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10-17-2021, 06:57 PM   #76
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Well, I'm at it again. It seems to be a fairly clear sky here for a change. Maybe I'll get a bunch of Star Trails this time. Have the camera pointed north - from experience here, I get curved trails from doing so.... This time I covered the lens with my arm, careful not to touch and shake the camera, on the first press of the remote with bulb exposure selected. Gonna try to remember to reverse that action with ending the exposure. Gonna try for an hour exposure this time....

I always find that there is just one thing that I forget to do, which a lot of times will ruin the final image - be it wrong aperture on the manual lens, dialed in wrong ISO, didn't focus to infinity, etc.....

Addendum: Took a 1 hour exposure, now just waiting out the camera doing whatever it does for a very long time, before I check to see what I have....Smiles....

---------- Post added 10-17-21 at 07:55 PM ----------

Wow, now I have a bit of a problem. It was 44 degrees Fahrenheit outside during the 1 hour exposure. I brought my camera inside, now I have condensation inside the optical viefinder - even after about 20 minutes in the house.


Hmmm. The k-s2 is suppose to be be water resistant, but that certainly doesn't stop condensation...


Any tips on what I should do or should not do. I read that a blow dryer is a definite no no and to perhaps take the lens off and let if sit in a dry place for a few days. I suppose the old drowned electrical device placed in a sealed zip lock bag with rice isn't recommended either, eh?

Regards,

Michael


Last edited by Michael Piziak; 10-17-2021 at 07:37 PM.
10-17-2021, 08:12 PM   #77
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QuoteOriginally posted by Michael Piziak Quote
Addendum: Took a 1 hour exposure, now just waiting out the camera doing whatever it does for a very long time, before I check to see what I have....Smiles....[COLOR="Silver"]
Michael, you have LENR (long exposure noise reduction or dark frame subtraction) enabled or lens correction or something else enabled on your body. It should only take a couple of seconds for the file to write out to the card. If you are taking a 60 minute exposure, and the camera "waits" for an additional 60 minutes, then its LENR for sure - just disable LENR and you will save yourself a lot of time.

QuoteOriginally posted by Michael Piziak Quote
Wow, now I have a bit of a problem. It was 44 degrees Fahrenheit outside during the 1 hour exposure. I brought my camera inside, now I have condensation inside the optical viefinder - even after about 20 minutes in the house.

Hmmm. The k-s2 is suppose to be be water resistant, but that certainly doesn't stop condensation...

Any tips on what I should do or should not do. I read that a blow dryer is a definite no no and to perhaps take the lens off and let if sit in a dry place for a few days. I suppose the old drowned electrical device placed in a sealed zip lock bag with rice isn't recommended either, eh?
Yes, the camera body is sealed, but it does have a rather large hole where the lens mounts. The lens can be WR/AW too, but the lens still "breaths" letting air in and out - especially when focusing. What is happening is that humidity within the air is getting in the camera body and then condensing on the colder parts. You can cold soak the camera prior to going out - just let it equalize in temperature on the back porch or somewhere cool. Also, after use - let it gently warm up gradually before bringing everything in the house.

Also, here is a video tutorial that covers all of this...


Last edited by interested_observer; 10-17-2021 at 08:46 PM.
10-17-2021, 09:12 PM   #78
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QuoteOriginally posted by interested_observer Quote
Michael, you have LENR (long exposure noise reduction or dark frame subtraction) enabled or lens correction or something else enabled on your body. It should only take a couple of seconds for the file to write out to the card. If you are taking a 60 minute exposure, and the camera "waits" for an additional 60 minutes, then its LENR for sure - just disable LENR and you will save yourself a lot of time.



Yes, the camera body is sealed, but it does have a rather large hole where the lens mounts. The lens can be WR/AW too, but the lens still "breaths" letting air in and out - especially when focusing. What is happening is that humidity within the air is getting in the camera body and then condensing on the colder parts. You can cold soak the camera prior to going out - just let it equalize in temperature on the back porch or somewhere cool. Also, after use - let it gently warm up gradually before bringing everything in the house.

Also, here is a video tutorial that covers all of this...

ok, I will look for the LENR in my K-S2 menus and try to turn it off, because it indeed takes forever to get the photo ready for me afterwards.

Addendum: According to this thread, some say that with astrophotography the exposure noise reduction is actually desirable to have on if one has the time:
https://www.pentaxforums.com/forums/38-photographic-technique/313423-noise-r...-settings.html
So I dunno if to turn it off or not a this point....


The condensation ended up being inside the lens, as I switched lens and found that out. The lens cleared itself up after about an hour. In the future I think I'll let the camera and lens cool down in the camera bag before using it outside. Then, I'll put everything int he camera bag and let it warm up before removing it from the bag inside.

---------- Post added 10-17-21 at 09:15 PM ----------

This is the last time I'll post in this thread. In the future I'll put my photos in the photo critique thread....


From my 1 hour exposure.

Post processed. I covered the lens when the exposure began and covered it again before ending the exposure. Still ended up with the "up tick" at the far right of each star trail though - hmmm. Also, if you look closely you can see the effects of the bight area(s) in the photo (as is evident from the black photo [2nd photo down]).



Also post processed - same image. I dunno what the bright spot in the middle is - dunno if it's light pollution or the condensation on the lens affecting the center of the image. There certainly does not appear as if there is any light pollution in the center of the sky when taking the image...



And original image without any post processing.


Last edited by Michael Piziak; 10-17-2021 at 10:18 PM.
10-18-2021, 03:57 AM - 1 Like   #79
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One of the advantages of taking multiple short exposures and stacking them for trails (using Starstax or Startrails or Sequator) is that if errors occur, you can adjust or discard the particular frame affected - like the curly tail. The second advantage is that you turn the long exposure noise reduction OFF and having multiple frames will in effect greatly reduce the noise by averaging it out across all the frames you took - commonly described as "stacking for noise reduction". It is just as effective as using in camera noise reduction but if you want to be sure, you can take the dark frames at the same time but separately (lens cap on) using the same ISO and shutter speed as the light frames you are going to stack and Startrails, Starstax or Sequator will subtract them the same way as the camera does - without taking as much time. A third advantage is you can adjust exposure for the frames at the start and end and get nice tapers on your star trails.

For the condensation, you can buy lens warmers that wrap around the lens and keep the condensation away. They are relatively cheap - search on fleabay.

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