Tamron SP 70-210mm F/3.5 19AH: won't focus at infinity

21st-Century Cameras wrote:
On Wed, 09 Sep 2009 05:55:09 GMT, "David J Taylor"
wrote:

"Robert Coe" wrote in message
...
[]
Incidentally, the greatest value in an aftermarket screen is that
you can have
grid lines etched on it. (KatzEye offers about a dozen variations.)
For architecture and seascapes, I couldn't function without a grid.

Bob

One of the delights of the Nikon D5000 - it has gridlines in the
viewfinder you can turn on and off.

Cheers,
David

One of the delights of any CHDK supported camera, it has as many
grid-lines designs as you want, designed by you or others. Grid-lines
that you can turn on or off (with a quick short-cut button press), or
interchange, or combine any time you want. You don't have to send
your camera off to a custom repair service to change your grid
pattern. Just load a new one from a simple to write text-file made of
very basic graphic commands. Keep all of your grids definition files
on your memory card and load any one of them whenever you desire.

A sampling of 34 different user-designed grids and alignment aids
that you can use in any CHDK camera: http://chdk.wikia.com/wiki/Grids
If you don't see one there that you like you can simply write your
own.

There's no reason to continue to support crippled camera paradigms of
last century.

You were doing all right until you got to that last part. Learn to resist
the urge to take a parting shot.

On Wed, 9 Sep 2009 07:34:55 -0700 (PDT), TJ wrote:
: We were on the beach at Ocean City, and some of our shots included the
: skyline of Atlantic City, which is ten or fifteen miles away. That's
: infinity for any lens this side of Mt Wilson.
:
: Bob
:
: Ah so! That is a sharp lens.

I was using a Sigma 50-150mm constant-aperture f/2.8; my wife was using a
Canon 28-135mm f/3.5-5.6 IS. Both are pretty good lenses.

: But you could not see the 'snake eyes' on the dice in AC, no !!!

No, but we could see the windows in the buildings. ;^)

: I found a screen in HK for $20 delivered.

Not bad. Let us know how you make out installing it and whether you can still
see the focus points.

Bob

David J. Littleboy wrote:

Canon seems finally getting their act together: 7 fps, electronic horizon
(level), grid lines, weather sealing, real HD video, new competitive AF
system.

But rather small pixels.
I'll have to see how RAW high-ISO shots (3200+) come out ...

A dedicated high-ISO full frame camera with the newest sensor
technology (maybe even with a backlit sensor and with some
filterless pixels) with, say 8-12 MPix, and hopefully not too
expensive ... that would be interesting. Something like 3-4
stops better at high-ISO than the 5D2 ... I can dream, can't I?

Grumph. I got 3 great years of use out of the 5D, the 5D2 was a fantastic
upgrade (the resolution and manual focus in live view are wonderful), but it
sounds as though the 5D3 will be not much more than a year after the 5D2.

You'll still get the same quality out of your 5D and 5D2 as before,
they just won't be the newest cameras out there any more ...

-Wolfgang

Wolfgang Weisselberg wrote:

A dedicated high-ISO full frame camera with the newest sensor
technology (maybe even with a backlit sensor and with some
filterless pixels) with, say 8-12 MPix, and hopefully not too
expensive ... that would be interesting. Something like 3-4
stops better at high-ISO than the 5D2 ... I can dream, can't I?



Uh, no. The 5D-II is basically photon limited. That's not to say it is
perfect: all cameras still could use improvement in the 1/f noise
of their amplifiers so that the dark areas have a purer "photon noise"
look than they do today. The current "streaks" and "splotches"
need to go. But they will never be "film look" dark areas:
they are already far better than that. Photon noise is isolated
barely visible light pixels on a pure flat background.

Doug McDonald

"mcdonaldREMOVE TO ACTUALLY REACH "mcdonaldREMOVE TO ACTUALLY REACH wrote:
Wolfgang Weisselberg wrote:

A dedicated high-ISO full frame camera with the newest sensor
technology (maybe even with a backlit sensor and with some
filterless pixels) with, say 8-12 MPix, and hopefully not too
expensive ... that would be interesting. Something like 3-4
stops better at high-ISO than the 5D2 ... I can dream, can't I?

Uh, no. The 5D-II is basically photon limited.

Of course it is, practically all digital cameras are.
Including almost all P&S cameras.

You'll agree that even good photon limited P&S cameras won't come
close in high-ISO performance to the 5D2, so why the "Uh, no"?

Doubling (or tripling) the pixel size: 1+ stops.
Backlit sensor: 1 to no more than 1.5 stops due to better QE.
Bayer patterns with clear pixels: 1 to maybe 2 stops.
Newest sensor technology: I guess no more than 0.5 stops, often
due to broader bayer pattern filters, better noise supression,
less fixed noise patterns ...

In my book that's at least 3 stops that can be archived with the
technology we have today, and maybe we can get another stop in
a couple of years, so my 3-4 stops better than the 5D2[1] may be
unmarketable, but not technologically impossible.

-Wolfgang

[1] that means the noise of the 5D2 @ ISO 3200 would equal the
noise of the high-ISO-cam @ ISO 25600 or ISO 51200.