From: Robert Spanjaard on
On Sat, 13 Mar 2010 00:47:17 +0100, Alfred Molon wrote:

> In article <e560e$4b9ab539$546accd9$13071(a)cache90.multikabel.net>,
> spamtrap(a)arumes.com says...
>> You don't even
>> understand what the term "full frame CCD" refers to.
>
> Nope, you are not expressing yourself clearly.
>
> There are full frame transfer and interline transfer CCDs, but you are
> talking about "full frame CCD", which is imprecise.
>
> With "full frame" cameras people usually refer to cameras with 24x36mm
> sensors. See here
> http://en.wikipedia.org/wiki/Full-frame_digital_SLR

http://en.wikipedia.org/wiki/Charge-coupled_device#Architecture



--
Regards, Robert http://www.arumes.com
From: Michael Benveniste on
On Sat, 13 Mar 2010 10:56:27 +0900, David J. Littleboy wrote:

> I don't think it was Oskar's fault. The "normal" lens is the widest lens
> you can make easily with the Triotar, Tessar, and Planar sorts of
> designs, and any longer lens would require a larger camera.

The histories I've read stated that when Oskar was building
the first fixed lens models, he chose 5cm because he felt
that he couldn't get enough sharpness out of a shorter lens.
But when it came time to sell interchangeable lens cameras,
he stuck with 50mm as the "kit" lens even though that was
no longer the case.

If I remember correctly, the 50mm f/3.5 Elmar and the 35mm f/3.5
Elmar came in 1931 or 1932. Both are 4-element, 3-group designs.
I know that Zeiss made a 40mm Tessar and a 45mm f/2 Planar,
and Nikon's made a couple of 45mm Tessar-style lenses for 35mm
as well.

> Doesn't the AF system beep at you when you use MF lenses on the AF
> versions of the Pentax 645?

My 645n can beep, but I still find a prism viewfinder easier for
manual focus. I'm convinced this is an area of photography
where each person has to work out what's best for themselves.

I do know that KatzEye has found a very nice niche business
adding prism finders to various dSLR's.

--
Mike Benveniste -- mhb(a)murkyether.com (Clarification Required)
Amo conventum instituti. -- Artifex Hannibal
From: stephe_k on
David J. Littleboy wrote:
> <stephe_k(a)yahoo.com> wrote:
>
>> So shooting a hand held quick test of the very center of the lens on a
>> different camera proves this Pentax can resolve enough for this pixel
>> density to be useful beyond marketing numbers? OK, I'm sure you believe
>> this :-)
>
> It clearly shows that there's no problem producing sharp images with MF
> lenses at that pixel density, and that your claims of unsurmountable
> problems are silly, unfounded BS.

My only claim was this MP density isn't needed at the resolution these
lenses have. I'd be shocked if you could see any difference in say a
30MP version of this same crop camera. You might be hard pressed to see
improvement over a 20MP version. Did I say anywhere this would be a
"unsurmountable problem"? What I posted was this MP density was likely
chosen for marketing reasons rather than any performance concerns.

Clearly you can use a sensor/film that is higher resolution than the
lens without problems as far as resolution.

Stephanie
From: David J. Littleboy on

<stephe_k(a)yahoo.com> wrote:
> David J. Littleboy wrote:
>> <stephe_k(a)yahoo.com> wrote:
>>
>>> So shooting a hand held quick test of the very center of the lens on a
>>> different camera proves this Pentax can resolve enough for this pixel
>>> density to be useful beyond marketing numbers? OK, I'm sure you believe
>>> this :-)
>>
>> It clearly shows that there's no problem producing sharp images with MF
>> lenses at that pixel density, and that your claims of unsurmountable
>> problems are silly, unfounded BS.
>
> My only claim was this MP density isn't needed at the resolution these
> lenses have.

That's a stupid claim, then. But it wasn't your claim: you were clearly
claiming that the resolution of MF lenses wasn't adequate. And that's dead
wrong.

> I'd be shocked if you could see any difference in say a 30MP version of
> this same crop camera.

That's bad logic. Think about it: your "you could[n't] see any difference"
isn't transitive. Why bother with 30MP when you can't see the difference
between 30MP and 24MP. Why bother with 24MP when you can't see the
difference with 20MP. Do this a few more times, and 1 pixel will be all you
need.

> You might be hard pressed to see improvement over a 20MP version.

Here you are dead wrong. A doubling of MP count represents a 40% increase in
linear resolution and that is very significant. Reality check: people shoot
4x5 and larger for good reason. But we're still not up to 4x5 and larger
resolution levels.

> Did I say anywhere this would be a "unsurmountable problem"?

Yes. You've been squawking that MF lenses aren't good enough, and you are
dead wrong. Go back and read what you wrote.

> What I posted was this MP density was likely chosen for marketing reasons
> rather than any performance concerns.

It was chosen because there are professional photographers who need this
performance. This is a market of professionals who know what they are doing
and don't waste their money on equipment that isn't needed, not amateurs who
never print larger than A4.

> Clearly you can use a sensor/film that is higher resolution than the lens
> without problems as far as resolution.

But you still haven't realized that 40MP in a 33x44mm sensor isn't higher
resolution than the lens. In fact, it's a very good match for 645 lenses.

--
David J. Littleboy
Tokyo, Japan



From: David J. Littleboy on

"Michael Benveniste" <mhb(a)murkyether.com> wrote:
> On Sat, 13 Mar 2010 10:56:27 +0900, David J. Littleboy wrote:
>
>> Doesn't the AF system beep at you when you use MF lenses on the AF
>> versions of the Pentax 645?
>
> My 645n can beep, but I still find a prism viewfinder easier for
> manual focus. I'm convinced this is an area of photography
> where each person has to work out what's best for themselves.

Good point. I ran into a bloke with a split image in a 20D, and it worked
really well. My Mamiya 7's rangefinder is hard to use, and the Fuji GS645S,
which is otherwise a great camera, is a bear to focus.

> I do know that KatzEye has found a very nice niche business
> adding prism finders to various dSLR's.

Grumble: they don't make one for the 5D or 5D2. I'd try it if they did.

--
David J. Littleboy
Tokyo, Japan