Antoine Pret Posted April 20, 2021 Share Posted April 20, 2021 I'm searching for a zoom lens to use with a Bolex H16 reflex, c mount, that covers at least 18mm at the widest. What I would like is to not have a rotating front element so i can use it with a clamp on matte box. I currently have the vario switar 18-85mm f2.5 wich looks fine optically, so something similar or slightly better. Thanks ! Link to comment Share on other sites More sharing options...
Antoine Pret Posted April 23, 2021 Author Share Posted April 23, 2021 (edited) I have still not found a good lens to own for the bolex h16 RX to use with a clamp on mattebox despite my advanced searches. What I found is the canon 8-64 mm T2.4 and other zeiss zooms that are used with heavier S16mm production cameras, they look really good and pratical (especially the canon, i love the look of it) but it's really something to rent considering it's price. I found a zoom lens that could be good, the Schneider Variogon 18-90mm F.2 . It has a rotating front element but it's a parfocal lens and it is pretty light and can be used with a handgrip on the bolex. (Wich is a problem to use with the kern paillard vario switar, you can't use the grip and it makes shooting handheld not very handy). I saw some footage of the Schneider on BMPCC's and liked the look but I saw nothing using 16mm film. I know that some of these lenses were packed with the Beaulieu R16 camera. I would like to know if there would be any problem to use this lens on a bolex reflex regarding to the prism mechanism ? I found infos that said you could only use non-RX lenses above 50mm otherwise it will create abberations. And you need to stop down the lens to about f3. Is this the case with this lens ? Would it be worse than the vario switar ? If anyone has an answer to this or other lenses recommendations, thanks! Edited April 23, 2021 by Antoine Pret mistake Link to comment Share on other sites More sharing options...
Premium Member Dom Jaeger Posted April 23, 2021 Premium Member Share Posted April 23, 2021 It’s hard to think of any C mount zooms that don’t have rotating fronts - I think you need to move up to PL as you’ve discovered. There are PL to C mount adapters, but the weight on the C mount (and possible flexing of the turret) could be an issue unless you support the zoom on rods. Definitely use the top turret lock and the bottom lens port lock to prevent the turret from flexing if you don’t use a lens support. Bolexes were designed to use the behind the lens filter slot, but you could also get a compendium/matte box and fit filters to the front. There was a special parallel one made for zooms: http://www.bolexcollector.com/accessories/filter60.html The S16 Canon zooms are excellent, as is the Zeiss 10-100 (or 11-110 S16 version). I don’t know the Schneider zoom. Most zooms work fine on a reflex Bolex since they tend not to be too fast and they usually have a deep exit pupil - which is actually the main factor which determines whether the reflex prism will adversely affect the image. The exit pupil is the image of the iris seen through the rear element. If it appears deeper than about 5 or 6 cm then the emerging light rays are parallel enough to traverse the prism without introducing aberrations. Focal lengths longer than 50mm tend to have deeper exit pupils, hence the lack of a need for longer RX lenses. 1 Link to comment Share on other sites More sharing options...
Antoine Pret Posted April 25, 2021 Author Share Posted April 25, 2021 (edited) Thank you Dom for clearing things out ! I would have liked to use 4x4 filters but it seems a bit complicated/ not in my budget for now with the lens options i have. The compendium looks not that practical either. I feel like I should just use the filter behind the lens, this is gelatine right ? I have the slots but they are filled with old stock kodak filters and are scratched all over the place. Are those filters still being made today ? Would the quality be sufficient to get a good picture in comparaison to using standard 4x4 ? Edited April 25, 2021 by Antoine Pret Link to comment Share on other sites More sharing options...
Premium Member Dom Jaeger Posted April 26, 2021 Premium Member Share Posted April 26, 2021 Maybe someone else has more experience with Wratten filters, as far as I know they are fine to use. I think Kodak still makes them, but there is lots of "new/old" stock on ebay at more affordable prices. 1 Link to comment Share on other sites More sharing options...
Volker Bendt Posted April 26, 2021 Share Posted April 26, 2021 Hi Antoine, you should consider the Kern Vario-Switar 1,9 / 16-100mm POE, which was available both with bayonet and c-mount. I have this lens with my RX4 Super-16, it's fast and sharp and covers S-16 through the entire zoom range and all distances down to 1,20m. Rotating front, Wratten gelatine filters still available. No problem with the original Bolex grip that aktivates the side release knob. Good luck, Volker 1 Link to comment Share on other sites More sharing options...
Antoine Pret Posted May 5, 2021 Author Share Posted May 5, 2021 Thanks Volker, I will be looking if there is a good deal on this zoom for a future upgrade. Also i found some ND wratten gelatine filters made by a company named IRIX for 15$ I don't know how they hold up but i guess this should do the trick https://www.amazon.com/Irix-Gelatin-Filter-29x29mm-Lenses/dp/B073M4RY13?ref_=ast_sto_dp Link to comment Share on other sites More sharing options...
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