Greetings one and all!

So very wonderful to have discovered this site during my research of micro four thirds.

I've pretty much decided that I will enter this universe shortly, but have a few questions that I hope one of you can answer.

Mostly, I plan to use two of my Leica M lenses with my (future) E-P1. I know I need an adapter, which seem to range for $80 on eBay up to $250!

My confusion comes in as follows; My one lens is 35mm... when placed onto the E-P1 does this mean I now have a effective 70mm lens?

Or do I still have a true 35mm?

New and Confused!

Thanks!

ok, so basically I just need to look at my collections and double everything!

yay, my 90 is now a 180!
boo, my 35 is now a 70!

oh well!

great glass, will have to find something in the 20mm region about some point!

but thank you.. this clears things up 100%

And the 17mm pancake (which comes with the E-P1 kit) is your new 35mm. So you will have a complete set of lenses.

Another brilliant suggestion!

I love this place... love the concept behind Four Thirds!

This is so exciting!

the pro photographer has given you bogus information ,

the angle of view changes only not the light transmission, no loss of f stops at all

your misinformed friend is probably  confusing the properties of the micro 4\3 system with those of teleconverters  for 35 mm that sit between lens and body to double focal length, these do lose light , 2 stops for for a 2X converter .  the apparent doubling of focal length for the ep-1 and the gf-1 is unrelated to this phenomenon .

when using  full frame lenses  it does not suffer light loss at all , in fact you are treated to the central sweet spot of full frame lenses , lense will perform better on m4\3 bodies than on full frame counterparts , at least optically  

if anything you will be getting more light as the light falloff at the edges of the full frame lenses and also loss of sharpness at the edges of full frame is not "seen"  by the image sensor of m4\3 cameras  that only use the central portion of the image circle cast by full frame lenses

I've looked up and down the interwebs for somebody who could do a better job of explaining it better than I. I may have finally found it. Here's a quote from the article:

The 'crop factor' does affect the apparent depth of field of the taken image: with the magnification of 2, the DOF is effectively doubled (again, it is important to note that this perceived effect is due to the FOV 'crop'; the same depth of field is present, but you are viewing it at twice the magnification).
It is important to note that neither the light gathering ability of the lens, nor any of its traits are actually affected: a 50mm f2 lens on a 4/3rds body has the same f-stop and depth of field as a 50mm lens on a 35mm camera, but the 4/3rds sensor only records the equivalent field of view of a 100mm lens. As a general rule of thumb the depth of field of a lens is halved as its focal length is doubled (if the aperture remains constant). The end result is therefore that a 4/3rds camera has twice the depth of field as a 35mm camera with a lens covering the same field of view.
Returning to the above example, a 50mm f/2 OM lens used on a 4/3rds digital body is effectively equal to a 35mm camera with a 100mm lens set at f/4.

And the url to the article:
http://www.camerapedia.org/wiki/Micro_Four_Thirds

HTH.

To sort of give my own words to it. The 4/3 sensor only gathers the light from the center of the 35mm frame's area, so that is all you are getting. Your lens is still what it is, but it behaves differently on the m4/3 camera.

-Jon