On 2016-04-05, Alfred Molon wrote:
If you check this article:
http://www.fujix-forum.com/threads/w...-professional-
mirrorless-was-a-fatal-mistake.54299/

the author is claiming that because the body is small, the lenses must
be bigger to maintain the distance to the sensor.

But is it perhaps because Sony is using an old lens design (suitable
for DSLRs where the lens is further away from the sensor)? And if Sony
used a different lens design, the lenses could be smaller (with the
rear element closer to the sensor)?

Here's what I think:

If you can keep the rays of light coming from the lens more or less at
right angles to the sensor regardless of the effective focal length and
right across the picture then all your lenses will inherently be well
matched to the sensor. Keeping a good distance between the sensor and
the back of the lens achieves that. Lenses designed to make room for an
SLR mirror will also meet that requirement, if fitted to a lens mount or
adaptor that makes up for the slimmer body of a mirrorless camera. That
isn't a bad thing.

If you have lenses with a 'cone' of light coming out onto the sensor,
you need to arrange the position and alignment of each sensor element to
match the angle of the light in the cone at that particular spot. You
can indeed make the lenses come closer to the sensor if you do that, but
each lens will need a different sensor element arrangement to match the
different 'cone' of light - or you'll get bad vignetting and distortion.
This is much less of a problem with film, which responds pretty evenly
regardless of the angle of the light cone from the lens, which is why
lenses for film rangefinder cameras can be so compact and fit so close
to the film.

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-- Whiskers
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