Sigma SD14: Quick Look at a Quirky Wonder
by Wesley Fink on June 3, 2008 4:20 AM EST- Posted in
- Digital Camera
Our Digital Sensor Part 1 and Digital Sensor: Part 2 articles got us thinking again about the state of the Foveon sensor. The Foveon hadn't been in our hands since our early fascination with the first Foveon camera, the Sigma SD9. As there are some very serious devotees of the Sigma Foveon and even an active Sigma DSLR discussion forum at DPReview, our curiosity was burning on whether the Foveon had improved any since that error-plagued early attempt by Sigma. After many launch delays, the SD14 has now been shipping for almost a year and it has gone through several rounds of firmware and software updates. Time has likely made the SD14 as stable as it will ever be.
The Sigma SD14 is the current Foveon sensor Digital SLR, but since it has been on the market for almost a year it will not be dissected as a new model. The emphasis instead will be Foveon performance and SD14 workflow questions. This is a closer look at how the SD14 operates - the speed, typical workflow, and image quality across the available ISO range. The SD14 is the first Foveon DSLR to actually have the option of saving in JPEG mode. However, JPEG saves are very slow and still much poorer quality than RAW on the SD14. As a result most SD14 users work in RAW mode. Since that is how most users work it is how we will evaluate the SD14.
Here you see the SD14 decked out with the optional Power Grip PG-21. Sigma also offers an extremely broad line of prime and zoom lenses for the SD14. Sigma has produced lenses for their digital SLR cameras for more than 15 years, and even the early Sigma-mount lenses attach and work well. The current lens line even includes new models with Optical Image Stabilization that is said to provide up to four stops of improved performance.
Foveon fans will not likely be swayed by much that we report, but our out-of-the box experience with the SD14 was anything but an auspicious beginning. We were somewhat prepared for the SD14 to be slow in operation, but we were not really prepared for almost nine seconds from camera turn on to being able to take an image of any kind. We were also not prepared for the initial lockup where the interminable blinking red light - that indicates the camera is busy - would never turn off.
After formatting both 8GB CF cards a second time with an external USB2 card reader, the camera finally came to life after eight blinks of the CF card busy light and a couple of quick flashes while it set up the CF file system. To err on the caution side we updated the firmware, which strangely required two update sessions in the correct order to end up with Firmware version 1.07. The firmware update didn't stop the once-in-a-while lockups, but a "drive-dial" off and on usually fixed locks and we didn't have to go to the extreme step of removing the battery to recycle the hangs but once. Clearly, Sigma still needs some refinement in their camera firmware as users of a Canon or Nikon would never settle for this buggy operation.
If it were strictly about the camera itself we would have given up at this point, but we trudged on because every photographer knows it is about the image - and the second generation Foveon is a totally different beast from other cameras.
UPDATE: After the review was published we received several emails from current SD14 owners who reported 1 second start up times and few if any lock-ups with 1.07 firmware. We looked further into the slow startup and lockup problem. We had used three different 8GB CF cards in the course of testing for this review. All were 280X cards based on Samsung memory chips, and all 3 cards have worked fine with every other camera we have tested at AT.
After receiving the reports from SD14 users of startups of 1 second or so, we tried two new CF cards of different brands - a 16GB and a 4GB. BOTH the new cards initialized in about a second and we have not experienced a lock-up yet in shooting with either card. Image write times remained very slow with every card we tested. THE STARTUP DELAY AND LOCK-UPS APPEAR TO BE THE FAULT OF CF CARD COMPATIBILITY ISSUES AND NOT THE SD14 CAMERA. The rest of this review has been revised to reflect these new findings.
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chibimike - Tuesday, June 3, 2008 - link
Layer-per-primary is not the future.It is a great idea, but passing through the first two layers to get to the red layer eats too much of the light. To make up for it, they make the red layer supersensitive, which then leads to clipping or extremely complex attempts at color correction. Unless there is some breakthrough material to make the sensor out of, it will always be noisy.
aeternitas - Tuesday, June 3, 2008 - link
I see your point, and its a good one.Except useing this method of three layer technology and pretending thats the only way is pretty close minded and short sighted.
Their are better methods than what Foveon has, but layer-per-primary as a base WILL be the future of digital photography. Its a technology in its infancy, and hinestly, do you see any other method that would even come close to haveing the same future potential? If you mention fuji ill shoot you.
Justin Case - Wednesday, June 4, 2008 - link
Potential is irrelevant when the current technology has aready hit the "lens wall".Bayer pattern sensors are already at the limit of lens resolution, and can still be pushed forward. Unless Foveon can suddenly increase the resolution of their sensors by 300%, fix all the color problems, and Sigma releases lenses that can beat the top Nikon and Canon models, they simply don't offer any advantage (note that there are sharper lenses than Canon's or Nikon's - Leica, Hasselblad, Voigtlander, Zeiss - but they're used by less than 0.1% of people).
If anyone is interested in improving the quality of Bayer sensors, the way to go is tetrachromacy (Sony is experimenting with that), but that makes processing more complex and offers only a very slight little advantage, so I don't see that happening, either.
