Questech, Hello! I also shoot with Fujinon previous model and I want to ask you as an expert on this subject. what lens do you have on contrast and quality Fujinon B4 or B4 Canon and something that is better extender 2x can be retrofitted, or use the built-in lens extender. thank you!

@abdulganis Look at eBay

Hello kris... sorry, I haven't been here in a long while.

I don't have any more lenses other than the ones I am using right now, I cleaned house.

For my GH3s I have a Fujinon Internal Focus version of the one in the video. I like the IF because you can have a matt box and other accessories mounted without having to worry about the lens moving in and out when you focus, but other than that I find them identical in general operation.

AM

You are confusing the 1/2" bayonet mounts with the 2/3" B4 mount.

There is only one 2/3" B4 bayonet mount standard. Sony is no different. The flange focal distance is 48 mm (in air) for green, and actually red and blue are slightly different. Please enjoy reading about the standard: http://www.arib.or.jp/english/html/overview/doc/4-BTA_S-1005v_B.pdf

For 1/2", there's the standard, and then there's Sony, with two different flange focal distances, both different from B4 2/3".

'B' in the Fujinon model number often indicates an integrated neutral density spot filter. But I'm not sure if that's what it means in a lens of this vintage. The '-9U' indicates something about the electrical interface between the servo controller and the camera.

Your lens is meant for a 3-CCD camera with a beam splitting prism. Your Pentax Q camera doesn't have a beam-splitting prism, so a proper converter has a big block of glass in it to accomplish the same effect as the prism as far as changing the flange focal distance based on the angle of the light from the rear of the lens. The Abakus 1060 is such an adapter for the Pentax Q. http://www.abakus.co.uk/B4toC.htm If you use a plain mechanical adapter with no glass, you'll get focus aberrations (low contrast and haziness) that are worse when the aperture is set wider. Stop down to reduce the haziness.

I from my experience, if you are going to try this, it is best to use a B4 lens with 2x or 1.7 extender engaged and add a 1.4x extender like the Kenko Telepus Pro 300. You will need a B4 to Canon Adapter and Canon to NX1 or E-mount. With the 1.4x extender and B4 extender it should cover the APS-C sensor, without the extra 1.4x extender you could probably cover the GH4 in 4k mode. At the long to medium end these lenses can look good with extender engage and added, probably because of all the glass you are putting between the standard B4 lens and sensor. At the wide end it can be OK or soft depending on the lens in not stopped down a little.

The B4 lens benefits are: servo zoom, professional throw focus ring, long zoom range and para-focal performance depending on the lens.

Once there is an APS-C sensor with IBIS (I realize there is already the A7RII in crop mode, but for some it's a little out of the reach) I believe certain models of Fujinon B4 lens variant will be come popular.

Just remember these require a bit more light as their typical 1.7 f is multiplied by 2x and then by 1.4x again when using them on APS-C, so that make is an 4.76 f and you may want to stop down a bit especially on the wide end depending the lens version.

Bottom line there is a lot ways this can go wrong, but if it meets your shooting style and budget, it can be a great tool. On the plus side the contrast and saturation of these lenses can be unique/pleasing as these were/are high quality broadcast lens with high end lens coatings.

@ balazer - thanks for the info on the converter - that is a great deal!