Scottelly wrote:
abera wrote:
Scottelly wrote:
abera wrote:
dellaaa wrote:
Reading a recent post that included a 60M pixel Bayer sensor shot, the the discussion turned into a debate as to whether the FFF would ever arrive.
Looking at the Bayer photo what do you believe the FFF sensor would have to do better than the current generation of Bayer sensors? What are the design criteria the FFF design team have?
I don't know but given the physics of the design and the past Foveons, low light performance would most likely not be on par with the Bayer, agreed?
Foveon has three photodiodes per pixel, none with correlated double sampling. This means very high read noise which means high noise floor which mean poor performance in areas with little light. This means poor low light performance and relatively low dynamic range.
If that's the case, then why did early Foveon sensors have so much more dynamic range than the Bayer pattern CFA sensors of their time?
Did they? Can I see some measurements proving it? I have never seen any.
The issue with read noise can not really be solved
Why not?
Two reasons:
Three photodiodes per pixel instead of one. This alone means sqrt(3*n^2) of noise per pixel compared to single photodiode.
The other is practical impossibility of CDS.
- there will naturally be more photodiodes, but also CDS is quite impossible to achieve with this kind of design.
What is CDS?
Correlated double sampling. It's used to eliminte the main pixel read noise element, the reset noise. With the Foveon vertical pixel structure it's hard to see this happening.
Some fancy non-destructive multiple sampling might be possible but it would not only slow things down even more, but also not be as effective.
From QE point of view the advantage of Foveon is not having colour filter array blocking light, but on the other hand there is plenty of dead space between the photodiodes. I'd guess one might be able to achieve slightly larger QE with Foveon which would help somewhat in low light situations, but not with the noise floor itself.
Historically, Sigmas have required extensive image processing both while taking the shot and afterwords (SPP). Will the FFF shoot at the frame rates of the current Bayers? Again, given the history, this seems doubtful.
Foveon's problem is the very poor color separation.
Huh? I thought it was supposed to be noise that was Foveon's "problem."
This was in the context of the paragraph.
Read noise isn't really a big problem for most photography as the maximum dynamic range is rarely needed (especially for JPG shooters it's quite irrelevant). Though for low exposure photography (e.g. hand held low light) this is an issue.
Color separation issue is on the other hand always there.
Foveon separates colors by taking advantage of the fact that different wavelengths of photons tend to be absorbed at different depth in silicon - the problem is that this is not a deterministic process, but a probabilistic one making the color separation very weak.
Also the photon absorption is quite a bit top heavy - as you know Sigma made the two bottom layer photodiodes four times the size of the top layer (areawise, depthwise they are also much larger). There is a reason for it - the bottom layers are simply relatively photon starved. Additional benefit is reduction in total read noise. It also indicates the difficulty of increasing the resolution of the bottom layers from image quality point of view - I think this is a good compromise even though it's a deviation from the original design, increases SNR somewhat with neglible resoltution loss, though maybe opens the door slightly to false color artifacts.
In principle this could be helped by placing narrow band color filters on top of the sensor, but then some wavelengths would be totally lost and could cause some interesting artifacts.
To get decent color out of Foveon the processing indeed will be rather strong - this increases noise for color photography.
Where do you get this idea?
From the weak color separation.
Page 177 of this . Note the spectral sensitivity chart and the color matrices.
So with low light and speed out of the equation, whats left, detail and color rendition.
The main advantage is reduction in false color artifacts (e.g. moiré). This advantage goes away once diffraction (and lens deficiencies) does anti-aliasing, but it's still a long way from today.
Detail situtation has many variables, but regardless of them lots and lots of pixels would be needed in this hypotetical FFF to compete.
Color accuracy is vastly better on conventional sensors. That's why the CFA is there for.
Wrong. The Quattro generation was one of the most color accurate sensors of its time.
Wrong. From the above document:
One does not get more accurate colors from exremely weak color separation. One gets less accurate colors with more noise.
Technology has moved on, but for the money you probabky coukdn't get a camera with a more color accurate sensor than a Quattro.
Likely all conventional Bayer CFA cameras have more accurate colors from hardware point of view.
