Grad Filter / Counting Shutter Speed

[jpwild]

Just a quick question regarding use of grad filters. Obviously when taking metering from the sky and ground have to work out the difference to find which strength grad to use.

My question is this: Do I count in full shutter speed or thirds or halves? Or do I just count full shutter speeds to work out which strength grad to use?

Thanks,

 

[HoppyUK]

Filters are usually marked in full stops, so that's your answer.

But it seems like a complicated way of doing things when you can just make an educated guess, pop it on and take a test shot, and check the LCD image. You should make a few test exposures anyway, to see if you want hard or soft cut, and to adjust the position of the grad line.

Bear in mind that the effect of the filter varies a bit with f/number. Higher f/numbers strengthen the grad line, and vice versa. It's a by product of the depth of field effect of changing f/number. In practise, you can soften a hard cut grad in this way, but you can't harden a soft cut.

 

[Soulman]

I shoot in manual when using ND grads. Generally spot meter sky and then ground, choose a suitable filter to bring sky within dynamic range aaaaand then shoot (chimp the lcd, guess at some compensation and try again).