On 2 Jan 2003 07:36:11 -0800, harryhydro@hotmail.com (harry) wrote:

> I find myself looking over pictures for detail, namely the

>sharpest focus of distant objects. I've seen specs on lenses that use

>lines-per-millimeter. I suppose this in on the surface of the film.

>One particular old lens for an Alpa had a number of 80 lpmm or so..

>Do they still spec camera lenses like this today? Is there a finer

>grade? I'm looking for a camera with the best focus on distant

>objects. Any pointers?

As others have pointed out, "sharpness" is a combination

of resolution and contrast - and a lens that can resolve

"80 lpmm" can actually look rather poor. Also, lenses can

vary considerably in performance with the particular sample,

the stop used, where in the frame you are looking, and

with focus distance - and "lpmm" tend to be measured at

too-close distances for some lenses to show much about

infinity-focus performance... In my lens evaluations,

I use "subjective" viewing of real-world infinity-focus

subjects shot at the widest reasonable stops for the

lens type for arriving at the basic evaluation numbers

(and note the differences, if performance is noticeably

different around 5'-focus). This method tends to cover

the lens image "variables" better than "objective" tests

can (without making them VERY complex).