Aperture vs shutter speed

[DeeDoubleYou]

These two shots were taken with a S5 IS at its shortest focal length, both at ISO 80 and Auto WB. I was experimenting with various combinations of aperture values and shutter speed times. The curious thing to be noticed is the image of the moon and how it takes on a star-like quality with a higher aperture value. I would greatly appreciate if anyone could shed some light on my night shots. The first shot is at f2.7, 2.5sec and the second at f8.0, 15sec.

[chestercopperpot]

I *think* the starburst effect results from the longer exposure time.

[TomPierce]

I believe that your camera has a 6-bladed aperture. This means that the hole in the lens is not perfectly round, but is 6 sided. When you have a bright light source in the picture, it takes on the shape of the aperture. Look closely at the f2.7 shot and you will see the image of the moon is 6-sided instead of perfectly round. In the f8 shot, even the lights on the tree are beginning to show the 6 pointed star shape.

If you had another camera with a 8 bladed aperture, the 'stars' would be 8 pointed as well.

[DeeDoubleYou]

Thank you Tom. Would a ND filter help in keeping the light of the full moon from taking over?

[TomPierce]

I'm not sure what you mean. A ND filter will decrease the amount of light that is reaching the sensor. A Graduated ND filter (one that is only dark on one half of the filter and clear on the other half) would work, but they are expen$ive.

Why dont you just gobo it out? A gobo (literally 'goes between') is something that is used to block light from entering the lens.

A black piece of cloth (T-shirt?) held so that it blocks the light of the moon will effectively prevent the moon from showing at all.

If you block the moon 1/2 of the exposure time, then you have decreased its brightness by half. Since these are long exposures, it should be easy to do.

[brantfordbandit]

the smaller the aperature the more likely you are to get a starburst in th lights, try squinting when u look at lighting it's the same thing. a large aperature is like having your eyses and pupil wide open.