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Author Topic: Step Down Ring Vignetting?  (Read 4117 times)

JB Rasor

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Step Down Ring Vignetting?
« on: August 23, 2014, 04:00:04 am »

I'm in the process of Cine Modding my glass (focus gears and standardizing the filter thread to 80mm with step up rings), but two lenses have an 82mm filter thread. Namely, the Canon 16-35mm f/2.8L Mark II, and the Tamron 24-70mm f/2.8 Di VC.

Duclos Lenses makes a step down ring, 82mm to 80mm, but I'm wondering if vignetting would occur, particularly on the Canon 16-35mm? Obviously the good folks at Duclos will probably know the answer to this question, but I was curious if anyone on the forum had some knowledge about this combination.

Once modded to 80mm, I'll probably add a clamp on hood with an 82mm variable ND inside. I'm looking at this model: http://www.bhphotovideo.com/c/product/310726-REG/Cavision_LH80_LH80_Lens_Hood.html
Cheap but effective and it threads 82mm filters.
So, add that hood and a variable ND with step down rings and I may start running into issues. But maybe not. Anybody?

Thanks guys!
JB
 
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Morgan_Moore

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Re: Step Down Ring Vignetting?
« Reply #1 on: August 23, 2014, 10:55:06 am »

You dont mention your sensor size.

S35/APSC - no worries I guess

I have a Nikkor 18mm with an 86-77 step down ring

FF35? Could be a bit tight - do some experiments with your fingers - see when the come in shot..

S
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Sam Morgan Moore Bristol UK

JB Rasor

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Re: Step Down Ring Vignetting?
« Reply #2 on: August 23, 2014, 11:12:22 am »

Morgan,

Right now I'm mounting everything on the A7s, but the glass will be on S35 occasionally. Everything is EF mount and mostly for use with full frame. Probably hard to know until everything is modded.
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Morgan_Moore

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Re: Step Down Ring Vignetting?
« Reply #3 on: August 23, 2014, 11:33:36 am »

Well FF 16mm 82 front is gonna be a challenge

VND is a double glass filter and quite thick - Id guess you need to be onsize not stepdown.

Overall ND is a world of sh*t - whatever way you go round it it is a royal PITA

Basically I got went from my FS100 to the F3 just to get ND filters - Now Im prepping to a job on the black magic and back to the horror of ND.

Pick a filter size and step up to it - thats what Ive done - 77mm

I have tiffen VND too - £500 down the pan unless green is your thing.

The BMC job we have 2 solid B+W 3 stops and 2 solid B+W 6 stops enabling me to shoot while the A/C preps the next lens.

In reality Ill stick to two lenses 35-70 and 18 to cut filter fandangle.

Coots has/had a Lee clip on system 100mm that I actually found very impressive.

As for my 96mm front nikkor 50-300 4.5 - well I just made a pigs ear out of a fan cover..









« Last Edit: August 23, 2014, 11:36:01 am by Morgan_Moore »
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Sam Morgan Moore Bristol UK

JB Rasor

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Re: Step Down Ring Vignetting?
« Reply #4 on: August 23, 2014, 02:51:09 pm »

You're not kidding Morgan...ND is a total pain!! I'm saving up dough for an F5, and one of the selling points for me, over say a C500 or Scarlet Dragon (sorry Coots), is built in ND.

But in the meantime I'm trying to streamline everything and make life easy. Standard 80mm front diameter, 80mm clamp on variable ND, boom, done.

If I could turn back the clock I'd have cine modded everything years ago, instead of amassing 15 different filters and sizes haha. By the way, I got the idea for the clamp on ND from Jason Wingrove. Not personally lol, but in this video: http://www.fxguide.com/quicktakes/rc-special-whats-in-jason-wingroves-epic-kit/

Thanks for the help Morgan. I'll let you know how it turns out.

JB
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Morgan_Moore

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Re: Step Down Ring Vignetting?
« Reply #5 on: August 23, 2014, 04:11:51 pm »

I think the C500 has ND??

I do think it is worth checking out and understanding the Lee 4X4 clip on system that Coots uses.

Lee are crap at describing it or selling it.. that is where I would go especially with glass that doesn't turn at the front (unlike some of my manual nikkors)

Basically you add a ring to every lens with a V slot in it, the filter tray and optional bellows then move really fast from one lens to the next.

The abomination you see above is for a single shoot with a BMC - all my cameras have ND - if I were rekitting for no ND world and photo lenses Id go with the Lee system.

Lee 100mm system..
https://www.youtube.com/watch?v=x5kZLZRwXOw&list=UUnpkaQjKtWwrmUO0tTi6nkA
 http://www.leefilters.com/index.php/camera/system

Beyond the filter holder it is possible to add bellows to control some flare, also 4.4 filters do the job no need for these 4.5 unles you are going grad.

S

« Last Edit: August 23, 2014, 04:27:03 pm by Morgan_Moore »
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Sam Morgan Moore Bristol UK
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