# Odd Friday idea: EOS R adapter with leaf shutter



## Jim Saunders (Sep 21, 2018)

Indulge my curiousity: Ignoring the question of integrating the electronics, is there a reasonable amount of room for a leaf shutter in the volume of one of the various adapters? Asking for a friend who has this weird thing with flash sync speed...

Jim


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## privatebydesign (Sep 21, 2018)

20mm is plenty of room for a leaf shutter.

Your friend is going to have to learn how flash works, or invest $10,000's in high end strobes. Most strobes duration at decent power outputs is in the sub 1/500 sec range, so sync speeds faster than that become 'interesting' to actually use. At very high shutter speeds the leaf shutter works as a second aperture diaphragm too.

Global shutters with very fast read speeds are the answer for the future for high speed sync, but even they don't overcome the flash duration issues.


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## Jim Saunders (Sep 21, 2018)

Perhaps I'll just wait a bit until an off-the-shelf solution presents itself. I mean I've *seen* DIY microsecond flashes but that doesn't mean I have any business trying it myself. 

Jim


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## padam (Sep 22, 2018)

A leaf shutter has to be matched to the lens itself (or placed in a camera where every interchangeable lens available is matched for that), so it is not a feasible idea, not going to happen. While a rear drop-in ND filter is also not 100% ideal (at least in theory), it works without any problems if implemented well, that is different.

So the solutions are fixed-lens cameras or camera systems with leaf shutter lenses.


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## LDS (Sep 22, 2018)

Jim Saunders said:


> is there a reasonable amount of room for a leaf shutter in the volume of one of the various adapters?Jim



AFAIK leaf shutter to work well must be placed in precise positions in the light path - just like the diaphragm. So putting them in the adapter won't give you what you expect.

Canon could make R lenses with a leaf shutter, though - just leave the focal plane shutter open, and use one of those new pins to command the leaf shutter...


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## privatebydesign (Sep 22, 2018)

padam said:


> A leaf shutter has to be matched to the lens itself (or placed in a camera where every interchangeable lens available is matched for that), so it is not a feasible idea, not going to happen. While a rear drop-in ND filter is also not 100% ideal (at least in theory), it works without any problems if implemented well, that is different.
> 
> So the solutions are fixed-lens cameras or camera systems with leaf shutter lenses.





LDS said:


> AFAIK leaf shutter to work well must be placed in precise positions in the light path - just like the diaphragm. So putting them in the adapter won't give you what you expect.
> 
> Canon could make R lenses with a leaf shutter, though - just leave the focal plane shutter open, and use one of those new pins to command the leaf shutter...


I'd like to see some evidence of that, obviously there is an optimal position for a leaf shutter as traditionally they are inside the lens and the speed that the blades move can be mitigated by the shutter being in a narrower point of the light path, but it is just a set of blades that opens for the light, like focal-plane shutters, their position isn't critical.


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## LDS (Sep 22, 2018)

privatebydesign said:


> I'd like to see some evidence of that, obviously there is an optimal position for a leaf shutter as traditionally they are inside the lens and the speed that the blades move can be mitigated by the shutter being in a narrower point of the light path, but it is just a set of blades that opens for the light, like focal-plane shutters, their position isn't critical.



I believe that if a leaf shutter could move at an "instantaneous" speed. where you put may not matter much. But because there would be speed constraints, the larger the shutter has to be, the more difficult is to avoid vignetting and so on at higher speeds. Otherwise, why not put a leaf shutter on the focal plane, and get the best of both types? Also, I believe there would more difficulties to put a larger shutter inside the lens barrel.


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## privatebydesign (Sep 22, 2018)

LDS said:


> I believe that if a leaf shutter could move at an "instantaneous" speed. where you put may not matter much. But because there would be speed constraints, the larger the shutter has to be, the more difficult is to avoid vignetting and so on at higher speeds. Otherwise, why not put a leaf shutter on the focal plane, and get the best of both types? Also, I believe there would more difficulties to put a larger shutter inside the lens barrel.


I know of the limitations of the speed of the various types of shutter, I also know that as nothing travels instantaneously, leaf shutters, as I already said, are poorly understood and at high speeds they work badly, they can affect the dof, cause vignetting and badly impact bokeh as well as having the effect of dramatically lowering your flash power. 

What I'd like is a link to a knowledgable source that says they have to be in a single place inside the lens, I don't believe that. I also believe that one could be put in an EF to RF adapter though it might well be bulky.


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