[panoguy]

If I want to play with this type of sensor (mostly landscape and close ups, but less for portraits type of shots), what would be a better combination, a package of DM2 and DM3 or SD1 and lenses. Assuming for the purposes of an answer that I want to get best image quality, or close to it. The cost of the two is a little less than the SD with a lens, but the lenses can be had with stabilisation. Thoughts?

Go for the DP3 and DP2 Merrills. The lenses are *perfectly* matched to those sensors and bodies. I had a DP2M and now have an SD1 Merrill. Same sensor, but interchangeable lenses... and guess what? Most Sigma lenses are out-resolved by the sensor! The macro lenses acquit themselves nicely, and so do the newer "Art" series (I have the 18-35mm f/1.8 now - damn you scratchpaddy!) but there are tons of useless lenses for an SD1 that are great on other cameras.

[Rob01]

Go for the DP3 and DP2 Merrills. The lenses are *perfectly* matched to those sensors and bodies. I had a DP2M and now have an SD1 Merrill. Same sensor, but interchangeable lenses... and guess what? Most Sigma lenses are out-resolved by the sensor! The macro lenses acquit themselves nicely, and so do the newer "Art" series (I have the 18-35mm f/1.8 now - damn you scratchpaddy!) but there are tons of useless lenses for an SD1 that are great on other cameras.

Thank you for your reply. I was thinking of the SD1 and either the 35mm F1.4 Art (we know it is very sharp and it would be fascinating to see it on the SD1) or the 18-35mm F1.8 as a start (perhaps other Art lenses as they come out and if they are good)... but then after reading half way through the thread I got an impression how good the lenses for DP3 and DP2 Merrills are... with a couple of these and some thought I think I can get done just about everything I would want to. The only system I have right now is a Pentax K5IIs with a few too many lenses and a LX7... so I can go fresh into this.

The only remaining thing I dislike is lack of bulb mode or a longer exposure time in the DPs. I am perplexed as to why this is not updated through firmware... overheating or battery problems?

I assume you have tested the 18-35mm F1.8 on the SD1? Thoughts?

[scratchpaddy]

The only remaining thing I dislike is lack of bulb mode or a longer exposure time in the DPs. I am perplexed as to why this is not updated through firmware... overheating or battery problems?

It's not much better on the SD1. There is a bulb mode, but it cuts off at two minutes, with no way to override it. I'm assuming it's a noise thing, and maybe heat, as you say. I've done 30-second exposures, and they're noisy even at ISO 100. I stick to my K-5 IIs for nighttime. During the blood moon this past week, my Sigma gear stayed home.

I agree with Panoguy, you should get a DP. They'll give you the best the Foveon has to offer, resolution-wise. Plus, the SD1M, coupled with any lens worth using on it, is very big.

(I have the 18-35mm f/1.8 now - damn you scratchpaddy!)

Ha ha! Resistance is futile! And you got a 180mm macro too? I had my eye on that lens for a while, but I don't shoot telephoto or macro enough to justify it.

I took the 18-35 and 12-24 on a 15-mile hike about a month ago, and I only took out the 12mm once. I'm starting to like it more and more. I took the DP2M as well, and I actually liked the colors from the SD1M better. I always have trouble working with the colors from this sensor, so the closer I can get out-of-camera, the better. I know it's the same sensor, but almost everything I get from the DP2M comes out too green, while the SD1M comes out purplish, but closer to how I like it. Here are some of the pictures from that hike, clickable for full-res, as always:

23mm f/1.8


18mm f/5.6


35mm f/2.2


DP2M, f/5.6


There's no reason for me to get the 35mm Art, since I have this zoom, but that new 50mm...

[Rob01]

It's not much better on the SD1. There is a bulb mode, but it cuts off at two minutes, with no way to override it. I'm assuming it's a noise thing, and maybe heat, as you say. I've done 30-second exposures, and they're noisy even at ISO 100. I stick to my K-5 IIs for nighttime. During the blood moon this past week, my Sigma gear stayed home.

