How to prevent "whatever problem this is" from appearing. (Pic)

[l bo]

So I am still learning my lens, camera, and photo basics. I believe there is a term for the "dots" that appear in the sky. I was leaving my neighborhood, saw the flag and decided to take a few shots.

These dots appeared on some other extended exposure pics too, but not all. Is there something I can do to prevent this, is it dirt/dust on the lens? If you look close it looks like a reflection from the lights on the dock directly below the spots. I did use a hood to prevent unwanted light from entering, not sure how to prevent this. Any tips appreciated.

300D with Tamron 28-75 lens

http://i6.photobucket.com/albums/y231/Donny1994/Flag.jpg

Shooting Mode
Manual
Tv( Shutter Speed )
4
Av( Aperture Value )
4.5
Metering Mode
Center-weighted averaging
ISO Speed
100
Lens
28.0 - 75.0 mm
Focal Length
28.0 mm

[Tom W]

Ghosting. It generally occurs when very bright spots are in the image where everything else is dark. Some lenses do it more than others. Filters, especially poorly coated ones, can exhibit this effect as well.

One solution is to take the image when it is not quite totally dark, so that your exposure level is a bit lower. The combination of a slightly brighter sky and a slightly lower exposure level will mask the spots.

Also, you can try a smaller aperture with higher ISO and/or longer time. The stopped-down aperture diaphram might block some of the internal reflections in the lens that cause this.

[pierrot]

You might also try setting CF2 (noise reduction during long exposures) to 1 (on) ? ;)

But at a second look, it seems that these spots are not hot dots but rather specular reflections of the lamps on the ground...

If this is the reason, you could try another shooting angle, or aperture setting. Not sure it will make them disappear, anyway... :?

[PhotosGuy]

Another UFO pic! In formation, too. You're so lucky! ;-)
Notice how they're spaced just like the lights around the parking lot? If you have a cheap filter on the lens, then take it off. Or patch them out in PS.

[Chazs]

Another UFO pic! In formation, too. You're so lucky! ;-)
Notice how they're spaced just like the lights around the parking lot? If you have a cheap filter on the lens, then take it off. Or patch them out in PS.

Somewhere I read that this could even be a reflection off the sensor, bouncing off the rear lens element and back to the sensor. Might not be caused by a filter, cheap or expensive. Definitely a reflection of the lower lights though. A test shot without a filter might reveal where the source of the reflection is.

[l bo]

Thanks for the tips. I had no filter, could understand if I did. Thats why I am concerned, is it an indication of an inferior lens (tamron 28-75) or just happened that the angles of the lights caused it.

I took others that had these "ufo" images, and some that they weren't there. So increasing the iso, making the aperature smaller should help prevent this?

[shiato storm]

could be hot pixels on the cmos?...has been known to happen. I know someone who took 20D back 5 times for various sensor related problems. not saying he got the same one back by the way, he had 5 different ones!

[drisley]

Those are definately reflections caused by the lights at the bottom of the picture (just look at the pattern of the lights... 2 close together, large space, 2 close together...).
Why you get them? I'm not sure. I initially would have said it's caused by a uv filter.
However, you said you dont have a filter. I would assume it's the lens. I dont know if that lens is known for that problem or not, or maybe yours specifically has a problem.

[Persian-Rice]

Umm have you upped the contrast by 200%? That might be one reason they are so visible.

[drisley]

Umm have you upped the contrast by 200%? That might be one reason they are so visible.
But why is he getting the glare/reflections of the lights on the bottom to cause this in the first place? That's what I can't figure out?

[Tom W]

I've had this effect with my old 70-210 on film, so it's not just a digital thing (though the reflective sensor filter doesn't help much). Filters with poor coating are the number one culprit, but many lenses (and maybe even all lenses if you try hard enough) can do this without filters attached. Every piece of glass in that lens is a potential source for this effect. Coatings help immensely to reduce it, as does the shape of the lens elements. But if the light is intense enough, the background dark enough, and the angle is just right, the reflection can find its way back to the sensor as a ghost.

[l bo]

Thanks again, I really appreciate the feedback. For comparison purposes I posted a couple other pics, unaltered (reduced from 3072 pixels wide to 800 only editing)

In this pic, the same appear PLUS an awful orange color.

http://i6.photobucket.com/albums/y231/Donny1994/Cruisers002a.jpg

This pic was of a putt-putt golf course, without contrast adjustments you can faintly see more "ufo's"
http://i6.photobucket.com/albums/y231/Donny1994/Cruisers006.jpg

Same pic, but with higher contrast to highlight the foriegn unwanted lights:
http://i6.photobucket.com/albums/y231/Donny1994/Cruisers006b.jpg

That same night, another long exposure but no noticable ghosting:
http://i6.photobucket.com/albums/y231/Donny1994/Cruisers011a.jpg

My questions are; is this to be expected, or is this lens defective? If it's poor amature shooting techniques I can deal and learn from my mistakes, if it's the lens I would like to send it in (just got it) I am afraid to capture a great image at somepoint and the ghosting will appear, if user error just want to learn how to avoid it in the future.

Thanks again, you guys are a big help for an amature like myself :D

[drisley]

These are all examples of lens flare/ghosting.
Personally, I've never had that much trouble with any of my lenses.
Is the Tamron lens just more prone to this?

[karusel]

I've once had a few nice ghosting examples done with the 100-400L and the moon. It was the filter for which I'd figured, hey, I don't need a good one, I want a cheap one that would only protect my front lens element. Boy was I wrong.

As to the problem above, I don't know, perhaps there is some ghosting in every shot with blown highlights and it becomes more noticeable when contrast is boosted? I do not think this is a lens problem. I wouldn't just blame a third party lens maker for that.

[CyberDyneSystems]

Filters... or UFO....

I'm thinking UFO