On 9/14/2016 2:15 AM, bj@xxxxxxxxxxxxxxx wrote:
I have to confess that this issue puzzles me. Yes, I know it is not
the only one ...
For some time I have been somewhat disappointed by
the amount of image detail provided by OM digital cameras.
It's hard to know just what you find disappointing without more description
and/or examples.
The best two I have are very close in performance as far as I can tell; these
are
the E-3 and the DE M5.
It sounds like you are treating MP numbers as linear indicators of resolution. This is not the case. MP is an area
measure, while resolution is a linear measure. The increase from 10 to 16 MP might lead some to expect a 60% increase.
But look at the dimensions.
E-3 = 3648 x 2736, E-M5 = 4608 x 3456
So nominal linear resolution has increased by 26%, not 60%. I say nominal because sensor systems aren't all created
equal. For example, when I moved up from a Canon 300D with APS-C size sensor to a 5D with full frame sensor, the number
of pixels on the APS-C portion of the 5d sensor was less than that of the 300D. Yet, in careful testing, I found that
the 5D resolved slightly MORE details than the 300D. [I see AG has had a similar experience with E-3 and L1]
Some experts, or at least folks with lots of experience testing cameras, say that any increase under about 20% is
unlikely to provide more visible detail. I could go into more detail as to why this may be so, but the point is that it
has been my experience as well. Because of the need to demosaic the RGB patterns of sensors, most color sensors are only
about 50% efficient at rendering the resolution that the lens delivers to them. Some of the difference is in the quality
of the sensor system, some, for those who shoot RAW, in the demosaicing algorithms in the Raw converters.
So, It's not really surprising that you see little difference between these two
camera bodies in resolution.
I also need to refer back to your last post of images. You shot at f22, and were pleased with the DoF, and apparently
with the resolution? This is a real problem for resolution. F22 is getting deep into diffraction territory on a 4/3 size
sensor.
If you were to look at a test like this of the 12-50 you are using (and that I use extensively), you might be forgiven
for thinking that stopping done has little effect on resolution, especially at the long end.
<http://www.photozone.de/m43/827-olympus1250f3563ez?start=1> But if you are paying attention, you'll notice that the
charts don't go past f11, for the reason that things get a lot worse. Then notice the text "Since the lens is quite
slow, it basically runs immediately into diffraction effects so stopping down has only a slightly positive effect on the
outer image region whereas the center quality decreases."
So what happens with a fast lens? Here's the excellent M.Z 75/1.8. <http://www.photozone.de/m43/830-oly75f18?start=1>
Resolution is wonderful at larger apertures, the best they had tested at the time. BUT, by f8, it's essentially the same
as the 12-50 @ f8. Again, "Diffraction has a limiting effect from f/5.6 onward . . ." Diffraction is the great leveler
that can bring the finest lens to its knees.
While the sensor is 16 MP, you are choking it down to 4 MP or less. Chuck guesses under 2 MP. If your sensor were 36 MP,
you would still get little resolution, because the lens just can't deliver it, a fact of optical physics. You need to
avoid carrying over ideas of usable apertures directly from FF to 4/3. While f22 isn't too very bad for some uses where
lots of DoF is needed on FF, and display size is modest, it just whacks resolution on the smaller sensor.
AG says that it isn't quite this bad, that in practice, you get 1-2 stops better than theory says. He's proposing that
the above sort of tests overstate the blurring from diffraction. But what he's saying is that f8 isn't too bad, not that
f22 isn't awful.
If you are shooting 4/3 @ f22 and expecting good resolution, you are bound to
be disappointed.
Beyond all that, firmware and software DO make a difference. I recall that you mostly shoot JPEGs, thinking they
penalize little but save disk space (really, really inexpensive disk space). The practical truth is that shooting only
JPEG simply throws away some resolution. Sure, there's some combination of camera sensor system, lens and subject,
somewhere, where it doesn't, but in ordinary use, it just does.