Well if that is true, then you're saying Sigma knows how to coax better color out of sensors than Nikon.
No they can't.
I find that hard to believe, but I guess it's possible. There have been several fp L users here who have multiple systems, and they prefer the colors they get from their Sigma cameras.
Sure, but that's a personal preference, not accuracy thing.
All the camera manufacturers try to create JPG colors which sell cameras, thus they don't go for accuracy, but for pleasant output. Typically different manufacturers have a different idea on what sells, thus you have Nikon colors, Canon colors, Fuji colors etc.
The point here was image sensor and it's capability to create accurate colors.
To get accurate colors, the JPG engine (in camera or raw-converter) is typically calibrated with light from a couple of different spectrums and if one were to shoot in a similar (or the same) light, one can expect very accurate results. Change the light and that's where the challenge is. The better quality data one gets to work with, the better quality the output can be - when the color separation is very weak, the data has low quality information. Essentially it's about SNR on chrominance information.
Other small companies have been known for their color too, such as Leica, Hasselblad, and Phase One.
Foveon type multi layer system might work better in the future with different materials, maybe organic materials or perovskites. Plenty of perovskite developement is being done due to their potential for solar cells and at least one multilayer demonstration does exists (with hideous image quality). Maybe 15 years from now?
As for detail, how would the specs of the proposed FFF stack up against the 60M plus Bayer sensors? Would the advantage in detail make up for the shortcoming?
No. You need likely something like 70% of the pixel count to match conventional sensors, maybe more nowdays as AI-based demosaicing is on its way. This also diminishes the false color advantage.
Anyhow, as even 10MP is enough for very large prints...
The remaining design criteria, is color. Would Sigma's color rendition be enough for people to buy it?
Some like it's different colors and I'm sure many fans would buy because of them, but as the colors can be very problematic and lack in accuracy and because the conventional cameras are not exactly lacking in color accuracy, it's hard to see how the general public would get interested in this.
I don't know and would like rational, opinions as just what will the FFF bring to the table, and why any non L mount people in 2023 would buy it when 100M pixel Bayers are on the horizon that take great low light picture at high frame rates.
At this point, fanboys aside, the fact that we are still discussing this seems a bit absurd to me, so why did I start this thread lol?.
Foveon is very interesting concept and I'm happy it was brought to life. But it feels more like a hobby project, a niche project for those who desire something different. There aren't really any advantages over conventional sensors
Huh? You already gave one in your own reply here above . . . "The main advantage is reduction in false color artifacts (e.g. moiré)."
I said "really any advantages" - meaning that there aren't much relevant advantages. But I can agree that I should have used more careful wording.
As long the the sampling rates of conventional sensors are low enough for diffraction (and lens flaws) to not be enough to eliminate false color artifacts, this can be a small advantage.
Of course it could esily be corrected by using strong enough anti aliasing filters, but since pixel peeping is part of camera reviews and those sell cameras, AA-filters are now largely gone or very weak (and often unidirectional as well.
while the drawbacks may cause issues.
I hope a FF Foveon does see the light of day, but not only I'm not holding my breath, I'd expect the product to be a very low volume very high price item.
Of course the first FFF will be low volume and high priced, but for all we know Sigma will make a future generation in ten times the volume
How? In order for Sigma FFF be a large scale products it would need to have tangible advantages without tangible disadvantages. This is not the case. Also it would need to offer similar marketing (including indirect marketing like camera clubs, peer pressure etc.) and support networks, camera shop visibility and so on. There is no reason to believen any of this will happen.
There have been many products put on the market, which dominated a niche in their industry without a large support network or a significant marketing presence. The product just has to work well. Today, with the Internet, that is even more likely, because of how easy it is for people to find the information.
...and disinformation
There is very small market for "different" cameras which have practically no advantages over conventional cameras. The market shrinks even more if the product is more expensive and underperform in many ways.
, allowibg them to price it very low, so it sells quite well.
So it will sell well because it's price will go down because it sells well? Something circular in that argument.
No. It will sell well, because its price will be set low by the manufacturer from the beginning, because the manufacturer doesn't need to sell it for such high prices, because it costs less to make, since it is being manufactured in higher volume.
