Sigma 15-30 and Cokin P

[rikkirby]

Does anyone here use the sigma 15-30 with a Cokin P series filter system? I've seen much speculation about the smaller sensor size meaning vigneting doesn't occur when using the lens cover with the 82mm thread but no confirmation.

Does anyone own this combination? My main use would be grad filters.

rik

[rut]

Originally posted by rikkirby
Does anyone here use the sigma 15-30 with a Cokin P series filter system? I've seen much speculation about the smaller sensor size meaning vigneting doesn't occur when using the lens cover with the 82mm thread but no confirmation.

Does anyone own this combination? My main use would be grad filters.

rik

I've do some tests.
At 15 mm, with lens cover and UV filter (normal mount) attached, you can see a little vignetting.
At 17 mm, no vignetting.

R.

[steve bingham]

OR - use Photoshop for a gradation filter. With the Gradient tool, choose Foreground to Transparent. Choose your foreground color. Black, gray, orange, whatever.

Create a duplicate layer. On the top layer click on mask. Make black your foreground color. On the top layer select multiply. Dragging the gradation filter from bottom to top PROTECTS the bottom part of the picture while multiplying the top part. (100% density change). For less density adjust the top layer transparency. For more density, flatten and repeat.

The advantage with this system is COMPLETE control over where the gradation starts (or ends), exactly how much gradation, and tint of gradation. By the way, the gradation and mask combination can be an incredible tool for many applications besides the obvious. How about a gradation in a circle form - or stripe, or wedge. The gradation transition can also be varied from soft to hard. And, using the eraser tool it can be made VERY precise.

For a few more EASY Photoshop tricks, visit my site www.dustylens.com.

Hope all this helps. By the way, I do have the 15-30 and love it. Especially at 15 at f11. Very sharp.

[steve bingham]

Correction to above. For more density simply duplicate the top layer - repeatedly if necessary. Simplier.