The Fotodiox Excell+1 Will Uncrop A Sensor and Gain You A Full Stop Of Light

Fotodiox just released a pretty cool accesory called the Excell+1. The Excell+1 is a lens booster which means that it has internal optics to concentrate the light coming from a lens into a smaller area.

now, why would you want to do that? 

What is a lens booster


A lens booster is a small device that goes between the lens and the camera’s native bionet. If the camera lens combo is such that the lens is a full frame lens while the body is using a crop factor sensor, some of the image from the less “spills” around the sensor.

A lens booster manipulates the light coming from the lens so it only overlaps the needed sensor. So basically a lens booster uncrops a lens/camera combo.

There are two effects to this uncropping, the obvious one is that you loose the ‘zoom’ factor crop sensors create. So a 100mm lens will actually perform as a 100mm lens even if you are using a smaller sensor. (on a Nikon DX sensor, it would appear to be 150mm for example)

The other effect is that you are getting more light into the sensor, so whatever f rating the lens has gets a +1 upgrade. Kinda like in the Mario brothers arcade. Here is what you gain:


When can you use a booster?

Since the booster depends on the camera bionet, the lens bionet and the crop factor, the boosters are camera/lens specific.

The Excel+1 comes in two flavors: Nikon F-Mount G Lens and Canon FD Lens both build for the micro four thirds on the camera end. That means that those specific ones will work with the pocket BMCC as well as any m43 camera.

I have not tested those personally so I am not sure what the optical impact is, but it would sure be an interesting experience, and if you consider the price shift from an f/1.8 to an f/1.4 lens the $160 may be  absolutely worth it.

[via SLR Lounge | nofilmschool]

  • Shachar Weis

    Isn’t that video misleading ? Yes, you gain 1 stop because you get more light overall on the sensor, but also the image is bigger. So the image would not be brighter. Am I right, or am I missing something ?


      No, it does give you an extra-stop of aperture. For instance if you adapt a 50mm f/2 in a Micro4/3 camera, it will give you a similar FOV to an APS-C, the 70mm described in the video, but the max aperture will be – and also behave – like a f/1.4, the bokeh also will look like a f/1.4 one.

    • thebeline

      You are missing something. The image gets wider, not bigger.

      If you have a lens that projects an image this wide:

      But your sensor is only this wide:

      You lose image (I counted dashes):

      BUT, with this (which is a reverse tele), your image circle actually decreases, causing your image to become wider (as you can see the stuff on the edges now) and compresses the density of the photons (much like a liter of water is taller in a cylinder one inch wide than a cylinder a foot wide):

  • Jim Huang

    Isn’t it the same as the speedbooster?

  • NutSpark

    Someone really needs to proofread the posts. Bionet? I assume that’s supposed to be bayonet. ‘some of the image from the *less* “spills” around the sensor’? Lens?

    • udi tirosh

      holy cr*p, thanks for the catch!

  • colcam

    This type of design was used for 35mm lenses on 16mm motion picture cameras back in the 1950’s, and the quality of the glass is paramount to the performance, but the flange depth control of production assembly can still soften the image.

    Test, test, TEST before you trust any teleconverter or inverse teleconverter design.


  • Rev

    Fotodiox fails again. Every test hitting the web right now has proved that this adapter is an optical mess. Blurry, inconsistent images, unusable wide open, and is an utter waste of money and time.

    This is a “3 strikes your out” scenario for me with Fotodiox… Again, they tricked customers into thinking this “Excell+1″ is a “new” product and that it’s been “beta tested”, which it is completely and utterly false. There is no way anyone who knows how to use a camera actually tested these out.

    Bohus puts his name and reputation out there as the face of Fotodiox, and if I was him, I’d be completely ashamed of myself and of Fotodiox right now. This is the exact same scenario for many a while back when the previous adapter turned out to be unusable as well… Instead of getting rid of bad product, they are trying to cleverly re-sell the adapter as a “stylistic lens: Light Canon”… Do they really think that the indie filmmaking and photography market is that stupid? I think not.

    Skip out on this Fotodiox debacle, save yourself a bunch of hassle, pony up the dough for the Metabones Speedbooster, and leave Fotodiox to their shame.

    • Chris

      It hasn’t even been shipped yet so there are no “tests hitting the web.” Troll.

      • Rev

        You are 100% incorrect Chris. Google it. Troll.

        Here’s one for you:

        Was that so hard?

        • Rev

          And for the record I got mine on Friday, direct from Fotodiox’s website, because I paid for upgraded shipping.