Wide angle + ND filters question?

[xarfaxus]

Can you help me please.
I'm a student (you get the money status from there )

So i finally saved some money and i'm buying sigma 10-20mm f4-5.6 Lens (77mm filter size).

and i would like to shoot some long exposure shots >10 seconds or more.

what nd filters would you suggest me to buy, ones with holders or screw filters?

I heard that cokin filters give unwanted color to picture, also is there difference between filters for 10-20mm and >20mm lens?

 

[Big Mike]

The problem with wide angle lenses and filters, is that the view from the lens is so wide, that something you put onto the lens, may easily been seen by the lens, and thus end up in your photo.

For this reason, I'd avoid the holder and go with a screw in filter.

I'm not sure about your particular lens, but you should be able to use at least one filter, without it showing up in the image (at 10mm). But it may depend on the thickness of the filter ring. You can buy 'thin' filters, that will help to avoid this 'vignetting', but that may or may not be necessary.

As for which filter to buy, to get 10 second exposures...that depends on the light you are shooting in. In broad daylight, you may need a 4 stop or 8 stop ND filter, but when it's darker, you may only need a 2 stop filter, or no filter at all (just a small aperture and low ISO).

 

[Freelancephotog25]

I agree with Big Mike!

 

[tirediron]

...I heard that cokin filters give unwanted color to picture, also is there difference between filters for 10-20mm and >20mm lens?

Cokin ND and G-ND filters can impart a red/orange colour cast to the image when shooting toward or near the sun, however this is easily controlled in almost all cases with the simple expedient of a lens shade. I keep an 8x10" piece of matte-black craft foam (Wal-mart $00.29) in my bag which I bed to suit.

The only difference between filters for wider-angle lenses is that they naturally need to be larger. You will definitely need the Cokin 'P' size (or equivalent) and possibly even the 'Z' size for such a wide angle lens. Measure the physical diameter of the front element (NOT the lens filter diameter, although the two are likely similar, and then visit the Cokin, Lee, or Singh-Ray website to determine which filter size you require.

 

[xarfaxus]

Thank you guys!

But i dont understand the

however this is easily controlled in almost all cases with the simple expedient of a lens shade

part?

and, IF filter gives color cast, is it managable in photosop?

 

[tirediron]

Thank you guys!

But i dont understand the

however this is easily controlled in almost all cases with the simple expedient of a lens shade

part?

and, IF filter gives color cast, is it managable in photosop?

The colour cast is generally only a problem when shooting toward the sun. I use the black craft foam as a shade which I hold above the filters. Generally, if you hold the shade correctly (and sometimes it takes a bit of trial and error, depending on your shooting position relative to the sun) the cast is eliminated. In the most extreme cases, you may have to do some red channel adjustments in post to clear it up.

 

[xarfaxus]

why, thank you ;D