Graduated ND filter

[mangobreeder]

OK as an impulse buy i am now the proud owner of a Cokin ND Grad Kit.

Please teach me how to use it.

i.e where do i set the dividing of the tin it, at the horizon, and how do i meter tog et exposure etc..

Many thanks in advance.

Mango

 

[Derek W]

Experimenting with the filter is the best way forward

Generally I slide the filter in to match the horizon so the shaded part reduces the sky down (however many stops the grad filter is) and meter on the ground so that'll be exposed properly with the grad filter (hopefully) reducing the sky down so its exposed the same

 

[mangobreeder]

(however many stops the grad filter is)

Doth didn't think of that

for the sake of argument say i have a 2 stop filter in.

should I be metering the ground so that the sky is 2 stops over exposed according to the light meter.

Or just stick the filter in get the filtered bit to match the sky, and meter the ground so its correctly exposed then shoot? < how do i know if 2 stops for the sky will be enough and need to add another filter?

 

[olv]

It becomes immediately obvious when you are using it whether or not you are doing it right.

 

[mangobreeder]

It becomes immediately obvious when you are using it whether or not you are doing it right.

thank you for your very helpful comment, I will treasure it

 

[olv]

Well it's massively self explanatory. You cover the bright bits i.e. the sky with the dark bit of the filter and set your camera to manual, set an appropriate aperture and ISO value and then experiment with the shutter speed until you get a good balanced exposure.

Unless you have every single third of a stop increment of ND grad you are not going to get a perfect exposure so you just had to work with what you've got.

 

[D.P.]

Easy, Put on the filter approximately in the middle, adjust while looking through the viewfinder. In A/Ap mode set the aperture to something sensible for landscapes (f/11 for starters), click away and let the auto exposure get the basics (use matrix metering).

With the modern technology of DSLRs you can check the results immediately, in particular display the histograms to check for clipping and for a middle peak. Also look at the sky and the foreground to see if the sky is blown or the foreground too dark. Then you can either flip into manual mode taking the auto-exposure readings as the starting point, or simply use exposure compensation (not a big difference when tripod mounted).

Adjust exposure to suit your needs, conventionally exposing to get the foreground at its optimum but getting a balance between sky and ground may be fine if you post process RAW files. For ultimate IQ you can over expose as much as possible before the sky starts clipping and then in photoshop bring the exposure down to the right level - this minimizes noise and maximizes the available colour rendition (the sensor record more information in the highlights than the shadows, while increasing exposure on an underexposed image increases noise).

There are ore advanced techniques using UniWhiteBalance etc.

 

[mangobreeder]

thanks, does what type of metering i use affect anything, should i be using spot, Evaluative etc?

when you say get a good balanced exposure, should i be looking for a good exposure of the ground, or the middle or the sky (tinted) bit?

 

[olv]

The whole point of an ND grad is that it brings down the brightness of the sky so that a good balanced exposure leaves the ground and the sky correctly exposed.

 

[D.P.]

thanks, does what type of metering i use affect anything, should i be using spot, Evaluative etc?

when you say get a good balanced exposure, should i be looking for a good exposure of the ground, or the middle or the sky (tinted) bit?

Use matrix metering to get a first evaluation. The fine tune (either in manual mode, or with EC).

 

[mangobreeder]

perfect thank all, ill post some pics once i get the hang of it