Because we do allow microstock companies to do that and do not value our own work, thats why. Even $20 is pretty cheap in most cases...

In fact there is NONE really good and reasonably priced basic zoom on APS-C Canon but psst - everyone knows they are the best I have crappy Olympus so Im completely mad when I have tiny noisy sensor and everyone knows that Oly has no really good lenses and even those "not-good" are only few  

RF and RM licences are restricted, thats true. But "micro RF" has nearly no restrictions - is 250.000 prints restriction? I bet not!

If we started ethical topic - let the prices stay alone, but is it ethical to shoot session paid by client and offer those pics not choosed by that client to micro - even if they are very similar for those choosed and paid? Isnt that dumping price which is illegal in many countries? Is it legal/ethical to sell many picture with obviously high costs on micro, where is very clear that the picture despite hundreds to thousands of downloads will never really earn single dollar? Is it legal by agency to delete your portfolio and grab all the money on your account just because you disagree with them on some phorum? Is it ethical by agency to keep up to 80% from the final price of the picture if they offer no real service like legal help, CC fraud protection, do not even bother to mail you a yearly overview of money earned with proper info for tax bureau? 

Frrezingpictures: Yep, it might be rejected based on senzor size, I would strip all exif info. Reviewers should judge the picture quality, not senzor type/resolution.

OxfordSquare:
You probably missed the point - EVERY sensor except Foveon uses brutal firmware interpolation in camera - every pixel records ONLY one from RGB color so you must interpolate the rest to get normal picture! So in fact Foveon is the only one widely available non-interpolated sensor. You guys better do some reading about how it works. Interpolation is not allowed? Then you should not post any picture from any camera except Sigmas Foveon sensor equipped ones, right? I will tell it once again - to get the same size of the picture as from any other sensor, you need to interpolate image recorded by Sigma DP1 4x and its roughly the same interpolation and size recorded by common camera. Its impossible to get uninterpolated picture from anything else, you just do that in PC later and not in camera! Every other camera DOES interpolate during firmware trasformation of raw data into picture. Even raw is interpolated, if not, you will get just crazy map of red, green and blue dots!   

Dook:
DP1 will very likely smash any low end DSLR with kit or average lenses in detail, colors, dynamic range and sharpness, so what are you talking about? Its completely different technology and much more advanced in some points, you cannot compare that based on common "sensor size" myths. Eg. "small" 4/3 sensor in E-3 has about same noise as "large" 40D up to iso800 - which is far beyond the iso you should use for stock. So what is the advance of "larger" sensor? None, right? Its not that simple as just comparing megapixels or sensor size. It depends on many more things then just this.

It has no bayer mask = no interpolation = really effective pixels, not those "effective pixels" all other manufacturers claim, while they use bayer mask and thus each pixel is for only ONE of the three RGB colors (on Sigmas DP1 Foveon each pixel records all 3 colors per pixel). Sigma claims to be equivalent of 16Mpix sensor with Bayer mask, because of the square RGGB color mask in front of those sensors - in fact it bahaves more like 12Mpix to be honest, but all those reviews saying "its just 4Mpix" are simly complete nonsense. Many of 10Mpix DSLRs with average lenses (and I dont mean cheap kit lenses with word average) will be in big trouble against Sigmas result.

It has superb optics and picture quality, however fixed focal length and its pretty slow. I can imagine DP1 for landscape shots, but definitely walkaround camera. Its definitely well above cheap setups like cheap DSLRs with kit lenses, I would place it about semi-pro. I also saw some reviews and tests (I think it was on Popco), where guys tested Sigma DP1 against Canon 5D + 17-40/4L and Sigma was obviously winner in the colors, detail and dynamic range. There were some issues with green color cast on higher iso, but I think it was later solved with firmware update.

Conclusion: Yep, pretty good for landscapes or other uses, where the slow speed and wide fixed focel length arent problem. It delivers excelent picture quality.

Yep, micro is heavily damaging prices. If there are only easy made simple pics for low price (where micro started), then its great idea. Those foolish talks about "free market" are just abit incorrect. Extremely low pricing in micro and little commision (sometimes even less then 20%!) hurts photographer in two major ways - they do 80% of work and get just 20% of final price which is really extremely low. Second it errodes prices of other photographs because clients often do not make much difference between easily made low-cost pics and difficult or rare shots where costs are up several hundred times higher and expect the same price as on micro. So if you are or are not on micro, it doesnt matter - it will decrease your earnings.

I would really like to see real costs (studio, staff, gear, locations, models...) of top-contributors and their revenue per picture. Even those $10/h. mentioned by Perry are far too optimistic for most microstockers, maybe top-contributors have such huge sells that it covers their costs but always remember that most of them shoots also contracts and many used to be pro before, they have many other sources of money to cover studio and gear - then micro could be extra income for them. Shooting only micro is a different story for most of us - my average revenue is just few $$ per picture on micro and I bet many others "small fishes" are on the same boat.

Xalanx: I disagree, sorry. Best price/value wide lens is Tokina 12-24/4 which smashes Canon EFS 10-22 into pieces and still costs HALF! EFS 10-22 is way overpriced lens with average optics, I dont see any reason to pay 100% more then for Tokina 10-17, Tokina 12-24 or Sigma 10-20 to get disputably same or even worse quality. Check eg. dpreview.com to see detailed tests and reviews.

