New MTF Services lens adapters: Electronic EOS to Sony F3/FS100/Panasonic and B4 to EOS/Sony F3/FS100

By Dan Chung

I’ve been using Mike Tapa’s adapters for 35mm lenses for several years now. I first came across them when trying to mount Nikon long lenses onto my Sony EX3 – a long time before the advent of HDSLRs. Since then his company MTF Services has expanded its range of products to include lens adapters for many popular large sensor cameras such as the Panasonic AF100, Sony F3 and FS100. I took the opportunity of meeting Mike and visiting his London workshop over Christmas.

A Canon B4 mount broadcast lens fitted on the Canon EOS60D using a MTF adapter

His latest two adapters are a B4 broadcast lens to EOS / Sony F3 / FS100 adapter and an electronic EOS to Sony F3 / FS100 / Micro 4/3 lens adapter which offers full aperture control and image stabilising with appropriately equipped lenses.

The B4 lens adapter has been the dream of many DSLR and large sensor camcorder users who might occasionally want the flexibility of a long all-in-one zoom and ENG style lens operation – without the expense or bulk of a proper 2/3 ENG camera. Developed by Mike with cameraman Alistair Chapman (of XDCAM user fame) it physically adapts a 2/3 inch broadcast lens to a Canon EOS mount. At the same time it optically expands the image so that it is large enough to cover a Super35mm sensor size. To do this requires the user to engage the 2x range extender built into many broadcast lenses, which is then combined with extra magnification from the MTF adapter.

This does result in approximately 2.5 stops of light loss, but given the high sensitivity of new cameras this is less of a problem. The depth of field characteristics will remain the same as if you were using the lens on a regular 2/3 inch camcorder – don’t expect super shallow depth of field when using it. The adapter does not power the electric functions of an ENG lens so there is no servo zoom or VTR trigger sadly. If you do want to enable the zoom servo motor there is a possible solution to power it using an adapter cable from Ebay.

Please note that it does not cover the full frame sensor of the Canon 5D mkII or 1D X, but does work with the 7D, 60D, 600D/T3i, 550D/T2i (and should work with the C300 too). The adapter can also be used in combination with a EOS to Sony F3 or Sony NEX adapter to allow the B4 lenses to be used on these cameras. Price is not yet confirmed but should be in the £800 – £900 + tax range.

As you can see from the video above I’ve been testing the B4 adapter on a Sony F3 and also a Canon 60D and so far the results are pretty good, even though I only have access to older standard definition 2/3 lenses at the moment. My old Fujinon A15x8 broadcast lens does show some chromatic aberration and softness at the edges of the image but this is to be expected on a lens that can be bought for less than £500 these days. I would expect much better performance from a newer HD lens. Hopefully I’ll get to try one of those with the adapter soon. The only competing adapter I have seen so far is the HDx35 B4/PL Optical Adapter from Abelcine and costs $5800 US. I have not been able to compare the two.

The MTF EOS electronic lens adapter is the first to actually be available to order for the Sony F3 and NEX. It also works with Micro 4/3 cameras like the Panasonic AF100 where it joins the already available Redrockmicro livelens adapter in offering aperture control, but adds the benefit of image stabilisation. American company Birger Engineering have also been working on a similar adapter for some time now and have even shown it working at the NAB show, but it is still not available to buy.

The MTF adapter consists of two parts – a control box and an interchangeable lens mount in either Sony F3, Sony NEX or Micro 4/3 fit. If you change or add cameras you can simply add another mount part and use the same controller box.

A Canon 17-55 f2.8 IS lens with the MTF EOS adapter on a Sony F3

The control box is metal and powered by 4 AA batteries. It has an illuminated LCD that shows aperture value, focal length and whether stabilisation is on or off. Aperture can be adjusted in 1/8th stop increments using the control dial.

I’ve been testing a pre-production unit and found the aperture control to be quite reliable. A word of warning though – don’t spin the aperture dial too fast or the lens will have trouble keeping up, although the lens will eventually correct itself.

Mike tells me that pretty much all EF lenses work, apart from those few that use fly-by-wire manual focussing. The main lens of this type that doesn’t currently work is the 85mm f1.2L USM lens. Mike says he’s trying to fix this.

In use the adapter does pretty much what it is supposed to and I’m rather happy with it. The only downside is that the control box is a bit on the large side and adds bulk to the camera. The production version of the box has 1/4 20 mounting holes to allow positioning of the adapter on a rig or camera. That said I would rather have a smaller control box without AA batteries inside, running instead from a power tap cable. Maybe we’ll get this in a future version?

The image stabilisation seems to work well on a Sony F3, although I need to do more testing.

The control box is priced at £645 + tax and the matching lens adapters are £350 + tax each. More details soon on the MTF website.

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