K3ii Astrophotography


paulcliff

Link Posted 10/08/2016 - 23:07
This is something I've toyed with in the past but never managed anything decent. Tonight I decided to finally give the astrotracer in the K3ii a go, but to tell the truth I'm fairly lost with it.

Can anyone share their experience with using it or help me in anyway with the general setup?

I basically pointed the camera at the sky, activated GPS and the astrotracer, it told me that 5mins was the maximum, I let it expose for 5mins and got a lovely white photograph of nothing.

I thought I could set my own exposure time, but the UI seems to indicate this deactivates the astrotracer?

In the end I left it in BULB which seemed to indicate the astrotracer was now on and just guessed how long I should expose for. It ended up being 118 seconds, and after some playing in Lightroom I got the following:




So it looks like the astrotracer is definitely working as there are no star trails, but the original image was so over exposed.

My settings:

118s | f2.8 | iso400

Should I be doing something like:

3mins | f10| iso200 ??

Thanks for any help!
Flickr: https://www.flickr.com/gp/cliffo88/513746

cardiffgareth

Link Posted 10/08/2016 - 23:37
Linked off my FB page. This is one I shot a few days ago. Bulb, 2 minute exposure, locked cable release. Like you, I turned the GPS on, activated the astrotracer and did it all manual. Didn't even see the max exposure warning, wherever that was!!



Gareth
Welsh Photographer

My outfit: K1 gripped - K3ii - two Z-1P - Pentax D FA 24-70mm - Sigma 70-200mm OS HSM - Pentax modified DA* 60-250mm f4 - Irix 15mm Firefly - Pentax FA 35mm - FA 50mm - Sigma EX 20mm - FA 28-70mm f4 - Tamron SP 90mm macro - Pentax AF 540 FGZ II

My Flickr
My PPG
Foundation NFT

paulcliff

Link Posted 10/08/2016 - 23:53
Wow what an awesome photo!

What settings if you don't mind me asking?
Flickr: https://www.flickr.com/gp/cliffo88/513746

alfpics

Link Posted 11/08/2016 - 06:32
Paul - just a thought - did you cover the viewfinder as any stray light could well seep in there during a long exposure.
Andy

paulcliff

Link Posted 11/08/2016 - 08:10
alfpics wrote:
Paul - just a thought - did you cover the viewfinder as any stray light could well seep in there during a long exposure.

No I didn't.....didn't know I was supposed to! so that would be for part of the exposure I assume, are there any rules here? Half the exposure....a few seconds?
Flickr: https://www.flickr.com/gp/cliffo88/513746

alfpics

Link Posted 11/08/2016 - 12:11
Hi Paul

The problem with long exposures is that any residual light around the viewfinder can get through and onto the sensor. So, eg, if you had a torch on behind the camera whilst you were night shooting, its light would be significantly brighter than what is coming from the sky. There was a thread about this recently
link

All you need is either the cap which came with the camera, although that is fiddly to fit in the field, so a bit of dark cloth or something and leave it there for the whole exposure

Hope that helps
Andy

paulcliff

Link Posted 11/08/2016 - 12:17
alfpics wrote:
Hi Paul

The problem with long exposures is that any residual light around the viewfinder can get through and onto the sensor. So, eg, if you had a torch on behind the camera whilst you were night shooting, its light would be significantly brighter than what is coming from the sky. There was a thread about this recently
link

All you need is either the cap which came with the camera, although that is fiddly to fit in the field, so a bit of dark cloth or something and leave it there for the whole exposure

Hope that helps

Thanks,

So I need to take 2 exposures, one of the sky and one of the dark cloth? (same exposure length?)

Do I then just combine the images in something?
Flickr: https://www.flickr.com/gp/cliffo88/513746

Gwyn

Link Posted 11/08/2016 - 12:42
paulcliff wrote:
alfpics wrote:
Hi Paul

The problem with long exposures is that any residual light around the viewfinder can get through and onto the sensor. So, eg, if you had a torch on behind the camera whilst you were night shooting, its light would be significantly brighter than what is coming from the sky. There was a thread about this recently
link

All you need is either the cap which came with the camera, although that is fiddly to fit in the field, so a bit of dark cloth or something and leave it there for the whole exposure

Hope that helps

Thanks,

So I need to take 2 exposures, one of the sky and one of the dark cloth? (same exposure length?)

Do I then just combine the images in something?

No, you put the dark cloth over the viewfinder during the exposure. It is to stop light seeping in through the viewfinder.

There are plenty of tutorials online for astro photography. I play now and again, never managed a photo as good as Gareths, though I did get some good Milky Way ones in Death Valley.

alfpics

Link Posted 11/08/2016 - 15:58
As Gwyn says above.

It is the viewfinder (where you look through) at the back of the camera that needs to be covered. For some reason most cameras are not light tight here and so any light from near the rear of the camera can find its way in reverse if you like through the pentaprism and (I am guessing) around the sides of the raised mirror.

If you cover the viewfinder whilst making a long exposure, then you should not get light leakage affecting the image.
Andy

cardiffgareth

Link Posted 11/08/2016 - 16:17
paulcliff wrote:
Wow what an awesome photo!

What settings if you don't mind me asking?

Sorry, took a while to get in front of the PC and read the EXIF

DA* 16-50mm @ 28mm
ISO 800
f4
124 sec

Not sure if these are the desired settings but they seemed to work ok
Gareth
Welsh Photographer

My outfit: K1 gripped - K3ii - two Z-1P - Pentax D FA 24-70mm - Sigma 70-200mm OS HSM - Pentax modified DA* 60-250mm f4 - Irix 15mm Firefly - Pentax FA 35mm - FA 50mm - Sigma EX 20mm - FA 28-70mm f4 - Tamron SP 90mm macro - Pentax AF 540 FGZ II

My Flickr
My PPG
Foundation NFT

paulcliff

Link Posted 11/08/2016 - 16:29
Ahh, viewfinder, that's me not paying attention sorry, I'm with you now!

Thanks for the settings Gareth, I'll have a play tonight whilst watching the meteor shower (if the weather is kind to me).

Thanks everyone for your help...results to follow.
Flickr: https://www.flickr.com/gp/cliffo88/513746

alfpics

Link Posted 11/08/2016 - 17:00
Look forward to the fruit of your labour!
Andy

AndrewH

Link Posted 11/08/2016 - 22:06
I had a play at the coast at the weekend with my new tripod and Tamron 10-24. I don't have an Astrotracer (yet), and managed these, which I think might be the Milky Way? I need to work on location a little to avoid the aerial/chimney, but it was about 1 a.m and I was just 'playing'






flickr

gtis

Link Posted 11/08/2016 - 23:08
Hi there is a astro group that's worth joining on the USA Pentax forum
cheers Neil
pentax k3 k5
DA* 300 f4 DA* 50-135 f 2.8 smc DA* 16-50 f2.8 50mm f1.7 pentax1.4xhd converter





Panasonic Dmc Fz200

rusman

Link Posted 21/10/2018 - 20:29
hello all
so with the astrotracer feature, does anyone know if the sensor still has a IR filter?
I have K10, K5, K3 ii, KP
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