D40 Spots on photos

[jhpope]

Sorry not sure where to put this. I've found this happen only in my long exposure night shots. I'm using photoshop now to get the spots out but this is a good example.

http://farm2.static.flickr.com/1256/584509299_0173fa4c53.jpg (http://www.flickr.com/photo_zoom.gne?id=584509299&size=o)
Click through for original resolution.

As you can see there are darker spots on the exposure. The biggest example is right side center, but they can be found all over. They occur in the same spot every long exposure.

What could cause this? I am using the kit lens and have not take it off more than once or twice since I got the camera. I have a tiffen haze-1 filter on to protect the lens. Could this be from something on the lens or filter or sensor?

Thanks!

[ELAY]

May have an easy fix for you.

On long exposures you can get weird spots from overheated pixels on the sensor. If you turn in-camera noise reduction on, then the camera will do a magical process called dark frame subtraction and erase the noise caused by these hot pixels.

I'll warn you though: the way the camera does this is by taking an exposure with the shutter closed equal in length to your original exposure, so it doubles the time to take a shot.

Hope it works for you.

EL

[Nicole]

Well, first, let me recommend taking the filter off when you're doing long exposure night shots. The first thing that I noticed was that the sign on the tallest building had essentially caused a reflection to show up in the sky.

Second, dust can get in to your camera pretty easily. For an easy way to see if it's dust or your pixels overheating, try taking a picture of a bright blue sky (or white wall) with your aperture set at f/16. If there's dust on your sensor, that's where you'll start noticing it. If there's dust, keep on reading.

For the most part dust won't necessarily be visible, but sometimes it is (especially if you take a lot of pictures at small apertures). Unless you never change your lenses (and that's just kinda silly, and no guarantee since your camera probably hasn't been in a 100% dust free environment from the second of its creation) you'll probably get dust on your sensor. You could try holding your camera so the lens opening on the body is pointed down and using a blower thing to get some of the dust out. Or there's always sensor cleaning kits. Cleaning the dust off is something that you'll probably get used to after a while ;)

You might also want to make sure that there aren't any especially grimy parts on your filter.

Good luck getting everything back to clean :)

[inkista]

Sure looks like dust on the sensor to me. I second Nicole's suggestion of using a blower and holding the body face-down while you clean it. Works great for me--(I'm constantly swapping lenses). Typically, you won't see the dust on your sensor in an image unless you're at a small aperture. With a bulb blower (I like the Giotto Rocket Blower), make sure you don't touch anything inside the body--and whatever you do, for god's sake, don't buy "canned air"--you'll just spray liquid crap all over the inside of your camera.

[NaturesPixel]

lol welcome to the world of SLR.
my D80 had dust on it right out of box ;) they just need a good cleaning every now and then

if you get into some humidity your micro dustbunnies will be welded.. then you will either need to clean it via a sensor cleaner or send it away to get cleaned...

info here
http://digital-photography-school.com/forum/showthread.php?t=926&highlight=copper+hill
http://digital-photography-school.com/forum/showthread.php?t=938&highlight=copper+hill

[jhpope]

Thanks for all the help and suggestions. Yes from now on I will take the filter off during long exposure night shots. I recently took some shots for a panorama and saw how it causes reflections.

I'll test out shooting at the wall when I get home from work. I guess it could be something on the sensor since the night shots are taken at a small aperture and exposed for a long time.

What does everyone suggest for lens/sensor cleaning kits? Are they expensive?

[jhpope]

@ NaturesPixel - Thanks for those links...they were very helpful and after seeing some example pictures I'm positive I have some dust or gunk on my sensor. I ordered a kit from Copper Hill and can't wait to get rid of the dust!

[RexK_Cozumel]

While sensor cleaning kits are not very expensive I would not recommend using them except as a last resort. While it is not hard to clean the sensor if something does happen and you scratch your sensor you might as well just go buy a new camera as replacing a sensor is very expensive. if you were to decide to clean your sensor yourself attach your camera to a power source and use the mirror lockup function which will lock the mirror in place giving you plenty of time to clean the sensor. if you dont know how to do that you can just turn your camera setting to bulb and using a cable release open the shutter and clean the sensor. You just need to make sure that the cable release is locked down so that the shutter does not close on you while you are cleaning the sensor because you can scratch the sensor or break the shutter. Anyways I would recommend getting a one pass sensor swab which means that you only have to make a single pass on the sensor some sensor swabs are smaller which would require you to make multiple passes on the sensor to get it cleaned. While either method will work the single pass swabs are better because first it takes less time than the smaller swabs and secondly you are a lot less likely to leave streak marks on your sensor if you are using a single pass. What I do is make a single pass with the sensor swab being sure to get the entire sensor then adjust the cloth on the swab and then make a second pass. This way I am cleaning the sensor and then using a clean part of the cloth I make a second pass getting anything that I might have missed. This method works very well for me however again I would not recommend cleaning the sensor yourself unless you camera is not under warrenty and you have to pay for the sensor cleaning or if there is no where around that will even clean your camera (which is the case with me.. damn carribbean islands)

Good luck