Can the HX20 or RX100 serve as your only camera?

Started Aug 8, 2012 | Discussions thread
tbcass
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Re: Can the HX20 or RX100 serve as your only camera?
In reply to LSHorwitz1, Aug 11, 2012

LSHorwitz1 wrote:

It was never my contention that the HX20V is superior to all such cameras, all such lenses, or any other particular interchangeable lens camera combination. Thus I will not try to extend my claim to any of these topics, and indeed cannot hold such a belief in general terms either.

Thus, I think we are in total agreement here, and some mix of camera body and lens may very well outperform the HX20V in this regard. I will say confidently that neither my Sony or Canon DSLRs and mirrorless cameras and long lenses come anywhere near focusing as quickly as the HX20V.

Since I see in your profile that you are a retired engineer, and know how we retired engineers tend to think and analyze and discuss such matters, I will conclude this comment by saying that the comparative burden of quickly focusing a small lens and a small sensor such as used in the HX20, which is roughly 89mm focal length (for an effective crop of 500mm) versus the APS-C sized 325mm lens (for an effective crop of 500mm) puts huge additional requirements on the servo system. The additional mass, the inertia, the slew rate, the energy damping to prevent blur, and, most of all, the enormously more critically accurate positioning which is demanded by the much more shallow DOF make the liklihood of buidling a faster DSLR / lens combination quite challenging.

Good point about the inertial properties of a large vs small lens and the deep DOF of small sensors. Such cameras can focus quite rapidly in good light with high contrast subjects. The down fall of these cameras, which use contrast detect auto focus, occurs in less than bright light when the camera cannot find an edge to focus on. That is one of the reasons I bought my first DSLR. When I became a grand parent my old Fuji s9000, which focused quickly in sunlight, simply could not keep up with small children indoors.

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