Black Swallowtail

Images taken in a controlled environment or with a posed subject. All subject types.

Moderators: rjlittlefield, ChrisR, Chris S., Pau

Olympusman
Posts: 5090
Joined: Sun Jan 15, 2012 12:31 pm

Black Swallowtail

Post by Olympusman »

Black Swallowtail Papilio polyxenes
Black Swallowtail.jpg
Michael Reese Much FRMS EMS Bethlehem, Pennsylvania, USA

MarkSturtevant
Posts: 1942
Joined: Sat Nov 21, 2015 6:52 pm
Location: Michigan, U.S.A.
Contact:

Re: Black Swallowtail

Post by MarkSturtevant »

Excellent!! On my laptop, the compound eyes come up with this moiré pattern, presumably because the size of the facets align in some way with the size of the computer screen pixels.
Mark Sturtevant
Dept. of Still Waters

rjlittlefield
Site Admin
Posts: 23543
Joined: Tue Aug 01, 2006 8:34 am
Location: Richland, Washington State, USA
Contact:

Re: Black Swallowtail

Post by rjlittlefield »

MarkSturtevant wrote:
Sun Sep 06, 2020 6:51 am
On my laptop, the compound eyes come up with this moiré pattern, presumably because the size of the facets align in some way with the size of the computer screen pixels.
It's definitely moiré, but it's mostly (or entirely) because of the image pixels, not screen pixels. The image can be blown up to cover arbitrarily many screen pixels, and the moiré pattern remains.

These patterns are difficult to avoid completely, without reducing all the facets to mush.

But they can be significantly reduced by prefiltering the original image, before downsizing.

There are some tips for minimizing the problem using that approach, at "Reducing moiré effects in downsizing for web posting".

Switching thoughts...

Olympusman, I notice that this one is missing the finely reticulated pattern shown clearly in your recent "Eastern tiger swallowtail". Is this black swallowtail a dried specimen also?

--Rik

Post Reply Previous topicNext topic