parfocal for studio camera ?

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Videobegin

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parfocal for studio camera ?

PostWed Dec 08, 2021 2:38 am

Hello,

I'm looking for a parfocal solution for a studio camera 4K pro... if possible !

The idea is to switch quickly between performers, within close caption.
Recomended zooms lack of parfocal function and suffer of low aperture.

I think of a dzo linglung 10/24 with follow focus but not sure it's the best solution considering result vs price...

Any comment ?
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Kim Janson

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Re: parfocal for studio camera ?

PostWed Dec 08, 2021 6:17 am

I have plenty of old B4 lenses if you are interested to test :)



These are inexpensive, but you need the B4 to MFT adapter. These also have only the analogue lens control and that is not guaranteed to work.

These are standard SD lenses. I think the image quality is pretty ok above f4, it can be very creamy at f1.8 especially at wide end.

Great lenses to test if something like this suits your purpose and then maybe look into a bit more modern B4.

This one with a simple 3D printed adapter, it covers the Micro Studio sensor when in lens 2x extender is used and not too bad CA.



(but the 3D printed adapter I do not provide, it was just to test)
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Videobegin

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Re: parfocal for studio camera ?

PostThu Dec 09, 2021 10:00 am

Dear Kim, your offered the best answer/solution... but not what I was hopping ;)

In my country, B4 lens is a very small world with very rare second hands offers, mostly with very old items not appropriate to BMD sensors.

I accept B4 lens gift :lol: But I'm afraid that I will have to ask Father Christmas for a subsitute.
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Kim Janson

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Re: parfocal for studio camera ?

PostFri Dec 10, 2021 2:32 pm

These do perform quite nicely with BMD sensor, and provide plenty of character and no OPLF filter needed :)

On this video the first part with old B4 lens and the second Canon EF 50 mm f1.8 SMT



More in here

viewtopic.php?f=2&t=130233&p=712122&hilit=snow#p712122

These Old B4 lenses go between 150 to 500 euro. They have many flaws, but beautiful to handle, huge zoom range, f1.8 somewhat usable on long end, on wide end for artistic purposes only :) but pretty ok at f5.6
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rick.lang

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Re: parfocal for studio camera ?

PostSat Dec 11, 2021 1:37 am

Great illustration of the capabilities of old B4 zooms versus a stills lens. They have a place, especially for events where you need as much flexibility as possible with live action always shifting your attention.
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Kim Janson

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Re: parfocal for studio camera ?

PostSun Dec 12, 2021 6:14 pm

Thanks Rick. Now that I look it after long time, I actually find the B4 image on some regards more pleasant. the Canon EF 50 mm f1.8 SMT + speed booster out of focus areas sometimes have some kind of echo on the edges.
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rick.lang

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Re: parfocal for studio camera ?

PostSun Dec 12, 2021 9:30 pm

In less than two weeks I’ll resume recording theatrical performances with my Fujinon zoom and I’m getting all my related gear ready now as it will be two years since I used that stuff due to the pandemic lockdown and restricted groups. That’s a long layoff.
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Videobegin

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Re: parfocal for studio camera ?

PostMon Dec 13, 2021 3:38 am

Kim, you leave interesting informations with nice images as proof of concept ;)

Used Fujinon is hard as to find (confidential market). Snipping tools are armed !

Fotodiox have medium feedbacks but you use it with success. Did you you tryed it with studio camera ?
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Kim Janson

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Re: parfocal for studio camera ?

PostMon Dec 13, 2021 6:23 am

This was with Micro Studio, but recorded only as FHD (with old 5" VA) and we did not pay any attention to the colours etc. as the test was for the geopointing. On this set we use modified lens electronics, to control it with SW.



There was some corner cutting, for some reason it looks like the image circle is not at center

Screenshot 2021-12-13 at 8.25.43.jpg
Screenshot 2021-12-13 at 8.25.43.jpg (184.25 KiB) Viewed 405 times


On long end this problem does not exist and the lenses I have with inbuilt 2x extender remove this problem when the 2x extender is used. The image circle size varies a lot on the B4 lenses I have, depending of Zoom, inbuilt extender and lens. It is important to test the lens, MFT/B4 converter and camera combo on the full zoom range.

BMD does the B4 adapters for the URSA cameras, I hope they would do that also for the other cameras, especially the new studio camera.
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carpentermike

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Re: parfocal for studio camera ?

PostTue Dec 14, 2021 11:58 am

Videobegin wrote:
Fotodiox have medium feedbacks but you use it with success. Did you you tryed it with studio camera ?

I have a Fotodiox too and i have a problem in various situations with a white ghost image in the middle of the picture especially with bright frontlights.
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Re: parfocal for studio camera ?

PostTue Dec 14, 2021 7:49 pm

Happy New Year

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