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B4 lenses and mounting solutions
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  • @Roberto with 2x extender (to fill the sensor) enabled it loses two stops and it goes to f3.4

    @Ebacherville well the B4 setup is the ideal Run and Gun solution for the gh2, and we are all using the cheap old SD lenses and we hope that soon the second hand HD lenses will drop prices (something must happend, like TV broadcast standard goes to 2k or even more, I don't know),

    soft corner issue is coming from that gh2 has the multi aspect sensor, so in the 16:9 modes the crop is actually 1.86 not 2, so we use the portions from the lens that are ment to be cropped, on the GF1 that is not an issue

    the crossover eng lens will be the solution for the soft corners issue, but anyhow if you stop down a little bit the lens it goes away

  • here is the best priced adapter I've seen so far.. for one that is adjustable and allows you to get the lens correctly positioned. the really cheap ones would put the servo controlls on the bottom of the lens.. not really ideal

    Same adapter with a mounting standoff for a extra $50

  • As for the crop and corner issues, yeah the GF2 GF3 have a smaller sensor size also, they have a bit softer sensor anyway, I feel the GF line would pair well. IF VK gets manual controls figured out these would make a great body for a B4 SD lens. I brought this up and have some sample images with a Cmount lens showing the difference of the crop on GF2 vs GH2

  • @oneday My Fujinon doesn't even have a 2x extender. If you do use one - and you need the lens aperture wide open, you just use ETC mode. I don't see any problem - these lenses cope well with ETC.

  • I have been following this thread for a while and finally bought a Fuji b4 lens from ebay for my GH1. I still need an adapter, and @Ebacherville looks to have found the best one so far. Having a mount on the adapter is probably important if you don't have a rail system for support, which I don't. I was a local tv photographer for over 10 years, so I am looking forward to using one of these lenses again!

  • @oneday I can't follow you on the sensor sizes and the crossover lens. A 2/3" lens will have circle of good definition of 11 mm diameter, so with the 2x extender on it will be a 22 mm diameter. The GH2's 16:9 sensor imaging area has a 21,6 mm diameter (as it is a multi-format chip). That's within the circle of good definition of the lens, isn't it? So would the effect soft corner effect not be caused by the extender being built to output a 11mm image circle instead of 22mm. As I read on another forum: wouldn't this soft-corner problem be solved by using a photo-extender. So, did anybody see my m4/3 2x extender?

    @Roberto in ETC mode you will lose the widest angles, don't you? As the GH2's ETC 2,6 crop factor results in a image diameter of 8,3 mm, which is a 1,3 crop factor compared to my ENG camera. So my 8x5,5 Funijon Argus wide-angle lens gives me only the same FOV as a 7,3 'normal' lens.

    Maybe off-topic, but I couldn't find any other place to post: Yesterday I have tested a Angeniuex T15x8,3 lens with doubler. Both in ETC mode or normal mode with the 2x extender, I found that it has a sort of bleeding of white area's. Like in dream-scene's on tv. What could that be?

    Another - kind of off-topic - question: did anyone test the 1/2" lenses on a GH2 in 1080 mode? Those should have a circle of good definition of 8 mm, so could work really well with the 8,3 mm diameter of ETC mode. It would give us access to a lot of cheap wide-angle lenses that might become obsolete for ENG use in the near future, and are already pretty cheap.

  • @DirkVoorhoeve my 8x5,5 Funijon Argus wide-angle lens gives me only the same FOV as a 7,3 'normal' lens

    Yes, you got it. You may find you can use your lens in non-ETC mode at some focal lengths, too. And yes, it has also occurred to me that ETC mode uses the sweetest spot at the centre of a lens - (like when we use f8).

  • Mine, Fujinin Pegasus II is also 1.7

  • @DirkVoorhoeve I am saying that GH2 produce the 16:9 image from the different parts of the sensor rather than cutting upper and lower part of the 4:3 area, and the lenses without crossover on 2/3 sensors do not goes outside of the 4:3 borders, in this case we have the gh2 forcing the crossover but we do not have crossover lens, so the 16:9 image on 2/3 sensor will have the diameter of 9.9mm and with the doubler you have 19.8mm instead of 21.6mm needed for the gh2

    that is how I figure it out, maybe I am wrong

  • @DirkVoorhoeve I did try the B4 to Canon adapter & was not satisfied with it. It does replace the mount on your Canon camera however I had trouble getting the mount off my 60D. You would have to buy a dedicated camera and just leave the B4 mount on there, you can't go taking your mount on and off all the time.

    But the worst part was that it doesn't work with Canon Tele-Converters. I'm using the Kenko brand and the mount holes are different. After I re-machined the adapter to fit the Kenko mount holes, I found that on a tele-converter, the B4 lenses only focus to infinity at the long end of the lens. I spend a lot of time and money on the project and eventually gave up. :(

  • I don't think that the tripod mount from funkykoval2001 adapter looks as strong as the one from ciecio7. I have the ciecio7 mount in stock and will sell for $275 shipped within the U.S. If anyone is interested send me a PM.

