Re: primes vs zooms

[Joseph Tainter]

"Question 1:

"I assume that a prime lens of 50mm, let's say a FA 50 1.4, is always 
going to be sharper than a FA 28-105 set at 50mm. Is this true, assuming 
that both were set at the same f-stop?"

Pentax 50 primes are probably sharper than any of Pentax's 28-105s at 
50. Other lenses (such as the Tokina ATX-AF Pro 28-80 f2.8, which I own) 
are nearly as sharp as some Pentax primes, and sharper than others. I 
posted a test on the list some months ago, but it was at f8 -- not a 
systematic test across all f-stops. Still, the Tokina and the FA 20-35 
f4 shined, easily holding their own against primes.

"Question 2:

"Is a FA 100 2.8 Macro as sharp as a FA 135 2.8 at infinty for 
landscapes? Can I kill two birds with one stone by getting that Macro?"

I'm not crazy about the performance of my FA 100 f2.8 at infinity. It's 
okay, just not as sharp as close up. Just a perception, not a systematic 
test. I haven't tried the FA 135.

Joe