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Will a speed booster make a crop sensor lens into a full frame lens?

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Understatyment

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Recently bought an Sony a7s and I have several canon apsc lens.I did some reasearch and was wondering if a speed booster would give it the full frame feel?
 
Understatyment said:
Recently bought an Sony a7s and I have several canon apsc lens.I did some reasearch and was wondering if a speed booster would give it the full frame feel?
Click to expand...
A speed booster works the other way: it makes a FF lens work on a crop sensor by reducing the image circle size.

What you are looking for is a traditional teleconverter, which widens the image circle size.
 
Understatyment said:
Recently bought an Sony a7s and I have several canon apsc lens.I did some reasearch and was wondering if a speed booster would give it the full frame feel?
Click to expand...
It won't - the speed booster works by using the extra light that would otherwise miss the sensor and directing it as the smaller target.

You may find however, that the image circle on the APS-C lens doesn't leave as much black in the corners as you might think. If I put an A-mount kit zoom on my full-frame, I get the whole screen illuminated from about 35mm up.
 
Mark Scott Abeln said:
Understatyment said:
Recently bought an Sony a7s and I have several canon apsc lens.I did some reasearch and was wondering if a speed booster would give it the full frame feel?
Click to expand...
A speed booster works the other way: it makes a FF lens work on a crop sensor by reducing the image circle size.

What you are looking for is a traditional teleconverter, which widens the image circle size.
Click to expand...
 
MikeC-1961 said:
Mark Scott Abeln said:
Understatyment said:
Recently bought an Sony a7s and I have several canon apsc lens.I did some reasearch and was wondering if a speed booster would give it the full frame feel?
Click to expand...
A speed booster works the other way: it makes a FF lens work on a crop sensor by reducing the image circle size.

What you are looking for is a traditional teleconverter, which widens the image circle size.
Click to expand...
Not 100% positive but pretty sure a traditional teleconverter doesn't have any effect on the image circle size, rather it simply increase the focal length of the lens IE 200mm F2.8 lens plus a 2x Tele con = 400mm @ F 5.6.
Click to expand...
Wrong. A TC works by enlarging the image, so it usually increases the size of the image circle.

The TC has almost no effect on the focal length of the lens, other than by the physical thickness of the TC itself. But the effect of that enlargement is to make the image bigger so that instead of its size from a 200mm lens it increases to the size from a 400mm lens. The TC does nothing to the aperture (which is in the lens in front of the TC) which is why its f-stop is changed by the apparent change in FL.
 
Gerry Winterbourne said:
MikeC-1961 said:
Mark Scott Abeln said:
Understatyment said:
Recently bought an Sony a7s and I have several canon apsc lens.I did some reasearch and was wondering if a speed booster would give it the full frame feel?
Click to expand...
A speed booster works the other way: it makes a FF lens work on a crop sensor by reducing the image circle size.

What you are looking for is a traditional teleconverter, which widens the image circle size.
Click to expand...
Not 100% positive but pretty sure a traditional teleconverter doesn't have any effect on the image circle size, rather it simply increase the focal length of the lens IE 200mm F2.8 lens plus a 2x Tele con = 400mm @ F 5.6.
Click to expand...
Wrong. A TC works by enlarging the image, so it usually increases the size of the image circle.

The TC has almost no effect on the focal length of the lens, other than by the physical thickness of the TC itself. But the effect of that enlargement is to make the image bigger so that instead of its size from a 200mm lens it increases to the size from a 400mm lens. The TC does nothing to the aperture (which is in the lens in front of the TC) which is why its f-stop is changed by the apparent change in FL.
Click to expand...
 
Gerry Winterbourne said:
MikeC-1961 said:
Mark Scott Abeln said:
Understatyment said:
Recently bought an Sony a7s and I have several canon apsc lens.I did some reasearch and was wondering if a speed booster would give it the full frame feel?
Click to expand...
A speed booster works the other way: it makes a FF lens work on a crop sensor by reducing the image circle size.

What you are looking for is a traditional teleconverter, which widens the image circle size.
Click to expand...
Not 100% positive but pretty sure a traditional teleconverter doesn't have any effect on the image circle size, rather it simply increase the focal length of the lens IE 200mm F2.8 lens plus a 2x Tele con = 400mm @ F 5.6.
Click to expand...
Wrong. A TC works by enlarging the image, so it usually increases the size of the image circle.

The TC has almost no effect on the focal length of the lens, other than by the physical thickness of the TC itself. But the effect of that enlargement is to make the image bigger so that instead of its size from a 200mm lens it increases to the size from a 400mm lens. The TC does nothing to the aperture (which is in the lens in front of the TC) which is why its f-stop is changed by the apparent change in FL.
Click to expand...
Gerry, would a front-element mounted close-up lens filter diopter accomplish the goal of mounting an APS-C lens on FF? If it functionally works, is it worth the effort from an IQ point of view? Do you lose infinity?
 
Bob Janes said:
Understatyment said:
Recently bought an Sony a7s and I have several canon apsc lens.I did some reasearch and was wondering if a speed booster would give it the full frame feel?
Click to expand...
It won't - the speed booster works by using the extra light that would otherwise miss the sensor and directing it as the smaller target.

You may find however, that the image circle on the APS-C lens doesn't leave as much black in the corners as you might think. If I put an A-mount kit zoom on my full-frame, I get the whole screen illuminated from about 35mm up.
Click to expand...
 
techjedi said:
Gerry Winterbourne said:
MikeC-1961 said:
Mark Scott Abeln said:
Understatyment said:
Recently bought an Sony a7s and I have several canon apsc lens.I did some reasearch and was wondering if a speed booster would give it the full frame feel?
Click to expand...
A speed booster works the other way: it makes a FF lens work on a crop sensor by reducing the image circle size.

What you are looking for is a traditional teleconverter, which widens the image circle size.
Click to expand...
Not 100% positive but pretty sure a traditional teleconverter doesn't have any effect on the image circle size, rather it simply increase the focal length of the lens IE 200mm F2.8 lens plus a 2x Tele con = 400mm @ F 5.6.
Click to expand...
Wrong. A TC works by enlarging the image, so it usually increases the size of the image circle.

The TC has almost no effect on the focal length of the lens, other than by the physical thickness of the TC itself. But the effect of that enlargement is to make the image bigger so that instead of its size from a 200mm lens it increases to the size from a 400mm lens. The TC does nothing to the aperture (which is in the lens in front of the TC) which is why its f-stop is changed by the apparent change in FL.
Click to expand...
Gerry, would a front-element mounted close-up lens filter diopter accomplish the goal of mounting an APS-C lens on FF? If it functionally works, is it worth the effort from an IQ point of view? Do you lose infinity?
Click to expand...
 
JimH123 said:
techjedi said:
Gerry Winterbourne said:
MikeC-1961 said:
Mark Scott Abeln said:
Understatyment said:
Recently bought an Sony a7s and I have several canon apsc lens.I did some reasearch and was wondering if a speed booster would give it the full frame feel?
Click to expand...
A speed booster works the other way: it makes a FF lens work on a crop sensor by reducing the image circle size.

What you are looking for is a traditional teleconverter, which widens the image circle size.
Click to expand...
Not 100% positive but pretty sure a traditional teleconverter doesn't have any effect on the image circle size, rather it simply increase the focal length of the lens IE 200mm F2.8 lens plus a 2x Tele con = 400mm @ F 5.6.
Click to expand...
Wrong. A TC works by enlarging the image, so it usually increases the size of the image circle.

The TC has almost no effect on the focal length of the lens, other than by the physical thickness of the TC itself. But the effect of that enlargement is to make the image bigger so that instead of its size from a 200mm lens it increases to the size from a 400mm lens. The TC does nothing to the aperture (which is in the lens in front of the TC) which is why its f-stop is changed by the apparent change in FL.
Click to expand...
Gerry, would a front-element mounted close-up lens filter diopter accomplish the goal of mounting an APS-C lens on FF? If it functionally works, is it worth the effort from an IQ point of view? Do you lose infinity?
Click to expand...
Click to expand...
 
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