It's a bold assumption that it (i.e. the "second generation FFF") would sell in great numbers (vs. the "first generation FFF") allowing for lower prices, while offering no reason why the sales would go up. The product is and will always be a small niche product - it offers little to no practical advanages, even fewer in the future as diffraction removes false color artifacts (and other aliasing, from Foveon too too), offers several disadvantages, has far less marketing, support, visibility and so on.
Don't get me wrong, I like Foveon, but not because I think it's better, but because it's different.
You seem like a pretty well informed person.
Thank you. I know a bit of some stuff.
It's difficult for me to believe you don't know how this works.
I think I do know. I think I've been quite logical here.
Your comment brings into question your motives, and makes me wonder if you just have an axe to grind. Are you just trolling here?
That's quite childish. To me it seems like you have a emotioinal need to protect Foveon from what you perceive to be an attack on it. Hard to see why you'd go on this road otherwise. Dish me more this and I'll return the favor. Ruins the thread from others though and mods will likele finnish it.
Do you know Sigma's history in the camera world?
Yes, pretty well. Both lenses and cameras. Actually one of my all time favorite lenses is a Sigma - the 1st generation 30/1.4 APS-C lens was splendid for street shooting.
Do you realise they've been selling cameras for about 20 years?
Yes, and frankly you're being quite impolite. If you don't have an argument about the topic, then don't say anything. You don't need to defend the "honor of Sigma or Foveon".
Do you know Foveon sensors have been improved time and time again,
Of course - for example the first generation had a read noise of something like 40 electrons if I don't remember wrong, while the most recent ones have cut it well below 10, maybe even below 5.
I wonder if conventional sensors have improved at all...
(The above was of course sarcasm.)
and Sigma cameras have continued to offer some of the best quality digital imaging,
Not from the cameras. They have one basic strength - no (or less) false color artifacts compared the CFA sensors without (or with weak) AA-filters. The weaknesses are numerous. Foveon is a different product and I appreciate it for that, but I don't delude myself into believing that it's an all-a-round superior product.
The lenses are on the other hand nowdays absolutely stellar. They often used to be quite hideous several decades ago, but in addition to the typical lenses they also often had some options other manufacturers din't have. Slowly the lenses got better and nowdays they're easily among the leading manufacturers when it comes the quality, and if I recall right, the leading when it comes to quality.
against the massive industry for all those years?
They've not been "against" the industry, but part of it.
I call that amazing,
Why? Sigma is just another corporation among others.
Would you call Canon, Nikon, Sony, Leica, Volkswagen also amazing? They all started from nothing as well and are doing pretty well inspite of competition
and I prefer the images from the SD Quattro H to everything else,
Good for you. But this thread is not about your personal preference.
except a 100 MP (or more) medium format camera,
Wouldn't 99MP be enough? Does it have to be MF - would a 100MP FF be enough?
as do several other photographers here, despite the dynamic range disadvantage,
I feel temptend to ask what you think DR is, but maybe I shouldn't
I guess SNR isn't relevant to you since you did't mention it.
and despite how slowly the Sigma cameras operate. That alone should tell you something.
Sure, you like your camera. You. That's a personal thing. Not an objective statement of performance of some imaging technology.
I have used Canon, Nikon, and Sony cameras (several from each brand), yet I prefer to shoot with Sigma cameras. That's not because I'm stupid, ignorant, or a masochist, but because my Sigma cameras produce better images.
No, it's because you like the results of your Sigma cameras.
For your own sake you should understand that your personal preference is not the same as objective reality.
First it would need to exists - if it will ever exist, the long depelopement doesn't really indicate that the mythological "next generation FFF" following it would be developed fast or that it would have enough tangible advantages when the competition will at that point have 200MP or more and be cheaper than it's predecessor.
When even medium format seems to have stopped moving forward in resolution, what makes you think that will ever happen?
Likely for two reasons - not much competition to push the resolutions up, and also processing/storage needs). New image sensors ordered for MF aren't cheap as the sensors are big (yields go down with size - deficient pixels aren't necessarily problems, but for example an ADC would be) and the volume is low.
Have you noticed how mobile phone cameras have now broken the 100MP barrier?
Competition drives things.
