That was a busy night - mine, looking at Derby's bricks... ;-)
Thanks again - and I agree with your evaluation of the lenses. I
uderstand they are original DA projects, with the possible exception of
the 40mm. Both the 40mm and the 70mm fall short as of this test, but
could be used with limits. Add this to the point some oldsters leave
just an extra hairline of space by habit, and we may end using some DA
lenses with 35mm film with acceptable results. Some possible uses.
Of course light falloff and image coverage are just part of the issue,
but the corners of those wide open tests aren't so hideous as I feared.
Actually looks promising. If you ever update the tests, pls post... Thanks!
Boris, thanks!
LF
Derby Chang escreveu:
Hi Luiz,
Some time ago, I took these shots that Boris has been gracious enough to
host. I probably should do an update with a few more DA lenses I have now.
http://boris.isra-shop.com/da_lim_on_film.html
hope this helps
Derby
Luiz Felipe wrote:
Guess they could sue me if I end up finding some DA lens CAPABLE of
marginal (but acceptable to some extent by me) 35mm coverage...
If I sell someone a PC that is not intended to video edition, has no
real video capability but the user stubbornly uses it to edit video,
I'm ok with that.
Let's accept the truth, handed from wherever by any means, that Pentax
offers no DA lens intended and guaranteed to work 35mm. My question
still remains: is there any experience proving lousy 35mm coverage by
said DA lenses? Since it's not the accepted use, I won't hold sacred
Pentax responsible for my results... they will be my entire
responsibility. All mine.
LF
JC OConnell escreveu:
If some dont cover full frame than its pretty obvious
to me that DA lens series is not intended nor guanateed
for full frame usage, they are for APS usage. Just like
some K series full frame lenses could work on larger formats
than but were not sold nor intended for use on larger formats
than 35mm. I would think that the DA lens series is NOT for full
frame usage according to pentax.
JC O'Connell (mailto:[email protected])
"Honesty is the first chapter in the book of wisdom" - Thomas Jefferson
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
Mark Roberts
Sent: Wednesday, April 29, 2009 12:56 PM
To: Pentax-Discuss Mail List
Subject: Re: image circle of DA lenses: how much smaller than FF?
Luiz Felipe wrote:
I was looking for data on the available 180~200mm 2.8 lenses for K and
EF mounts, and found some story about how the DA* 200 2.8 is related
to
the former 200mm full frame and so it possibly would cover said full
frame.
That got me wondering if one of the tech-oriented actually knows the
image circle dimensions for the DA lenses, and how much is missing.
I know the difference should be proportional to the difference from
APS-C
to 24x36mm, but would like ko know the size and borderline falloff
evolution on the DA lenses.
Just wondering, TIA. :-)
It varies. Some DA lenses cover full frame, some don't (it's the wide
angle ones that don't, in general).
As far as anyone can tell, the "DA" designation indicates that the
lens is optically optimized for digital and that it doesn't have an
aperture
ring. It doesn't seem to specifically relate to the image circle.
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Luiz Felipe
luiz.felipe at techmit.com.br
http://techmit.com.br/luizfelipe/
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