Problem with star trails.

Hi all. Last night i went out to the field next to my house and tried oh lets say about an hour and 10 minutes of 30/sec exposure (without a remote ) All was fine and dandy and when i was finally finished I went and did a quick review of the pictures the last say 35-40 pictures were not takin correctly because the lens had fogged due to condensation over time. Is there anything i can do to prevent this next time i have a go at it? Thank you.

-Joe

The lens needs to acclimate to the environment it will be used in. I'd recommend a ziplock type bag big enough to hold your camera and lens combination. Before you plan to go out of the house place the camera in the bag with the lens attached. Bring the camera outside and leave it in the bag for about 20 odd minutes. By doing so, you will allow the camera and lens to slowly equalize to the temprature outside the bag. Once this is done just remove the camera and use it. Follow the same procedure when returning the camera indoors to avoid condensation build-up as well.

GPFocussed wrote in post #8659075
The lens needs to acclimate to the environment it will be used in. I'd recommend a ziplock type bag big enough to hold your camera and lens combination. Before you plan to go out of the house place the camera in the bag with the lens attached. Bring the camera outside and leave it in the bag for about 20 odd minutes. By doing so, you will allow the camera and lens to slowly equalize to the temprature outside the bag. Once this is done just remove the camera and use it. Follow the same procedure when returning the camera indoors to avoid condensation build-up as well.

awesome... thanks for the tip. Will try this next time i go out.

You might look throught these Dew Heaters and see if there is a size you could use for your lens . Otherwise you could use a hair dryer close by when you start seeing dew on the lens . Are you using a lens hood ? They do help in cases like this also .

Celestron wrote in post #8659098
You might look throught these Dew Heaters and see if there is a size you could use for your lens . Otherwise you could use a hair dryer close by when you start seeing dew on the lens . Are you using a lens hood ? They do help in cases like this also .

Nope, I don't have a hood yet, when the nifty fifty comes into my camera shop im going to grab a hood. I'm really impressed how well the 500d and the kit lens can pick up some of these dimmer stars. I need to read up on infinity focusing. I think i missed my focus on the stars here.

Hard to say if you missed focus but i can see black halos around the stars which indicate that if you used USM to sharpen with then the Threshold was set too low . What does the original image before PP look like ??

heres the original

Looks like your very close . What direction of sky is this , the Southern area ?

I was facing north-northwest

Lens are made of glass and are densier than air therefore will condense the humidity. Canon suggest using a heat pad to keep the lens warm. I use a Kendrix strap available from Kendrix in Canada. Keeps the fog off my lenses. Both methods work fine.

When bringing the equipement back inside after a long evening it is a good thing to put the lens and camera body in a zibbag. This will prevent the humidiy from inside the warm house to condense on your equipement.

VIGER wrote in post #8660425
Lens are made of glass and are densier than air therefore will condense the humidity. Canon suggest using a heat pad to keep the lens warm. I use a Kendrix strap available from Kendrix in Canada. Keeps the fog off my lenses. Both methods work fine.

When bringing the equipement back inside after a long evening it is a good thing to put the lens and camera body in a zibbag. This will prevent the humidiy from inside the warm house to condense on your equipement.

thanks so much. I can't believe how much i have learned from this site after just a month. Thanks to everyone.

-Joe

I don't think it looks that bad, personally. Much like my first one, but in better focus, LOL. This place is most definitely a wealth of info, and most of the people here are great for helping out beginners.

drevilsmom wrote in post #8661111
I don't think it looks that bad, personally. Much like my first one, but in better focus, LOL. This place is most definitely a wealth of info, and most of the people here are great for helping out beginners.

Yeah I need to work on nailing my focus but that will come with time. Practice, practice, practice for me it is... I personally didn't think this photo had a nice "subject" it was just a quick shot. I took several that night in different directions to practice on my focusing and exposures. Thanks for the comment mom!

Went out tonight to try and get some pictures of deer. (Plus hunting season starts in 3 days and i needed to scout my field.) Needless to say no deer however there's always a nice tint in the sky after sunset.

Damn clouds