Well they do. What is the fastest lens in the Hasselblad line? f/2.8 for the leaf shutter lenses (500 series), f/2 for focal plane shutter cameras (200 series). That 100 f/2 is spectacular by the way.
They don't seem to constrain lens design options for Hasselblad.
Interesting. View camera users insist that some leaf shutters cause severe vibration..
If FP shutters are that good, why does my Hassy have a facility to lock the mirror up and use the leaf shutter for exposure? To presumably cut down on vibration.
I've never understood this because in an SLR by the time the mirror hits the bumper the picture has been taken.
Where'd you get that idea? The shutter starts moving after the mirror reaches the bumper at the top of the miror box. Otherwise, the mirror would cut off part of the image from most lenses, and light from the eyepiece could enter the mirror box and reach the film.I've never understood this because in an SLR by the time the mirror hits the bumper the picture has been taken.
Where'd you get that idea? The shutter starts moving after the mirror reaches the bumper at the top of the miror box. Otherwise, the mirror would cut off part of the image from most lenses, and light from the eyepiece could enter the mirror box and reach the film.
They don't seem to constrain lens design options for Hasselblad.
I don't know but diaphragm shutters are quieter and will synchronise for flash at any speed.
But why?
Please explain.
Thank you Ralph and Steve, as I never thought about that aspect. I suppose in theory a leaf shutter could be engineered to only open and close at a diameter to match the working aperture?
I think there have been shutters without separate aperture blades where the shutter blades only opened to the required aperture size then closed again but I suspect that they were difficult to keep accurate and would still suffer from the difference in time between opening a small amount and opening fully.
Something else to consider is that if you are using a very fast shutter speed, i.e. one which requires the shutter to open then immediately close again without delay, then with the aperture blades wide open, the actual exposure is made at all apertures from wide open to pinhole. The longer the shutter speed, the less this will have any effect.
Steve.
It's an explanation with graphic representation of the efficiencies of shutters, as you asked.
So my opinion, in a 35mm camera, a focal plane shutter is about the best kind. I like when they are mechanical and of fine construction quality, but have to admit an electronic focal-plane shutter is probably the most precise.
I don't know any electric leaf shutters, so the only fair thing would be to compare mechanical to mechanical.
With a focal plane shutter, mechanically you need to get the base speed precise. Then the curtain openings are the only changes to make. So long as both curtains travel the same speed, and the first curtain starts rapidly, you will get an accurate exposure.
A leaf shutter needs to get its higher speeds through faster and faster action against resistance. Some achieve their high speed by an extra spring, whose tension might vary over its lifetime.
So I think focal plane shutters are more easily kept accurate at the higher speeds.
Slower speeds, I think both kinds would be the same, since it's the time for escapement to pass its course.
Where'd you get that idea? The shutter starts moving after the mirror reaches the bumper at the top of the miror box. Otherwise, the mirror would cut off part of the image from most lenses, and light from the eyepiece could enter the mirror box and reach the film.
I wonder if it would be possible to engineer a double leaf shutter, where one is closing as the other opens, with the time for each computer controlled to give an overall accurate exposure time?
Interesting. View camera users insist that some leaf shutters cause severe vibration.
The way it was explained to me is the light coming to the film on a focal plane shutter is the same anywhere on the film plane while on the other hand the blade shutter allows slightly more light in the center than to the edges of the film plane because the blades must travel to the edges and back at whatever shutter speed was selected. My eyes have never been good enough to see the difference on my negatives.....RegardsBut why?
The way it was explained to me is the light coming to the film on a focal plane shutter is the same anywhere on the film plane while on the other hand the blade shutter allows slightly more light in the center than to the edges of the film plane because the blades must travel to the edges and back at whatever shutter speed was selected. My eyes have never been good enough to see the difference on my negatives.....Regards
However,they(diaphragm)tend to overexpose at small apertures.Focal plane shutters areeaposing independent of apertures,and therefore aremore efficient.
I have not noticed that overexposure error yet.
On the other hand, focal plane shutters can distort the image because, at top speeds (say, 1/1000), instead of having a full shutter that opens and closes, what we have is a narrow slit that "sweeps" the film area in a speed slower than 1/1000...
And in certain cases this can give a slant distortion to the image.
This does not happen with central shutters.
So I could argue that a camera with a FP shutter that tops at 1/2000 and synchs with flash at 1/90, is honestly a 1/90 speed camera, for moment-freezing purposes. While a camera with a leaf shutter that tops at 1/500 is really a honest near-1/500 speed camera.
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