Opinions Needed: Olympus OM 24mm VS Canon FDn 24mm

Started Nov 26, 2011 | Discussions thread
uhoh07 Senior Member • Posts: 1,580
Re: Opinions Needed: Olympus OM 24mm VS Canon FDn 24mm

cxsparc wrote:

uhoh07 wrote:

cxsparc wrote:

@uhu: You didn't write the used aperture. To my eye, even at this low res pic I can see the corners being very soft.

Guess you do understand what SA means?

No, I don't. Instead of writing such an informative reply, why not simply spell it out?

I wrote "It is also sharper in the center than just about any 25, but has SA issues which preclude proper focus on the edges"

Had you asked-- what is SA? before describing the edges as soft, i would have been happy to reply.

Instead you ignored the sentence altogether and made a mindless observation which I had already explained.

earning my snarky response.

a) Spherical aberration. Basically, a beam of light passing through a lens parallel to the optical axis converges to form 3 focused image on the film. Spherical aberration is the term for an optical fault caused by the spherical form of a lense that produces different focus points along the axis for central and marginal rays.

the lens is not soft on the edges---that means you cannot get sharp edges. The lens shows alot of SA on the nex----you CAN get razor edges, but the centers suffer.

@ russell you are spot on as usual ;). I should do some detailed expeirments at f/16 to see if you can get it all together. It's a shame, since the lens looks as if built for the nex, and really is wonderfully sharp.

That shot is at f/4 I think.

The 42/1.2 has no SA and is also very sharp at f/8

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