Panasonic just made two new cameras, and were either of them high-resolution, with a sensor that offered more detail capture than their first high-resolution full-frame camera? No. How about what Nikon, Sont, and Canon have put out recently? No.
There are lots of reasons - from marketing, manufacturing, COVID related supply issues and so on.
If 200 MP sensors are coming, why are there no full-frame cameras from Canon or Nikon with sensors over 45 MP,
Sony has 61, but I guess it doesn't count as it doesn't fit you agenda.
Why would that be the end? It's kind of hard to sell new cameras if the specs don't improve.
even though Canon made a 50 MP camera years ago, and Nikon made their first 45 MP camera (the D850), which was a DSLR, years and years ago?
There can be a million reasons. But none of them is what you seem to think (i.e. that Bayer CFA cameras has now peaked and will forever remain in this spot and this will bring glory to Sigma and it's loyal supporters.)
For example to use smaller pixels one wants to use finer geometries in manufacturing and their availability is limited. Image sensors tend to use fab lines which are obsolete for their original use. I think that one major reason - now this is only my educated guess - for the relative slow progress of increase in pixel counts over the last few years has been because of lack of fabs. Mobile phone cameras, automotive cameras and all other kinds of small pixel cameras need (relatively) fine geometries making them unavailable for larger sensors unless they put up enough cash. Considering that (large) image sensors are already by far the most expensive part of the cameras, doubling (or more) it's cost might be a problem.
So I think it's mostly been a manufacturing resource issue. But since small sensor production is no longer skyrocketing (at least the numbers and market studies say so), and have even for a while stalled, more older fab lines should become available for larger sensors at reasonable prices.
I'm not suggesting Sigma will fix all the problems with their in-house sensors, but thise sensors have improved in the past, and I have no doubt they will improve in the future too.
Sure. But the last new Sigma sensor came out when? Do you think Sigma has the resources to compete with the rest of the world - Sony and Samsung and others pour billions after billions into R&D getting constantly not only more refined products, but also all kinds of innovations.
I think there will always be a market for good quality, unique products, which offer something different.
Of course - I don't think I said anything contrary. I think I said something quite similar actually
But if you believe that Foveon sensor is some kind of game changer, I'm afraid you're significantly in error.
Leica keeps making monochrome cameras. That is a niche product, but obviously a successful one, or they wouldn't keep doing it.
Sure - though Leica has extreme brand value which gives them possibility of making that kind of "niche of niche" product. It's also dirt cheap for them as sensor without color filter array isn't any more expensive than one with it - likely slightly cheaper even in relatively low volumes and the revamped image processing is a job of a day or so for a software engineer. (They may have done more, but that's the general idea.)
Anyhow, Pentax is another intereting brand - it seems to become the one last DSLR manufacturer providing a DSLR "difference" in mirrorless world. It likely provides modest but solid income to Ricoh and will likely remain a good little niche.
I believe Sigma will continue to improve on the Foveon sensor, making more "niche" products with them in the future, and differentiating themselves from the competition by doing so.
Sure it's entirely possible and even likely. And i hope so. But it'll never be more than a niche player with this technology and an additional problem is that the relative advantage(s) of this technology get smaller and smaller every year. Also I doubt it'll ever try to go head to head with the big boys as the investments would be significant and the risks large. The competition is stiff and the markets aren't as good as they used to be before mobile phone camera revolution.
Sigma is a leading lens manufacturer. To me the cameras are a love child, a hobby - it's (AFAIK) a privata corporation, so they can afford to have such proyects. I do hope Foveon keeps on being developed and produced just for the sake of uniqueness. It makes the world richer. Though, in time it'll lose the false color advantage fully and then it's just game over. This is not that far away, thus investing heavily in dead-end technology is not likely, even if it is a hobby.
FWIW, here's a link to an interesting image about the vertical structure from Chipworks. The comments by Eric Fossum may be of interest. (EF is the inventor of for example 4T pixel structure commonly used in sensors.)
This might help you understand Sigma cameras:
https://medium.com/ice-cream-geometry/an-ode-to-the-sigma-merrill-506dd0864169
I actually do understand how Foveon sensor works, likely better than the person who wrote that love letter of an article.