Then again, you use only free software. Raw conversion by FastStone is second rate, that with Oly Viewer pretty good,
but not excellent. AG casually mentions when talking about diffraction effects that it's not as bad at portrayed in part
because of "because of sharpening tools available". I also find this to be true. To MikeG's puzzlement, in spite of the
theory/math, deconvolution processing ("sharpening") does somehow recover some of the resolution lost to diffraction. So
f8 can be more like f5.6 or so. But he is not referring to simple USM sharpening, such as that used by FS. He's talking
about tools you have to pay for, and learn to use properly.
I also know that other aspects of your technique are decreasing detail resolution. You steadfastly refusal to use
negative EV compensation in bright, high contrast situations, witness the extensive blown highlights in your recent
daffodil image. I've written before, more than once, explaining how this eliminates detail - reduces resolution, in
highlight areas. I'm not going to repeat the details yet again here, but it's true.
In summary, at every step, from choice of aperture through post processing, you make decisions and take actions that
reduce resolution - then complain about the results. It's like keeping a hedge trimmed carefully to three feet, then
complaining that it gives no privacy. If the folks rebuilding your house were to be as sloppy in their work, you would
be livid.
I've just taken delivery of John shaw's book "Digital Nature Photography" in
which he points out that he uses
exclusively Nikon gear and the Nikon D800e has 36.30 Megapixels.
First of all, you aren't even coming close to the resolution the camera you
have can deliver.
Second, there is a price to pay for very high resolution on a 24x36 mm sensor. Nikon does this by eliminating the AA
filter effect on the 800e, and eliminating it entirely on its replacement, the 810. The price is moire effects,
including very bad false colors in fine repeating patterns.
A Nikon 810 is far, far more expensive than proper Raw conversion and editing software, and requires more attention to
details of use/technique than you are apparently willing to expend on your excellent, 16 MP camera.
As to what the camera is capable of, back in April 2012, when I was contemplating buying the same camera you are
complaining about today, and that I did buy that Aug., TOP offered a sale of Ctein 15x20" prints made from the very
first µ4/3 camera, the 12 MP E-P1. I bought one, and can say that it's much more impressive than the web posting shows.
Detail resolution is spectacular.
<http://theonlinephotographer.typepad.com/the_online_photographer/2012/04/how-i-made-the-1995-print.html>
As the first comment on the blog points out, this is a careful effort by a PS expert and master printer. I'm not
suggesting that you should try to match that. I am suggesting that it shows that our cameras and lenses are generally
capable of greater visible detail than we manage to get out of them. Blaming it on the camera is usually wrong, a
convenient way to excuse what I've done with it.
So I thought I'd see how that impressive figure compares with the M5's 16.1 MP.
The first site . . .
As I recall, the Nikon had no visible advantage.
That's silly, unless the test technique is poor - or - display size is small - or - they are looking at prints, even
quite large ones. Tests of the effectively about 40 MP High Res Mode of the E-M5 II show it to be in some ways superior
viewed at 100% to the 810, as in many examples here.
<http://www.imaging-resource.com/PRODS/olympus-e-m5-ii/olympus-e-m5-iiTECH2.HTM>
I found the same sort of thing, where the slightly higher resolution of the 810 is offset by loads of false color.
<http://www.moosemystic.net/Gallery/tech/X-T1_E-M1_D750/FON.htm>
I mention the HR Mode not to encourage you to buy an E-M5 II, but to draw a parallel. As I recently wrote, the
difference between the 16 MP of the E-M5 (and 5 II) and the HR mode of the II, while apparent when pixel peeping, does
not make more than very subtle visible difference in large prints. I believe the same would be true of the 810.
There are many sites about he M5, but few making the comparison I want.
I assume this is for the simple reason that's it's an unfair comparison, that doesn't show anything useful. The Nikon
810, and Canon eq. do indeed resolve more detail then that of which the E-M5 is capable. BUT, the E-M5 is capable of far
more than you are getting out of it.
Moose D'Opinion
It might have
to be phase 10 !! :-)
Brian
--
What if the Hokey Pokey *IS* what it's all about?
--
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