New C-mount wide angle test by Seb Farges


It’s always interesting to see how C-mount lenses do work on the Panasonic GH2 with 1:1 crop mode. Seb Farges tested three lenses:
This is a movie shot with three lenses, from 6mm to 3.5mm, which is 15mm to 9mm for micro 4/3 sensor (24X36 : 31mm to 18mm). 1st part with the 6mm (more info:​20766631), some shot with polaroid variable ND filter. Second part, same lens but with a Pixco 0.45X lens converter, found for 16€ on ebay, it’s 40.5mm screw mount filter size lens is perfect for the Pentax. The third part is shot with a new lens I’ve found on Ebay for 46€, a C-mount Rainbow 3.5mm 1.6, perfect for the crop function ! It’s very wide, little fish eye effect, but I have a little focus problem with my copy, so I have to closed the aperture, but not too much because it seems I have problem of intern dirts, that can be viewed in more closed apertures.
I like this 3.5mm Rainbow C-mount lens, it’s fun and very wide. I hope you’ll enjoy the shots.

C-mount Pentax 6mm 1.2 on eBay (Click here).
C-mount Rainbow 3.5mm 1.6 on eBay (Click here).
Pixco wide angle lens converter 0.45X on eBay (Click here).

  • Ulli

    excellent clip! i wonder if i use those lenses on olympus how much i would need to crop the heavy vignetting area away, and what would be left. the fast f values keep the dof to a reasonable level, i like that. and those ebay prices…i should check them immediately to see if i can get one too for such low bid :-)

    • Thanks Ulli. If you use the digital 2X function instead of the ETC 1:1, it will vignetting a little, but bad fully the digital zoom is not very good in video.

  • andrew

    like it a lot. great story. very versatile lenses and cool music.

    • Thanks Andrew :)

      • andrew

        i watch this movie again and again and wonder how ep2 or epl2 would compare?
        i notice lack of detail when panning, but shadow and noise seem controlled in low light.
        if you could do a similar test with the same subjects idea and lenses, I think a very interesting comparison.
        I do understand video capabilities are different between gh2- ep2/epl2.
        what do you think seb?

        • Thanks Andrew. Yes GH2 is much better than ep2… I was thinking about shotting a repetitive scene with all my lenses. stay tune :)

  • Kevin

    so if I used it on a PEN w/out cropping, there’d be heaving vignetting yea? otherwise I’d buy them in a heartbeat @@

    • Yes, you’ll have heavy vignetting on the Rainbow 3.5mm like the Pentax 6mm, you can see the vignetting of the 6mm at the beguinning of this test :

  • andrew

    also would be good of you could post exif and data about lenses dof fps etc….

  • Miroslav

    Thanks Seb Farges, excellent video, very interesting test. If I’m not mistaken 1:1 crop means something like 6.7x zoom, the camera takes data only from central 1920×1080 pixels of the sensor. What are the focal lengths of those lenses then?

  • Bu

    A little long but nicely done, thanks for sharing!

    • Thanks Bu, yes you’ll have to watch to see the 3.5mm shots :)

  • Video is shaking a lot. Difficult to watch.

    • “Video is shaking a lot. Difficult to watch.”, it’s a little hard comment :) I hope you did not watch my movies with 25mm and 35mm lenses ! Well it’s not so easy to film my crazy daughter on a scooter from one hand the GH2, the other hand my bicycle ! :)

      • Zaph

        Have you seen these Seb? There was a GH2 video on here or of skaters done using one, looks stellar for this type of work.

  • Joey

    nice shots, very well edited, like it a lot :) where was this filmed?

    btw andrew the music is Justice – genesis

    • Thanks Joe :) Most of the shots were taken in Bordeaux (french west coast) and in Maubuisson (near the atlantic ocean coast).

  • Ahem

    I can’t believe I just watched 3 minutes of someone’s family footage. That’s pretty damn cool home video. Very nice music, and cute kid :)

    • Thanks Ahem :) Family movies is my speciality, I like filming the people I love , and try to interest the audience, and my daughter is such a phenomenon ! :)

  • Luke

    You have a lovely family. Without meaning to sound too creepy….more of your wife, please ;)

    Impressive video….Great work!

    • Thanks Luke, I will tell her ! :)

    • Fish

      That was an excellent video. I wish my home movies looked so professional!

      (and +1 on Luke’s comment)

    • rampart

      Nope, sounds creepy no matter how politely you say it.

  • pmt

    Thanks for the video. Am I missing something? The field of view on the shots looked very normal–as in it felt like a 28-50mm lense. I didn’t get the same wide feel I would get with the nikon 14-24mm on my full frame Nikon.

    What is the crop factor with c-mount lense on a 43 sensor?

    I so much want to like the GH2 since Nikon video just isn’t there yet, but the lack of true wide angle lenses for 43 sensors make me hesitant.

    • Thanks pmt. The field of view of the shot are, in 24X36 eq. 31mm for the Pentax, maybe aroud 25mm for the Pentax + Wide converter, and 18mm for the Rainbow. To obtain this, for example for the Rainbow 3.5mm you have to calculate : 3.5mm X 2.6 (for the GH2 crop 1:1 function) X 2 micro 4/3 crop factor (for the 24X36 eq.). So for 40€ you can have a fast 18mm F1.6. If you want an equivalence of your 14mm, you’ll have to take the Panasonic 7-14, that will give to you a 14-28mm eq, for 800€ and and F4 aperture.

      • pmt

        Thanks for the info sebfarges.

  • Riki Rocket

    Hello! Very cool video! and awesome music!
    Stupid-amateur question, with the rainbow lens, which adaptor you use?

    • Thanks Riki :) The Pentax and the Rainbow are C-mount lenses, so you’ll need a C-mount to micro 4/3 adapter to use them on the GH2. You can find on Ebay for 20$

  • Tulio

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