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Re: [OM] Image sharpening

Subject: Re: [OM] Image sharpening
From: Jim Nichols <jhnichols@xxxxxxxxxxxxx>
Date: Wed, 28 Sep 2016 09:37:04 -0500
Thanks for the link, Wayne. He obviously gets results, but he also leaves me with a headache. He does reinforce some of my choices in image processing, though.

Jim Nichols
Tullahoma, TN USA

On 9/28/2016 12:53 AM, Wayne Harridge wrote:
I just came across a website with some articles on image sharpening, it
seems to be well written (though I haven't read it all yet).
This is the link to the intro:
http://www.clarkvision.com/articles/image-sharpening-intro/

...Wayne


-----Original Message-----
From: olympus
[mailto:olympus-bounces+wayne.harridge=structuregraphs.com@xxxxxxxxxxxxxxxxx
] On Behalf Of Chuck Norcutt
Sent: Wednesday, 28 September 2016 9:06 AM
To: Olympus Camera Discussion <olympus@xxxxxxxxxxxxxxxxx>
Subject: Re: [OM] Look here Brian...

But don't forget that it's all relative to display size.  f/22 works for
that image since the output size is little more than 1 MP.  The full
resolution of the E-M5 should support a large wall print of 18.4 x 13.8"
at 250 dpi.  Blow your original image up to 100% and you'll see where the
resolution is missing as it most certainly is.

Chuck Norcutt


On 9/27/2016 8:14 AM, bj@xxxxxxxxxxxxxxx wrote:

Moose wrote

On 9/26/2016 4:10 PM, Chuck Norcutt wrote:
No, I don't
accept that. Pixel pitch of the E-M5 and 6D are about the same. Also
remember that Ken said the image was heavily cropped. As Moose has
said, you can't shoot the E-M5 at f/22 and then be surprised that
there's not much detail or sharpness to the image.

In fact, since the
6D has about the same pixel pitch you can't shoot it at f/22 and
expect razor sharp results either.

Weeelll, correct, but easy to
misunderstand. The 6D is FF, so for the same display size,
magnification is less and one may stop down further for the same
visually apparent loss to diffraction. I'm sure you can run your
calculator on it, if you wish. My experience says 1.5 to 2 stops.

Ken was shooting at
f/4-f/5.6. Brian should probably stay at f/9 or less for sharp images.


Yup, although without deconvolution "sharpening", f5.6 is safer for
maximum resolution.


.......................................................................


When I shot the Sigma 90 macro images at f/16 and f/22


http://zone-10.com/tope2/main.php?g2_itemId=20781
http://zone-10.com/tope2/main.php?g2_itemId=20784


I did so in order to obtain the maximum DOF. Which I did. What's more
that was achieved in the 1200 pixel image easily, with fine detail
showing from the fine hairs on the ovary to the tips of most of the
stamens.

Any loss of that goal due to diffraction effects is negligible. At one
end or other of the flower the image would be quite out of focus which
in my opinion would be much worse than what diffraction effects might
do, by several orders of magnitude.

I've
just spent the last 2 hours (it's now 1.11 am) watching a video of the
Clinton/trump 'debate', I've had a long day touring around distant
countrysides with my daughter, so discussion of other matters will
have to wait.

Brian


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