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Speedbooster


Lucian
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Hi Speedbooster users,

 

I was hoping someone could enlighten me on how these things work.

 

Most fast lenses are actually pretty un-usable at their top speeds. So what I'm wondering is; lets say you have a f2 lens that is really too soft to use until stopped down to 2.8, does that mean when using the speedbooster you could now use that lens at the equivalent of f2 and it would be sharp?

 

I'm assuming so, because there is really no point in making most lenses faster unless their open aperture performance increases parallel...

 

 

Thanks!

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You are wrong. Actually the speed booster increases the sharpness a bit. If your lens is unusable at f/2, probably you don't want to use it wide open with the speed booster either, but since you win a stop of light, it will act like f/2 lens when set to f/2.8. With the speed booster you still get the performance increase that comes with stopping down the lens.

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You are wrong. Actually the speed booster increases the sharpness a bit. If your lens is unusable at f/2, probably you don't want to use it wide open with the speed booster either, but since you win a stop of light, it will act like f/2 lens when set to f/2.8. With the speed booster you still get the performance increase that comes with stopping down the lens.

Glad I'm wrong! Just looked up this slrlounge review, which shows a significant improvement in sharpness around the center of the image, although the edges don't seem to fare as well wide open.

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Guest Ebrahim Saadawi

How do these things work anyway? I've been hearing of them for quite sometime, can someone put it simply please?

Do they focus a large-format lens's image circle on a smaller sensor thus gaining the extra brightness and wideness?
If it's the case, does this mean it can be possible to apply the same concept on any large-format-lens-being-used-on-smaller-sensor situation?
For example mounting an EF lens to an EF-S body. An FX lens to a smaller sensor DX body. That would be something for 35mm camcorders like the c300/100s! (using the full EF lens image)

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Yes Ebrahim, that is how it works. But you need space for the adapter, so that's why it is available only for mirrorless systems. Dslrs have a longer distance between the mount and the sensor (because of the mirror) so you can use this space to add the speed booster on a mirrorless camera and use it with dslr lenses. It won't work for EF / EF-S, because both mounts use the same distance to the sensor. In theory a speed booster for dslrs would be possible, but then you would have to use medium format lenses.

@Lucian, exactly. It's a little piece of magic I think!

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Guest Ebrahim Saadawi

Thank you for explaining and clearing this up, Julian. I totally forgot about flange distance.
So I take from your words about only suiting mirrorless, that the concept could work on Eos-M mounts? Meaning using full-frame EF lenses on Eos-M mounts, does such a thing exist? Interested because I think Eos-m mounts will be on future Cinema-line cameras. Just a rumor but it would make sense, esp. if canon could produce an EF to M "speed booster", not that would be interesting!

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