Will there be Speed Boosters® for M42 and Pentax K? We will be looking into M42 and Pentax K in the future. We do not have an estimated date yet. Disclaimer: this shall not be construed as a commitment to ship - we are not done prototyping any of these yet but we will conduct testing to decide if these lenses are free of interference issues with the optics of the Speed Boosters® before we will be able to turn them into actual products. Will there be Speed Boosters® for DSLR camera bodies? No. The mirror gets in the way but there is no room for the optics. Will Samsung NX cameras be supported? No. Unfortunately, it is not possible to fit the optics inside the Samsung NX mount owing to flange distance and physical interference issues Why don't we have a 0.5x MFT Speed Booster® for Micro Four Thirds? With the amount of available room prescribed by the MFT mount, 0.71x is the lowest we can go while maintaining compatibility with the broadest range of MFT cameras. Our MFT Speed Booster® XL 0.64x has a protruding rear element which does not fit every MFT camera and it is the the lowest we can go without compromising image quality. We do have a 0.5x Speed Booster but that is for the Pentax Q mount, made possible by its smaller sensor. Does Speed Booster® for Nikon G lens work with Nikon F lens? Yes! Nikon G supports not only Nikon G lenses, but Nikon F mount lenses, too, including non-AI, AI, AI-S, AF, AF-D, AF-I, AF-S, etc., etc. However it does not have any electrical contacts and does not support autofocus, optical VR, or E-series Nikkors with electronic aperture diaphragms. Do the aperture rings on some Speed Boosters® have click stops? Contarex and Nikon G Speed Boosters® have integral aperture rings to adjust the aperture of the lens. The aperture ring on Contarex Speed Booster® has no click-stops. Since September 2013, Nikon G Speed Boosters® are shipped with no click-stops, with optional parts included to convert it clicked operation. Cinematographers who purchased the first batch of Nikon G Speed Boosters® may contact Metabones for conversion to clickless operation. How does Speed Booster® affect the depth-of-field? The short answer is Speed Booster® on an APS-C sensor gives essentially the same depth-of- field effect as if a full-frame camera body were used. The long answer is complicated. If we are referring to depth-of-field in the mathematical sense, that depends on the aperture, magnification and circle of confusion (CoC). Magnification in turn depends on distance and focal length. The 50mm lens now becomes a 35mm lens which behaves very differently in terms of perspective. The question is, do we still keep the distance the same? Should the CoC be kept the same? There are many missing variables we need to choose and fill-in before we could get a meaningful answer. When people claim Speed Booster® does not change the depth-of-field, they usually neglect to state the implicit assumption that the distance is kept the same (thereby changing the object size) and the CoC is kept the same. The same logic would lead to the conclusion that an APS-C camera has the same depth-of-field as a full-frame camera, too, which under the same implicit assumptions is mathematically true (the depth-of-field formula is format-size-agnostic, after all), but with which many people would disagree from practical experience. However, when most people ask about depth-of-field, they are not interested in mathematics, but rather, they are after a certain kind of shallow depth-of-field "look". If this is the case, the short answer above applies. How does Speed Booster® affect bokeh? From practical experience, Speed Booster® has negligible effect on bokeh. In most cases the resulting bokeh is that of the lens alone. Speed Booster® does not leave its own "character" or "signature" in the pictures. It is very neutral. Why is there so much confusion about all these focal length multipliers? "Equivalence" has always been a confusing topic. Speed Booster® does not make it any more confusing than it already is! Focal length, maximum aperture and depth-of-field are physical quantities that do not care about the size of the sensor sitting behind the lens. Speed Booster® physically reduces focal length and increases maximum aperture (smaller f-number) of the lens. The "35mm equivalent focal length" is not a focal length at all, but a measure of field of view (FoV). Speed Booster® physically reduce focal length by a factor of 0.71x and the APS-C camera body reduces FoV by a "cropped factor" of approx 1.52x, so the 35mm equivalent focal length (cannot be overemphasized this ia a FoV measure) of the combined system is approximately 1.08x. Once we are very specific about whether we are referring to a physical quantity or a 35mm equivalent measure, it is no longer confusing! Does the Speed Booster® increase only T-stop of the lens leaving F-stop unchanged? This is one of the common misconceptions about the Speed Booster®. However there is a contradiction right within that assertion since T-stop cannot be any faster than F-stop. It is not possible to experimentally observe a T-stop increase unless the lens has a corresponding F-stop increase. The logic of the allegation is that since the depth-of-field of the lens does not change, therefore neither does the F-stop of the lens (untrue). What had never been under any dispute was that the T-stop of the lens did increase, as could be seen with the increased exposure in the resulting footage or photograph. Before we clear up this misconception, let's find out why there is so much confusion in the first place. Focal length, maximum aperture and depth-of-field are physical quantities that are independent of sensor size. These quantities do not care whether a full frame, APS-C or m4/3 sensor sits behind the lens. Speed Booster® makes the focal length 0.7x shorter. F-number is simply focal length divided by entrance pupil diameter. Since the former reduces by a factor of 0.7x but the latter remains the same, F-number also becomes 0.7x smaller, or one stop faster. The F-stop increase is real. Note that a 35/1.0 lens (from 50/1.4 + Speed Booster®) will always have shallower depth-of- field than a straight 35/1.4 lens at any given distance. Compatibility (Canon EF lens) Is my Speed Booster® or Smart Adapter™ compatible with full-frame camera bodies? Smart Adapter™ I, Smart Adapter™ II and Speed Booster® are NOT compatible with NEX full-frame camera bodies. If the full-frame camera body is configured to auto-crop mode, cropping will be automatically applied and only the center of the frame will be used. Smart Adapter™ III/IV has a large rectangular opening and is compatible with full frame camera bodies. It will detect whether the Canon lens used is a full frame lens or a cropped lens and inform the camera body accordingly, if the camera body is configured to auto-crop mode. Why is there no video AF on Olympus? We encountered technical difficulty getting IBIS to work in conjunction with video AF so we made the tough decision of disabling the latter. You may still AF before video recording commences. IBIS is functional for both stills and videos. Can I use a manual focus lens with the Smart Adapter™ or Speed Booster® for Canon EF lens? When a manual focus lens with no electronics whatsoever is attached to the Metabones EF Lens to E Mount Smart Adapter™/Speed Booster® , the electronics of Smart Adapter™/Speed Booster® is completely turned off, and behaves as a dumb adapter. However, proceed with caution when stacking another mount adapter on top of Smart Adapter™ or Speed Booster®. The following is a non-exhaustive list of common issues found in the past. Some Canon EF mount adapters with focus-confirmation "chips" may be incompatible with Smart Adapter™ or Speed Booster™. Remove the "chip" from the Canon EF mount adapter before using on Smart Adapter™ or Speed Booster®. Some improperly-made M42 screw mount lens to Canon EF mount adapters may short the electronic contacts of the Smart Adapter™ or Speed Booster™ which may cause serious damage. Some manual focus lenses (e.g. OM 28/2.8, OM 50/1.8 and Leica-R 15/3.5) have rear protrusions which may scratch or damage the optics or the housing of Speed Booster®. Such lenses need to be modified before they can be safely deployed. Remember those days when the Canon 5D first came out and there were numerous reports of manual focus lenses interfering with the mirror, causing damage? It's deja vu, this time being the manual focus lenses' rear protrusions hitting the optics of Speed Booster®. Check and make sure there are no rear protrusions before attaching the manual focus lens/adapter combination onto the Speed Booster®. Any damage caused by rear protrusions is NOT covered by warranty. Does Canon Lens Image Stabilization (IS) work? Yes, IS is supported. The Canon IS lens is powered by the camera body and no external power source is required. Is this adapter going to be compatible with all future cameras and all future Canon lenses? We are not sure. We are not licensed, approved or endorsed by Blackmagic Design, Canon, JVC, Micro Four Thirds, Olympus, Panasonic or Sony.