Ad
Ad
Ad
Pages: « 1 [2] 3 4 5 »   Bottom of Page
Print
Author Topic: SIGMA DP-1  (Read 32191 times)
:Ollivr
Newbie
*
Offline Offline

Posts: 37


WWW
« Reply #20 on: March 11, 2007, 11:39:59 AM »
ReplyReply

Well anyways although I am a quite happy user of a Foveon-based camera I dont want to advertise/defend their product any more than this (except for they pay me for it). Let me just say its a different way of capturing images with different artifacts. Its a relatively young technology (more so than the bayer grid) and still has some disadvantages, one of which being that it is less user-error-proof. Advantages are the sharpness and rendition of subtle color transitions (if you do it right). Relative to the small community of foveon users, there are loads of bad images out there as you just cannot really "point and shoot" the older Sigma cameras. Lets see what MR thinks about the newer Sigmas.

O.
Logged
JLK
Newbie
*
Offline Offline

Posts: 35


« Reply #21 on: March 12, 2007, 11:26:31 AM »
ReplyReply

Quote
It seems that Sigma has listened to the feedback on announcing the advent of the DP-1 at Photokina: external optical viewfinder, hotshoe for flash and RAW capability. I'll bet it becomes the poor man's Leica M8
[a href=\"index.php?act=findpost&pid=105498\"][{POST_SNAPBACK}][/a]

Indeed, Sigma does listen to the feedback that they get from users. I had the opportunity to handle the DP1---it's a very sweet little camera. The accessory viewfinder is very nice. As mentioned previously, the f4 lens takes up quite a bit of space already---I doubt they can go with f2.8 without making the body taller. Clever manual focusing mechanism as well

With the new imaging pipeline for this product (TRUE), I believe the hope is for a stop or two better than the SD14. I got to shoot the SD14 for a few days, and it produces outstanding images. I got to see some head to head comparison of "artifacts" from the SD14 vs CFA sensor cameras (think D200, 5D). While there can be some luminence aliasing in the SD14, it's way better than the trashing that goes on with regards to color moire (and it's removal) in the CFA cameras. The edge aliasing is really not an issue when printing 99% of Sigma photos---and the prints at PMA were certainly proof of that.

It's a very exciting introduction---I expect it will do very well with photographers.
Logged
Jo Irps
Jr. Member
**
Offline Offline

Posts: 52


« Reply #22 on: March 13, 2007, 05:12:57 AM »
ReplyReply

JLK

thanks for your very interesting report of the DP1 and the SD14.
Did Sigma give you any hints of shipping dates of the DP1? Cant wait to get my hands on one.
Logged
JLK
Newbie
*
Offline Offline

Posts: 35


« Reply #23 on: March 13, 2007, 08:34:36 AM »
ReplyReply

Quote
JLK

thanks for your very interesting report of the DP1 and the SD14.
Did Sigma give you any hints of shipping dates of the DP1? Cant wait to get my hands on one.
[a href=\"index.php?act=findpost&pid=106383\"][{POST_SNAPBACK}][/a]

I have heard "hints", but I hesitate to put stock in them. I know that they wished to have the SD14 shipping before Christmas, but they ended up having to make a hardware fix in the camera that delayed the shipping until this month.

I would expect that you would be able to get your hands on a DP1 by summer (end of June), barring any unforseen major circumstances. They had working pre-production units there, but were not letting images out because they are still working on the imaging processing pipeline.
Logged
John Sheehy
Sr. Member
****
Offline Offline

Posts: 838


« Reply #24 on: March 14, 2007, 08:44:54 AM »
ReplyReply

Quote
I see how the bricks look weird at the edges but I wonder wether it is camera body artifacts.

Of course it is.  How could a lens cause a snap-to-grid effect?  A lens is an analog device, it only errs in an analog fashion, totally unrelated to pixels.

Quote
Just doesnt look like aliasing to me. As far as the jaggies are concerned I can only tell you about my own: Its mostly user error due to not setting sharpening to -0.8 in the raw converter.
[a href=\"index.php?act=findpost&pid=106040\"][{POST_SNAPBACK}][/a]

Softening jaggies after capture is not the same thing as never capturing them in the first place; same for any kind of aliasing.  An AA filter (or a lens that effectivcely acts as one) filters away frequencies above the nyquist, so they are never captured.  An unfiltered capture captures frequencies above the nyquist, and after capture, they are indistinguishable from other "mirror" frequencies below the nyquist.  You have to filter away valid frequencies to remove the aliased ones.

