Often the manufacturer of the camera has made decisions, either informed or due to lack of expertise, to not process for noise at high ISO. Cameras that appear to exhibit much increased noise at high ISOs are sometimes capable of much lower noise. The poor noise performance is sometimes the result of decisions by the camera maker in how files will be converted to RAW or JPEG files in camera or in post-processing software.

The Sigma SD14 Wakeup Call
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  • yyrkoon - Monday, July 28, 2008 - link

    I have been curious for some time now why you guys work with JPEGs. Hell, I would not even consider myself either a professional photographer or image re-toucher, but I can do rather well with image manipulation given enough time. Either realistic correction, restoration, or artistic.

    Ideally most everyone I know that re-touches images works with RAW, or TIFF. Now, I am not trying to tell you what to do, but I suspect if you guys used one of the above formats, and THEN posted your results afterwards in JPEG . . .

    Also I have to agree with the poster above me, heavy handed filtering is not good, and layers exist in Photoshop for a reason ; )
    Reply
  • Wesley Fink - Monday, July 28, 2008 - link

    ALL SD14 images were shot in RAW and processed in Sigma Photo Pro and saved as highest quality JPEGs. We did not shoot any SD14 images using in-camera JPEG.

    As pointed out in the article Noiseware does not work on RAW files - the standalone works on JPEG, TIFF, BMP, and PNG files. Even Photoshop plug-ins do not work on RAW since Camera RAW is a plug-in itself.

    We have had endless discussion in-house on how to present files in photo articles, as no one, including the most repected sites, does a very good job of presenting photo files. If you read through at some well-respected sites you sometimes wonder if you can possibly be looking at the same file you are viewing. They can be calling it "sharp" or noisy" and it looks completely different on your monitor.

    We are very open to suggestions on how you would like photo files presented. We try to publish the original image as well as crops, normally with EXIF data as well. This often lands us in hot water which may be why some of the large, well-respected sites don't do this with their test images. We would still prefer to disclose as much imfo as possible even if it invites stoning.
    Reply
  • VirtualMirage - Tuesday, July 29, 2008 - link

    If you use the RAW converter Bibble (Pro or Lite, an excellent and VERY fast RAW converter from Bibble Labs), it comes with a lite (but free) version of Noise Ninja.

    If you have a registered copy of Noise Ninja, it will unlock the full featured Noise Ninja built into Bibble. The lite and registered versions provide noise reduction on the RAW file (in a nondestructive manner like most RAW converters) prior to it being converted to a JPEG or TIFF, this allows the noise reduction to be processed on the highest quality version of the image without worrying that jpeg compression artifacts or file conversion degradation will effect the process.

    And an another plus, is the registered version of Noise Ninja in Bibble does unsharp mask and performs the sharpening alongside the noise reduction properly (instead of before or after with a seperate tool) so as to retain as much detail as possible.

    The only possible negative I have to say about using a dedicated noise reduction program, or one like Noise Ninja, is that they can give you almost too many controls to fine tune with. But with that ability you can also get amazing results once you understand how they work. Luckily there is an auto profile and typical default settings beginners can work with.

    Paul
    Reply
  • Wesley Fink - Tuesday, July 29, 2008 - link

    Paul -

    Thank you for your suggestion. I had forgotten that Bibble processes most RAW images and includes a lite version of Ninja Pro. Bibble certainly sounds like a useful tool for Pentax K20D and Sony A350/A700 users. Unfortunately Bibble does not support Sigma RAW so it would not be as useful for the small group of SD14 Foveon users.

    I certainly intend to give Bibble another look in the near future.
    Reply
  • yyrkoon - Monday, July 28, 2008 - link

    Well I have to say that aguilpa1 had a point that you should have tried to remove croma noise when imported into CS3 or whatever application you used. HOWEVER, since this is a software noise removal review, that would not be true to what I think you guys are trying to show us. i.e. 'we' want to see how this filter/program does on its own. That said, it would be hard to say how this should have been done from every single readers view point.

