••Fujinon TV Lens on GH-1...Don't Drool••

Thanks lvlinux! That was helpful. Just read a bit about flange focal distance and I think I'm starting to understand. Just a bit more help would be appreciated though.

Specifically: If I had this item: ...

then:

1. judging by the pictures, does it look like it's possible to remove the c mount(?) attach a Nikon mount to it?
2. What exactly is the correct Nikon mount to get, and where can i get one? (I'm not sure what exactly to look for on ebay).

Also:

3. is there something better than gluing it? Even with super-glue, I feel that might be a bit loosey-goosey / unreliable....

And: apart from the usual 2x teleconverters, I've seen a nikon 1.4x teleconverter. I'm guessing whether or not 1.4x is sufficient depends on the fujinon lens itself. Any thoughts there? Here's a 1.4x teleconverter: http://www.keh.com/camera/Nikon-Manual-Focus-Lens-Converters/1/sku-NK10000002000N?r=FE
 
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qwerty123 said:
Thanks lvlinux! That was helpful. Just read a bit about flange focal distance and I think I'm starting to understand. Just a bit more help would be appreciated though.

Specifically: If I had this item: http://cgi.ebay.com/ws/eBayISAPI.dl...773123&ssPageName=STRK:MEWNX:IT#ht_7214wt_882

then:

1. judging by the pictures, does it look like it's possible to remove the c mount(?) attach a Nikon mount to it?
2. What exactly is the correct Nikon mount to get, and where can i get one? (I'm not sure what exactly to look for on ebay).

Also:

3. is there something better than gluing it? Even with super-glue, I feel that might be a bit loosey-goosey / unreliable....

And: apart from the usual 2x teleconverters, I've seen a nikon 1.4x teleconverter. I'm guessing whether or not 1.4x is sufficient depends on the fujinon lens itself. Any thoughts there? Here's a 1.4x teleconverter: http://www.keh.com/camera/Nikon-Manual-Focus-Lens-Converters/1/sku-NK10000002000N?r=FE
Click to expand...

Can't tell for sure about that lens, but from the looks of it I don't think that it will work. The barrel might be too large to fit a Nikon mount around it - I'm not sure, you'd just have to try it (but you can get cheaper lenses that you could try with).

As for which mount to get - pretty much whatever - I used one from an old parts Nikkor lens, one from a PK-3 extension tube, and one from a cheap Nikon extension tube set on eBay. They are all different, so you just have to wing it with whatever you've got. The only thing I would stay away from is using the mount from an old teleconverter, since often they have extra metal hooked to them that prevent you from working with it properly (but with some lenses it would just depend and even that would work - a mount I had from an old Vivitar Nikon teleconverter would not fit around the lens barrel of any B4 or B3 lenses that I have). The PK-3 extension tube can be obtained for under $20 on eBay so it would probably be your best bet.

You are correct about the 1.4x tele - it just depends upon the lens. If you do use one instead of a 2X, then you will have a slightly wider lens that you would with the 2X. I think for a 2/3" or 16mm lens you would have some vignetting with the 1.4x at the wide end, or possibly throughout the range. But it should be fine if you get a 1" format lens.

I wouldn't just use super glue if I were you - it will be unreliable and come off in a few weeks probably. I use JB-weld and it works fantastic - it's like you welded the mount on the lens and it ain't comin off :-)
I use superglue to put the pieces together when I have it aligned properly, and then after it sets (4-5 minutes) I put on the JB weld and let it cure overnight.
 
qwerty123 said:
Thanks lvlinux! That was helpful. Just read a bit about flange focal distance and I think I'm starting to understand. Just a bit more help would be appreciated though.

Specifically: If I had this item: http://cgi.ebay.com/ws/eBayISAPI.dl...773123&ssPageName=STRK:MEWNX:IT#ht_7214wt_882

then:

1. judging by the pictures, does it look like it's possible to remove the c mount(?) attach a Nikon mount to it?
2. What exactly is the correct Nikon mount to get, and where can i get one? (I'm not sure what exactly to look for on ebay).

Also:

3. is there something better than gluing it? Even with super-glue, I feel that might be a bit loosey-goosey / unreliable....