There is a strange idea going around that a digital camera should be able to record a black pixel next to a white one.  It is impossible to do so, and have an accurate recording.  What all cameras need for better *real* subject sharpness is more pixels; technology and storage issues are holding that back.  With enough pixels, color resolution is no longer an issue with Bayer arrays, and aliasing is no longer an issue (no AA filter needed).  Bayer is currently ahead in the miniaturization race.

If the DP-1 had even the mildest of AA filters (which is all it really needs), I would seriously consider buying one (mainly for B&W photography).  Without an AA filter, I will not purchase one.
Logged
Graeme Nattress
Sr. Member
****
Offline Offline

Posts: 582



WWW
« Reply #25 on: March 14, 2007, 08:55:46 AM »
ReplyReply

John, you put that very well indeed.

Graeme
Logged

www.nattress.com - Plugins for Final Cut Pro and Color
www.red.com - Digital Cinema Cameras
JLK
Newbie
*
Offline Offline

Posts: 35


« Reply #26 on: March 14, 2007, 09:15:43 AM »
ReplyReply

Quote
Of course it is.  How could a lens cause a snap-to-grid effect?  A lens is an analog device, it only errs in an analog fashion, totally unrelated to pixels.
Softening jaggies after capture is not the same thing as never capturing them in the first place; same for any kind of aliasing.  An AA filter (or a lens that effectivcely acts as one) filters away frequencies above the nyquist, so they are never captured.  An unfiltered capture captures frequencies above the nyquist, and after capture, they are indistinguishable from other "mirror" frequencies below the nyquist.  You have to filter away valid frequencies to remove the aliased ones.

There is a strange idea going around that a digital camera should be able to record a black pixel next to a white one.  It is impossible to do so, and have an accurate recording.  What all cameras need for better *real* subject sharpness is more pixels; technology and storage issues are holding that back.  With enough pixels, color resolution is no longer an issue with Bayer arrays, and aliasing is no longer an issue (no AA filter needed).  Bayer is currently ahead in the miniaturization race.

If the DP-1 had even the mildest of AA filters (which is all it really needs), I would seriously consider buying one (mainly for B&W photography).  Without an AA filter, I will not purchase one.
[a href=\"index.php?act=findpost&pid=106591\"][{POST_SNAPBACK}][/a]

While lumenescence aliasing can be distracting in some cases with the x3 sensor (and no AA filter), it usually provides better, more pleasing output than a CFA sensor with an AA filter---the combination leads to many more issues, especially in the area of color detail. In casual conversations with Foveon, they have tried AA filters over their sensor and the verdict apparently was the images were better without.

CFA technology is definitely more mature, and they are not only ahead of the miniaturization race, they are at their limit (with regards to image performance). That's the nice thing about the "less mature" x3 technology---they still have some headroom to grow. Eventually they may get to the 10 x3 (30 MP) crop sensor, and a 20 x3 mp (60 MP) FF sensor. It's gonna take some hefty pipeline processing to get those to run as fast as a Mk III, however.
Logged
:Ollivr
Newbie
*
Offline Offline

Posts: 37


WWW
« Reply #27 on: March 14, 2007, 03:51:47 PM »
ReplyReply

Quote
Of course it is.  How could a lens cause a snap-to-grid effect?  A lens is an analog device, it only errs in an analog fashion, totally unrelated to pixels.

That is clear to me. The question is not body or lenses here but body or computer. The Artifacts can very easily occur when processing the raw, particularly with sharpening methods that work well with bayer cams.
Then, as I said before, the sharpening slider in the Raw software sitting at zero does not mean no sharpening is applied. As some folks found out, it needs to be set to -0.8 Otherwise you start out in PS with artifacts caused by wrong treatment of the raw file. CAs and stuff like that would in fact be sharpened prior to any removement attempts or resizing.


Quote
Softening jaggies after capture is not the same thing as never capturing them in the first place; same for any kind of aliasing.  An AA filter (or a lens that effectivcely acts as one) filters away frequencies above the nyquist, so they are never captured.  An unfiltered capture captures frequencies above the nyquist, and after capture, they are indistinguishable from other "mirror" frequencies below the nyquist.  You have to filter away valid frequencies to remove the aliased ones.

