Posted by Spex on 12/21/07 14:58

Steve King wrote:
> "David Ruether" <druether@twcny.rr.com> wrote in message
> news:476af1cb$0$11001$4c368faf@roadrunner.com...
>>
>> Canon certainly got their act together on this one - the
>>
>> HV20 is one heck of a good tiny HD camcorder! The
>>
>> picture at the wide end is superb (very sharp to the
>>
>> corners, free of artifacts, and with excellent color and
>>
>> color neutrality). Zooming through the (marked) zoom
>>
>> range away from WA to about 1/2 way gradually
>>
>> introduces a tad of CA, but nothing bad and with
>>
>> nothing else to complain about. Zooming to about 3/4
>>
>> of the range toward tele introduces still more CA, but
>>
>> it is acceptable, and sharpness, while declining a bit,
>>
>> is still very good. Beyond that point, the image quality
>>
>> declines rapidly, the CA is excessive at the long end,
>>
>> and sharpness isn't all it could be (but I prefer WA, so
>>
>> this isn't a "deal breaker" for me). In the zoom range I
>>
>> will use it in most of the time, the picture quality is
>>
>> astonishing (viewed on a particularly sharp 42" LCD
>>
>> at 6.5'), especially for the absurdly low price of $750
>>
>> (and with a $75 gift card thrown in to cover some
>>
>> accessories, at B&H). I thought I would miss a Lanc
>>
>> input, but Canon has provided not only a nice zoom
>>
>> control for a small camcorder (with an unusually slow
>>
>> lowest speed - very nice!), but a menu selection for
>>
>> choosing a fixed zoom speed so you can "mash" the
>>
>> controller and still get a predictable zoom rate. To my
>>
>> surprise, the "peaking" and 2X magnification aids for
>>
>> helping with manual focus were quite usable. Also to
>>
>> my surprise, the 24P mode was not as ugly with
>>
>> motion as earlier versions (of 30P) that I tried were.
>>
>> The "film mode" did help with skin color under some
>>
>> conditions, and appeared to help with highlight
>>
>> blow-out (but I have not checked this carefully, and
>>
>> I generally prefer the look of "standard" mode...).
>>
>> There are some modest-range picture-modifying
>>
>> controls, but I have not yet checked out these. I
>>
>> went through many of my shelves full of WA lens
>>
>> converters, and was surprised how good four of
>>
>> them looked, but all but one was less than perfect.
>>
>> The VERY wide Sony ES-06 was *very* slightly
>>
>> soft in the corners and had some slight CA, but it is
>>
>> compact and very light (but ***ANY*** dust on
>>
>> its front shows as big blobs in the image, so I will not
>>
>> use it...). One generic fisheye adapter was quite sharp
>>
>> and extremely wide, but my camcorder CCD is
>>
>> decentered top to bottom, so the cropped circular
>>
>> image is not satisfactory without further cropping in
>>
>> post (this reminds me that the HV20 VFs show quite
>>
>> a bit less than the full recorded area - and that the
>>
>> various available VF grids and lines were too
>>
>> intrusive). The Raynox .66X was quite good, but it
>>
>> was not fully zoom-through, and at the wide end it
>>
>> was bettered a bit by the winner, a Canon WD-58.
>>
>> This .7X was designed for the Canon GL-1, but
>>
>> was excellent on the various Sony 58mm-threaded
>>
>> Mini-DV camcorders (see comparison frame grabs
>>
>> here from various 58mm WA converters --
>>
>> www.donferrario.com/ruether/WA-converters.htm).
>>
>> Though rather heavy, it appears to affect the image
>>
>> in no way I can see, throughout the zoom range. It
>>
>> may still be worth trying the far smaller and lighter
>>
>> $200 .7X made for the camcorder, though... I did
>>
>> find that the camcorder is not left-eye friendly, and
>>
>> I also found it useful to put small sticky-backed bits
>>
>> of soft material at the VF top corners to protect
>>
>> eyeglasses from the hard VF surround material.
>>
>> Since I shake, I use a large handle that extends up
>>
>> and forward on the left side, and I may add a belt
>>
>> pod (I have a tank of a pro fluid-head video tripod,
>>
>> but.......................................;-). Anyway, this
>>
>> camcorder is amazing! The output is a huge
>>
>> improvement over even the best Mini-DV, and while
>>
>> it is well short of the very best broadcast HD, it looks
>>
>> to me to be about up with "average" HD broadcast
>>
>> quality, not a small thing for such a cheap and simple
>>
>> camera.
>>
>> --
>> David Ruether
>> d_ruether@hotmail.com
>> http://www.donferrario.com/ruether
>
> Okay. I'll admit that I am not much of a techy, when it comes to
> photography and lenses. So, I had to look up 'WA'. Google is my friend:
> Cocaine Anonymous, or a virus solution, or the state of California, or
> Chartered Accountant, or Certificate Authority, or Computer Associates, or
> the chemical symbol for Calcium. I think I'll go with calcium. Grrrrrrrr!
>
> Steve King
>
>

I think you meant CA not WA

Chromatic Aberration.

Around contrasty areas you'll see green and purple or blue and red lines
caused by the refracting at different wavelengths. It has always been
there just not as obvious in the low res world of SD.

Lens can be coated to reduce this but it can lead to ugly bokeh if the
lens is over optimised. I believe the new Sony EX1 actually corrects CA
in the DSP which is another completely valid way of reducing its
appearance. I can also be fixed in post by rescaling the R,G&B components.

The standard Canon XL-H1 lens was the worst offender I've ever seen for CA.

[Back to original message]