I agree with Panoguy, you should get a DP. They'll give you the best the Foveon has to offer, resolution-wise. Plus, the SD1M, coupled with any lens worth using on it, is very big.

There's no reason for me to get the 35mm Art, since I have this zoom, but that new 50mm...

Thank you for the reply guys. I think I'll start with a couple of DP#s... maybe the 1 and 3 or 2 and 3... have to think (they can be had through amazon and ebay for around $550 each out of Japan). Scratchpaddy, if you say that the SD1 is noisy at 30 second exposures, it is probably a heat problem... after all, if the battery runs down quickly, the heat has to go somewhere (the good news is that this is probably solvable in the next generation of these cameras and sensors) I will think on whether there is a work around - I like to shoot HDR so even if the mid-point will be within tolerance, I do not think I can go more than +- 2 stops with the Merrills (in low light).

The reason to get the 35mm Art with SD1 is because it is razor sharp and so is the sensor (plus it has a an extra stop or two for low low light)... but yes, the money and the weight add up.

P.S. I have to say that after this thread I feel like I know your dog

[Rob01]

Yes, the new 50mm Art would be brilliant on the SD1M My dream team for this camera is 8-16mm (or the rumored extra wide zoom if it is part of the Art series), 35mm Art and either the 50mm Art or a longer sharp Art series lens that may appear in the near future (the 105mm OS Macro also sounds good on paper).

Scratchpaddy, the flat cacti on the left have aberrations around the edges. Correction failed? Or was not applied?

I'm bidding on the an DP1M right now on EBay... with four batteries and a lens hood. If that fails, I will get the DP2M from BH. In a fortnight I should be able to contribute some test pics and ask for tips For the rest I will see how I go with the first one... and then if SD1M gets replaced with the Quattro, get the old one before it disappears. I hate the idea of the new Quattros having only 5 Megapixels for two of the colours The current sensor is unique and I will stick with it one way or another.

[Mr Bassie]

Two from my trip to the UK last summer:

The aptly named Vine House in the Cotswolds:




The City of York, taken from the city wall:



Rob01 the Merrills are a great way to start with foveon. They are selling so cheaply right now that I think they are the best bang for the buck in photography.

I suspect the quattros will be slightly better image quality and greatly improved usability.

[Rob01]

Two from my trip to the UK last summer:

The aptly named Vine House in the Cotswolds:




The City of York, taken from the city wall:



Rob01 the Merrills are a great way to start with foveon. They are selling so cheaply right now that I think they are the best bang for the buck in photography.

I suspect the quattros will be slightly better image quality and greatly improved usability.

Mr Bassie, I am not convinced that the Quattros can have better overall image quality with less colour resolution than the Merrills... "I cannae change the laws of physics captain!" The Quattros will have a little higher gray scale resolution, be faster, etc... but better IQ?

This is why if the system works for me, I am sticking to the Merrills... and let others test the Quattros for a year or two and see what happens in the Foveon SLR space. If SD1M ever goes on sale for under 1 K... or if the SD1 Quattro has the same photosites for all colours... that kind of thing.

Enough of my chatter though... be back when I have some photos.

[Mr Bassie]

Dick Lyon, one of the co-founders of Foveon had some interesting posts at DPReview:

Kendall, long time...

You're right that there won't be much aliasing. A lot of people seem to have the idea that aliasing has something to do with different sampling positions or density, as in Bayer. But that's not the key issue. The problem with Bayer is that the red plane (for example) can never have more than 25% effective fill factor, because the sampling aperture is only half the size, in each direction, of the sample spacing. If you take the Fourier transform of that half-size aperture, you'll find it doesn't do much smoothing, so the response is still quite too high way past the Nyquist frequency. That's why it needs an anti-aliasing filter to do extra blurring. But if the AA filter is strong enough to remove all the aliasing in red, it also throws away the extra resolution that having twice as many green samples is supposed to give. It's a tough tradeoff.

