ND filter inside lens adapter

I suggested to Metabones that they make something like this when they first released the EOS-NEX adapter. At the time they said most people who'd benefit from such a feature probably already own screw-in filters or matte boxes.

I like the concept, but the the goal of $12500 seems a bit steep. Also, it seems like this adapter wouldn't have any electronics for EOS lenses aperture adjustment?

PS What's with the name "Holy Manta"? Is this some kind of Swedish pun?
 
Definitely interesting, but for those who have electronic lenses as well, it would be a necessity to have at least a manual iris control ring. Otherwise I think many people will be left out here.
 
Is this even a good idea? Rick Burnett experimented with this idea and came up with the conclusion that it's not practical; adding an optical element like an ND filter between the lens and the sensor means that you're throwing the focus off, so you'd ideally need an additional custom-made optical element to get the lens to focus properly, and putting a variable ND filter in the optical path means that 1) you're always going to be giving up two stops of sensitivity at a minimum, and 2) you're always going to have the softening and color shifting attributes inherent in the variable ND filter that's chosen. Some of us avoid variable ND's whenever possible, so to have one inherently in the optical path is not necessarily the best idea. But, for those who do use them, maybe this is a convenient solution.

I mean, it's kind of an obvious idea, but other people have tried it and haven't been able to overcome the obstacles. Hopefully the inventor here has addressed all these issues; it would certainly be nice to at least have the option of a filter in place for daylight use, but there are certainly obstacles to overcome.
 
Barry_Green said:
Is this even a good idea? Rick Burnett experimented with this idea and came up with the conclusion that it's not practical; adding an optical element like an ND filter between the lens and the sensor means that you're throwing the focus off, so you'd ideally need an additional custom-made optical element to get the lens to focus properly, and putting a variable ND filter in the optical path means that 1) you're always going to be giving up two stops of sensitivity at a minimum, and 2) you're always going to have the softening and color shifting attributes inherent in the variable ND filter that's chosen. Some of us avoid variable ND's whenever possible, so to have one inherently in the optical path is not necessarily the best idea. But, for those who do use them, maybe this is a convenient solution.
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Just to note that the vari-ND in this adapter is in fact not permanently in the optical path. It can be lifted and stored in the bay on the top right.

Re: interence with focus... I hadn't thought of this, but of course you're right. But doesn't that apply also to built-in ND wheels?

Re: sharpness. The maker claims his vari-ND is sharper than others and has a few sample screenshots. How trustworthy I don't know. Personally I'd rather have a multi-ND wheel.
 
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aly324 said:
Also, it seems like this adapter wouldn't have any electronics for EOS lenses aperture adjustment?
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But how many active adapters are out there? I have a GH3 & the little searching I've done all I've found is the Red Rock Live Lens for $500. I'm hoping the Metabones m43 adapter is an active adapter, but there is currently to ETA on that.

aly324 said:
But doesn't that apply also to built-in ND wheels?
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I was going to ask Barry the same thing. Doesn't every camera with built in ND come between the end of the lens & the chip? I want to go look inside a camera now to check it myself, but this is how I've always thought it worked & I don't ever remembering seeing any optical correction for the ND filter in there.

aly324 said:
Re: sharpness. The maker claims his vari-ND is sharper than others and has a few sample screenshots. How trustworthy I don't know. Personally I'd rather have a multi-ND wheel.
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Off, 1/4, 1/16, 1/64. I'd totally take a non-variable version if it was sharper & cheaper. Even if it wasn't self contained & the adapter was like a matte box where you pull ND filters in & out.
 
zijital said:
I was going to ask Barry the same thing. Doesn't every camera with built in ND come between the end of the lens & the chip? I want to go look inside a camera now to check it myself, but this is how I've always thought it worked & I don't ever remembering seeing any optical correction for the ND filter in there.
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Build in NDs always have a clear glass at one position of the filter wheel with the same optical refraction index as the NDs.
 
aly324 said:
Just to note that the vari-ND in this adapter is in fact not permanently in the optical path. It can be lifted and stored in the bay on the top right.
Click to expand...
Nice, hadn't seen that!

Re: interence with focus... I hadn't thought of this, but of course you're right. But doesn't that apply also to built-in ND wheels?
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In short, no. In long, yes, but it's not a problem, because the ND filter wheel has an additional clear glass position, which does the job of correcting the optical path. So when you have a camera with a built-in ND filter wheel, it's calibrated to focus properly through that additional optical element, whether it's a clear or ND filter.
 
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