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Do you have 2/3" B4 mount lens experience?
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PostPosted: Fri Dec 15, 2017 2:17 pm    Post subject: Do you have 2/3" B4 mount lens experience? Reply with quote

The B4 mount 2/3" lenses would seem an interesting lot. Am curious to know, if you have experience with these, the severity of problems resulting from using these lenses on camera bodies having but a single sensor. These lenses were designed for use with cameras having three sensors.

My research points to problems being mitigated by selection of aperture setting other than wide open. But am trying to gather more information and would appreciate your input if you are "hands on".

Incidentally my intent, should purchase of one of these lenses ensue, would be to strip off the servos, thereafter focusing and zooming the lens manually. I am intrigued by and attracted to the parfocal zooms, my introduction having come via Angenieux. But considerable wealth being a prerequisite to expanding one's collection there, I am seeking other avenues of approach which offer more affordable, but still possibly quite interesting, alternatives.


PostPosted: Sat Dec 16, 2017 1:16 pm    Post subject: Reply with quote

Hmmm. Well, OK. My B4 inquiry appears to have garnered a number of readers but no replies so far. I might as well tell you what I did. Please bear closely in mind as you read this I am "last of the big time spenders". Very Happy

My FF dreams for Christmas evaporated after the help everyone very generously provided me here:

http://forum.mflenses.com/need-help-camera-body-selection-for-my-mf-lenses-t78367.html

Following realization there are certain laws of physics even I am unable successfully to disobey or circumvent, I moved forward intent on violating other, different, laws of physics. However the new violation attempts, should I fail and fall short, will have come at FAR lower cost than purchase of a FF camera body. This entire B4 boondoggle is coming in at cost south of US$100. Also I get a new lens (I love lenses) and, some people at least have made a success of this approach! Sadly for me those people are a whole lot smarter than myself. So you can regard this very much as a student project.

First, the B4 lens. It's a beauty, to my eye anyway, but it was extraordinarily poorly described. There are not enough photos of the lens. However, I was able just barely to make out the critical "A" leading the model number. If I'm right, this is a 2/3" lens. If I'm wrong, well, I'm in a really bad spot. Here is the lens:

Click here to see on Ebay

On chance it might not be clear at first glance, that lens is a Fujinon TV-Z 9.5mm-152mm f1.8. I do not know yet exactly which model it is (see below).

Next there was the issue of the B4 adapter for a 2/3" B4 lens. These darn B4 adapters are expensive, but without an adapter you cannot use the lens. I posted yesterday about the great deal I was able to find here in the USA with the thought others might want to participate. Guess not, but here is the link anyway:

http://forum.mflenses.com/affordable-2-3-b4-m4-3-adapter-with-usa-shipment-t78406.html

So there it is, the grand experiment. Further research indicates I will likely have to stop down to f4 to achieve decent color convergence, that lens being what it is and the laws of physics being what they are. Also, absent a "doubler" (we call 'em "teleconverters") I will not be able to fill my m4/3 sensor. I don't care. I just want to experiment a bit and have some fun. And I LIKE that lens.

For other, more rational, people:

I bought a pig in a poke. I'm hoping the lens is an Eagle II. It's probably not an Eagle lens at all. Clearly the lens is pre-HD and can be expected to be soft. I read somewhere these lenses can only resolve about 30 lines/mm.

However, it IS a parfocal zoom lens and I'm very intrigued by parfocal zoom lenses having zoom ratios over 10 to 1. So I will fool around with the lens, have some fun, and try to learn what I can. Wink

Whoo Turtle


PostPosted: Wed Dec 20, 2017 9:55 pm    Post subject: Reply with quote

Just to update this:

I was wiped out. My lens arrived. The seller did not send the lens shown in the auction ad photo (see above post). Instead seller sent a Fujinon 1/2" lens having similar appearance. But it is a completely different lens.

The seller apparently never even owned a copy of the lens pictured, the lens I thought I was buying. Instead, seller used a "stock photo" without any advance notification to bidders/buyers. This was poor fortune. Am trying to recover.


PostPosted: Wed Dec 20, 2017 10:50 pm    Post subject: Reply with quote

Latest update:

The seller refunded my entire payment, including shipping, and told me simply to keep the lens they shipped in error.

The lens I received is a brand new "S" series lens. It was in the original Fujinon box with special supports. It is a beautiful lens. The lens does have a mount similar to B4, but because it is a 1/2" lens, and not a 2/3" lens, the pin diameter is too large to use with my B4 adapter. I will need to attempt removing the pin because I'm not going to buy a B3 adapter. Whether pin removal will work I do not know yet.

1/2" Fujinon TV-Z lenses have a spot size too small to be useful with m4/3 camera sensors, even when a doubler is used. At least that is my best understanding. However, I now own the lens for free so I can experiment with it at zero cost and perhaps still learn something.

Would this lens work with a BMPCC? I dunno.

Still intend to purchase an "A" series (2/3") Fujinon TV-Z lens if I can locate one at reasonable cost.


PostPosted: Tue Oct 02, 2018 4:02 am    Post subject: Reply with quote

I suppose you know that 2/3" cine lenses have an extremely small image circle, and are not designed for high resolution work, since they only had to resolve for SD (720x576 pixels). You will find most of them with quite a bit of CA in the corners. The 1/2 inch lenses have an even more limited image circle. There is no issue with the fact that the original cameras for which they were designed had three sensors, since the optical block had a beam splitter. Newer digital cams have a single sensor and the same lenses work with them, although these days there is not a single SD camera on the market. All are HD or 4K, and the lenses for those are considerably more expensive, but still with a limited image circle--less than 20mm.