Why fixed focus?
All Super-Eye™ lenses are fixed focus, but with continuously adjustable, lockable apertures. These telecentric lenses are meant for your industrial applications, not as laboratory tools to evaluate an infinite variety of tasks. While we encourage experimentation and are always very happy to assist with your application challenges, we know that a plant floor installation needs firm, fixed optics.
If you’ve ever spent hours chasing down a machine vision system problem, only to find that someone had bumped the lens, or made an adjustment to "improve" performance, you know what a mixed blessing a focus ring can be. For even more fool-proofiing, Super-Eye™ lenses can also be supplied with fixed apertures.
But don’t worry about flexibility. We’ve made set-up easy by designing our lenses so that a simple change of extension rings or spacers can change the working distance with little or no change to the nominal magnification.
But all these lenses look alike! [ are there a bunch of pics here? this may not make sense]
Well, that’s not quite true, but to the extent that it is, "it’s a good thing." All Super-Eye lenses share a common form-factor, with model differences being confined to the length of the secondary barrel and the aperture position. In this way, you can mount every Super-Eye lens by the same method.
You tell me the MTF, but so what?
A lot more information is being provided these days by makers and vendors of lenses about image quality and modulation transfer function or MTF. We do too, in our DEFINITIONS and SPECIFICATIONS pages. For example, we tell you that our model SE-300 at F/32 and a frequency of 16.7 line pairs per millimeter (lp/mm) has an MTF depth of field measured at the 0.3 points of +12mm, -14mm. But how will the image look with your camera? Like this!
[insert pictures]
-14mm, corner of FOV Best Focus, Center +12mm, corner of FOV
Here are three unprocessed images captured using a Pulnix T-200, 1/2" format camera and the SE-300 lens. At 640 x 480 capture resolution, the pixel size at the camera is 0.010mm. The actual fields were larger, we just isolated the 5.0 lp/mm target to show here.
With a magnification of 0.300, the frequency of the image of the target is 16.7 lp/mm, or about 3 pixels per single line width. We show the target at the corner of the field of view when it is 14mm closer than the best focus distance, the well-focussed target at the field center, and the target at the field corner while being 12mm farther than best focus.
These worst cases are at the limits of the stated MTF Depth of Field. Some vendors may specify greater depth of field for lower target frequencies or smaller MTF cut-off points, but check and see what the images really look like at the their limits.
Don't forget the Adjustable Field Splitter!
We’ll certainly remind you. In addition to being great telecentric lenses the Super-Eye™ line is also a perfect partner for our patented Adjustable Field Splitter (AFS). The AFS lets your single camera view two different objects or fields at once, or the same object from two different angles. Save money, time, resolution and space with an AFS.
