Date: Fri, 12 Aug 2016 15:04:06 -0700
From: Moose<olymoose@xxxxxxxxx>
To: Olympus Camera Discussion<olympus@xxxxxxxxxxxxxxxxx>
Subject: Re: [OM] Perseid meteor, IFO, light pollution, questions
On 8/12/2016 12:00 PM, Lawrence Woods wrote:
>. . . I was in my backyard 14 miles NW of Boston MA, a few hundred feet from
a well-lit main road.
>I used a 12-40 f/2.8 m.Zuiko set to 2.8 and 12mm on an E-M5, original mark I
model. I had the camera on a tripod,
>used the 2-second anti-shock shutter delay, manual exposure mode, and had
image stabilization turned off. The light
>pollution was so severe that to maintain any semblance of a dark sky over a 20
second exposure, I had to crank the ISO
>down to 200.
>
>This is an example of what I
got:http://zone-10.com/tope2/main.php?g2_itemId=20573
>Lowering the ISO took its toll. The meteor trail to my eye was brighter than
an ember in a fireworks display.
>
>I also caught an IFO (identified flying
object):http://zone-10.com/tope2/main.php?g2_itemId=20576
>
>These pictures have no post-processing. I'm probably doing something wrong,
but when I tried to darken the sky, the
>stars and trails got dimmer as well.
He did say that post-processing is necessary. Then he says he uses LR, which is
probably why he needs to get so far from
urban light and still has ambient light in his images. (He is not as expert as
he might be. Look at the big halos around
the trees in his fisheye example.)
Getting what I think you want is fairly straightforward in PS.
<http://www.moosemystic.net/Gallery/Others/Woods/perseid_2016.htm>
The first three steps are to take care of the light pollution.
- Before doing any of this kind of stuff to a JPEG, convert to 16 bit.
1. Levels to kill the low level light. That also loses the meteorite, but wait
. . .
2. Different use of Levels to bring out the lights in the sky.
3. A graduated mask over 2. Shows the best of both. (See, I don't know if this
is advanced PS. It's darn simple.)
4. Raise Brightness to really bring up the Meteorite. Next step takes care of
background.
5. Use Select Color to select all the dark stuff, invert the selection and
apply as a mask.
Voila! Bright stars and meteorite in a velvet black sky.:-)
It's interesting how spending a lot of $ on hardware and a lot of time/money on
travel to an area with little light
pollution all makes sense, but spending much less on the right post tool and a
little time learning how to use it for
the purpose seems like too many $ and too much trouble. Can't have taken me ten
minutes to eliminate the light pollution
and perk up the little lights. Longer to explain and illustrate what I did,
though.
>I have a couple of questions about how the E-M5 functioned...
>
>1) Can the Mark I E-M5 display progressive results on the LED screen during a
time exposure? Page 89 of the manual is
>not at all clear on what exactly Live Bulb and Live Time do, and trying Live
Bulb didn't seem to do anything.
No idea. I've never tried that stuff. Live Composite might be what you are
thinking about? That's not on the Mark I.
Explained
here.<http://www.creativeislandphoto.com/blog/olympus-live-composites-star-trails>
>2) After the shutter closed, it took about 40 blinks of the orange SD card
symbol (~15 seconds?) to write the picture
>to the card before I could start the next exposure. Why did it take so long
after a time exposure?
I imagine that's dark noise correction. After a long exposure, the camera takes
another one with the shutter closed.
Noise from that second exposure is subtracted from the first one. Not only Oly,
everybody does this. You can set it in
Adv. Menu G, Noise Reduction.
>The night-sky files were actually smaller than normal hand-held daylight
pictures, running around 5.3 MB, versus 6.4
>to 8.4 MB.
Many maker's Raw files are lossless compressed. A night sky shot with noise
subtracted has very little detail in large
parts, so it compresses more.
If you have PS, and would like a full size PSD file, showing exactly what I
did, and allowing you to tune it to your
taste, or would like a full size JPEG of the result, let me know.
Darth Himmel Moose