Graduated ND filter for wide angle? - Page 2

Classvino · 07-25-2008, 02:57 PM

Originally Posted by HermanLee

I was thinking to get Sigma 10-20mm too in the future. Will it work with this one too?

Yeah the P series will vignette on the 10-20, but, as Ben suggests, only at the extreme wide end...

There is a wide angle P Holder available that only has one filter slot, which might not vignette on the 10-20. Another solution I've read about would be to buy an extra P holder, and saw or 'dremel' off the extra filter spaces...

*Russell-Evans* · 07-28-2008, 04:23 PM

I have taken a Drimel to a ebay knock off P filter holder, changing the way it mounts on the lens and used an Exactor saw blade to remove the front slot of the holder. The 77mm adapter now threads through the filter holder instead of sliding in behind. The Sigma 10-20mm lens hood threads/mounts act as a back stop.

With this setup on the Sigma 10-20, I can rotate the filter holder up to about 43 degrees before seeing any vignetting at 10mm. From 43 to 48 degrees there is a very slight darkening. I could remove the second slot to remove this too, but zero to 43 degrees of rotation has been plenty so far.

With the Drimel I drum sanded the back of the holder flat, drum sanded the inner circle of the holder down to the outer circle (if you look at the back of the holder the circular cut out is cut in two levels), and snapped the screw mount in through the front after removing the front slot. The plastic holder is a lot thinner around the base, but with the metal mount in the holder it still feels pretty sturdy. It took about 40 minutes for me to complete.

Thank you
Russell

Classvino · 07-29-2008, 11:00 AM

Originally Posted by Russell-Evans

I have taken a Drimel to a ebay knock off P filter holder

Sounds good - I'd be interested in seeing a photo of the finished holder, if you had the time to take and post one....

*Russell-Evans* · 07-29-2008, 02:49 PM

Originally Posted by Classvino

Sounds good - I'd be interested in seeing a photo of the finished holder, if you had the time to take and post one....

It is a little rough looking, but it works. You can see how the filter ring of the lens now fits through the holder allowing the screw in mount to be used from the front to secure the holder on the lens. For other lenses, I use step up rings.

Links removed

Thank you
Russell

axl · 07-30-2008, 01:15 AM

Looks good russel, I think it's wort trying and maybe I'll give it a shot bit later, but...
with filter holder adjusted like this you can't use coking P size CPL, can you?
anyway, I don't think I'd be using CPL at 10mm

so I think I'll give it a shot...
thanx for posting the pics...

*Russell-Evans* · 07-30-2008, 11:26 AM

Originally Posted by axl

you can't use coking P size CPL, can you?

I don't think you can use the CPL without reducing the field of view at 10mm. I have never bought one, or seen one in person, but looking at photos of it, it just looks like the cog looking flange is too thick for an ultra wide. Maybe I'm wrong?

If I'm wrong, and you don't want the Cokin P holder for GNDs, just turning the non modified P holder 90 degrees works to remove all vignetting at 10mm. You can use the Cokin CPL and any, full ND, solid color, and most special, filters this way. The only issue is with filters that need the vertical alignment or adjustment.

My plan for a CPL is to do another version that leaves the third slot on the holder and uses a slim screw in CPL for the mount. I didn't really have to remove the third slot on the other one for the holder to not vignette. I removed it to get 43 degrees of rotation. I might just use my current modified holder for this and just live with one slot. I just haven't decided.

I think if I remove the first slot's protruding plastic slot, I can get a slim CPL in and use it to mount the holder on the lens. I think it might need a very thin plastic washer for the mount as the CPL doesn't have flange the Cokin mount has. For the thin plastic washer, I have some leftovers of one of those thin flexible cutting boards from another project that I think will work. I'll probably have to color the plastic in some way as it is translucent and I don't want any reflections

It is on my todo list, I just haven't started it.

Thank you
Russell

Ben_Edict · 07-30-2008, 12:07 PM

Originally Posted by Russell-Evans

I don't think you can use the CPL without reducing the field of view at 10mm. I have never bought one, or seen one in person, but looking at photos of it, it just looks like the cog looking flange is too thick for an ultra wide. Maybe I'm wrong?

The Cokin CPL has an open diameter of the glass of app. 73mm and a very thick rim of nearly 7mm! I never tried it on the Sigma, though, as I don't find it very useful. With such a wide angle of view, a polarizer cannot work over the full angle, but you get a graduated sky horizontally. But I think, the thick rim alonw will lead to some vignetting anywhere near the short end of the zoom.

Ben

cmv · 08-10-2008, 12:08 AM

I second checking out the Hitech filters -- 2filter.com has them and they are a reasonable choice between Cokin filters and the upper end filters that are quite expensive. I haven't actually used them yet but they were hard to find when I was searching for them here so...

Big Dave · 08-10-2008, 02:37 PM

Herman,
Both of the lenses that you mention are full frame lenses. If you are using a DSLR, vigneting wouldn't be a concern, since the image circle is much larger then the APS-C sensor.

Dave

Originally Posted by HermanLee

Does anybody know if this Graduated ND filter :

CF7332GD6 Sunpak 67mm Graduated Neutral Density Filter (.06GND)

will be good on my FA*24mm/2 or FA-J 18-35mm ( both has 67mm thread)?

I'm a little bit worried that it will vignette.

Also, is that a good filter? I'm thinking to buy DA*16-50 in the future, so should I get the Cokin P series instead and a step down ring?

Thanks.