And: apart from the usual 2x teleconverters, I've seen a nikon 1.4x teleconverter. I'm guessing whether or not 1.4x is sufficient depends on the fujinon lens itself. Any thoughts there? Here's a 1.4x teleconverter: http://www.keh.com/camera/Nikon-Manual-Focus-Lens-Converters/1/sku-NK10000002000N?r=FE
Click to expand...


I have a lens like that. Vignettes badly even when used with a 2x converter. It was designed for a small sensor.

You need to look for a lens that was designed for something 2/3 or larger and has a 2x converter built in. They work better than the external converters.

try:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=370292033919&ssPageName=STRK:MEWAX:IT

or :

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160448690700&ssPageName=STRK:MEWAX:IT
 
cool. I found out somewhere that the lens is apparently "2 inches wide"--i'm guessing that's the diameter for the lens, so the rear should be smaller... hmmm. thanks for the pk 3 ext tube and jb weld idea.

EDIT: Thanks for the info Svart! I just looked at the Canon ENG thread, and that seems to be the way to go. Guess I'll be returning that fujinon!
 
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qwerty123 said:
cool. I found out somewhere that the lens is apparently "2 inches wide"--i'm guessing that's the diameter for the lens, so the rear should be smaller... hmmm. thanks for the pk 3 ext tube and jb weld idea.

EDIT: Thanks for the info Svart! I just looked at the Canon ENG thread, and that seems to be the way to go. Guess I'll be returning that fujinon!
Click to expand...

The physical size of the lens has nothing to do with the format size we are talking about - we are talking about the sIze of the image circle that is projected by the lens, which is 2/3". The GH1 has a 4/3" sensor, so usually a 2X extender will make the image circle bigger - often right at 4/3" or sometimes a little bigger.
I put some pictures of my setup in the Canon ENG thread and more info on what I did in there so yes check that one out.
 
Will this work for GH1 without vignette?

The Xenoplan 1.9/35mm Compact C-Mount Lens covers a 2/3" format sensor with an 11mm image circle. It is broadband coated and corrected for uninterrupted imaging from 400-1000nm (Visible through Near IR spectrum). The Compact Series of lenses offer outstanding optical performance and a solid mechanical design that is able to withstand harsh environmental conditions.
 
@lvlinux: Gotcha. I was mentioning the lens diameter because I was trying to figure out if nikon mount would fit around the barrel of the lens.

@Cam123: from what lvlinux and others have been saying, it appears that 2/3" image circles may not sufficiently cover the the 4/3" sensor of the gh1 (makes sense). So you may get a vignette...
 
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lvlinux said:
so usually a 2X extender will make the image circle bigger - often right at 4/3" or sometimes a little bigger.
Click to expand...

Only sometimes. Changing the magnification *can* change the circle diameter but it's not a guarantee. I have a few 2/3 lenses with external 2x extenders that do NOT work.
 
Interesting. Do we have an explanation for why it sometimes works and sometimes doesn't? There must be some other variable affecting the ability of the 2x teleconverter + 2/3" lens to project a sufficiently large image for the micro 4/3 sensor.
 
You have two different things happening. You have magnification but you also have changes to focal distance. The focal distance can be from the lens to the object you are viewing or from the lens to the sensor. They are independent issues but tend to be combined when you use a teleconverter. Since the purpose of the teleconverter is to magnify the image, you can get in increase in focal distance to the object you are viewing which may or may not modify the projected image's size. You could change the focal distance on the side of the sensor to get the projected image large enough but most of the time the image will be out of the focal distance of the lens's design. In other words, once you get the picture large enough, your distance between the lens and the sensor is too great and your image will be out of (back)focus. More corrective optics are needed which will lose more light and likely distort your image.

I did an experiment with one of my lenses where I used a 2x converter. It still vinetted badly but the image was *slightly* larger. When I figured the distance from the 2x teleconverter to the rear element of the lens that would give me a projected circle large enough for the sensor yet still be in focus, it couldn't be done. The teleconverter would have to be further forward in the lens system than even the rear element.

This is why I think the lenses with built in 2x teleconverters are the best option. They place the tele portion far enough forward in the design to magnify the image to the size we need yet it doesn't change the focal distance from the rear element.

These aren't perfect though. The design was still meant for a 2/3 sensor so even though you get a projected image that is large enough for the 4/3 sensor, the outer edges have some distortion since the glass was never meant to be used edge-to-edge like that. On full zoom-outs I see lots of blur on the edge of the circle.
 
