Johnny Johnson wrote:
> At 10:29 PM 7/23/2007, Jay Maynard wrote:
>
>
>> What I'm getting at is that you can pack more pixels in a larger sensor.
>> Yes, there are limits to lens sharpness, but do lenses get less sharp as the
>> image circle gets larger at the same rate that the number of pixels
>> increases? (I'm not quite sure how to ask that question.)
>>
This is a question almost as old as photography. When greater
film/sensor area coverage in required, the set of optical compromises
that create a lens inevitably result in some loss of absolute
resolution, as simple line pairs/mm.
Generally, the answer has been that the total detail resolved by the
combination of larger film format and appropriate lens has been greater
than that of the smaller format with 'higher resolution" lens, given the
same subject coverage and same size final image.
With digital, and it's several sensor sizes, the whole thing gets hard
to sort out. dpreview has taken an interesting approach by normalizing
their resolution tests as lines resolved over the vertical image area,
Lines per Height, LPH. This measurement is designed to answer exactly
the question you are asking.
It's not perfect, as it is dependent on the lens chosen and doesn't
quite account for different aspect ratios. But I've not seen anything
better for comparing cameras with different sensor sizes.
In the particular case at hand, you can see the E-410 compared in this
way to it's competition. See how he image from the 4/3 body is enlarged
to match the larger sensor cameras.
http://www.dpreview.com/reviews/olympuse410/page26.asp
For the E-410 vs. the APS sensor cameras, the answer is that the D40x
clearly has more resolution at its default settings, but the E-410 comes
very close with better settings. I wish they would use RAW for these
comparisons, but understand the the range of parameters then becomes so
large they'd only manage a couple of reviews a year. :-)
As to FF sensors, the 13 mp 5D resolves more detail, LPH, than the
smaller sensor cameras, and the 17 mp 1Ds II resolves significantly more
than the 5D, so it would appear that the limits of the better FF lenses
hasn't been reached yet.
Don't be confused with the issues of very wide angle lenses on FF
sensors. It's pretty much impossible here to separate actual lens
performance from the effect of lenses designed for film with current
sensor designs. The ZDs,with their much more telecentric designs have an
advantage here. Koduck/Leica, with innovative sensor lens design and C
with redesigned lenses have shown that this issue will not last.
The other question that you haven't asked, but which is significant, is
how detal resolved will compare at higher isos. Noise and/or NR eat up
detail.
So the answer, as I understand it, and at the moment, is that FF bodies
resolve more detail, on a comparable basis, than the smaller sensor
bodies, and 4/3 is a hair behind he others with slightly larger sensors.
However, I doubt if you will ever see the difference between 4/3 and APS
sensors at low isos in even quite a large print.
For subjects requiring higher isos and for larger image display sizes,
the FF bodies will make better large prints, and/or crop better, in
return for more size, weight and money. I don't think the E-410/510 can
do this:
http://www.moosemystic.net/Gallery/MPhotos/Calif/PtLobos/LobosSparrow.htm
Moose
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