no nifty fifty for the 4/3 mount?

[howfly]

Originally Posted by Doug Pardee

With the micro-4/3 system, lenses are not required to be telecentric. The flange-back distance is mainly limited by needing enough room for non-telecentric lenses to get a decent amount of light into the corners and edges, and of course leaving room for the shutter mechanism and all of the stuff stuck on the front of the sensor.

Now I'm thoroughly confused (not unusual for me).
A shorter flange-back distance in u4/3 means the rays to the corners of the sensor are
at a higher angle from perpendicular. If the lens is not telecentric, then either the sensor must employ u-lens offset or the image processor must compensate for vignetting, CA, etc, introduced by the sensor. If it's the latter, then the image processor must know the characteristics of the lens re telecentricity. If true, then only u4/3 lenses in shorter focal lengths would perform well. Just how confused am I?

[kalendae]

is there any downside (other than having to MF) to getting an OM adapter ring and getting a lens like a 28mm / 2 or some such? wouldn't that be the same as a 50mm/1.8 on a nikon/canon line? (actually slightly wider and closer to 50mm at 35mm equivalent even).

I've seen those go for about $100 on ebay.

[inkista]

Originally Posted by kalendae

is there any downside (other than having to MF) to getting an OM adapter ring and getting a lens like a 28mm / 2 or some such? wouldn't that be the same as a 50mm/1.8 on a nikon/canon line? (actually slightly wider and closer to 50mm at 35mm equivalent even).

I've seen those go for about $100 on ebay.

Well, you lose all electronic communication between the lens and the body, so you don't just lose autofocus, you also lose the ability to shoot in anything but Manual and Aperture-Priority modes, and your EXIF won't have focal length or aperture information, and you won't have any autofocus confirmation, unless you get a chipped adapter. Some of the eBay sellers out there are using a chip that fakes being a four-thirds lens on the mount.

A chipped adapter is doubly worth it with four-thirds, though, because it can give you stabilization as well. So, I wouldn't necessarily discount picking up a 50/1.8 (or 1.4 or 1.2) either.

Originally Posted by howfly

Now I'm thoroughly confused (not unusual for me).
A shorter flange-back distance in u4/3 means the rays to the corners of the sensor are
at a higher angle from perpendicular. If the lens is not telecentric, then either the sensor must employ u-lens offset or the image processor must compensate for vignetting, CA, etc, introduced by the sensor. If it's the latter, then the image processor must know the characteristics of the lens re telecentricity. If true, then only u4/3 lenses in shorter focal lengths would perform well. Just how confused am I?

Very. First of all, you're making the assumption that a lens has to be telecentric to be well designed and able to control the factors. It doesn't. It's just one way of making a normal lens perform better with a simpler design. There are others, such as exotic glass elements or using a telephoto design. But basically, the bane of wide angles of all types is getting the light into the corners evenly and well-placed. All the tech that was mentioned are all just different ways of doing that--someone may come up with additional methods. None of this is "have to", more like "different ways around the problem."

[windrider86]

I purchased a 50mm om lens off of Ebay for $15/ And it is in perfect condition. If you dont mind manual focus its perfectly fine
I also use my 35mm lens with a teleconverter on it a large portion of the time. Produces wonderful images