Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
10-10-2011, 02:53 PM   #1
Pentaxian




Join Date: Jun 2009
Location: GMT +10
Photos: Albums
Posts: 10,849
You want 8800mm with Pentax glass?

Get a Q




The planet Jupiter

Pentax Q+smc Pentax M*800mm f6.7 ED+2X Rear Converter

From Flickr: nkenji's Photostream

10-10-2011, 02:55 PM   #2
Pentaxian
aurele's Avatar

Join Date: Jan 2011
Location: Paris, France
Photos: Albums
Posts: 2,968
ask clinton and his A*12000 f8, maybe you can get something closer of this Jupiter

(i'd love to see this setup : A*1200 and Q)
10-10-2011, 02:59 PM   #3
Site Supporter
Ex Finn.'s Avatar

Join Date: Nov 2007
Location: Southern Maryland.
Photos: Gallery | Albums
Posts: 6,298
I take it that that is not a crop?,
10-10-2011, 03:02 PM   #4
Site Supporter
Ex Finn.'s Avatar

Join Date: Nov 2007
Location: Southern Maryland.
Photos: Gallery | Albums
Posts: 6,298
Is that a 100% crop?.

10-10-2011, 03:05 PM   #5
Pentaxian




Join Date: Jun 2009
Location: GMT +10
Photos: Albums
Posts: 10,849
Original Poster
I don't think that is a crop.

Atmospheric conditions etc make for the haze I expect. Urban Japan probably isn't the best place to do astro-photography.
10-10-2011, 05:07 PM   #6
Site Supporter
Ex Finn.'s Avatar

Join Date: Nov 2007
Location: Southern Maryland.
Photos: Gallery | Albums
Posts: 6,298
I did not think so, scary magnification and looks good.
10-10-2011, 07:11 PM - 1 Like   #7
Veteran Member
steve1307's Avatar

Join Date: Mar 2010
Location: Sydney
Photos: Gallery | Albums
Posts: 1,129
QuoteOriginally posted by Ex Finn. Quote
Is that a 100% crop?.


could probably work it out?


The posted image "original" on flickr is 2048 x 1536 pixels and by scaling the subject it measures about 230 pixels across.
The orignal might be resized or cropped from 4000 x 3000

FL is what?? 800mm x 2 = 1600mm
sensor is 6.17 x 4.55 mm

The diameter of Jupiter is about 140,000 km.

So, if its just resized the frame is about 1.2467 million km x 934,956 km.
Calculating the distance that works out to 329 million km which is a bit close.

If its a 2048x1536 crop from the original 4000x3000 then the full sensor image would cover
2.4348 million km x 1.8261 million km
Now the subject distance calculates out to about 642 million km. (kind of about right)


Its should be between 588 and 968 million km from Earth but how far away was it last Tuesday night?

Anyone got NASA's number?


So assuming I havent cocked up the numbers (quite probable) it looks like it is a bit of a crop to half size from 4000x3000 to 2048x1536.

Pretty impressive for "a toy camera" as some people refer to it.

I wonder how thin the DOF is out there.?
10-10-2011, 07:20 PM   #8
Pentaxian
v5planet's Avatar

Join Date: Jan 2010
Location: Seattle
Photos: Albums
Posts: 1,913
I have also photographed Jupiter with a Pentax camera. It was with my K-7, attached to a 2000mm Schmidt-Cassegrain telescope. I can assure you this outdoes my effort.


jupiter

There are advantages to small sensors.

10-10-2011, 07:28 PM   #9
Veteran Member




Join Date: Jul 2009
Location: Mount Joy, PA
Photos: Gallery | Albums
Posts: 533
QuoteOriginally posted by rawr Quote
Pentax Q+smc Pentax M*800mm f6.7 ED+2X Rear Converter
You just blew my mind.
10-10-2011, 07:29 PM   #10
Pentaxian
v5planet's Avatar

Join Date: Jan 2010
Location: Seattle
Photos: Albums
Posts: 1,913
Incidentally, according to Sky & Telescope's Jupiter Javascript utility, Jupiter is currently approximately 4 astronomical units from the earth.

That is roughly 600 million kilometers. I'm going to agree with steve's analysis that this is an approximately 50% crop of the original image.

edit: http://www.skyandtelescope.com/observing/objects/planets/3307071.html?page=2&c=y#
10-10-2011, 07:44 PM   #11
Veteran Member
steve1307's Avatar

Join Date: Mar 2010
Location: Sydney
Photos: Gallery | Albums
Posts: 1,129
Yeah I looked it up here Solar System Live

and its about 600million km away at the moment. 1 AU = 149,597,871 km
so Jupiter is currently 4.012 AU away = 600 million km which looking at the diagram is pretty much as close as they get.

My calc of 642mil km is a bit out because I was scaling the pixels from the fuzzy edges and was only guessing the crop h might have done.
10-10-2011, 07:52 PM   #12
Pentaxian
v5planet's Avatar

Join Date: Jan 2010
Location: Seattle
Photos: Albums
Posts: 1,913
QuoteOriginally posted by steve1307 Quote
Yeah I looked it up here Solar System Live

and its about 600million km away at the moment. 1 AU = 149,597,871 km
so Jupiter is currently 4.012 AU away = 600 million km which looking at the diagram is pretty much as close as they get.

My calc of 642mil km is a bit out because I was scaling the pixels from the fuzzy edges and was only guessing the crop h might have done.
Yeah, given the clarity of the cloud belts out almost to the edges of Jupiter's disc, I couldn't think that the fuzzy edges would add more than about 25% error.
10-10-2011, 07:59 PM   #13
Pentaxian




Join Date: Jun 2009
Location: GMT +10
Photos: Albums
Posts: 10,849
Original Poster
I think a video of Jupiter and it's satellites would have been groovy. Or a time-lapse - the Q has some sort of time lapse utility built-in, apparently.

This is the basic rig I think nkenji used for the shot, with the addition of a 2X convertor:




using 3 adapter
Q to C, C to N, N to 67
4400mm (forcal length in 35mm)

This is another of his setups - a handy 990mm walkabout :




Pentax Q with Voigtlander 180mm f4
(990mm focal length in 35mm)
10-10-2011, 08:07 PM   #14
Senior Member




Join Date: Oct 2011
Posts: 188
Really makes me wish I had a Q-K adapter or go out and buy the Q-C and C-K adapter right now. I have a 650mm (3600mm equivalent after crop factor) telescope with an equatorial mount that also has a motor to keep the image centered on the subject. Perfect for astrophotography and doing time-lapse movies.

I think this is the power of the ILC cameras and the Q's smaller sensor size.
10-10-2011, 08:37 PM   #15
Site Supporter




Join Date: Apr 2011
Location: Oklahoma
Posts: 309
QuoteOriginally posted by LowVoltage Quote
You just blew my mind.
Agreed! I think I will give up now on astrophotography with my K-x...
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
flickr, k-mount, pentax, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Older Pentax Glass Kim C Pentax SLR Lens Discussion 4 05-16-2011 06:13 PM
Minolta glass vs Pentax? axl Pentax SLR Lens Discussion 9 02-11-2010 02:05 PM
old Pentax glass superior to new??? kiwao Pentax SLR Lens Discussion 37 01-06-2010 06:13 PM
Question re using K200D, Kx, K7 w/Pentax M glass atown Pentax DSLR Discussion 7 11-01-2009 03:57 PM
Autumn colors - old glass is a good glass andrei46 Post Your Photos! 5 10-26-2007 09:35 AM



All times are GMT -7. The time now is 08:47 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top