Blackmagic Forum

Use 77mm or 82mm filters on your Sigma 8-16

Sorry I don't have any photos yet, but this process is pretty straight forward.

1) Purchase some Schedule 40 4" PVC pipe
2) Cut about 1/2" off of the end
3) Attach an 86->82mm STEP DOWN ring to the end of the PVC pipe using some gorilla tape around the edges.

4) At this point, the PVC pipe is too wide of a diameter to fit properly over the sigma lens. Two options:

a) Buy a new sigma lens cap, cut it, and attach the pipe to it. I have the lens cap but haven't gone this route yet.

b) Add some padding to the inside of the PVC so that it fits snugly over the sigma lens. I used two layers of 3M Heavy Duty mounting tape, leaving the red plastic backing on. It is a perfect fit.

5)
If you have an 82mm filter, you can attach this to the bracket and then mount it on your lens. Although I haven't tried, I suspect that you can do a full 8mm with an 82mm filter.

Otherwise purchase a 82mm->77mm STEP DOWN ring. Then use 77mm filters.

You will get some vignetting with 77mm filters at 8mm. If you are shooting 2.4:1 then it is not a problem. Otherwise you need to zoom to approximately 9.5mm to completely clear up the vignetting.

Hope this helps people filter their 8-16 lenses!

Scott

P.S. I would love to post this on BMCUser, but I have not been able to verify my email and I can't make a post asking for him due to this issue. So if somebody can help me out there then I can spread the word to them on this topic as well!

Scott,

thanks a ton, great! One plea: could you provide some pictures for the ones like me (not native English speaker so some terms might be more obvious with a pic beside and mechanically dumb).

I can copy and paste your instrcutions and post it at BMCuser if you want me to.

EDIT: http://www.bmcuser.com/showthread.php?3 ... #post54101

Sorry I still haven't had time to post pictures.

However I can confirm that using this technique and an 82mm filter, there are no vignetting problems at 8mm on the Sigma or with the Samyang 8mm Fisheye! This is great news for the fisheye. In my opinion 77mm filters on the 8-16 at 9.5mm is also fine.

Thanks a lot. Going to try this.

Hearnie,

it would be awesome if you can post a photo then! THX!

I had to order the step down rings. I will post photos when I do it.

Thanks, looking forward to it!

Scott can you describe how to attach the 86mm step down ring to the PVC pipe? Mine looks quite a bit smaller than the pvc pipe - like tape just wouldn't attach it in the first place.

Here's how I did this. I found a rubber plumbing pipe with a screw clamp instead of PVC. I found it in Home Depot in the same aisle as the PVC. I like this solution much better. It does work also; my 77mm ND filter works from about 9.5mm onwards, just like he said. There's a small amount of vignetting at 8mm. If you were cropping anamorphic you could probably get away with it.

Thanks a lot Hearnia!

E D I T for intelligibility:

Just got my BMC and a owldolly matte box II, which let me put a filter in front without vignetting at 8mm:

I would rather pay someone to make this, I don't have the time or patients...Any takers?

Darryl Gregory wrote:I would rather pay someone to make this, I don't have the time or patients...Any takers?

I'll trade you one. Buy me an SLR Magic 25 for the pocket camera.

Darryl Gregory wrote:I would rather pay someone to make this, I don't have the time or patients...Any takers?

Just buy a Tokina 11-16mm. I'm selling my Sigma on eBay to get a Tokina now that the flange issue has been solved, its not fast enough and the filter issue is a pain in the backside. I have a lovely 77mm Heliopan Variable ND that I can't use on the Sigma.

So at what fstop does this lens start to look like crap? what is the sweet spot or ideal aperture?

Adrian Musto wrote:

Darryl Gregory wrote:I would rather pay someone to make this, I don't have the time or patients...Any takers?

Just buy a Tokina 11-16mm. I'm selling my Sigma on eBay to get a Tokina now that the flange issue has been solved, its not fast enough and the filter issue is a pain in the backside. I have a lovely 77mm Heliopan Variable ND that I can't use on the Sigma.

Unless your filter blocks IR, you probably won't want to use it for higher ND values.

cls105 wrote:So at what fstop does this lens start to look like crap? what is the sweet spot or ideal aperture?

Tough call. At F16 the diffraction blurs out the moire/aliasing that this camera exhibits. The downside is that any significant dust on the front of your lens will be visible.

Around F8 is good if you aren't in a heavy aliasing situation...

I no longer have a BMCC and am looking to sell my Sigma 8-16mm with filter adapters.

Email me at:
scott pultz ( @ ) hotmail . com

Remove the spaces and the ( ) and you have my address