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04-21-2010, 06:38 PM   #106
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M51

This is a picture of M51 (Whirlpool Galaxy) taken with K-X.
Taken with Meade DS2090 90mm F9 refractor and ebay "CG5 type mount". Took about 40 frames of 30 sec each, processed with DSS, no darks, no flats.
After that, levels, curves and color balance with Gimp, denoise with Helicon Filter.

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04-21-2010, 10:20 PM   #107
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Thats nice.

I saw an article on how to white balance out light pollution so I want to try that. Dealing with a week of rain thou

QuoteOriginally posted by MetClub Quote
This is a picture of M51 (Whirlpool Galaxy) taken with K-X.
Taken with Meade DS2090 90mm F9 refractor and ebay "CG5 type mount". Took about 40 frames of 30 sec each, processed with DSS, no darks, no flats.
After that, levels, curves and color balance with Gimp, denoise with Helicon Filter.
04-22-2010, 12:14 AM   #108
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These pics are all incredible. I've been loving my K200D, but you're pretty good salesmen for the K-x. Keep it up and you will separate me from my money!
04-22-2010, 05:03 AM   #109
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QuoteOriginally posted by UnknownVT Quote
Haven't heard of that one neither of my 2 Pentax lenses focus past infinity -
if they do I cannot see it -
because the depth of field probably would take care of that.

If a lens can be racked past infinity and the Pentax dSLR cannot focus -
why would it focus on infinity - and not just stop at the "infinity end"? -
how would the camera actually know where infinity is anyway - if it can't see well enough to focus -
or is there something amiss with my understanding?
I know for sure that my kit lens does so (I would assume that it's to allow for differences at different focal length settings), and I was surprised to find, back in the day, that even my excellent Sigma 30mm f1.4 focused a bit past infinity.

If you check the most detailed EXIF data you can find, you'll find that Pentax DSLRs are in fact aware of the focus distance they're set at. When the lens cannot find focus, infinity is the logical point for the camera to reset the lens to (not just for pentax, I used this trick with my olympus as well).

04-22-2010, 09:06 AM   #110
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QuoteOriginally posted by er1kksen Quote
If you check the most detailed EXIF data you can find, you'll find that Pentax DSLRs are in fact aware of the focus distance they're set at. When the lens cannot find focus, infinity is the logical point for the camera to reset the lens to (not just for pentax, I used this trick with my olympus as well).
Thank you for clarifying that -
that's very useful information.

EDIT to ADD -

sorry to come back - but I think we're both wrong in certain aspects.

Because I was still somewhat dubious I did an experiment.

I used the K-x with 18-55mm kit lens (mk 1)

First I tried your method used AF on the featureless sky and the K-x obviously could NOT focus and stopped - flashing the green hex sign indicating inability to focus. Being careful not to touch anything on the lens I flipped the switch to MF to be able to take this shot - crop shown:

EXIF still attached (caveat: PhotoBucket can drop metadata)
crop from PhotoME on this shot:

note the highlighted distance.

Now I focused on the tree in the center:

EXIF attached - clearly this is "different"
crop from PhotoME of this shot:

notice the distance info looks exactly the same as the shot above - and yet clearly the shots are different - and quite noticeably.

The first shows that the K-x managed to set the lens to something other than infinity - probably PAST infinity - the AF sounded like it stopped at the end stop (at the infinity end).

So I had to check - set the K-x on MF (Manual Focus) put the focusing ring to the infinity end stop, and took this shot:

EXIF attached
crop from PhotoME of this shot

notice the distance info looks exactly the same as the two shots above
Yet all three shots are different - this one is only very slightly different from the No Focus shot - so I would hazard a guess (and it is only a guess) that the K-x when it cannot focus places the lens at or near the infinity end stop?

So I was wrong my kit 18-55mm Mk 1 seems to be able to focus past infinity -

BUT the K-x does not seem to be able to find true infinity when it cannot focus -
and stops at or near the infinity end stop.

So coming back on topic -
advice now to the person who could not set or focus on infinity -
is to flip the K-x to MF and look for a distant object like the stars in the sky
and use one's eyes to manually focus the lens.

Last edited by UnknownVT; 04-22-2010 at 10:23 AM. Reason: infinity experiment
04-22-2010, 01:15 PM   #111
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Hmm, seems my old trick isn't so surefire after all. Makes me wonder what I did to get good focus on the last star trails I did... I can't entirely remember. I thought that was what I had done. Maybe there was enough contrast near the horizon.
06-01-2010, 12:56 AM   #112
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This stuff is amazing.

I went out last night with my new K-x and got an "alright" picture - A stack of 11 frames. It wasn't that great because of the city light. Not bothering with darks or anything of the sort just yet. Are you guys just shooting on a 2 second shutter delay, standard tripod and wide as possible? (18-55mm kit lens for me). Is there any easier way to get 20+ frames, other than standing there pressing the button every 30-35s?

Any tips appreciated.

