Wednesday, April 18, 2012

More on evaluating lenses

My last post rambled on to the effect that you need data to make comparisons between lenses. This is a big topic and it requires a grasp of two technical terms: line pairs per millimeter and modulation transfer function.

I could devote a month’s worth of blog posts to explaining these, but I don’t need to because Scott Israel of 1st Vision has done it for me in a video presentation titled “Debunking the Megapixel Lens Myth!

The video gets pretty technical, although to avoid reinventing the wheel Scott uses some material from Edmund Optics presentations on the same theme. Over the course of almost twenty-three minutes Scott delves in to why more pixels means smaller pixels, making use of star target patterns, and best of all, why it’s “hogwash” to talk of a five megapixel lens. (You’ll have to watch the video to learn why.)

The bottom line though is that it’s very hard for the end user to figure out which lens is best for a specific application, so call Scott and ask him to do it for you.


Scott Israel said...

Appreciate this. You might be the only person to make it thru the whole presentation without falling asleep;-)

Am looking at making a shorter, more basic presentation. Scott

Anonymous said...

Lots of excellent points.
Hard to handle much in such a short presentation. Great info here.

In the world of machine vision it is optics, optics, optics.

Some notes here on 3-D distortions, active senor area, color filters,(so people would get this spatial resolution thing) and telecentric would be nice.

As an always learning rookie, with just enough knowledge to make me dangerous, I am constantly befuddled by many peoples choices of lens.

Way to many applications get a bad name just because the choice of optics was made on cost alone.

Optics and lighting first, get this right and everything else is easy.