Pocket Camera and B4 Lenses

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Gan Eden

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Pocket Camera and B4 Lenses

PostWed Sep 11, 2013 4:44 am

Has anyone tried this configuration yet? Would like to see footage if anybody can share some please. Does the pocket need B4 2/3" lenses with a 2X extender or not? Cheers
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Oskari Mörsky

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Re: Pocket Camera and B4 Lenses

PostWed Sep 11, 2013 5:21 am

Gan Eden wrote:Does the pocket need B4 2/3" lenses with a 2X extender or not? Cheers


It need 2x extender or it will suffer extreme vignettening.
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Paul Kapp

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Re: Pocket Camera and B4 Lenses

PostWed Sep 11, 2013 11:19 am

Gan Eden wrote:Has anyone tried this configuration yet? Would like to see footage if anybody can share some please. Does the pocket need B4 2/3" lenses with a 2X extender or not? Cheers

I'm thinking the same thing and have been researching this for weeks. On a large sensor like M43, F3, BM4K, x2 is definitely needed and 1.7 extender as well. For theBMCC only ax2 is needed.
But for the Pocket, x2 may not be needed.
I have a good SD Canon ENG zoom with 2x.
This lens is very sharp and CA is minimal on 2/3" ccd cam but am wondering how it would work on the Pocket.
I don't accept the idea that B4's are designed to focus different colours at different lengths. It's more like they are engineered to have minimal CA to reduce overall CA as additional CA is introduced by dicroic prisms.
On a single sensor I expect the lens to perform better than on a 3 ccd.
It will be some time before I acquire a Pocket and test this B4 lens on it.
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Alan Dater

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Re: Pocket Camera and B4 Lenses

PostWed Sep 11, 2013 1:16 pm

If I understand you correctly you want to mount a Canon B4 SD zoom on your BMDPC?...You will need an adapter..MFT to B4..it will vignette. You will need to zoom in/use the doubler. I have in the past mounted my B4 lens on my PL mount Aaton (s-16). To do that I have the Abakus PL to B4 adapter. It is an optical adapter that resizes the 2/3" image to match the S-16 frame. In anticipation to getting my BMDPC I have purchased a MFT to PL mount adapter from Wooden Camera. So I will be able to use my old video B4 mount zoom lens as well as my PL mount Canon 8x64 S-16 lens.
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Gan Eden

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Re: Pocket Camera and B4 Lenses

PostWed Sep 11, 2013 2:35 pm

leze23 wrote:
Gan Eden wrote:Does the pocket need B4 2/3" lenses with a 2X extender or not? Cheers


It need 2x extender or it will suffer extreme vignettening.

Any evidence of this?
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Gan Eden

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Re: Pocket Camera and B4 Lenses

PostWed Sep 11, 2013 2:37 pm

greenmountain wrote:If I understand you correctly you want to mount a Canon B4 SD zoom on your BMDPC?...You will need an adapter..MFT to B4..it will vignette. You will need to zoom in/use the doubler. I have in the past mounted my B4 lens on my PL mount Aaton (s-16). To do that I have the Abakus PL to B4 adapter. It is an optical adapter that resizes the 2/3" image to match the S-16 frame. In anticipation to getting my BMDPC I have purchased a MFT to PL mount adapter from Wooden Camera. So I will be able to use my old video B4 mount zoom lens as well as my PL mount Canon 8x64 S-16 lens.


Yes I do and I have the adapter already and have used the two lenses great on the GH3 with the doubler, but the sensor of the Pocket is a lot smaller so I'm thinking it maybe possible to get away with using the lenses without the 2x extender to gain the extra stops.
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Peter J. DeCrescenzo

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Re: Pocket Camera and B4 Lenses

PostWed Sep 11, 2013 3:42 pm

Gan Eden wrote:
leze23 wrote:
Gan Eden wrote:Does the pocket need B4 2/3" lenses with a 2X extender or not? Cheers


It need 2x extender or it will suffer extreme vignettening.

Any evidence of this?


I haven't used a B4 lens with a BMPCC pocket cam yet, but I strongly suspect a lens with an optical extender/doubler will be required (in addition to a B4-to-MFT adapter), at least at the WA end of the zoom.

Set this FOV comparator to 2/3" and S16 to see an approx. of the vignetting that may occur w/o an extender/doubler. YMMV.:
http://www.abelcine.com/fov/

-
http://www.peterdv.com
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Paul Kapp

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Re: Pocket Camera and B4 Lenses

PostWed Sep 11, 2013 8:03 pm

The Abelcine FOV calculator gives a crop factor of 0.8 so it will vignette at the wide end but be ok the rest of the way, without the doubler I guess, so it should be pretty sharp.

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