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12-14-2020, 08:04 PM - 6 Likes   #1111
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No astrotracer? No EQ mount? No problem.

Just stack.
And stack.
And stack some more.
Then you stack.
And stack again.

Neowise with 300 exposures taken with a Pentax-A 50mm 1.7.



12-18-2020, 04:20 PM   #1112
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If ISO-setting was just a Preset ? at least beyond Analog-Gain ?

QuoteOriginally posted by DrMindbender Quote
No astrotracer ? No EQ mount ? No problem.
Just stack.
And stack.
And stack some more.
Then you stack.
And stack again.
Neowise with 300 Exposures taken with a Pentax-A 50mm 1.7....
Wow ! Congrats for that Huge Job, DrMindbender !
- At which F/ - ISO - SS were they shot ?

If ISO-setting was just a Preset...
... I would suggest you to re-build this stack at lower ISO-setting...
I bet you would get less noise in the final picture...

I think the K-5 is at it's best at ISO~800...
... many users say beyond that, its just Digital Gain...
so it's better applying the Digital Gain by yourself, after stacking ?

ie: when the SNR is Maximised ?
Don't you think so ?

K5s don't fear Under-Exposure at all :
Photos tagged "ISO-80": Galleries: Digital Photography Review
- the First ISO-less DSLRs

12-20-2020, 07:29 PM   #1113
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I prefer to use my tracking mounts
12-20-2020, 09:50 PM   #1114
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QuoteOriginally posted by geo444 Quote
Wow ! Congrats for that Huge Job, DrMindbender !
- At which F/ - ISO - SS were they shot ?
F2. ISO 400. 3/5s.

Unfortunately, I started getting a handle on stacking as Neowise was pulling away. (This was taken on the night of July 24-25th.)

12-20-2020, 10:06 PM   #1115
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QuoteOriginally posted by geo444 Quote
Wow ! Congrats for that Huge Job, DrMindbender !
- At which F/ - ISO - SS were they shot ?

If ISO-setting was just a Preset...
... I would suggest you to re-build this stack at lower ISO-setting...
I bet you would get less noise in the final picture...

I think the K-5 is at it's best at ISO~800...
... many users say beyond that, its just Digital Gain...
so it's better applying the Digital Gain by yourself, after stacking ?

ie: when the SNR is Maximised ?
Don't you think so ?

K5s don't fear Under-Exposure at all :
Photos tagged "ISO-80": Galleries: Digital Photography Review
- the First ISO-less DSLRs

I found mine performed best with noise reduction and in body darks off and operating long exposures of ten minutes or more guided at 200iso. 400 and up showed aberrations that I couldn't remove with stacking despite running the square# vs. of the gains.
A comprehensive test of different gains with the same setup showed the sweet spot. I would note however that Indilib/gphoto doesn't have the special deep well iso 80 enumerated. I was just curious about dynamic range vs gain initially.
Everything above unity is applied off sensor and so stores as a lower bit count by the factor given by the digital amplification.
12-21-2020, 12:01 AM   #1116
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If ISO-setting was just a Preset ? at least beyond Analog-Gain ?

Sorry, I just forgot 5 words here :
.
QuoteOriginally posted by geo444 Quote
Wow ! Congrats for that Huge Job, DrMindbender !
K5s don't fear Under-Exposure at all :
Photos tagged "ISO-80": Galleries: Digital Photography Review
- the First ISO-less DSLRs
.
The Closer to Base-ISO 80, the More it's True...

QuoteOriginally posted by DrMindbender Quote
... F2. ISO 400. 3/5s....
.
I think I understand where the Noise comes from :

F/2 is Good, it's the aperture I would have choosen too...
ISO 400 is Good too... I think you can go until 800...
3/5 sec. is way Too Short Exposure given the 3 other Parameters

Camera Simulator, Exposure Calculator, Light Value -49 to 69 Ev.

Please go to this page... then select 1/3 Ev Steps...
then select 02 Ev Dark Streets at Night, Dark indoor...
then select F/2... then select ISO 400... then select 1/1.6 sec.~3/5
then click on CalcSLV = Compute Scene Light Value an you get 0.7 Ev !

The whole Range of my Astro-Photos is within - 3.5 Ev down to - 6 Ev !
Photos tagged with "nx-mini": Galleries: Digital Photography Review
Photos tagged with "iso-80": Galleries: Digital Photography Review

I would have choosen at least 2 to 4 sec. for the Exposure duration :
4 sec at ISO 800 at F/2 click CalcSLV that gives - 3 Ev !
given the downsizing you applied to your pic.

QuoteOriginally posted by DrMindbender Quote
...This was taken on the night of July 24-25th....
.
So this was shot within the Hottest and shortest Nights ?

What was the " Camera Temperature " recorded in Exif Datas ?
if ExifTool is on your PC, the Command Line is :

" Exiftool -T -FileName -T -CameraTemperature *.PEF "

Thanks DrMindbender

Last edited by geo444; 12-21-2020 at 12:20 AM.
05-03-2021, 05:48 AM   #1117
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Cap Rock at Joshua Tree National Park

A first quick attempt with a K-5 with the SMC-DA 18-55mm WR. A simple 30-second one-shot exposure at ISO 3200, no special processing. A first step, I'll refine the process as time goes on!

Cheers, Allan

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05-03-2021, 08:19 PM - 1 Like   #1118
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Beautiful!!

How could you make this any better?
05-19-2021, 08:59 PM - 1 Like   #1119
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QuoteOriginally posted by PhotosbyV Quote
Beautiful!!

How could you make this any better?
Thanks! I suppose I could take multiple low-ISO exposures and stack, or use the Astrotracer for the sky and superimpose the foreground from a separate exposure. But for this I just wanted to keep everything simple and see how it worked.
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