K7 - Live View Focussing

alun
Posted 01/09/2009 - 20:26 Link
I am considering buying the K7, primarily for its live view focussing ability, as I am interested in astro-photogaraphy, and focussing accurately on the stars through the view finder is not easy.
So how does focussing by live view compare with using the viewfinder?
jackitec
Posted 01/09/2009 - 20:29 Link
You can zoom in with live view to get more accurate focusing
Anvh
Posted 01/09/2009 - 21:00 Link
Focusing on stars...
I believe setting it to infinite is far enough or not?
Stefan
Comment Image

K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
Edited by Anvh: 01/09/2009 - 21:00
alun
Posted 01/09/2009 - 21:20 Link
Hi Anvh
My understanding is that most lens will focus a little past infinity to allow for expansion and contraction, OK in normal use but it creates problems with stars
Kenty
Posted 01/09/2009 - 21:57 Link
I'm lost - or thick:

How does a camera - K7 or otherwise - focus past infinity? Am I missing something?

I've used live view on a couple of occasions but prefer the viewfinder - mind you I've not tried stars yet. Live view is good for movies on the K7.
On a dark desert highway, cool Pentax K5 in my hand.
My Kit
K5 & 18-55 Kit lens, K7, Pentax 18-250mm lens, Sigma 10-20mm lens, Sigma 105mm Macro lens, Pentax 50mm 1.7 lens, Cokin P Series Filters
alun
Posted 01/09/2009 - 22:02 Link
Here is a link explaining the focus difficulties:

http://www.astropix.com/HTML/I_ASTROP/FOCUS/INTRO.HTM
Kenty
Posted 01/09/2009 - 22:18 Link
Thanks Alun - very interesting - a whole new area to consider if I want to photo stars! I've got OK results with the moon but never tried stars. The moon is nearly full at present - when we have a new moon I'll try out the live view to see what it's like for stars. That link was very interesting.

BTW bearing in mind light pollution where would you go to 'shoot the stars'?

Cheers...John
On a dark desert highway, cool Pentax K5 in my hand.
My Kit
K5 & 18-55 Kit lens, K7, Pentax 18-250mm lens, Sigma 10-20mm lens, Sigma 105mm Macro lens, Pentax 50mm 1.7 lens, Cokin P Series Filters
jackitec
Posted 01/09/2009 - 22:28 Link
Alun I have problems trying to get a decent photo of the Moon and that link gave me an insight to focusing, so tomorrow I will try again and give it all I've got, thanks for the link,
Jack.
alun
Posted 01/09/2009 - 22:32 Link
Hi Kenty
Our village in South Devon is fortunate in having no street lights; we can see Saturn and even one of our nearest galaxies, Andromeda, from the front garden with binoculars. Anywhere without much artificial light is conducive, the visibility is improved in the winter due to the reduction of convection driven air currents, and the South sky is usually more interesting.
Kenty
Posted 01/09/2009 - 22:34 Link
Many thanks - think I'll have to move away from Birmingham!!!!

This will date me but I remember seeing the Milky Way in all it's glory in London! I was 4 and it was the blackout so NO light pollution and my mother pointed it out - it stuck in my memory.

I've had clear views since (no photos) in the wilds of Canada where my brother lives but 1944 was the best.
On a dark desert highway, cool Pentax K5 in my hand.
My Kit
K5 & 18-55 Kit lens, K7, Pentax 18-250mm lens, Sigma 10-20mm lens, Sigma 105mm Macro lens, Pentax 50mm 1.7 lens, Cokin P Series Filters
Edited by Kenty: 01/09/2009 - 22:38
Anvh
Posted 02/09/2009 - 07:46 Link
alun wrote:
Hi Anvh
My understanding is that most lens will focus a little past infinity to allow for expansion and contraction, OK in normal use but it creates problems with stars
Quite right but I didn't said to set it past infinite but on infinite
Stefan
Comment Image

K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ

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