I need help setting the f-stop for long shutter speeds.

nikon5700ite 16 1.8k
3 Dec 2005 11:19PM
Have a browse through this webpage starting here and looking at other pages.

The problem with the average digital camera is that you have a minimum aperture of only f/8 which means that in bright sunlight the minimum shutter speed youy can use for a correct exposure is 1/250.

A DSLR lens closing down to f/22 in the same situation permits a shutter speed of 1/30. To get longer shutter speeds you need either less light[don't shoot in sunlight] or the same thing in a different way .. a Neutral Density filter, the strongest you can find. A polarising filter kind of works like a ND with a 1.5 to 2 stop cutting back of the light except it cuts light which is polarised one way which may not be the effect you require..

Checking the site to see if the link works the idea comes to mind that if your DSLR lens doesn't close down as much as you like you could get a piece of thin tin or brass, cut it to fit the front of the camera, use a nail to punch an dimple in it's centre, then carefull file down the dimple until you have a hole. You now have a very small aperture. [f/ number is focal length of lens/diam aperture]. Way back I made these by drilling holes in half-penny coins which matched the home movie camera lens I was working with. War Surplus gun-camera lens, complete camera 50p.

That will not work if you are using a zoom lens and will simply result in serious vignetting ... sorry Smile It is the way zoom lens are built, you need prime lens to make it work. Aperture is best in the middle of the lens but usually works reasonably well either close in front or close behind the prime lens. A zoom lens is often [sort of Smile] a prime lens with other adjusting elements in front so you can't place a 'Waterhouse Stop'in front of it... it vignettes.

Have fun! Smile

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