Re: DA 16-45/4 is finally available

[Joseph Tainter]

"Joseph Tainter a �crit :"

"Alex, help with a little test, would you? Set the *ist D to mtf (custom 
function 1), then test it outside in program mode on a day with good 
light. What f-stops do you get at different focal lengths? I got the 
following, which seemed odd:

"16-28 mm. f4.0

"35 mm. f4.5

"45 mm. f5.6"

"It is normal, MTF mode does not propose the fastest aperture, but that 
where optical quality remains good. Chage custom fonction or use green 
program to avoid f/4 constant.
"Michel"

Pardon, Michel. I have not made myself clear. Je m'excuse.

MTF function in program mode should give the aperture that gives the 
best image quality. It is unusual for this to be wide open (f 4.0 at 
16-28 mm.) Most lenses are best when they are stopped down a little, 
usually about 2 stops. On several of my other Pentax lenses, mtf will 
give me an f-stop about 1.5 stops down from wide open. So I have been 
wondering if my DA 16-45 has a defective chip.

On the other hand, I did shoot a test subject for sharpness at 24 mm. 
The lens is indeed surprisingly sharp wide open. To my eye, though, it 
looked sharper at f5.6.

If any other PDMLers outside North/South America have the DA 16-45, 
would you be willing to perform the above test for us?

Thanks,

Joe