Oh, and for anyone new to image stacking, read this guide -> http://www.asignobservatory.com/index.php?option=com_content&view=article&id=84&Itemid=125

Last edited by maxwolfie; 06-01-2010 at 01:03 AM.
06-01-2010, 04:26 PM   #113
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Astrophotography Conversion

Would something like this conversion work good? Spencer's Camera - Digital Camera Infrared IR Conversions & IR Photography - AstroPhotography Found this at alpha mount world while doing some research on which camera to get. Leaning toward a K-x. I haven't done any astrophotography but it looks interesting. They also convert to Infared. Only thing is your camera is now dedicated to this. Might be good for someone that has an older model to convert and is looking to upgrade to a new body.

12-31-2010, 04:16 PM - 2 Likes   #114
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Newbee

I'm new here but I saw Andy's astrophotos on faceBook and I was sold on the K-x.
I know one of the draw backs with the cam was the lack of a cable release, so I made a bracket and thought I'd share it.

It's 1/8" PVC sheet stock from my local hobby and a hotshoe adapter from eBay.
Total cost is $13 with the cable release and it works great.

I haven't had a chance to try the camera yet. I live in Syracuse, NY and we've had 76" of snow just for December.
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12-31-2010, 05:43 PM   #115
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I'm awarding bonus points for matching your camera's body color. Now that's doing the job right! ;-)
01-03-2011, 05:02 AM   #116
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Hi to all,
This is my first post here.

I have a question. I will receive my K-r in 3 days, I've read the manual but I still can't find the answer to my question.

I bought a IR remote for my K-r and I want to shot a night sky in Bulb mode.
My question is: Is there any kind of lock option when it comes to keeping shutter button pressed? Manual states that the shutter will open as long as the shutter button is pressed. It would be kinda inconvenient to keep the button pressed for +10min. (I want to keep the stars movement).

Also, will the KIT lens (18-55mm) allow me to shoot galaxies, nebulas or some clusters?
I've read they have a quiet irritating chromatic aberration.
If not, is there a cheap MF lens easily avaiable on eBay?

Sorry for my newby questions, I'm a total beginner


Thanks in advance.
01-03-2011, 06:11 AM   #117
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The kit lens is too short for galaxies. The biggest galaxy that's easily visible is M31, the Andromeda Galaxy, which is about 1/5th of the frame of a 100mm lens. So unless you like seeing a small oval blob, the 18-55 would be too short.

At the risk of getting flamed (again) if you want an excellent MF lens for galaxies etc. get the Nikon 180mm f/2.8 ED Ai-S. This will mount on any Pentax body without modification and is an excellent lens for astrophotography. It ain't cheap though ($400 plus).

Some people swear by the Pentax screw mount Carl Zeiss Jena 135mm f/3.5 Sonnar. Cheaper (under $100).

I tried my D-FA 100mm macro. Chromatic aberration galore at f/2.8.
01-03-2011, 06:32 AM   #118
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Nice piece on DIY kit phat bob!
01-03-2011, 11:56 AM   #119
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QuoteOriginally posted by McG Quote
Would something like this conversion work good? Spencer's Camera - Digital Camera Infrared IR Conversions & IR Photography - AstroPhotography Found this at alpha mount world while doing some research on which camera to get. Leaning toward a K-x. I haven't done any astrophotography but it looks interesting. They also convert to Infared. Only thing is your camera is now dedicated to this. Might be good for someone that has an older model to convert and is looking to upgrade to a new body.
You might want to do a forum search on "Spencer's Camera" and read some of the previous posts.

YMMV
01-03-2011, 08:23 PM   #120
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QuoteOriginally posted by phatbob02 Quote
I know one of the draw backs with the cam was the lack of a cable release, so I made a bracket and thought I'd share it.
I appreciate your effort and it looks like a great job making a cable release. I once made a similar bracket of metal to go over the button of a Nikon CoolPix. I used the mechanical cable release from a K1000 SLR to press the Nikon's button.

But....

You are in a thread about long exposure astrophotos. What is missing from the Kx that my older K100Ds and filterless K110D have and everyone wants is an electrical cable release. We want a computer or handheld controller to time dozens of exposures of minutes each.

I once came within an hour or so of ordering a Kx. What stopped me is when I read on this forum that it lacked the electrical connector for a cable release, the connector for external power, and the ability to take long exposures without Noise Reduction (AKA Dark Frame). All these items are on a K100D.

These anti-astro changes on the new Pentax models are what drove me to stop using my DSLRs for astro and buy a new SBIG ST4000XCM. My DSLRs are wonderful for daytime photos.

I have recently read that some of the new Pentax cameras have been hacked and there is an option in the Debug menu to turn off NR.

There is a kludgey power adaptor that you insert in the Kx battery holder. It has a lead with a connector that goes to the same power supply that plugs directly into a K100D.

I did mount a K100D Super on a scope for the recent Lunar Eclipse. Power, Electronically timed shutter, no NR - I used all the features the Kx does not support.

Finally my K100Ds are not supported by Pentax Remote Assistant. I can't control the shutter through USB on any of my DSLRs except the istD.

I hate to sound down but starting with the K20D with not being able to disable NR for long exposure I feel Pentax does not care about us astrophotographers.

Last edited by LeoTaylor; 01-03-2011 at 08:32 PM. Reason: added conclusion, extra sentence.
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