[Leica] speed booster

[simon.apekop at gmail.com (simon jessurun)]

But for now, we tip our hats to Metabones for releasing a product that
accomplishes what many had thought nearly
http://www.dpreview.com/articles/2667195592/first-impressions-metabones-speed-booster
.


On Mon, Feb 4, 2013 at 7:27 AM, Frank Filippone <red735i op verizon.net> 
wrote:

> Thanks for the lesson.....
>
> Now maybe a 35 f0.47 sounds good, but only if you own a Nocti to begin
> with.....
>
> More practical for a greater segment of the market is......a 50 Summilux
> with this gizmo...
>
> Imagine  $600 + 50 Summilux = 35mm  Noctilux... now there is something I
> can sink my teeth into....
>
> If only they made one for the M Mount....
>
> Frank Filippone
> Red735i op verizon.net
>
>
> -----Original Message-----
> From: lug-bounces+red735i=verizon.net op leica-users.org [mailto:
> lug-bounces+red735i=verizon.net op leica-users.org] On Behalf Of Howard
> Ritter
> Sent: Sunday, February 03, 2013 11:44 AM
> To: Leica Users Group
> Subject: Re: [Leica] speed booster
>
> Well, no. But a 35mm f/0.47, yes.
>
> The Metabones is a focal reducer, the opposite of a tele-extender. Such
> are well known to astroimagers for increasing the field of view of a
> telescope and the brightness of the image it produces. If you use a
> positive lens to reduce the effective focal length of an objective without
> restricting the aperture, you have lowered the f-ratio. And that's what the
> Metabones does: reduce the focal length by a factor of 0.71, which is
> approximately = v2/2. Since the brightness of an image at a given f.l.
> varies with the square of the aperture (therefore inversely with the square
> of the f-ratio), reducing the f.l. by a factor of v2/2 thus brightens the
> image by a factor of 2, or a full f-stop.
>
> Question is, does the Metabones have the throat (entrance pupil I believe)
> that would be required to accommodate the huge light cone from the
> full-open Nocti?
>
> It's related to the annoying fact that no passive optical assistance will
> make an object appear brighter than it would be to the naked eye at a
> distance where the object would appear the same size as the optic makes it
> appear. No free lunches in optics. Gaining any reduction in f-stop without
> decreasing the f.l., now that would be magic!
>
>  howard
>
> On Feb 3, 2013, at 1:40 PM, Frank Filippone <red735i op verizon.net> wrote:
>
> > Can you imagine a 50mm F0.47 lens?
> >
> > Oh please, an M mount on both sides?
> > Pretty please?
> >
> > On a similar note.... I just found my Komura Telemore II 2x Extender
> > for M cameras..... need to take it out for a test with the M9.... if
> > it focuses well, WOW!
> > I can stand some image degradation.. but out of focus drives me nuts....
> > It came with a Komura LTM-M adapter... to which I have several genuine
> > and non genuine adapters... must try a few to see if one works better
> > than the others....
> >
> > Frank Filippone
> > Red735i op verizon.net
> >
> > any thoughts on this :"
> >
> > http://www.metabones.com/info/105-info/154-speed-booster
> >
> > brgds
> > Simon
> >
> >
> >
> > _______________________________________________
> > Leica Users Group.
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>
>
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