Very well explained Svart.

Cam123: you will almost definitely get a vignette with that lens since it is made for a 2/3" sensor, rather than the 4/3" size sensor in the GH1.
 
I've just about finished my B3-M4/3 mount for my Fujinon A14X9.5 lens, I just need to get to the machine shop to shave 2.5mm from an extension tube. I want to add a couple points to the discussion, the first being that one real advantage for me with the 2/3" lens is the servo zoom. This is a huge advantage if you are doing a video style shoot rather than a film style shoot. To power the servo zoom you have to solder up an adapter to supply 12v to pin 6 and ground pin 3 on the Fujinon 12 pin connector.
Secondly, is yes, you need to get a lens with the 2X optical extender, It is soft on the outer edges when you're wide open, but It's hardly noticable if you are stopped down or zoomed in. you also have to multiply your focal lenths by 4 so my 9.5-133mm is actually a 38mm-532mm equivilent. I lose about a stop and a half, so I meter my f1.7 at f2.8. Also when making adaters for these lenses, your tolerences need to be less than .25mm, because that is about the range of the back focus adjustment.
I can't awit to post some footage with the machined adapter.
 
Wow you've given some great technical info concerning the back focus and the extender light loss. Thanks! Can't wait to see more footage. Haven't had time to hook up my servo yet or shoot much with any of my modded lenses other than a few shots at a wedding shoot a couple weeks ago.
 
LvLinux, I was wondering if you (or Jaybilizer) could fill me a little on the process of mod'ing a lens with a B3 mount (I have Canon HL-79E J13x9B3 IRS II-A and am getting a Fujinon Pegasus A14 x 9 (don't know the mount on that)).

I know that you had a post over on the Canon eng b4 thread, but I thought this might be a better place to discuss unless you think otherwise. It might be helpful to quote you from there as a starting point:

"I had to take the bayonet ring off in order to get my extension tube on it and access it with the glue. I just kept grinding it down with my hand on some walkway bricks and trying it on the GH1 with the Nikon adapter until it was the right distance. I would just hold the assembly together and fiddle with the zoom and focus to check for correct back focus distance. Before starting I set the lens back focus adjustment to the middle so I'd have leeway if I got the mount distance slightly off in the end (but you still don't have much room for error). I did all the testing with the lens 2X extender on since I knew that's how it would be used. ...After I got the mount the right distance, then I glued it on with superglue just to hold it temporarily - (and tested it again on the GH1) then smeared on the JB weld and let it sit overnight."

What I have: fotodiox micro 4/3 to nikon mount; Nikon Pk-3 extension tube 27.5mm (not sure what the number refers to, guessing extension distance?); superglue; JB-Weld. There's a pic below that might help me and hopefully others with your explanations.

A few questions:

1. How do I set the lens back focus to the middle? (Does it have something to do with the "F.B." mark and the red stripe on the back of the lens or?)

2. When you say you had to take the bayonet ring off, are you referring to the ring on the extension tube? (I think I did that in my picture: the bayonet ring of the extension tube is removed and sitting on the far left with the screws in the middle)

3. How are you guys putting baseplates on these lenses? Which baseplates are you using or can you recommend? (These lenses are obvious heavy relative to the regular still lens primes.)

4. My Pk-3 extension tube has some funky silver piece sticking out of it, which you can see on the pic. I'm guessing i need to get rid of it, although it's not clear how. Do I need to get rid of it, and if so, any suggestions how?

I'm looking forward to moding this as I think it has some great potential for documentary work and other video-ish work.

Thanks for any thoughts.

b3pk3.jpg
 
Ugh now I'm kind of withing I didn't sell the Angenieux 15-150mm f/1.6 I had that also had a built in 2x optical extender as well as a power servo zoom...got it for $50 and sold it for $300 - had a b4 mount I believe and I just never got around to modding it... d'oh!
 
qwerty123 said:
LvLinux, I was wondering if you (or Jaybilizer) could fill me a little on the process of mod'ing a lens with a B3 mount (I have Canon HL-79E J13x9B3 IRS II-A and am getting a Fujinon Pegasus A14 x 9 (don't know the mount on that)).

