# Leaf shutters



## Kim (Jun 11, 2011)

Am I the only one feeling the need for leaf shutter lenses? Of course one could upgrade to medium format if they have the money. But why doesn't Canon provide leaf shutter lenses for 35mm DSLR?

I would assume small dof and high flash sync speed would be attractive to many. Unfortunately, this can only be done with ND and powerful flash at the moment.

So why isn't there leaf shutter for 35mm?


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## gmrza (Jun 12, 2011)

Kim said:


> Am I the only one feeling the need for leaf shutter lenses? Of course one could upgrade to medium format if they have the money. But why doesn't Canon provide leaf shutter lenses for 35mm DSLR?
> 
> I would assume small dof and high flash sync speed would be attractive to many. Unfortunately, this can only be done with ND and powerful flash at the moment.
> 
> So why isn't there leaf shutter for 35mm?


One could ultimately probably summarise it as that a leaf shutter system for a SLR is commercially inviable, because of the technical challenges in building such a system and the limited market for it.
A leaf shutter needs to be built into the lens assembly - the optimal location is at the aperture diaphragm. That means, in an interchangeable lens system, that each lens must have its own shutter assembly. While leaf shutters have the advantage of high flash sync speeds, they are more limited in terms of absolute shutter speeds. For higher shutter speeds, they need to be relatively small. (You can see this in a number of point and shoot cameras that use a form of leaf shutter, where they can only achieve their fastest shutter speeds when the aperture is stopped down.)
I would venture that for a SLR system, a focal plane shutter has fewer disadvantages than a leaf shutter, and ultimately makes more sense. (At least for most users.)
While it is a compromise, you can achieve higher flash sync speeds using HSS, at the expense of absolute flash output power.
For 99.9% of photographers out there (amateaur and professional) a focal plane shutter system probably provides the best solution. It doesn't make commercial sense for Canon to chase that 0.1% niche. (99.9% vs 0.1% is my own hyperbole, those figures are not based on any fact.)


I have to admit I don't entirely follow your comment about depth of field. DoF is a function of aperture and frame (sensor) size, not the kind of shutter used.


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## awinphoto (Jun 12, 2011)

There's a few reasons I could think of... While I'd love to flash sync at 1/1000 a second, the leaf shutters, as they age get weaker and not only the aperture can become incosistant due to changes but so can the speed. On large format and some med format, you would have to take the lenses in every so often to be tested so you know 1/500 is REALLY 1/320 and so on... Let's be honest that most consumers aren't going to be on top of testing the lenses but will raise hell when the exposure is way off. Also due to this, an automatic ACCURATE light meter will be not poss in camera which means manual exposures plus manual light meters. I don't see that going over well. Lastly expect longer lenses (not much but longer nevertheless ) to fit the leaf and higher Prices...


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## Admin US West (Jun 12, 2011)

My first Film SLR had a leaf shutter, it was a nice camera, but the brand disapperred 40 years ago. It was wonderful when I replaced it with a Canon FTQL and its focal plane shutter.

I'm not against leaf shutters, my Hasselblad has one in each lens. It certainly does not seem to me to increase depth of field.


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## Hillsilly (Jun 12, 2011)

When Kim refers to small DOF, I assume we're talking about a situation when you are using fill flash on a bright, sunnny day. In such a situation, a slower shutter speed (eg 1/200) would necessitate a smaller aperture. With a faster shutter speed, you might be able to use a wider aperture, with corresponding shallower DOF. You would also be able to have more control of the light balance between the flash and the ambient light.

But I agree with the other comments. Everything comes with compromises. Leaf shutters generally have a slower maximum speed. I've got a few (Yashica Elctro 35, Mamiya RB67 and Mamiya 6) and they all max out at about 1/500. Most modern DSLRs can flash synch almost as fast as this (plus go much faster with FP synch), so there's no real advantage with the leaf shutter. Its not like we're still stuck in the 70's with 1/60 flash synch speeds. Admittedly, there are faster leaf shuttered lenses, but they tend to be costly. I think that the days of mass produced leaf shutter SLR systems have come to an end.

Kim, if you're keen to have a play with a leaf shutter lens, the prices for quality, second hand medium format film cameras are at rock bottom. Some, like the Mamiya RZ67 will allow you to add a digitial back if finances (or second hand prices) make that viable in the future. (Hasselblad have similar options, but their second hand values are still quite strong).


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