Current Bayer sensors have hit the resolution limit for lenses, and improvements to sensitivity and chroma range are more important than resolution. Since those are precisely the points where Foveon is further behind, its future isn't particularly bright. Some people will continue to buy them, because the concept "seems to make sense", but in the real world they're simply worse in every sense. Even if done "perfectly" (with materials that don't even exist yet), they'd be more expensive and the advantage wouldn't be noticeable without a major upgrade to lens quality.
chibimike - Wednesday, June 4, 2008 - link
No not fuji, great for pocket cams, not so hot for SLRs.I think one of two things. Either a new material with much lower noise properties. Or if costs keep going down, we could potentially see someone do a creative take on the three sensor design like they do in high end video cameras.
aeternitas - Tuesday, June 3, 2008 - link
PS.There is this new and great technology called PNG. No one expects you to display tiff or raw files. I'm not sure why a paragraph was put into explaining that to everyone.
Wesley Fink - Tuesday, June 3, 2008 - link
We use PNG all the time in our articles and reviews and it is a desirable lossless format like TIFF. However it is not really very suitable for photographic images. To quote from Wikipedia:"JPEG can produce a smaller file than PNG for photographic (and photo-like) images, since JPEG uses a lossy encoding method specifically designed for photographic image data. Using PNG instead of a high-quality JPEG for such images would result in a large increase in filesize (often 5–10 times) with negligible gain in quality."
For photographs PNG is no better than JPEG, but the files are MUCH larger. PNG is best with tables and line drawings. We need a new web format as neither TIFF or PNG are suitable and current JPEG is just 8-bit - perhaps an update of JPEG.
Justin Case - Wednesday, June 4, 2008 - link
PNG uses prediction and error coding, followed by entropy encoding. It's pretty much the best lossless algorithm you can get for photos.For line drawings and tables, GIF (LZ compression) will frequently produce smaller files than PNG, especially if they have regular dithering patterns.
If you think there's no difference between JPEG (even at the maximum quality allowed by Photoshop) and PNG, you need to have your eyes checked. Even though Wikipedia is hardly an authoritative source, the article you quoted says "a negligible gain in quality". Not "no gain". You're the one who extrapolated that to "PNG is no better than JPEG".
The meaning of "negligible" depends on the situation. Yes, the PNG files are significantly bigger. And yes, if you use a crappy camera, you'll get artifacts from the lens and sensor anyway. But when you're comparing high-end cameras and sensors, it definitely pays to use a lossless format (generated from raw, of course, not from an in-camera JPEG). Even better, post a couple of raw files and let people who are interested download and compare them using appropriate software.
BTW, there already is an "update of JPEG". It's called JPEG-2000 and gets about 40% higher compression for the same (lossy) image quality, and even supports lossless compression. If you can convince browser makers (namely Microsoft) to add support for it to their software, we'd be thankful. Until then, I doubt it'll catch on.
I have no idea why you need a higher-than-8-bit format "for the web", considering that about half the LCDs out there are actually 6-bit panels and that 99.9% of graphics cards are limited to 8-bpc. We definitely don't need browsers to become more bloated just so they can handle HDR or RPF images natively (which 99% of people have no use for in web pages).
For distribution and webpage "decoration", 8-bit JPEGs are fine. The question is whether they're fine for an article comparing minute differences between high-end digital sensors. And the answer to that is almost certainly no (just as MP3 files aren't really the right choice to evaluate high-end audio equipment).
Deadtrees - Thursday, June 5, 2008 - link
Last time I checked, JPEG2000 is pretty much dead and MS is trying to setup a new JPEG2000 like picture file system along with many other major companies. I forgot the details but it was open architecture and it was better than JPEG 2000.Justin Case - Friday, June 6, 2008 - link
JPEG-2000 is only "dead" due to lack of native support in Windows and web browsers. It's a significant improvement on JPEG.Microsoft's format (which has gone through three names, I think the current one is "MS HD Photo") is a DRM'd format which, in terms of quality vs. compression, is slightly inferior to JPEG-2000 and can only be manipulated through Microsoft's own APIs (very much not an "open architecture"). It does have support for several useful features (like floating-point HDR) but I really don't see those being relevant for a distribution format; if you want HDR data, you probably don't want lossy compression, and vice-versa.
A unified "raw" format for all camera manufacturers, on the other hand, would be nice, but considering the different sensor layouts, different bit depths, different processing required, etc., you would have a single file extension but effectively N different sub-formats.
aeternitas - Tuesday, June 3, 2008 - link
I understand the differance between the two.In context, when mentioning all those formats, and not mentioning png, its kinda off. Also, PNG with such tiny crops is negligible.
Aside from that, a contrustive suggestion would be, if youre going to do side by side images, have a single croped image, and several mouse-overable links that change the image dynamicaly. It gives a much much better result when trying to see subtile differences between cameras.
IMO that would one-up anandtech camera reviews compaired tomost online.