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11-29-2011, 09:26 AM   #166
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Right Lens?

QuoteOriginally posted by bossa Quote
Wow! These pictures are unbelievable.. and it's Sigma too....

Let me ask you one more time. Is this the HSM II Sigma? What is the exact name of the lens.. if you don't mind?

Actually, there's some weird coma happening with that lens in the last shot.... ..but all the same totally impressive.
I took a picture of the box I received the lens in. It also says HSM on the lens itself. Is this the one you're talking about? I don't really know of any other way to tell other than the serial number. Heck, maybe you can teach me about this thing??? Maybe this lens suffers from the 'coma'' effect? I hope not cos I paid a lot for it!

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11-29-2011, 02:13 PM   #167
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Thanks for that. Yes, that's the model.. the HSM II model.

Cheers

PS: I'd love to see the full resolution pictures that these web uploads came from. Also, did you crop these photographs?

Last edited by bossa; 11-29-2011 at 02:25 PM.
11-29-2011, 06:15 PM   #168
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QuoteOriginally posted by bossa Quote
Thanks for that. Yes, that's the model.. the HSM II model.

Cheers

PS: I'd love to see the full resolution pictures that these web uploads came from. Also, did you crop these photographs?
Well that's definitely good news about the lens. Most of the photos I post are not cropped at all. I see people talk about numbers and percentages when cropping but I have no idea what % I cropped. I just use the crop tool in Photoshop and snip away a tiny bit off the edges (of the stacked photos). Also, I think it's important to note that while stacking I did NOT use any flat frames. I still haven't even tried making a flat and I don't know the difference between a dark flat and a regular flat frame. I read on one website that a way to make a flat frame is to put a white T-shirt over the lens and point it at something evenly lit. I just haven't tried it yet. I know it will make the photos better and get rid of the vignetting. Everyone here is great help and I thank you again.
11-29-2011, 11:50 PM   #169
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The reason I ask about cropping is because I owned one of those lenses and the corners were pretty crappy. Stars would have been rife with coma and reduced to streaks radiating toward the corners. But I see none of that in your shots so I was keen to find out if you've copped a bit to delete the corners.

12-09-2011, 08:01 PM   #170
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I think you on the right road...great shots!!
I LOVE that K5 and can`t wait to get one(will be a long time though) clean ISO,I know stacking helps.My poor old computer just comes to a stop whenever I tried stacking...deep sky or registax so I`ll just wait til I get another but great results
12-10-2011, 04:15 AM   #171
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QuoteOriginally posted by Brian Mould Quote
I think you on the right road...great shots!!
I LOVE that K5 and can`t wait to get one(will be a long time though) clean ISO,I know stacking helps.My poor old computer just comes to a stop whenever I tried stacking...deep sky or registax so I`ll just wait til I get another but great results
Thank you very much! Yeah, DeepSkyStacker definitely bogs the computer down, and it's brand new. I'm practicing so hopefully we'll see some better results soon.
01-14-2012, 11:02 PM   #172
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Recents

Hello Everybody!

Hasn't been any activity on here in a while. Here are a couple I took recently.
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01-14-2012, 11:11 PM - 1 Like   #173
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SSgt., Really like the second one a lot!

01-15-2012, 08:00 AM   #174
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ssgt - great photos.

RE the story in the second one- Did Orion return the signal?

I think the second photo might be improved by changing the gradation in sky brightness from what it is now near the horizon to jet black at the top of the frame.

Last edited by newarts; 01-15-2012 at 08:06 AM.
01-15-2012, 08:04 AM   #175
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QuoteOriginally posted by GWARmachine Quote
Hello Everybody!

Hasn't been any activity on here in a while. Here are a couple I took recently.
Your Jupiter shot is not bad at all, though you could bring it out more clearly. But the second shot is a real winner - fantastic shot!

Ben
01-21-2012, 10:08 PM   #176
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power source?

As a lumper, I am adding to this thread. I am sorry if that offends some splitters. after much deliberation about whether to fix my k200d or upgrade, i am repairing it. This means i have a 90 day warranty to ensure it works. In that 90 days I want to put it through the paces and try some new things.

I want to take star trail photos. (wide angle long exposure so you see stars as streaks). I tried many times back in the film days with limited success.
-does one need an external powersource for that or are fresh AAs in the body good enough?
-is AC-adapter the only option for external power or is there a way to do this in a wilderness setting?
-time on this is clearly based off how long you want the trails, but generally how long are these exposures?
-how do i calculate the exposure time for a given ISO for a given situation?
Are these star trail type of photos the longest exposures of the astro type photography? 45 deg of earth rotation is 3 hours right? this could get long? is their risk of the sensor getting too hot?