Remains the question what is better: Nothing there above nyquist as with bayer cams or at least something, may it be irregular, captured. But again I am working with a DSLR since only 20 months roughly so the answer to this is beyond what I know (and probably dependent on the actual image and viewer).
Um, and another question: What about the artifacts occurring with the bayer capture? WHat about the moire and nasty stuff like that? Its not that a bayer cam is artifact-free, right?

I'd say let us wait for some reviews how both cameras perform in the real world. Taking pictures is more of an art and less of a science IMO. Note how film grain (what one could call the first artifact ever!) can look nasty and inappropiate in some images and totally great in others.

In fact, maybe they will release an add-on AA filter as sort of a bridge solution...

O.
Logged
Graeme Nattress
Sr. Member
****
Offline Offline

Posts: 582



WWW
« Reply #28 on: March 15, 2007, 04:26:05 PM »
ReplyReply

If you have the proper AA filter on a Bayer CFA sensor, you don't get moire nasties. It's funny that on the Foveon pages, they always show bayer images with no AA filter, which will make for colour nasties on edges.

Also, aliassing and moire are both very hard to remove after shooting, but quite easy to avoid if you have the correct level of optical AA when shooting.

About the worst you get on a Bayer image with optical AA is a bit of softness, and given the vastly greater number of pixels Bayer cameras have, this is generally a non-issue.

And, of course, the colour is so much more accurate due to the use of coloured dyes, rather than silicon depth as a colour filters.

Graeme
Logged

www.nattress.com - Plugins for Final Cut Pro and Color
www.red.com - Digital Cinema Cameras
KAP
Full Member
***
Offline Offline

Posts: 168


WWW
« Reply #29 on: March 16, 2007, 02:57:20 AM »
ReplyReply

OK it's not ideal you can argue about the lens speed and AA filter, but at the end of the day there is no other pocket size camera available that promises the results of this Sigma. Every other one is a tiny sensor and often jpg only. I'm looking forward to seeing the camera and results, on paper I wont one, I think they will sell truck loads. I saw prints from the new SLR and they looked very nice.

Kevin.
Logged
JLK
Newbie
*
Offline Offline

Posts: 35


« Reply #30 on: March 16, 2007, 09:21:30 AM »
ReplyReply

Quote
If you have the proper AA filter on a Bayer CFA sensor, you don't get moire nasties. It's funny that on the Foveon pages, they always show bayer images with no AA filter, which will make for colour nasties on edges.

Also, aliassing and moire are both very hard to remove after shooting, but quite easy to avoid if you have the correct level of optical AA when shooting.

About the worst you get on a Bayer image with optical AA is a bit of softness, and given the vastly greater number of pixels Bayer cameras have, this is generally a non-issue.

And, of course, the colour is so much more accurate due to the use of coloured dyes, rather than silicon depth as a colour filters.

Graeme
[a href=\"index.php?act=findpost&pid=106859\"][{POST_SNAPBACK}][/a]

Actually, you lose quite a bit of color resolution (color detail) with the "correct" (read high strength) AA filter. This is easily born out looking at test shots of finely detailed color samples under controlled studio conditions. Some camera manufacturers have either eliminated the AA filter (Kodak, Leica), made it optional (Kodak's older DCS series), or made it weaker (D70, D80). This gives you back SOME of the color resolution, but at the expense of color moire. If you remove moire with in software, you'll screw up color resolution in the rest of your image (unless you work very selectively---which is laborious).

With the Foveon chip, you rarely (if ever) see color moire. You will definitely see luminence aliasing (a B&W houndstooth pattern not being accurately reproduced), but it in general will not be as objectionable as the color moire you would get with a CFA sensor (or the mush you would get with a highly AA'ed CFA sensor).

With many subjects, the effects aren't as pronounced---but many of the Foveon-koolaid drinking photographers (myself included) like the "look" of a Foveon image over many CFA images. Another major advantage with the Sigma images is that those "sharp" edges make post production a breeze---including very large prints (you would have seen several if you attended PMA or Focus).