I know that you had a post over on the Canon eng b4 thread, but I thought this might be a better place to discuss unless you think otherwise. It might be helpful to quote you from there as a starting point:

"I had to take the bayonet ring off in order to get my extension tube on it and access it with the glue. I just kept grinding it down with my hand on some walkway bricks and trying it on the GH1 with the Nikon adapter until it was the right distance. I would just hold the assembly together and fiddle with the zoom and focus to check for correct back focus distance. Before starting I set the lens back focus adjustment to the middle so I'd have leeway if I got the mount distance slightly off in the end (but you still don't have much room for error). I did all the testing with the lens 2X extender on since I knew that's how it would be used. ...After I got the mount the right distance, then I glued it on with superglue just to hold it temporarily - (and tested it again on the GH1) then smeared on the JB weld and let it sit overnight."

What I have: fotodiox micro 4/3 to nikon mount; Nikon Pk-3 extension tube 27.5mm (not sure what the number refers to, guessing extension distance?); superglue; JB-Weld. There's a pic below that might help me and hopefully others with your explanations.

A few questions:

1. How do I set the lens back focus to the middle? (Does it have something to do with the "F.B." mark and the red stripe on the back of the lens or?)

2. When you say you had to take the bayonet ring off, are you referring to the ring on the extension tube? (I think I did that in my picture: the bayonet ring of the extension tube is removed and sitting on the far left with the screws in the middle)

3. How are you guys putting baseplates on these lenses? Which baseplates are you using or can you recommend? (These lenses are obvious heavy relative to the regular still lens primes.)

4. My Pk-3 extension tube has some funky silver piece sticking out of it, which you can see on the pic. I'm guessing i need to get rid of it, although it's not clear how. Do I need to get rid of it, and if so, any suggestions how?

I'm looking forward to moding this as I think it has some great potential for documentary work and other video-ish work.

Thanks for any thoughts.
Click to expand...
1. Yes there should be a little white dot near the "F.B." Mark. And there should be a set screw or knob or something that loosens the ring there to let you adjust the back focus. When you loosen it and turn the ring, you should see the rear element move in and out slightly. Usually when the white dot is opposite the "F.B." (which stands for "flange back" by the way) it will be in the middle. Be sure the macro setting is locked in the fixed position before trying to adjust the back focus. Let me know if you don't understand and when I have time I'll try to get a pic or two or video or something.

2. No, talking about the bayonet ring on the lens - the big silver mounting ring. There will be a small screw (usually philips head) in the side of the ring that you have to take out and then instead of stopping at one point, the bayonet ring will be able to be unscrewed, and I think it is the reverse direction. There is also a little set screw under the bayonet mount that needs to be removed.

3. As for baseplates - don't really have anything good right now - was just using a flash bracket thingy that sortof supported the weight - still working on a better solution.

4. Are you talking about the rabbit ears? If so you can leave those - it doesn't really matter.

You may want to consider using some other tube for the separator besides the PK-3. The PK-3 is a great little tube and nice and thick, which you might find overly hard to cut because of that. To see about how much you will need, do this:
Mount the M4/3-Nikon adapter on your GH1. Take the lens, set it to max wide, max aperture, extender on, infinity focus. Put the lens in front of the adapter and when you have it in the right spot you will see the image come into focus on the GH1 screen. It's kindof tricky to do and may be easiest to have the GH1 on a tripod, but you will see the approximate distance that the lens mount needs to be from the adapter. Then you cut your tube or whatever you decide to use, and then grind it to the exact right spot. You test for correct flange distance by picking an object that would be at infinity, set the lens to infinity focus, zoom in to the max, and the object should stay in perfect focus throughout the zoom range. It is a BIG BIG help when doing this to use the focus assist magnifier on the GH1.

Here's your picture with some info:
b3pk3.jpg


Maybe I should do a little video tutorial. Would anyone be interested in seeing that? Maybe I'll have some time next week or something possibly.
 
Great info as usual!

A video tutorial would be fantastic and probably useful to the gh1/dvxuser community.

Didn't know I had to CUT the extension tube... hmmm... I don't have much in the way of machining supplies... Not sure what to use in lieu of the pk-3. I'll have to look into that.
 
paulohlp said:
Thats a great topic don´t let it die.
Anay way. Did someone found a flawless way to do it?
Click to expand...

A flawless way to do it? hehe I don't think that is possible. There are so many different lens types that there is no magic bullet.

I'm still hoping to find time to do a tutorial soon. (been swamped lately)
 
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