on 29/08/2004 18:18, Joel Wilcox at jowilcox@xxxxxxxxxxxxxxxxxxx wrote:
> I know what you mean. There are times when it has been the only lens I've
> used for days on end it seems.
>
> Joel W.
>
> At 01:36 PM 8/29/2004 -0700, you wrote:
>> Hi Joel,
>>
>> Same here, a little soft between 180 and 250. I use it quite
>> frequently for landscape work... more than I thought I would.
>>
>> Richard
>> --- Joel Wilcox <jowilcox@xxxxxxxxxxxxxxxxxxx> wrote:
>>
>>> Nice job! How do you like your 85-250? Mine's a little soft at the
>>> long
>>> end ... :(
Hi Joel and Richard,
Should I assume I was lucky enough to find an 85~250 that is neither soft at
~200mm, nor does it show vignetting?
I remember Joel asking on 27/07/2004 10:30, about vignetting when using
tubes at 250mm.
I know your findings agree with data published by Gary Reese, and also with
those published at MP once upon a time.
How can I explain I didn't find according performance on mine ?
1- Until now, stopped down to f11 regularly.
One picture shot at 250mm f11 + tube @ 65mm + T-32 (-1 stop OTF) when
shooting yellow lapacho flowers after the rain, show somehow soft on Provia
100F, but honestly I can't tell if this wasn't due to slight flash
overexposure since next shot @ f16 is quite sharp (raindrops can be counted
one by one).
2- With a couple of exceptions, tripod mounted (I love its tripod collar,
though I must turn 180 degrees the Manfrotto 141RC).
Once, handheld 250mm @ f5 w/Velvia 50, subject was moving fast enough to
miss proper focus, and DOF is too shallow to asess sharpness but I must say
that what remained in focus was sharp enough. Overall image has good
contrast.
3- Main test shots @ 250mm were done on Velvia 50 @ f11.
Pincushion is negligible while looking closely at the iron bars on the fence
of my house.
Why Velvia? I don't fully understand why, so I'd better quote the following:
--------------------------
>At 11:32 PM 7/16/03, Joel Wilcox wrote:
>
>>Except that 100F also doesn't resolve as well as Velvia 50, according to
>>the Pop Photography review this month (81 lines to 100F's 72 lines).
>>
>>Joel W.
At 12:16 AM 7/17/2003 -0500, John L. wrote:
>I think this is what he said, although the sentence was long with fair
>number of pronouns (can cause ambiguities). In any event, their
>respective MTF curves explain why this is.
>
>I omitted my understanding of how to interpret MTF graphs in my previous
>posting (mea culpa). Look at the curve from about 10 lppmm through about
>40 or 50 lppmm. IIRC, Velvia 50 actually rises above 100% for a portion
>of this region. Those films (and print materials and lenses) that have a
>very high curve in this region tend to have higher accutance; i.e. they
>are capable of producing photographs that look sharper. This is in spite
>of how the curve rolls off in the high lppmm.
<snip>
This is what Peter Kolonia wrote in PP (have the article before
me): "Velvia 50, however, trumped the competition [between Velvia 100F and
E100VS] in resolving power, with the ability to distinguish 81 line pairs
per millimeter (lp/mm) in our resolution tests, compared to 72 lp/mm for
both Velvia 100F and E100VS. Is this significant? Probably not for general
photography, but it could be a factor in mural-sized enlargements" (PP, Aug
2003, p. 66).
John, where do you see the potential for ambiguity?
Joel W.
-------------------------------------
4- The more I look after it, the least I find any vignetting, even with a
Hoya MC Skylight 1A.
5- No mirror or aperture prefire since I only own a couple of 2/2n.
So, I owe myself a couple of test shots @ 250mm, one @ f5~8 and another @
f11~16. Hope to submit results on a next TOPE, a former one using this lens
was done @ 120mm.
HTH,
Fernando.
==============================================
List usage info: http://www.zuikoholic.com
List nannies: olympusadmin@xxxxxxxxxx
==============================================
|