What dSLR cameras can Olympus E-510 be compared to?

At the time they reviewed the E-510, http://www.dpreview.com compared it to the Sony DSLR-A100, Pentax K10D, & Canon EOS 400D.

HTH

Actually. the Olympus and 4/3 line up of lenses is quite extensive considering that the standard is only five years old. Many of the lenses listed for Canon & Nikon are either older designs or reworked designs of older lenses and, while most are very high quality there is a great deal of overlap in the available array for those brands.

Olympus has been very consistent in providing additional lenses since the introduction of the E-Series (and no longer lists lenses that it has phased out as it introduced newer variations or designs). For most users there is an excellent
selection of lenses (32 current models) especially if you include the Leica/Panasonic 4/3 mount lenses.

http://www.four-thirds.org/en/products/lense.html

What they have done is developed three “grades” of lenses to provide excellent optics with different characteristics –

“Standard” grade with lighter, smaller lenses that are less expensive but not as “fast” (bright) because they have smaller apertures. These are very reasonably priced, economy lenses with superior optical qualities when compared to most other brands.

“High Grade”, larger, brighter lenses with more rugged construction and dust/moisture seals for rougher usage. These lenses are clearly superior in construction and use metal fittings where some of the less expensive ones may use plastic but they are significantly more expensive. If you are a working pro or very serious amateur you will pay the extra $ $ to have the heavy duty equipment and best possible optical performance.

“Super High Grade”, very bright, using more special optical glass and often costing many times more than the cameras.
These lenses are stellar in performance.

Also, the E-Series can use nearly every lens ever made for the 35mm Olympus OM cameras (with an adapter) and MANY other brands of lenses, including many Nikon 35mm lenses with similar adapters.

For a brief history of the design check out the first site listed below -

Here are comparable models to the E510 based on features and price -

Canon Digital Rebel XTi (also known as EOS 400D)
Nikon D40X
Pentax K110D

I would compare them using a tool like the one at dpreview.com (The last link below).

BTW, I think the argument about sensor size is moot, largely because of a corollary to Moore’s Law (check Wikipedia for an explanation of the term, if you’re interested). Olympus was the first company to design a DSLR based solely on a digital construction and has already surpassed every limitation that the naysayers warned about in 2003. And the results speak for themselves.

Hope this helps. Email if you have more specific questions