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Speed boosters make lenses faster


JackAllTog Plus
9 5.3k 58 United Kingdom
30 Nov 2018 4:51PM
A canon patents discussion, also had me look at me look at metabones speed boosters.
I assume its only where you can use larger format sensor lenses on smaller or closer sensors, but it seems very interesting that you can potentially make a lens both wider and brighter with one of these gadgets.

In the forums i could only see ChrisV commenting on one of these - has anyone else used one who can recommend usage scenarios?

Cheers,

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ChrisV Plus
12 2.3k 26 United Kingdom
30 Nov 2018 5:32PM
Perhaps it was on the fact Iíd just got one of the Viltrox speedboosters (massively cheaper and as far as I can work out, just as good as the metabones)?

Specifically Iím using that on a Panasonic G9 with the Canon mount Sigma 18-35 f1.8 Art. It allows me to shoot wide open with aperture setting f1.2. Autofocus is slow, but such a fast lens is going to be wide open and that lens is noted for a bit of hunting at maximum aperture anyway.

In terms of equivalence AoV comes out like approx 25x50mm (that is 18-35x2x0.71) and thereís no more vignetting than you might expect even though the lens is only designed for the APSc imaging circle. The other bit of the equivalence equation is that it gives the same DoF character and the same overall light gathering performance as youíd get out of an f2.5 lens on a FF body! Itís a heavy combination but I was contemplating buying a new 35mm system. I donít need to if I can get very similar performance out of this combo. The lens is exceptionally sharp for a zoom and it will be faster (albeit with slightly less range) than the forthcoming Panasonic 10-25 f1.7 - which I expect to be about three times the price, at a guess.

The other use case I expect to put it to is to adapt a wide angle (10-20) for the same format. Range on that would work out at 14-28. Have a look at the eye watering price of the Panasonic 7-14 or (even more) 8-18 optics covering similar AoVs and itísfairly obvious why it makes sense.

I was half- expecting there to be a cost in terms of sharpness, but having compared my trusty Canon 70-200 f2.8 on my 5DII vs the same lens with an adapter on an mft body, if thereís any difference at all in sharpness itís not in favour of the native combo. The speedboosters really are a bit of a marvel and the only reason I can think that smaller format OEMs donít offer them is because it would seriously cannibalise sales of their native glass. Some of the newer PanOly optics are very good, but theyíre not fast enough for some purposes and theyíre incredibly pricey for what they offer.

As far as compromises go, the Viltrox booster is as close to best of both worlds as I can think. Youíll have gathered, Iím a fan.

One note of caution around some optics is that you canít infinity focus (the Sigma 20-20 for example in my case). But Iím led to believe this is achievable with a simple adjustment of the adapter. The rub of course is it may not then work perfectly with the 18-35. At just over £100 a pop, I think Iíll have the luxury of a second one to leave permanently attached to the wide lens...
Chris_L Plus
4 4.9k United Kingdom
30 Nov 2018 7:29PM
Just been looking in your PF to see if there are any example with the speedbooster.

I was totally attracted to one when I had MFT, there's an infamous video on YouTube where the guy's using a Sigma and a Metabones and getting impressive results, it sold more of those combos than any advertising did.
keith selmes 15 7.4k 1 United Kingdom
1 Dec 2018 6:39PM
I just looked up some reviews on Viltrox, and they're very, very mixed. Sounds like a bit of a gamble.
Also, not good for video.
Ross_D 4 783 1 United Kingdom
2 Dec 2018 9:10AM
I've obviously fallen behind when it comes to lens technology but how does a 'speedbooster ' work ? Surely a 50mm 1.8 lens will always be 1.8 because the max aperture is fixed ?

I've looked at Metabones and they appear to be nothing more than adaptors which allow you to mount lenses of one particular make onto the camera body of a different make...... but maybe I'm missing something ??
Philh04 Plus
13 2.0k United Kingdom
2 Dec 2018 11:01AM

Quote:Surely a 50mm 1.8 lens will always be 1.8 because the max aperture is fixed ?

Not really, they work like a reverse extender, therefore the focal length becomes less so the aperture does become wider according to the maths i.e focal length divided by the diameter of the aperture.
Ross_D 4 783 1 United Kingdom
2 Dec 2018 1:48PM
@Phil.........thanks, I see what you mean. I looked on the Metabones site and can see that the adaptors have an extra element . I was confused (easily done !) over the fact that a standard 'extender ' ( ie 1.4X or whatever) effectively decreases the max aperture.

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