K3-ll ASTROTRACER


Anstonian

Link Posted 03/01/2020 - 10:20
Hi, I have searched through the forum for information on the above but whilst there are a good number of posts on the Astrotracer facility I cannot find specifically what I want.
I am off to Grand Canarias in a couple of weeks and am keen to give the Astrotracer a go, hoping for some light pollution free sites. Thing is I have searched a number of websites to find out how best to use this facility but seem to come up with contradictory and confusing information. I read, for example, that the camera has to be in manual focus mode. In which case what do you focus on, just pick a star? What would be the best lens to use? (see my kit below).
I am looking for an idiots guide I guess in order for me to get the best from my kit. Once I understand the numpties guide I can play around with the settings in the future.
I have a K3-ll, Pentax 35mm prime, Sigma 10-20, Pentax 18-135 and Pentax 55-300 PLM.

I would appreciate any help that could be given or maybe point me to a definitive website for instruction.

Andrew
Andrew Goble

Darrel

Link Posted 03/01/2020 - 10:48
Hi Andrew - suggest you take a look at this series on YouTube:
https://www.youtube.com/watch?v=IlTk4w0PS2g&list=PLpqDLK5jtPTTcsSF2oz7xBhofIoVVN...

Best
Darrel

mikeprotts

Link Posted 03/01/2020 - 22:55
In brief (not something I've tried yet, but I'm looking into it).

Start with simple shots, to get an idea of what's possible in terms of sky view - use high ISO and accept the noise to start with. Probably will need to turn off shake reduction. Once you have the basics giving you an idea of what's possible, then try the aststrotracer. From my understanding, that should be the difference between a noisy shot with a few stars and something that will show the sky in more detail than you can normally see.

Use the prime, and get the best view of the sky possible. Nearby lights will cause problems, so learn how to cope with them. Experiment with the widest shots with the zooms as well, but also the longest zoom for some shots of the Moon, and maybe Venus (look West on a clear evening). I suspect the prime lens will be the best, but you need to experiment to see what suits your own style and preferences.

Use a good solid base (tripod or rock with a non-slip mat). If you can get hold of a remote trigger, that will help, but timer delay (to reduce initial shake) will probably be fine for stars,

Practice at home, in various light conditions so you can use the same technique based on what's possible when you arrive.

More important, enjoy experimenting.

Mike

Anstonian

Link Posted 04/01/2020 - 13:50
Darrel wrote:
Hi Andrew - suggest you take a look at this series on YouTube:
https://www.youtube.com/watch?v=IlTk4w0PS2g&list=PLpqDLK5jtPTTcsSF2oz7xBhofIoVVN...

Best
Darrel

Thanks for this Darrel. I guess I will have to spend some time on YouTube and see what I can find. The ones you point me to are a good start.
Regards
Andrew

Anstonian

Link Posted 04/01/2020 - 13:54
mikeprotts wrote:
In brief (not something I've tried yet, but I'm looking into it).

Start with simple shots, to get an idea of what's possible in terms of sky view - use high ISO and accept the noise to start with. Probably will need to turn off shake reduction. Once you have the basics giving you an idea of what's possible, then try the aststrotracer. From my understanding, that should be the difference between a noisy shot with a few stars and something that will show the sky in more detail than you can normally see.

Use the prime, and get the best view of the sky possible. Nearby lights will cause problems, so learn how to cope with them. Experiment with the widest shots with the zooms as well, but also the longest zoom for some shots of the Moon, and maybe Venus (look West on a clear evening). I suspect the prime lens will be the best, but you need to experiment to see what suits your own style and preferences.

Use a good solid base (tripod or rock with a non-slip mat). If you can get hold of a remote trigger, that will help, but timer delay (to reduce initial shake) will probably be fine for stars,

Practice at home, in various light conditions so you can use the same technique based on what's possible when you arrive.

More important, enjoy experimenting.

Mike

Thanks Mike. I guess it really is a case of trial and error. Hopefully I have enough time left to experiment before I have to learn on the job in the field, as it were. I am still curious regarding the focusing question though..
Regards
Andrew
Andrew Goble

Mannesty

Link Posted 04/01/2020 - 16:34
Anstonian wrote:
I guess it really is a case of trial and error. Hopefully I have enough time left to experiment before I have to learn on the job in the field, as it were. I am still curious regarding the focusing question though..
Regards
Andrew

I know nothing about Astrotracer or astronomy but it seems to me that, since our nearest star is several light-years away from earth, focussing at infinity should do the job. Your lens, however, may not be focussing at infinity even though the focus ring might indicate that it is. Focussing on any bright star should bring them all into focus I think. I'm sure others will shoot me down if I'm wrong.
Peter E Smith

My flickr Photostream

Gwyn

Link Posted 04/01/2020 - 16:59
In theory infinity is good, but in practice it may not be in focus.
Either focus on something distant before it gets dark and note exactly where that is on the lens markings, so you can back to it after dark, or use live view to zoom in on an area and get it in focus. That is actually harder than it sounds.
If you are including foreground in your shot make sure you get one still of that before using the astrotracer as any earthbound objects will be blurred by the atrotracer.
Play with it. Don't set the ISO too high.

If we ever get a clear sky again here I shall head out and have another play with mine on the K5II.

HarisF1

Link Posted 04/01/2020 - 19:50
Focusing on a bright star is more than enough for most uses. The lens is usually stopped down anyway for a bit more DoF/leeway.

If you must absolutely nail focus then there are things like the Bahtinov mask that can help. Also remember that as your equipment heats up or cools down (winter here) then there may be some effect on the focus.

RobL

Link Posted 05/01/2020 - 11:19
I would also add if you are using live view then turn off focus peaking or all you get is noise.
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