    The best way I can think of doing this (right now) would be first to:

    1) Import RAW images into CS3 making sure all import settings remain the same.
    2) Check Image-> mode bits/channel is set to 8bits/channel. Save an original at this point for showing the original image.
    3) Go to Image -> Mode, and set bits/channel to 16bits/channel.
    4) make multiple layer copies of the original, applying a few different levels of noise removal on each layer. Some kind of consistency will be needed if comparing filters of course.
    5) Mark all layers but the original un-touched layers as hidden, find a good noisy area, and select it.
    6) Set each individual layer as visible(one at a time,and hiding the others), and copy paste into a new image within photoshop. Making sure that the new->file bit/channel is of course 16bit/channel. This should also be done with one or more of the re-touches to be shown as a full sized image, after deselecting your selection of course.
    7) Go to Image-> mode once more for each image and change bit/channel to 8bit/channel before saving to JPEG.

    So now you could have the original to show, a full re-touched image, and several crops of a noisy area with different filter strength applied. Using 16bit/channel is something I have become used to while editing images to help ensure that colors do not get squashed too much while editing images, even if saving out to JPEG(which I usually do). In some cases it may be an un-needed step, but I never know if I will ever make prints of my work or not, AND this is something that really does not take much work.

    Anyways, some food for thought, and maybe you already do something similar to this already ?

    This is kind of a double edged sword, but if I went purely by the automatic settings of this filter/application, I would have to say that this filter is junk. In reality though this just means that the automatic settings for this application are way too harsh, but the filter/application *could* be very good when applied correctly. Now if something like i kind of laid out above was done, there would be more information for someone like me to make a better decision.

    Maybe someone else has a better idea ?
    Reply
  • aguilpa1 - Monday, July 28, 2008 - link

    I agree with the folks that say the use of noiseware with the Sigma pictures is horrible. It represents either the default or very heavy handed use of the filter. I use noiseware as a plugin with Photoshop CS3 but not always and carefully. If you don't use it carefully it will ruin your picture and turn it into a watercolor like what you have in those Sigma pictures. If you guys had taken your original SD14 pics in RAW and done some chroma noise reduction to remove the more offensive color blotchiness first than run your noiseware afterwards in PS without being so aggressive on your settings, preferably on a duplicate layer so you could (erase) the noise filtering on your more detailed subjects you would have gotten better results. Reply
  • Wesley Fink - Monday, July 28, 2008 - link

    As stated in the article all Noiseware processing used the AUTO mode, and should be considered the worst case or baseline of Noiseware use. As we pointed out there are many more controls available for custom tweaking and adjusting to parameters important to the user.

    The idea of this article was to expose people to the idea of noise reduction post processing. It may surprise some of the "experts" commenting on this article that most of our readers who use digital cameras do not even know programs like Noiseware exist or exactly what they do. This article was targeted at that audience.
    Reply
  • studio1 - Monday, July 28, 2008 - link

    The quality of digital photography analysis on this site is not up to par with the rest of the site. Serious readers choose sites like DPReview for their photo information. I wouldn't go to DPReview for info on the latest chipsets because they have the good sense to stay away from topics they aren't experts in. I wish Anandtech would do the same. Reply
  • kmmatney - Monday, July 28, 2008 - link

    Didn't you already have a whining post on the first page? Not all of find DPRReview all that useful. I went to that site before I bought my Canon and to be honest, it was no help at all. I ended up borrowing a friends camera, liked it, and then bought the same one. Here is the section on noise reduction at DPR Reviews web site:

    http://www.dpreview.com/learn/?/Glossary/Digital_I...">http://www.dpreview.com/learn/?/Glossary/Digital_I...

    Reply
  • strikeback03 - Monday, July 28, 2008 - link

    The glossary section of DPR is not great and out-of-date for the most part. Reading the reviews or the forums will give you much better information. Reply

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