I just bought a lens that appears to have just sat on a reseller's shelf. The lubricant in the helicals has turned to non-lubricating goo and the movement is very stiff and sluggish. I want to have it cleaned/overhauled and modified so that it is parfocal on the BMPCC throughout its zoom range.
Three names come to mind to bring this lens production ready: Bernie O'Doherty in New York Edward Koehler in Germany Les Bosher in Wales.
Does anyone have other recommendations for engineers who can do this work?
TIA
Well, pickings are slim for 1" lenses. There aren't so many, and they're mostly CCTV lenses, i.e., kind of cheap. The cams are a little loose and they don't keep perfect focus as you zoom in and out. If you are not zooming while shooting or if you use a small aperture setting, it's not an issue and any of the 1" zooms are fine. Just don't expect great performance from any of them wide open. They need to be stopped down 1-3 stops before they look good. And most of them are flare-prone.
If you are intent on that 16-160 f/1.8 monster, look for the Vicon lens with the same specs. It's a newer lens that's less likely to have stiff lube, though the optics are no better. It might need the mount retaining nut sanded down a bit to fit it to a Micro Four Thirds adapter.
The Fujinon 16-160 f/1.8 doesn't need modification to be mounted - just shimming. If the zooming is stiff, it's a huge job to clean and lube the zoom mechanism. Doing just the focus helicoid isn't terrible.
The Tamron 15-90 f/1.8, Fujinon C5x20 f/1.8, and the old Canon 15-150 f/2.8 are alright.
If you've got money to spend, there are converters that will let you use a B4-mount 2/3" ENG lens: http://www.abakus.co.uk/Cine.htm
Hello everyone, Edward Koehler here. I just wanted to clarify that I'm located in London UK, not Germany.
Also, there are plenty of 1" video zooms that work well on BMPCC. They adapt well from C-mount to m4/3 and fully cover the BMPCC sensor. Most were not CCTV, but rather designed for the Vidicon and Saticon tube sensors for broadcast and semi-professional use. The majority were designed for single tube sensor, so they do not have the built-in beamsplitter correction typical of 3CCD ENG zooms. They are parfocal by design, to hold acceptably sharp focus through the zoom range, and should not be 'loose' but some of them have suffered degradation of certain components over the past 40yrs or so, which can cause the focus to drift. This is an issue with Canon 1" video TV zooms in particular. Others simply require parfocal adjustment and set-up upon adaptation.
I perform complete refurbs on parfocal zooms, including the cleaning and relubrication of the zoom balazer describes above. A 1" video zoom like the Canon V6x16 would be worth it (especially if it is the better build broadcast version).
@ekoe, I'm curious how you deal with degraded components, especially cam follower bushings. On some of my Canon TV zoom lenses, they have disintegrated, and in other brands of lenses sometimes they are just too loose.
@balazer, they get replaced entirely. I fabricate new ones of delrin or brass and the entire zoom assembly is cleaned, regreased and rebuilt.
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