How to HDR night photography #2?

Ok, i asked this question earlier and people are asking for my settings. My ISO=100 F@ 8, Shutter speed@ 16". I took some decent skyline shots like that without HDR and had no grain. But when I add HDR yes! So take multiple shots I'm hearing but how many? My Nikon D3100 doesn't allow bracketing so its all manual. So lets say I have to shoot 3 shots so my settings would be like this?

shot1: 8"
shot2: 16"
shot3: 25"? Please give me the best possible shutter speeds for manual bracketing! Anything helps.

The shutter speeds seem fine but are variable with the amount of darkness/light where you're shooting. But i'm sure a tripod would help with the grains problem in case you're not using one already.

Try adjusting the aperture settings instead of shutter speed ( although its better to use the same aperture and adjust speeds to get the best from your lens ) As someone else stated make sure you use a tripod, and also don't forget to set your camera to a sharper setting ( or do it in photoshop ) and do shoot in raw. Its a lot of trial and error until you find what works best really

All fully adjustable dSLR's "allow" bracketing, just not automatic bracketing.

If you are trying to adjust for normal, one stop over and one stop under and your baseline exposure is 16 seconds, the while 8 seconds is a full stop under, 25 seconds is not a stop over. Try 32 seconds to get the full stop overexposure.

Many artists like the look of an over manipulated HDR shot, so may use five or even seven exposures to achieve that effect.

Since you can't use conventional meter readings to establish your basic proper exposure, you will need to experiment. Keep excellent notes and work from there

Shot #1 and 2 are correct. Shot #3 should be 32 seconds, but it will be 30 seconds as that is the longest time you can use on your camera without going into bulb mode.

At any rate, 30 vs 32 seconds will not be an issue.

Remember reciprocity and the inverse square law… +/- 1 EV is a doubling or halving of whatever control you select (shutter, aperture, or ISO).

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