The comment you made about dyes vs depth of light penetration in silicon is just wrong. Both are very reasonable ways to determine color, no method is inherently more accurate. The current advantage of Foveon's approach is that the color sensors are linearly colocated---so a "pixel" (in x,y terms) has 3 color information, as opposed to just 1 color in a CFA imager. 3 chip cameras that use beam splitters (Foveon did that in their early days) also work very well.
Logged
JLK
Newbie
*
Offline Offline

Posts: 35


« Reply #31 on: March 16, 2007, 09:23:27 AM »
ReplyReply

Quote
OK it's not ideal you can argue about the lens speed and AA filter, but at the end of the day there is no other pocket size camera available that promises the results of this Sigma. Every other one is a tiny sensor and often jpg only. I'm looking forward to seeing the camera and results, on paper I wont one, I think they will sell truck loads. I saw prints from the new SLR and they looked very nice.

Kevin.
[a href=\"index.php?act=findpost&pid=106936\"][{POST_SNAPBACK}][/a]

Kevin,

The prints from the SD14 are indeed, very nice. And I believe that Sigma has very reasonable expectations for this camera---if they sell "truckloads" (say the 200K that was mentioned before), they would be blown away.
Logged
:Ollivr
Newbie
*
Offline Offline

Posts: 37


WWW
« Reply #32 on: March 16, 2007, 10:02:41 AM »
ReplyReply

OK its one thing to discuss the different technologies and argue about to AA or not to AA - I have too little knowledge about those things to engage into a serious argument.
ANother thing is looking at actual photos. Maybe you will find these here interesting.
I made those pictures yesterday with my old an trusted SD10, over which the SD14 and the DP1 are said to have been improved a lot sensor-wise.
 
Both are original-size output from the raw converter, unsharpened, uncurved, unsomethinged.
Only thing I did in PS was reduce a bit of lens-related fringing on the smaller image (its a 100% crop), change color space to sRGB on both images and thats that.

Feel free to download and peek at it. As I said its completely unsharpened, depending on your taste you might want to add a tad of sharpening (maybe 20% and 1pixel Radius in Smart Sharpening) or change the colors a bit, did nothing on those.

Maybe someone can show me those nasty artifacts also.

Images here:
http://www.flickr.com/photo_zoom.gne?id=423098427&size=o
http://www.flickr.com/photo_zoom.gne?id=423097304&size=o

REgards,

O.
Logged
Graeme Nattress
Sr. Member
****
Offline Offline

Posts: 582



WWW
« Reply #33 on: March 16, 2007, 11:06:27 AM »
ReplyReply

Well, if you look at a raw foveon image in it's raw state, it has very little colour and needs some very strong calculations in the colour matrix to make it colourful, whereas bayer cfa images only need a slight matrix, usually adding just a bit of saturation to get a very colourful image. I think that shows that using silicon as a colour filter is not the best of approaches if colour accuracy is your goal.

Also, bayer cfa cameras generally have much much more resolution than foveon is capable of, so even if you have to downsample, you're still ending up with a larger image.

Interesting to talk of mush - that's just how the human eye sees things - they get blurry and indistinct as they go into the distance. We don't see false aliassing detail as things get small. We see straight lines as straight lines, not stair-steps.

Graeme
Logged

www.nattress.com - Plugins for Final Cut Pro and Color
www.red.com - Digital Cinema Cameras
JLK
Newbie
*
Offline Offline

Posts: 35


« Reply #34 on: March 16, 2007, 12:24:39 PM »
ReplyReply

Quote
Well, if you look at a raw foveon image in it's raw state, it has very little colour and needs some very strong calculations in the colour matrix to make it colourful, whereas bayer cfa images only need a slight matrix, usually adding just a bit of saturation to get a very colourful image. I think that shows that using silicon as a colour filter is not the best of approaches if colour accuracy is your goal.
Graeme
[a href=\"index.php?act=findpost&pid=107021\"][{POST_SNAPBACK}][/a]


Graeme,

If you look at either "set" of data in their raw state, neither have color. The readings are voltages proprotional to the number of photons absorbed. The CFA model gets the color from the fact that a pixel is covered by a "green" filter, so it must be 210 worth of "green". It then borrows values from it's red, blue, and green neighbors to get the color.

In the foveon model, the same thing happens for a "pixel", except the photosites that are used to interpolate the color are all spatially co-located. That's a good thing.

