Re: telecentric question

anatole@...
 

I understand that most sensors use microlenses, because there is a significant difference in efficiency without them. The pixel well has a significant gap between itself and the next well, so consequently without microlenses, a lot of light would fall between the pixel wells. Imagine something like this for a row of pixels: --_--_--_--_--

In the case of a gapless microlens design, each microlens touches the neighbouring microlens and thus most light that hits the sensor can be collected into the pixel wells. Off the top of my head, that increases efficiency by something like 3 times over a design without microlenses.

On the question of telecentricity – I think what you're thinking of are standard microlens designs vs off-set microlens designs. A standard design performs best with telecentric lenses. An off-set design, such as that found in Leica M cameras, has the the microlenses at the edges of the sensor off-set from the centre of the pixel well. That improves picture quality where light is coming at an oblique angle.

I believe that with telecentric lenses, an offset design will perform worse than a standard microlens design, since the offset implies that actually less light will be collected if light rays are approaching the sensor at a less oblique angle. Of course, that depends on the degree of the offset, and the specific angle of the light coming from the lens; after all, the light still will be coming at an angle at the sensor edges, rather than perpendicular to the sensor plane.

Join cml-glass@cml.news to automatically receive all group messages.