In the Foveon sensor, the reason no AA filter is needed is not because of where the samples are, or what the different spatial sampling densities are. It's because each sample is through an aperture of nearly 100% fill factor, that is, as wide each way as the sample pitch. The Fourier transform of this aperture has a null at the spatial frequencies that would alias to low frequencies; this combined with a tiny bit more blur from the lens psf is plenty to keep aliasing to a usually invisible level, while keeping the image sharp and high-res.

In the 1:1:4 arrangement, each sample layer has this property, but at different rates -- very unlike the Bayer's red and blue planes. The large area of the lower-level pixels is the ideal anti-aliasing filter for those layers; the top layer is not compromised by the extra spatial blurring in the lower layers, so it provides the extra high frequencies needed to make a full-res image.

Another good way to think of the lower levels is that they get the same four samples as the top level, and then "aggregate" or "pool" four samples into one. This is easy to simulate by processing a full-res RGB image in Photoshop or whatever.

The pooling of 4 into 1 is done most efficiently in the domain of collected photo-electrons, before converting to a voltage in the readout transistor. The result is the same read noise, but four times as much signal, so about a 4X better signal-to-noise ratio. Plus with fewer plugs, transistors, wires, etc. to service the lower levels, the pixel fill factor is closer to 100% with easier microlenses, and the readout rate doesn't have to be as high. Wins all around -- except for the chroma resolution.

The main claim of Bryce Bayer, and the fact that most TV formats and image and video compression algorithms rely on, is that the visual system doesn't care nearly as much about chroma resolution as about luma resolution. Unfortunately, trying to exploit that factor with a one-layer mosaic sensor has these awkward aliasing problems. Doing it with the Foveon 1:1:4 arrangement works better, requiring no AA filter, no filtering compromises. So, yes, the chroma resolution is less than the luma resolution, but you'd be hard pressed to see that in images.

If you throw out the extra luma resolution and just make 5 MP images from this new camera, you'll still have super-sharp super-clean versions of what the old DP2 or SD15 could do. Now imagine adding 2X resolution in each dimension, but with extra luma detail only, like in a typical JPEG encoding that encodes chroma at half the sample rate of luma. Whose eyes are going to be good enough to even tell that the chroma is less sharp than the luma? It's not impossible, but hard.

Speaking of stories from the old days, Foveon's first version of Sigma Photo Pro had a minor bug in the JPEG output, as you probably recall: our calls to the jpeg-6b library defaulted to encoding with half-res chroma. It took a while, but a user did eventually find an image where he could tell something was not perfect, by comparing to TIFF output, and another user told us how to fix it, so we did. It we could have gotten that original level of JPEG quality from the SD9 with 5 million instead of 10 million pixel sensors and data values, and could have gotten cleaner color as a result, would that have been a problem? I don't think so; except for marketing, and they had enough problems already. Same way with Sigma's new one, I expect; if 30 M values gives an image that will be virtually indistinguishable from what could be done with 60 M, but with cleaner color, will someone complain?

Probably so.

So, it's complicated. Yes, reduced chroma resolution is a compromise; but a very good one, well matched to human perception -- not at all like the aliasing-versus-resolution compromise that the mosaic-with-AA-filter approach has to face.

Dick

disclaimer: I've been away from this technology too long to have any inside knowledge. And give my apologies to Laurence for my too many words.More from Dick Lyon

Truman, I guess you missed the bit where I wrote "A lot of people seem to have the idea that aliasing has something to do with different sampling positions or density, as in Bayer. But that's not the key issue. ..." It must have been your comments that prompted that. What is "sub-alias sampling" supposed to mean?

Sure, there will be aliasing, as in all sampled images. If you consider the pixel pitch and pixel aperture, you can work out that the aliasing will be about like that of the SD15's sensor. That is, negligible; and that will only be in chroma, so even more negligible, visually. The key next step is adding a high-frequency luminance signal, uncorrupted by that aliasing. That's what's nearly impossible to get accurately in Bayer sensors, but trivial to get with the Foveon 1:1:4.