I wouldnt choose ultrazooms like 28-200, 18-200 etc. as they MUST be compromise in optical quality. Really noticable CA, distortions and not really good sharpness are absolutely normal with them and with ultra-pixel-peepers inspecting photos on micro insanely even over 100% is this big problem. Good zoom lenses cost about $400 and up for each and I dont think that set Tokina 12-24/4 + Tamron 17-50/2,8 + Canon 70-200/4 for about $1100-1300 altogether is too much. You would pay 2-3x more for original Canon lenses to get about the same quality.

Btw. absolutely best lens for outdoor photography is Zuiko 12-60/2,8-4,0 SWD but that doesnt fit to Canon  Choosing basic zoom for APS-C Canon is a really big problem, as there are no really best options, only compromises. Its pity the biggest DSLR producer in the world wasnt still able to deliver suitable zoom, only way overpriced stuff like 17-55/2,8 and EFS 10-22 with disputable quality and pretty bad focal length for 17-55 (there is NO tele starting under 70mm except Tokina 50-135/2,8!)

Vonkara:

Yep, you have rules. But always keep in mind that agencies are not setting rules just as they like, because we can shoot without them, but they cant sell anything without us. This is about cooperation photographer-agency but microstock is more into dictature every day, unfortunately. IS crossed the acceptable line for me and Im not going to upload anything unless their change their minds about this.

That about noise/artifacts is only partly true - every jpeg image just by the definition must have them, it just depends how much you try to find them. For me its very simple - A4/300dpi (so about 8-10Mpix cameras) is not 100 or 200% on your overcontrasted LCD - its just 25%! Your screen has 72dpi, not 300! So what editor does when he/she checks picture at 100-200% on the screen? Its just like printing 8Mpix image on A3 or even A2 and checking it from 10cm distance.

That about "no postprocess" is just BS. Every serious photographer knows you must edit pictures, images just straight from the camera could be good but nearly all can be better with some editing. I dont mean serious tweaking, boosting colors etc. - just little contrast, curves, levels...you know. I prefer to give out finished images looking the way I like it - not greyish unedited pics. Clients are sometimes so stupid to print that without any editing and with my name under it - big no-no. Not to mention client will  choose edited and good looking image, not unedited ugly looking or just average looking picture. Client will buy outstanding picture, it simpy must attract his/her attention and greyish unedited picture will definitely not...

I highly recomend start with some reading, its obvious you have no idea about lenses. Its hard to choose something if you dont know what you want.

For budget/quality compromise its probably best solution Tamron 17-50/2,8 and for tele Canon 70-200/4, both not really expensive and both pretty good.

I have some good contacts across editors and some printing agencies so I do sell directly to customers. Right now Im working on my website (not public yet) with gallery because its getting abit too complicated to send them pics via email all the time.
Its not arranged contract with exact limits - eg. I know we are preparing 3 calendars each year about gardening and plants, so I keep gathering good shots thru the whole year and then choose the best for each week at the end of the year. I know which pics each calendar compiler prefers so I can choose the right stuff for each of them.

Btw. I understand Im too specialised so the microstock isnt the best to sell my main-stream pics, Im now trying to keep nature/travel shots separate from the stuff presented at micro. 

Microstock has huge lacks of photographs - try to find common mammals and its fine. Try to find properly scientificly named and just slightly uncommon flower and there you go... not talking properly named insects except some common butterflies, invertebrates, uncommon birds etc. Shooting nature isnt about snapshoting 2-3 common flowers in your backyard and your dog and cat. 

I consider photo coverd costs after it earned $100 (and thats still * cheap!). Thats the reason why I do NOT put any really good nature pics on micro. I have channels to sell them much better paid and I dont wanna my clients to find the same stuff on micro. In case you have eg. some rare tropical plant, properly idied etc. and client needs it (because of course he is not able to find such stuff anywhere as most agencies dont see potential in this) - the client is gonna pay much more then just few cents like on micro. Hes gonna make you REAL offer covering your costs. Maybe such pics dont sell too often, but portfolio of couple thousand good nature shots with proper id, scientific names and good quality is in my opinion much better then having broad-subject microstock style images.
Example: I have about 260 pics online at micro on DT, SS and 100 on IS. The most succesfull picture did about $35 in a year (so its well bellow my $100 limit), average picture did $2 in a year so I need 50 years just to consider my portfolio did earned enough to cover work and gear. Is that ok for you? For me not... so I do not put my good nature/travel stuff on micro anymore.

Yep - the same with ranking Olympus or Nikon cameras - its D80/90 or Oly E-30 prosumer or entry level (plastic body)? Then E-3 is high-pro because it has probably best weather sealing, likely even better then 1D? Such categories are very disputable.

I would rather choose rank on megapixels (also pretty disputable) or sensor size - comapct - 4/3 - APS-C (both 1.5 and 1.6 crops) - FF and medium format or larger (we have Seitz and other insane cameras, dont we...).

Eg Im using Olympus E-410 though with high grade lenses - the body itself is very cheap however its much closer to D80 or 400/450D then to 1000D or D40/60 regarding its capabilities. And the Zuikos 14-54 and  12-60  are well above eg Canon 17-85 and likely even better then 24-105/4L. So what category? Entry level?  And while using older E-1 (high quality metal body with superb sealing) its Pro class?