  • I have the ciecio (polish) mount too, it's great and lets you mount the camera and lens with it's tripod mount. Just be aware that you can't use it together with the ownuser batterygrip.

    @Turbodog. I was afraid that it wouldn't work, thanks for sorting that out. Saves me a lot of hassle. Have you tried to find the B4 to Canon FD mount adapter like the Bumki version from 2010?

    @oneday For a true 4:3 lens the image circle diameter would be 11 mm. So at the introduction of 16:9, the image would indeed be cropped from a 4:3 sensor, while later on they started using 16:9 sensors that are cropped to 4:3 if needed. The crossover lens is a solution the FOV change from this cropping. But still, both the sensors have a native diameter of 11mm, so the image circle of all 2/3" lenses should be 11 mm, not 9.9mm. See this picture, it really helped me understand the difference between multi-format (same diameter on different aspect ratio's) versus cropping.

    @Roberto, tried that, but as this lens didn't have a doubler it was impossible to use it in non-ETC mode. I guess you mean using it in non-ETC mode with a doubler, am I right?

  • As I said, my Fujinon 10-120 can be used without ETC, doubler or vignetting, at some of its longer focal lengths only. Not that it's of much use - it's there if you want it, using the rear macro-ring to adjust focus.

  • @DirkVoorhoeve I had an impression that GH2 has an oversized sensor so in 16:9 mode it goes away from 4:3 borders also the crop mode in 16:9 is 1.86, for me this is a logic explanation for the soft edges on B4 lenses used on GH2 on wide shoots, otherwise what could be the reason?

  • oneday: The camera has been modified since then. I recently added a Zoom H4 recorder to the mix as well, I will be running my audio through that and powering that from the anton bauer as well. Looking into an adapter cable from 3.5mm line to 2.5mm mic for the GH2. Sadly I didn't get the H4N model, just the two channel H4..

    I might be able to get the lens remote for the camera working.. however I am allready using the port for the mic input.. Another option I've been thinking about is attaching some sort of headphone speakers on top of the GH2 so it captures the audio from the Zoom H4 for reference in the edit set. That would free up the mic/remote port so I could see if remote starting works..

    The GH2 itself is powered by it's own battery (I could convert it with the DC thingie but I prefer to keep it under it's own power.. That way I can also shoot without powering on the rig..

  • This is a picture taken from a 1080p25 GH2 clip with extender off on a Fujinon A15x8. The 16:9 yellow markings are what you see when you put the extender on. The 4:3 markings are what you see on a 2/3" 4:3 Camcorder (in this case an old Philips/Thomson LDK-110 Interline Transfer CCD 4:3 DVCpro camera).

    Position of the lens was the same in all 3 tests. image

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  • The reason why B4 lenses appear quite soft in the corners is because those lenses are made to focus the light rays passing through the beam split filter on fron of the 3 CCD's block. On the oter hand, GH2 and all the other DSLR's use a single focal plane sensor. Using the ETC mode a B4 lens becomes parctically unusable wide open, you need to close down a couple of stops to get acceptable results. Engaging the 2X externder you get the same effect because the 2 stops loosing, however the extender adds some softness and makes CA look worst.

    Mounting a B4 lens on a 4/3 camera is a compromise and has its downsides, but also some advantages, parafocal characteristics, usable ring for manual focusing, build quality, stepless aperture ring etc.

  • that makes sense for me "the extender adds some softness"

  • @FW200 very good picture! it would also be nice to have the same picture with ETC (no extender) so it's clear to all what the ETC crop-factor effect is on the field of view..

  • @FW200 if your good with electronics i think it should be possible to attach the output of your zoom to the camera's input? On the photo's you see the mic unit of the camera, it has a 4 cable connector you could solder a nice xlr plug to?

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  • I prefer not to solder directly onto the GH2.. Everything I have done so far does not affect the operation of the GH2 in any way. I can take it out of the rig and throw on a kitlens and I have a normal GH2 again.

    I will see about making some pictures with the ETC mode, I kinda forgot about that one..

  • Brave work, @DirkVoorhoeve !

    Does it look like you could relocate the mic PCB to a shielded, balanced break-out box.[Balun] with XLR/headphone connectors, say attached to the tripod connector at the camera base?

    See mods thread at

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  • @Turbodog I am interested to hear that the B4 to EOS adapter didn't work out for you with the Kenko 2x adapter. It sounds like there must have been an issue with the flange depth. Perhaps the Kenko ES mount on the extender is a different thickness to the camera one, in that case maybe it would work with shims or on a Canon extender?? I presume you tried playing with the backfocus adjustment on the lens.

    Even though you couldn't get it focussing to infinity at the long end, did you get it working well enough to determine if the corner image quality was improved over using an internal 2x teleconverter in the B4 lens? I would imagine it should be

  • I've tested with a few more B4 lenses but with all I get a glow around highlights. It's at all apertures, and everywhere in the frame (not on corners only). Anyone else got the same problem / solution?

    @Roberto Thanks for the link to the mod thread. We'll move this mic-idea there, shall we?

  • @DirkVoorhoeve do you use lens with built in extender?