I just got the Canon EOS 500D. I use a CS4/5 filter called Perfectly Clear, but think the setting on sharpening was too strong, creating undesirable artifacts. In your experience, should this camera's images be acceptable without noise reduction?

I have a 500D and you should be able to use it without sharpening or NR depending on the situation.  Right now I mostly use it for isolations in my studio.  At ISO 100, manual focusing and with decent lighting I never sharpen or use NR.  Outside I find that the Canon Rebels often have noise in the sky, even at ISO 100 and good lighting, but it is easily cleaned up with some light NR. I usually use Noiseware or sometimes Topaz Denoise, and only on the parts that need it.  If you're commonly having to sharpen or denoise the whole image then it's not the camera - it's either technique or poor lenses.  If you're using the kit lens then toss that sucker and get some good glass - it's hard to get sharp images if your lens isn't up to the task.  If you're just getting noise in the sky then that is normal, for me at least, and that includes all of the digital rebels including the 500D and 600D.

New images for the most part aren't doing much for me, either.  For the past 3 months, earnings from new images was about 6% of the 3-month total, over the past 6 months about 5% (didn't upload much for a while last fall), over the past year 30% and over the past 2 years 58%.  I've been trying to time my submissions to see whether acceptance (assuming a 5-day review period) on Monday or Tuesday versus later in the week makes a difference but so far have seen no effect - it doesn't matter when they get accepted. The boost from new images seems to be gone, at least for the kind of images I am making.

To turn back on the whole ranking thing.
I just noticed something, maybe its easy explainable, maybe not.

I sold my first file 2 days ago.
http://www.istockphoto.com/stock-photo-20023350-golf-scoring-board.php
It had only 17 views and 1 sale, its was a week online.
Since this sale the views gone grom 17 to 91 in 2 days.
while in a whole week it just got that 17.

All other photos are under 20 views
except for this photo. http://www.istockphoto.com/stock-photo-20069694-old-and-yound-hand-on-pregnant-belly.php
Am i watching to closely on these stats or is it that a sale might boost ranking?

Yes.  Trying to figure out what changes search rankings is a waste of time - changes all the time for reasons you can't control.  Some images get tons of views with no sales while others get a sale with almost every view - no idea why.  The only part you can control is the number and quality of your images - increase those and you'll do well.  What you're starting with looks good and you'll soon have more feedback on what sells and what doesn't.

My experience on DP last month worked out to about 0.064 sales per image.  If yours were downloaded at the same rate I'd expect about 10 sales in a month with 160 images.  I'm sure most people probably do much better than me.  Maybe it's just taking a while for yours to be found or possibly they are less commercially viable.  I'd just keep submitting and trying different things until you find some that sell.  Good luck!

I agree that the categories are not very useful and mostly a waste of time, but you can autofill them from previous submissions so it is a minor nuisance.  The sites that require you to prioritize keywords (e.g., FT, Alamy, PM) take much more time for me, and of course DA at iS.

About 30% less than March.  Down at all sites except DP, which has had a BME for the past three months.  Hopefully it will end up being the worst month of the year.

I had one earlier this year for $236, my cut was $94.40.  I would rather have had 60%, but that is still probably more than I will make on some of the smaller sites all year so no complaints.

I resubmit if I think I can fix the problem easily and if I think the image will get some sales.

Of all the agencies I've found the iS inspectors the most helpful in learning how to fix problems.  Some of their rejections - particularly the dreaded "Artifacting" - can be difficult to figure out the problem.  Sometimes an inspector has included an enclosure containing the part of the image with the problem.  Usually it has been some small CA or posterization that was not noticed by me or inspectors at other agencies.  Sometimes it was not visible (to me) at 100%, but was clearly there at 200%.  These enclosures have been very helpful and I've only received that kind of personal attention from inspectors at iS.  Now that I know what to look for I can find and eliminate those problems before submission, which has improved the quality of my images at all agencies.

By fixing and resubmitting you will get a better idea of what they are objecting to and can then correct those before submission.  In my experience, "over-filtering" can often be fixed by lowering the saturation a little.  Of course, for other agencies the "over-filtered" look may be more desirable and sell more so it's a balancing act.  If you feel you're still learning and want to figure out the reasons for the rejections then I'd recommend resubmitting - for me this has been a great help in improving my photography.  Of course they still might get rejected for other reasons as pointed out by BT, but at least you can have fixed one issue and will learn something in the process.

Very slow for me, too.  Down a lot on all sites except for DepositPhotos, which is a BME.  Might end up 30% off of the last couple of months unless something changes dramatically.

Thanks for the explanations - I think I understand it now.  The new PM license is RM because it is for a specific use instead of RF allowing for any usage.  However, this is not RM in the same sense as at e.g., Alamy, where it means that you know how the image has been used (although I suppose it could apply in the case of PM).  To be safe, I think I will keep my RM images at Alamy and elsewhere separate, but will certainly opt in to RM on PM - sounds like they are responding to a need and if it leads to more sales for higher prices we will all be happy.

Mine either.  Drat.

I suspect there is no way to find out unless the person who made the sale wants to brag.

I had two refunds in January of a large and an EL totaling $38.50, four days after the sales. - annoying but at least it was within a reasonable time.  If it was 7 months I would complain.  I agree with jsnover that there should be a limit for digital content - 7 days seems reasonable, 30 tops.

No sales there since April 7th.  Before that it was a good month...