If i did my homework right those fancy deep space ones average 20min exposures +/- 10, some as long as 50m. Is this right? if not how long? is AC or an external power source needed? No scope at this time so this is long range plans.

On stacked photo like PentaxPoke has on page one of this thread, how long of an exposure is each photo in the stack? is an AC/external powersource needed or advised?

Thanks, Pete

Last edited by cadmus; 01-21-2012 at 10:14 PM.
01-22-2012, 01:24 AM   #177
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Hello Pete!

QuoteOriginally posted by cadmus Quote
As a lumper, I am adding to this thread. I am sorry if that offends some splitters. after much deliberation about whether to fix my k200d or upgrade, i am repairing it. This means i have a 90 day warranty to ensure it works. In that 90 days I want to put it through the paces and try some new things.

I want to take star trail photos. (wide angle long exposure so you see stars as streaks). I tried many times back in the film days with limited success.
-does one need an external powersource for that or are fresh AAs in the body good enough?
-is AC-adapter the only option for external power or is there a way to do this in a wilderness setting?
-time on this is clearly based off how long you want the trails, but generally how long are these exposures?
-how do i calculate the exposure time for a given ISO for a given situation?
Are these star trail type of photos the longest exposures of the astro type photography? 45 deg of earth rotation is 3 hours right? this could get long? is their risk of the sensor getting too hot?

If i did my homework right those fancy deep space ones average 20min exposures +/- 10, some as long as 50m. Is this right? if not how long? is AC or an external power source needed? No scope at this time so this is long range plans.

On stacked photo like PentaxPoke has on page one of this thread, how long of an exposure is each photo in the stack? is an AC/external powersource needed or advised?

Thanks, Pete
Hello Pete. Although I don't do star trails often I have read and tried a few tips here and there. I think the power source provided should be plenty but a backup wouldn't hurt. You could switch out quickly in between shots if needed. If your using AA batteries then I have to recommend the Ultimate Lithium from Energizer. Those things are amazing in my K-x. They are by far the best batteries I've ever used. Also the longer you expose the hotter the sensor gets and the more noise will be in the shot (I'm not trying to insult anyone's intelligence here, just stating). Depending on the environment & light pollution of your area, I would keep the exposures relatively low, one to two minutes. Then stack your photos at the end of the night. I typically stick with 1600ISO and a wide open lens(or one f/stop down). Its really gonna depend though on your area and how dark the skies are. Every time I go out I start by taking a few different pictures at different exposure times just to see how bad the light pollution is.
There are a few great programs for both Mac & PC that are FREE that help to stack images to create star trails. Deep Sky Stacker is NOT recommended for star trails.

Show us your results please!

Here was one I took. I had to lower the ISO and f/stop because of the Moon. The original shot looked like a sunny afternoon because the Moon was high in the sky and past half-phase. I adjusted the sky with Photoshop.


K-x, DA10-17 fish-eye@10mm f/4.5, ISO 800, 325sec single exposure.
01-22-2012, 01:29 AM   #178
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Thank you!

QuoteOriginally posted by Ben_Edict Quote
Your Jupiter shot is not bad at all, though you could bring it out more clearly. But the second shot is a real winner - fantastic shot!

Ben
Hi Ben!
Thank you! Someday I'm gonna get one of my pictures on APOD. Astronomy Picture of the Day Archive. That was as sharp as Jupiter was gonna get for me. I cropped that picture WAY down and that was the best I could get it. Thanks though!
01-22-2012, 02:24 AM   #179
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Astrophotography Techniques contains info for doing star trails and there is a section on field power supplies. Other sections of this site have useful info on digital processing.

QuoteOriginally posted by GWARmachine Quote
Deep Sky Stacker is NOT recommended for star trails.
Some rave about www.Startrails.de-Home . I have never used it but I guess it is an option..
01-22-2012, 08:40 AM   #180
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Thanks GWARmachine,
Could you please clarify. What are you refering to as the "power source provided"?
QuoteOriginally posted by GWARmachine Quote
.... I think the power source provided should be plenty but a backup wouldn't hurt.
I have only AA at this time. I will invest in AC if needed. AC has limited benefit because I know of no place where I have no light pollution and AC access.
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