Need help with long exposure lens flair...

[Not Here]

I just returned from my first attempt at long low-light exposures and while the effort was mildly successful, I

have a serious lens (or sensor) flair. Has anyone seen this problem before and how can I correct this? Here are

the image values:

 

Nikon D80 - Nikkor18-200VR - 9:22pm - 18.0mm - 838.7s - f/7.1 - ISO200

 

Please note the two light flairs in the upper corners of the image. I have not modified the image in any way,

except to resize for posting. Thanks in advance for your help... Mike<div></div>

[Peter_in_PA]

That's why really long exposures like that are better on film. The sensor heats up and causes this problem. You can

sometimes correct it with long exposure noise reduction, but that would mean taking a second "blank" exposure of the

same length. (Not sure it would fix this kind of problem... I've never tried.) Do you have enough battery for that second

exposure?

[phule]

This is not lens flare, this is your sensor heating up over time and is a known aspect of the D80.

 

If you enable noise reduction (where the camera does a dark frame subtraction) you may reduce its impact (though I do not know if it will be eliminated completely).

[phule]

Oh look it's Peter "Phelps" Hamm

 

:)

[phule]

Michael,

 

See this recent thread as well:

 

http://www.photo.net/nature-photography-forum/00Qaph

[Peter_in_PA]

You'll see a little more about this here.

 

http://www.kenrockwell.com/nikon/d200/d200-dark.htm

[Peter_in_PA]

Rob, I don't get it? I can neither swim nor do gymnastics.

 

;-)

[Not Here]

Well, consider me enlightened (pun intended) although I'm a little disappointed that the issue has been known for so long by Nikon and not fully corrected. It seems the early "30" serial numbers were the worst, my camera is in the "33" generation and it's still there; although not as bad as the early models. I admit to forgetting to turn on the long exposure NR, because I don't use it and didn't even think about it. I'll give that a try on future outings.

 

What no one clarified is whether this amp noise or heating issue does any damage to the sensor through prolonged use. I rarely try this type photography, but should I refrain altogether to keep from burning the sensor?

 

Thanks for your help, by the way!! Mike

[Not Here]

Uh, the "no one" I referenced would be the reviewers and their articles... thanks again! Mike

[joe_a2]

Mike.... Looking at your shooting data, I think you could have done a few things to reduce the sensor noise you're

seeing. The image

above was about 14 minutes at f/7.1 at ISO 200. I cannot tell if noise reduction was on (did the camera follow-up

with a 14 minute dark frame?). I'm guessing noise reduction was off based on your image.

 

If you shot at ISO 500 or so you'd still have a very clean image, and it would drop the time to about 6 minutes. If you

also set the aperture to f/4, the exposure time would have dropped again to about 2 minutes. With Noise Reduction

engaged, I don't think you'll have a problem with a 2 minute exposure.

[Not Here]

Thanks Joe... NR was off and I'll give your exposure times a try. I'm new at this and thought it necessary to keep the ISO low for noise and a relatively small aperture for DOF, but I'll try a combination of all the above next time out. I was just shell shocked when this flare showed up this time and didn't even try anything else. Thanks... Mike

[lex_jenkins]

Film isn't inherently superior. Take it from a longtime, diehard long-exposure nighttime photographer. *Some* films are better for this stuff. Not all. It depends on factors such as the anti-halation treatment of film. I've got some long-exposure nighttime and even daylight shots with comparable flaws on film, where halation spread flare and ghosting to the unexposed film margins.

 

If I wanted to pursue long-exposure nighttime photography with a dSLR I'd get a body proven to perform well for this specific task. Even my D2H is merely adequate. Noise isn't the major problem at ISO 200, dynamic range is. But my few experiments so far predated HDR software. Experimenting with Photomatix's freebie version is promising for averaging some of my bracketed nighttime D2H shots, taken before I'd even heard about HDR. (Yup, I'm a clueless Luddite.)

 

Alas, there are some long-exposure techniques that don't lend themselves to bracketing. If it's not all captured on a single exposure the effect ain't the same.

 

FWIW, Michael, if you aren't allergic to create photo editing, even flaws like those shown in your photo can be corrected. I don't know if you've seen the b&w work of Michael Kenna, Rolfe Horn or other master printers, but those folks can work magic. Horn's website illustrates some techniques for transforming a rather mundane nighttime photo into something special. Careful burning of the edges and other areas where flare appeared in your photo might help, along with cloning and whatever rabbits you can pull out of your hat.

[Not Here]

Lex... That's great info. I'm not sure how deep I'll get into this long exposure shooting, but I just hate not knowing "how" to take these type photos if the need or desire were to arise. I'll check into the Horn site and give the techniques a try.

 

As for this picture, it was a totally random scene selection, just for an experiment, and in addition to the obvious flair I had a mountain of hot pixels. Not wanting to give up on the effort, I did produce a crop, left all the defects in place, added some heavy burning... <a href="http://www.photo.net/photo/7779034"> LINK to POST</a>... ah la Sally Mann, just to test the reaction of the viewers.... LOL, so far not a single comment... Oh well, back to the drawing board. I do appreciate your interest and response to my post though... Mike