If color accuracy is your goal, you should shoot an appropriate target under lighting conditions that you will use, process the RAW files in a way that you deem appropriate, and then measure the results. The Sigma cameras do pretty well.

Another piece of misinformation is:

Quote
Also, bayer cfa cameras generally have much much more resolution than foveon is capable of, so even if you have to downsample, you're still ending up with a larger image.

First, a sensor doesn't have "resolution". It has pixels. It's an important distinction. In addition, while it's believed that Bayer sensors are near their limit of usefulness pixel density (let's say 16-20 MP for a full frame sensor), Foveon sensors aren't. If you have a few million dollars (I'll toss in a few as well), I'm sure that Foveon would be happy to crank out a FF sensor based on the current pixel pitch would give you a 14.2 "MP" sensor (which would be called a 43 MP sensor). There's nothing inherient in the technology that limits them from doing that. It's a lot of data to push around, but they had a 48 MP (16 x3) prototype chip in 2000.

Currently, you will end up with much more x,y pixels if you shoot a 5D than if you shoot a SD14. The pixels in the 5D are not as high quality however---there are tradeoffs. B&W resolution will definitely be better with the 5D. Acutence will always be better with the SD14. Color resolution will be better under many situations with the SD14.

Quote
Interesting to talk of mush - that's just how the human eye sees things - they get blurry and indistinct as they go into the distance. We don't see false aliassing detail as things get small. We see straight lines as straight lines, not stair-steps.

Indeed, it's really interesting to talk about visual perception and how the eye works. The eye has amazing dynamic range, the ability to pick out fine detail, and a great processing system behind it. Even with a crappy lens! (As an aside, I had my eyes checked and dialated about a month ago---talk about CA with a wide open lens!!!)

One of the things that Foveon does very well is to hold fine detail, even if it's "false". Fine hair in portraits. Fishing line from a fishing pole. Fine fabric detail. The stairstep issues that are often brought up are normally not issues in printing---you don't see them under 99% of the conditions. Where they are issues, one can selectively blur in your favorite tool.

Compare to CFA images---they're non-selectively blurred by the AA filter, and then again by color interpolation. That's one reason for Bruce Fraser's immensely popular sharpening treatise---to regain some of that lost acutence. The reason I love the SD10 (and the SD14 that I've played with) is because making big prints is so easy compared to CFA cameras. The workflow is much easier. And I personally think the prints are better.

I'm not attempting to talk you out of your favorite brand of camera---but there are inherent differences in the Foveon technology that make it superior to CFA systems as a capture technology. This would be equally (or moreso) true for any full color systems. Scanning backs are terrific. 3-chip cameras are too. And perhaps Canon, Nikon, Dalsa, Kodak, or Sony will come out with something full color in the future---but right now, the x3 chip is the only game in town.
Logged
Bill in WV
Full Member
***
Offline Offline

Posts: 108



« Reply #35 on: March 16, 2007, 01:37:39 PM »
ReplyReply

Quote
The problem with this specialized a product is that everyone (almost) will have at least one show stopper.  For me, it's not the f4, but rather the lack of articulated screen.  I'd use this for unobtrusive street shooting, but after the Sony R1 I'll never give up an articulated LCD.  Just like I won't settle for no raw or more noise.
[a href=\"index.php?act=findpost&pid=105681\"][{POST_SNAPBACK}][/a]
Hey Tim,

I remember when we met last year, you were shooting with the R-1. Do you still have it? To me, that camera has so much to like, beginning with the lens and sensor but I am getting  a bit camera poor at the moment. I still have the D60 and have added a 30D and more recently the little G7. But there is something very appealing about the R-1. I guess I'm really holdiing out for a lottery win, and the new and improved Leica M-8a or b. But for now, I think I'll just try to find more time to shoot with what I have.

Real reason for the post - Have you seen Michael's new gallery yet? How hard is it going to be for we poor old West Virginians to find when it opens. Betty and I are looking forward to our next trip to Toronto and Michael's next show.