But you are certainly right, as I also said, that we will wait and see. My words and yours are not going to convince anybody of anything until they see it.

As I also said elsewhere, I'm both surprised and delighted, after 8 years away from Foveon, to see this concept making it into a Sigma camera. It shows that Kazuto had the courage to focus on image quality above all, not fearing the marketing difficulty of explaining the Foveon advantage a little differently and with lower pixel numbers than before. As Laurence said, Merrill worked on this idea from its inception; Foveon's cell-phone sensor project did enough testing to show it's a great idea. And I presume the rest of the Foveon team has continued to execute well on the potential in bringing it to the larger format. This may be Merrill's best legacy, even more than the ones named for him.

If I may summarize once more what I think is the key point: the tradeoffs and compromises about how to utilize the Foveon concept and technology have been thought through here, and developed and tested for many years, in a way designed to maximize image quality at both low and high ISO. The 1:1:4 architecture is surprising and non-intuitive, but it is what best exploits what the silicon can do (as Carver said, years before we started Foveon, "listen to the silicon" Wired 2.03: Listening to Silicon). Listening is not a theoretical exercise, nor something you do in computer models (though they help).

Dick

Read more at: https://www.pentaxforums.com/forums/76-non-pentax-cameras-canon-nikon-etc/251...#ixzz2zkdYa1oo

Read more at: https://www.pentaxforums.com/forums/76-non-pentax-cameras-canon-nikon-etc/251...#ixzz2zkdI3FhV

[Rob01]

Very fine B&W photos Mr Bassie ... and thank you for the info.

... at least Sigma TPTB are not hiding anything and admit that the Quattro has less colour resolution than the Merrill.

Translation: Bayer sensors with an alias filter lose half the resolution in each direction. Colour resolution is harder for humans to perceive than shades of gray (though not impossible). The Quattros will not lose the resolution through an alias filter. However, Quattros effectively have an alias filter through binning pixels in the lower levels. The colour and shades of gray resolution of the Quattro is the same as a 20 Megapixel Bayer sensor *without* an alias filter. Thus the K3 wins (I do not have a problem with artifacts in the type of photos I do)

For me the reason for even considering the Foveon cameras is the COLOUR resolution. I LOVE to play with natural colour and now is a good time (Autumn time in my area of the world). Otherwise my K5IIs is a fine machine. Thus I will stick to the Merrills and see if Sigma or someone else comes up with a newer non-quattro Foveon type sensor in the next 2 or 3 years. Not interested in the Quattro apart from the DP1Q if it really has an improved lens.

The important thing I have learnt through your info is that JPEG only encodes colour at a lower resolution?! I have to look into this as it would be a waste with the Merrills! Thanks

[ivoire]

From a trip to the I&M canal in Lemont IL

[IMG][/IMG]


[IMG][/IMG]

[carrrlangas]

Perhaps some of you might be interested in this:
https://www.pentaxforums.com/forums/76-non-pentax-cameras-canon-nikon-etc/258...lp-needed.html

[hoopsontoast]

Been to Amsterdam for a 'Hag'-'Do (Stag do but with the Bride)
I was traveling light so just the DP1X and DP3M with me.....

The Bride:























Heineken Tour:

[ivoire]

[IMG][/IMG]

[IMG][/IMG]

[IMG][/IMG]

[jeffshaddix]

Great info Mr Bassie, and great pics hoops!

I love that the co-founder of Foveon is still interested enough to post his thoughts. I really hope the technology continues to improve, and I'm hopeful that the Quattros will be excellent. I'm waiting to see how it fairs, but I still have my eye on that DP1M.

[Rob01]

Ok... I received today a secondhand DP1M to test out the Foevon sensor. What are the suggestions for optimal shooting and image processing with this camera? (I know shoot from a tripod) What else? Exposure compnesation? What is a good quality largest aperture? What settings should I use in the Sigma processing software? I will post some test shots on the weekend... Thanks

P.S. Is there are way to trick the DP1M to take a 5 shot auto bracketed set? Or is it a hard limit at 3 shots?