Re: Manual Focus Pentax Glass on istD

[Herb Chong]

not sharp enough. the FA 24-90 is one example. shooting Provia, it isn't 
easily distinguishable from any other excellent prime or zoom like the FA 
50/2.8 Macro or the FA* 80-200/2.8. with Velvia, with good technique, it 
shows a little less sharpness. on the *istD, the 1.5x crop factor turns a 
very good lens into an average one. that's not good enough and i don't use 
the FA 24-90 anymore except when i need a light set of 3 lenses to cover 
from 16 to 320mm. if weight is less of an issue, i would rather carry the 
FA* 28-70/2.8, or perhaps the set of 3 Limiteds and the FA* 80-200/2.8 and 
the FA* 400/5.6. the FA* 24/2, of course, has the chromatic aberration i 
don't like. i got rid of all my Sigma lenses, except the 12-24, for 
sharpness, bokeh, and chromatic aberration reasons. the 12-24 shows all of 
the above effects, but not to the degree of the other Sigmas. if there were 
a Pentax 12mm, whether prime or zoom, i would replace the Sigma. the DA 
14/2.8 isn't sharp enough for my liking.

none of these conclusions of mine are based more than seeing the effect of 
the 1.5x crop factor of the sensor. i don't have single examples to show of 
any of these. they are the results of observing my best lenses on both film 
and digital bodies and seeing which of my lenses are the worst with each. 
anything too much worse than my best, i put away, like the 24-90, waiting 
for the occasional roll of film i shoot, or for the day a full frame digital 
from Pentax finally arrives, or i sell.

the FA 50/2.8 Macro,  FA* 80-200/2.8, and the DA 16-45/4 are my benchmarks. 
if i can look at a 100% image from any other lens and can see a sharpness 
difference immediately, then it's not good enough. if i have to compare 
carefully to see a difference, then i keep the lens. wide open performance 
isn't as critical as f8-f11 performance. since i am almost always on a good 
tripod system, vibration movement isn't an issue.

Herb...
----- Original Message ----- 
From: "Shel Belinkoff" <[EMAIL PROTECTED]>
To: <pentax-discuss@pdml.net>
Sent: Monday, February 21, 2005 4:24 PM
Subject: Re: Manual Focus Pentax Glass on istD


In what way aren't they acceptable?  Can you provide an example?