Olympus-OM
[Top] [All Lists]

Re: [OM] ( DZ OM ) Value for money?

Subject: Re: [OM] ( DZ OM ) Value for money?
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Mon, 13 Jul 2009 14:40:12 -0400
What got me on this point to begin with was DPreview's test of the Canon 
70-200/2.8L which is one of the more revered zooms in Canon's stable.
Check this page which is the test of that lens on a 5D body.
<http://www.lenstip.com/115.1-article-Polarizing_filters_test.html>
Use the aperture slider and watch the resolution graph change. Only at 
f/5.6 to f/11 is the 70-200 able to equal or slightly exceed the 12.7 
megapixels of the 5D sensor (represented by the line labeled "Nyquist 
frequency").  Below f/5.6 some irregular things start happening and 
above f/11 diffraction begins its steady toll against resolution.  So, 
if this lens can just barely handle a 5D it certainly can't handle the 
pixel density of a 50D (15 MP on an APS-C size sensor).  At f/5.6 to f/8 
the 5D Mk II will pull a bit more out of the lens than the 5D but not a 
great deal.  To utilize the resolving power of the 5D Mk II you need 
very good primes.  Here you can see that the 50/1.4 can resolve to the 
level of the 1Ds Mk III (21 MP, like the 5D Mk II) at f/5.6 to f/8 (but 
not elsewhere).

Quite apart from noise, one reason to want a camera with larger pixels 
is to be able to find a lens that can resolve to the level of the 
sensor.  Little pixels just make the job harder on the lens.  That said, 
it's also easier to make a lens that resolves little pixels if the 
sensor is small and the lens doesn't have to cover a large area.

Chuck Norcutt


Joel Wilcox wrote:
> On Fri, Jul 10, 2009 at 8:47 PM, Chuck
> Norcutt<chucknorcutt@xxxxxxxxxxxxxxxx> wrote:
>> Not so long ago Olympus was talking about a planned 12 MP maximum for
>> the 4/3 sensor.  If you read the test of the DZ 50/2 you can see exactly
>> where the 12 MP maximum comes from.  At f/4.5 the lens is resolving 1500
>> line pairs vertically toward the outside and about 1600 dead center.
>> Come off f/4.5 though and resolution starts to drop.  A 4/3 sensor that
>> can resolve 1500 line pairs vertically has pixel dimensions of 3000 x
>> 4000 or... 12 MP.
>>
>> Since the DZ 50/2 must be one of the better lenses, if it can't go
>> beyond 12 MP it doesn't make much sense to go to even smaller pixels.
>> The same is true in the Canyon camp.  I suspect that there are precious
>> few lenses that can resolve the 15 MP of the 50D sensor and the same
>> holds for the 21 MP sensor of the 5D Mk II (although the 50/1.4 can do
>> it across the full sensor at f/5.6-f/8 but not above or below that).
>>
>> So, the sensors are now outresolving the lenses and even the best
>> lenses.  I guess we don't need any more pixels... but that won't prevent
>> the manufacturers from giving us more.  :-)
> 
> I will share this with a relative who bought a 5DmkII when they first
> came out.  He shoots at the half resolution setting, mainly because he
> didn't want to double his file storage instantly and didn't think he
> needed it for his purposes.  It sounds like he really doesn't need it.
> 
> Joel W.
-- 
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/

<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz