True full frame conversion speed booster for M43?

[Inazuma]

This is old news that some may not have figured out. The speed boosters for the APS-C and M43 both use the same magnification of 0.71x despite the difference in crop factor.

 

This means a 35mm lens adapter with speed booster will work out as:

35 * 0.71 = 24.85

For APS-C: 24.85 * 1.5 = 37.275mm

For M43: 24.85 * 2 = 49.7mm

 

This essentially means that on Micro Four Thirds, lenses adapted with speed booster end up close to the focal length if you were to just attach the lens to an APS-C camera (because a 35mm lens on APS-C becomes 52.5mm once you calculate the 1.5x crop).

 

Granted you still get the extra aperture stop from the speed booster, but it's still a shame that the focal length isn't closer to actual 35mm full frame.

 

Do you think there will be a company out that will engineer a 0.5x magnification adapter?

 

PS: Will the bokeh circles of a 17.5mm f0.95 be the same size as those on a 35mm f2 lens?

 

PSS: Anyone have any recommendations on small manual lenses in 28mm, 35mm and 50mm focal lengths with apertures wider than f2?

[itimjim]

Why is it a shame? What's with the obsession of full frame?

 

Hollywood sure doesn't use it (S35, approx 1.45 crop), closer to APS-C than anything.

 

Typically fast glass equals big glass, so you might struggle to find small faster than f2. Canon FD 28, 35 f2 and 50 f1.4 are all relatively small lenses.

[Inazuma]

It's a shame because that was meant to be the whole point of the speed booster.

 

Cheers

[richg101]

there are some physical constraints..

 

firstly, a 0.7x focal reducer is about as thick as can be fitted into the space between a e mount and ef mount lens.  the greater the focal reduction, the thicker the optics become.

 

it's also harder to obtain good results from greater levels of focal reduction in limited space.

 

also, a 0.5x focal reducer on aps-c will need lenses designed for image planes bigger than 36x24mm full frame.

 

metabones have just released special adaptors for use on the black magic pocket with stronger focal reduction, but this was only possible due to the smaller sensor of the pocket.  the same level of reduction would be very hard to deliver high quality when coupled to a bigger image plane.

 

if anything you should see the m4/3 situation as the optimal use of focal reducers since it crops away the edges of the image that a aps-c sensor would normally capture.  Aps-c with a 0.7x reduction is as close to full frame fov as you'll ever need.  but the true full frame aesthetic will never be attained without a full frame sensor.  

-On paper the way a full frame sensor resolves depth of field and fov using a 50mm f2 lens is the same as an aps-c sensor and the same lens with speed booster.  However the intricate steps between in focus and out of focus subject matter is resolved differently and the full frame setup will have a more defined 3d 'pop'.  

 

 

a set of olympus OM lenses can be had at f2 apertures right down to 21mm if budget can meet their costly but deserved market value.  

[tosvus]

There's advantages and disadvantages with m43. A benefit is that you can actually use some aps-c lenses with the speedbooster. That is not possible on aps-c cameras.

This is old news that some may not have figured out. The speed boosters for the APS-C and M43 both use the same magnification of 0.71x despite the difference in crop factor.

 

This means a 35mm lens adapter with speed booster will work out as:

35 * 0.71 = 24.85

For APS-C: 24.85 * 1.5 = 37.275mm

For M43: 24.85 * 2 = 49.7mm

 

This essentially means that on Micro Four Thirds, lenses adapted with speed booster end up close to the focal length if you were to just attach the lens to an APS-C camera (because a 35mm lens on APS-C becomes 52.5mm once you calculate the 1.5x crop).

 

Granted you still get the extra aperture stop from the speed booster, but it's still a shame that the focal length isn't closer to actual 35mm full frame.

 

Do you think there will be a company out that will engineer a 0.5x magnification adapter?

 

PS: Will the bokeh circles of a 17.5mm f0.95 be the same size as those on a 35mm f2 lens?

 

PSS: Anyone have any recommendations on small manual lenses in 28mm, 35mm and 50mm focal lengths with apertures wider than f2?