Bill Evans (AKA: Bill in WV)
Logged

Bill Evans

Currently shooting with Canon digital equipment
John Sheehy
Sr. Member
****
Offline Offline

Posts: 838


« Reply #36 on: March 16, 2007, 05:13:35 PM »
ReplyReply

Quote
If you look at either "set" of data in their raw state, neither have color. [a href=\"index.php?act=findpost&pid=107042\"][{POST_SNAPBACK}][/a]

I don't think you understand what he was saying; *when* you convert the RAW data to color, literally, without any saturation changes or hue shifts, the Bayer CFA shows much more distinction between colors than the Foveon RAW data does.  All three Foveon layers respond almost identically to colors in the blue to green range.  Colors in that range record as grey even in the colored version of the RAW data.  Only reds, oranges, and yellows have much saturation in Foveon RAW data.  Blues and greens, especially the in-between range, are extrapolated and greatly magnify the system and photon noise, leading to the chromatic noise that you see in sky and sea.  Deep shadows often have huge off-color blotches when you push them in color, due to doping inconsistencies.  Foveon recommends a filter to be used with their sensor, which would make the overall system more discriminating with color, but Sigma does not use it, as it would reduce the sensitivity of the camera greatly.
Logged
BernardLanguillier
Sr. Member
****
Offline Offline

Posts: 8344



WWW
« Reply #37 on: March 16, 2007, 07:13:50 PM »
ReplyReply

I feel that the automotive industry provides some good insight about the future of bayer vs foveon like devices.

There are better formulas than our rotating piston engines, but car manufacturers and suppliers have invested so much into the our current engines that they just are not interested in taking risk with something else since the benefits might not be huge for customers.

I personnally don't see Canon, Sony, nikon and the other guys jump shipping to a new sensor technology any time soon. Besides the original 1ds, Canon has been extremely conservative in all its DSLR releases eversince, Nikon isn't more of a front runner.

Sigma has adopted a interesting approach and I really hope that the risk they have taken will be rewarded somehow.

If I were Foveon though, I would focus on MFDB sensors...

- Those backs still have large photosites,
- Their users are used to non AA filter side effects,
- High ISO isn't too important there,
- At least some of the users are experienced enough to see the value of having true color capture instead of Bayer,

I guess that there might be some technological issue with producing larger sensor with the Foveon technology, but that is IMHO where they should concentrate their effort.

Cheers,
Bernard
Logged

A few images online here!
Graeme Nattress
Sr. Member
****
Offline Offline

Posts: 582



WWW
« Reply #38 on: March 16, 2007, 08:59:47 PM »
ReplyReply

JLK, I look at raw images (in the raw) all day. I spend a lot of time with demosaic algorithms, and know their strengths and weaknesses. Aliassing (visible stair-stepping) is the big weakness of the Sigma cameras. The slight softness on bayer cfa cameras is certainly there, but like any errors, an error of omission (some resolution) is generally less offensive than an error of comission (false detail).

When I talk about the colour of a raw image, you know exactly what I mean, so no need to say a raw image doesn't have colour. We all know that the colour matrix coeficients in a foveon camera are going to have to be a lot greater than a bayer cfa camera to generate accurate colour, and any gain you do in a matrix is going to increase noise and other nasties.

I'd hardly say bayer CFA sensors have reached their limits. I would say that silicon being a poor colour filter is a limit that has to be worked around for foveon to improve. Also, imagine how much better a foveon sensor would be if (like in 3ccd video cameras) they offset the red and blue array from the green and use that spatial information to increase resolution.

Graeme
Logged

www.nattress.com - Plugins for Final Cut Pro and Color
www.red.com - Digital Cinema Cameras
:Ollivr
Newbie
*
Offline Offline

Posts: 37


WWW
« Reply #39 on: March 17, 2007, 12:03:09 AM »
ReplyReply

Again, since nobody seemed to have noticed.
Can somebody show me the artifacts in those two images made with the older SD10? I am having a hard time here finding some. And I would be interested in an assessment about in which regard a bayer camera would capture color nuances better.
On a side note, I severely struggle to find the chroma noise in the shadows as well. Must be my monitor. Note this is unphotoshopped unsharpened raw converter output of an old Sigma DSLR.

Images here:
http://www.flickr.com/photo_zoom.gne?id=423098427&size=o
http://www.flickr.com/photo_zoom.gne?id=423097304&size=o

Regards,

O.
Logged
Pages: « 1 [2] 3 4 5 »   Top of Page
Print
Jump to:  

Ad
Ad
Ad