16 Unique Features That Your Camera Probably Doesn't Have

Started 4 months ago | Discussions thread
prsc Regular Member • Posts: 246
Re: Telecentric

Guy Parsons wrote:

Art_P wrote:

Thought 'telecentric' was dropped when they moved from 4/3 to M43?

I thought that the need for sensor side telecentricity diminished as sensor design moved to larger and maybe some offset microlenses over the pixels as they got further from the centre. That plus in-camera option image processing to reduce the vignetting.

As for "telecentric" then there's a few variations of that feature that the Olympus marketing name does not adequately address.

The usually referenced telecentric lens is explained here, it would be useless in a normal camera. https://www.edmundoptics.com.au/knowledge-center/application-notes/imaging/advantages-of-telecentricity/

The Olympus version (when it exists) is sensor side telecentric but not telecentric on the subject side.

Easy to check your lenses to see what is what.

Measure the diameter of the rear element of the lens, if the diameter of the rear element is the same as the diagonal measure of the sensor then it's a fair bet that it is a sensor side telecentric lens (properly called a image-space telecentric lens). If the diameter of the rear element is less than the sensor diagonal then no way it could be called "telecentric".

Though the Wiki article tells the true test "Image-space telecentric lenses have an exit pupil infinitely far in front of the lens; that is, if one looks in the back of the lens, the image of the aperture is very far away."

I am no expert, simply interested in truthiness. See the Wiki article https://en.wikipedia.org/wiki/Telecentric_lens for more info.

This is correct. They tried to design the system completely with digital in mind and in a sense went too deep. Early CMOS sensors actually didn't have microlenses at all, so the image-space telecentricity actually made some sense, but not for long at all. Only thing it really ended up doing was hurting the lens designs as it was pretty much just an useless restriction, I'm not sure if it was actually dropped during 4/3s time?

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tko
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