FZ70 Announced. Is This Just Another Frankencamera?

Started Jul 18, 2013 | Discussions thread
GeraldW Veteran Member • Posts: 8,304
Re: Hands On Preview at Imaging Resource.com - doesn't help.

That's also one of my causes.  Occassionally someone will do the research and publish it.  Camera Labs did that for a couple of long zooms including the SX10IS.  Some I've done myself, as you have; and in a few cases, from gallery shots you can look for the longest focal lenths for a given aperture and tabulate those.  Usually takes two or three galleries to get enough data points.

Plotted on semi-log paper one can see how the aperture changes with f/#.  I've found that plotting focal length on the horizontal logarithmic axis, and f/# on the linear vertical axis works best.  I use paper with 1" major linear divisions and plot one f/# per inch.  (f/1.4, f/2, f/2.8, etc)  Some lenses plot as a nearly straight line; but most show curvature.  The Panasonic FZ28 & FZ35, and the FZ150 plot as fairly fast and a straight line up to about 80% of max focal length and then curve upward sharply at the end.  A hockey stick shape.  Canons from the SX10IS onwards show a fast rise to smaller apertures and then fairly slowly over the rest of the range - a hump backed shape.  I much prefer linear or hockey stick as it gets a faster lens at middle focal lengths.


 GeraldW's gear list:GeraldW's gear list
Canon PowerShot S90 Canon SX220 HS Canon PowerShot ELPH 330 HS Canon PowerShot SX50 HS Panasonic FZ1000 +1 more
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