ADVERTISEMENT FEATURE CVP WHICH LENS COVERSWHICH CAMERA? To see how a huge range of lenses cover any of the major cine and video camera sensors, head over to CVP’s free online Lens Coverage and Camera Comparison Tool. The tool shows an actual example of how the lens covers the sensor, giving you an accurate indication of howmuch light loss you can expect across your frame. The tool also provides both camera and lens data – and even allows you to compare coverage across different sensor formats! Go to cvp.com/tools/camer a given flange depth. Canon’s EF mount has a depth of 44mm, but the introduction of mirrorless cameras means shorter flange depths are possible. Sony’s E-mount is extremely shallow at just 18mm. This means that adapting lenses has been incredibly popular over the past few years on mirrorless cameras that feature these short flange mounts. This is all possible with short flange cameras, but it’s not so easy with large flange systems. Generally, if the flange depth is greater than the system you’re working with, an adapter is warranted and should exist. If you’re trying to adapt a lens that has been designed for a shallower flange depth than the one you want to use it on, it won’t work. That’s worth knowing, because all of these focal reducers have been designed with this in mind. This is why most of them are adapting lenses on to lens mounts with short flange distances. It might seem complicated, but focal reducers are a fantastic tool for filmmakers. They allow you to achieve wider field of views at longer focal lengths, which is a key part of a ‘full- frame look’, can increase image quality, and give you an extra stop of light which could be handy! If you want to talk to someone about what focal reducer you need for your system and how to integrate it into your workflow, get in contact with CVP.
“Focal reducers are a fantastic tool for filmmakers. They allow you to achieve wider field of views at longer focal lengths–akeypart of a full-frame look”
notice vignetting, reduced sharpness, and increased aberrations towards the edges of your lens’s image circle. Ultimately, this depends on your lens’s performance and not that of the focal reducer. So, there are clearly some downsides to using these adapters, including another possible point of failure within your kit. Depending on the adapter, you might also have limited electronic support, such as autofocus, IBIS, iris control and metadata. And it also introduces possible movement in your lens set-up when pulling focus or zooming. Metabones produces Cine versions of their adapters, featuring a locking Canon EF mount that removes any potential play if configured correctly. Get the right mount There are so many options on the market now, but most Super 35 and Micro Four Thirds cameras with short flange lens mounts have options for focal reducers. Always look out for the compatibility of your lenses. This could be how the adapter handles the electronics, or relate to mechanical reasons, such as the rear element protruding too far. Flange focal distance, also known as flange depth or distance, is the distance from the flange plane, or the front of the lens mount, to the sensor’s focal plane. Each lens mount has been designed with a
though the lens is still letting through the exact same amount of light, it’s concentrated on to a smaller area, thus increasing the overall brightness. Next up is depth-of-field. This can be calculated based on focal length, distance to subject, the acceptable circle of confusion size and aperture. Using a 0.71x focal reducer, the focal length is reduced, but maximum aperture is increased. This means that these two changes effectively cancel each other out, and the depth-of- field remains the same. The benefits Perhaps the biggest advantage of using a focal reducer is the ability to achieve the full-frame look of a wider field of view, while using longer focal length lenses on a Super 35 camera, and getting an extra stop of light to play with. When it comes to focal reducers, image quality is another hot topic. Introducing more optics in front of your sensor can instigate more optical flaws, but at the same time, the increased image circle being used can make optical flaws less obvious. In that sense, it could go either way. Your image quality could be improved due to the fact you’re now using more of your lens’s image circle – naturally reducing how noticeable optical flaws are. Nevertheless, you may also
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ABOVE A Speedbooster on an MFT camera, such as this Blackmagic, increases field of view and gives an extra stop of light
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