Dear Canon, I'm not buying anymore DSLR Gear get on with the M

Started 9 months ago | Discussions thread
Photato
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Re: you have a narrow-minded view of the benefits of compact size
In reply to Rock and Rollei, 9 months ago

Rock and Rollei wrote:

But there's one huge advantage of retrofocus lenses - telecentricity. Retrofocus lenses automatically are quite telecentric, which means that rays of light hit the sensor at a perpendicular angle even at the edges; non-telecentric lenses don't have this property. With film, it didn't matter, because they would still penetrate the film layer and be recorded; the physical depth of the sensor makes that a lot more difficult, and without special measures, much of the light at the edges of the frame would be lost, leading to massive vignetting in effect. That's why it took Leica quite a while to dip their toes into digital with the M, and when they did, the M8 was APS-C - and so on with lens coding etc.

True, but M8 has an APS-H, not an APS-C.

The way round it has been with the design of microlenses angled towards the centre, allied with greater ampliciation of edges - and for most mirrorless designs, not going full frame, and having lenses specifically designed with this in mind - the 11-22 being a great example of how well it can be done.

But what happen with longer focal lengths and those shifted microlenses at the edge of the sensor?

Because of this Telecentricity the EF-S 18-55 kit lens has less vignetting than the EF-M one.

Incidentally, the issue of sensor depth and not-perpendicular image rays would appear to be the reason for the size of Sigma's Foveon sensor - the depth being more significant and critical with that design.

Probably.

BTW. It is puzzling to me how this issue was not even mentioned during the Sony A7 reviews.

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