Modified Nikkor lenses, worth it?
Posted 05 January 2017 - 02:41 PM
Posted 05 January 2017 - 04:18 PM
They're not terrible. They were designed to be the focal lengths that were reasonably easy to do well, and with at least partial metal construction they're probably better made than some big ticket modern stills lenses. They're also easy to declick, but it's rather destructive and permanent. The focus rotation is short for a cinema lens, of course, but again, longer than most modern stills glass.
They all extend when focussed, some of then quite a lot. None of them rotate, which is something at least. They do not provide any realistic option for consistent focus ring positioning. They are reasonably fast, match usably well and are small and lightweight. They also have full frame 35mm coverage, making them ideal for combination with a speed booster on shallow mounts.
There is nothing shorter than the 28, which tends to be a bit of a concern for indie filmmakers in poky locations. There's also nothing longer than the 135, which. Both of these issues can be solved, at some expense, with lenses from other ranges, though I'm not sure how they match with other things. I got the RMC Tokina 17mm f/3.5, which is... Well. Vastly slower than the Nikon Es, and doesn't perform well wide open.
In short they work pretty well if you just need... something. They're obviously not real cine lenses. I think the important thing is that I don't think there's any huge difference between the Nikon Es and much more expensive AI lenses.
Posted 05 January 2017 - 04:30 PM
. I 3D printed some gears for them, which in my view is the best way to go as the gear mounting is absolutely rock solid.
Phil, I've been thinking about getting some made for my Asahi Takumars. Finding a printer is easy, but the design stage has me confused. How did you go about it?
Posted 05 January 2017 - 06:33 PM
Wait you can buy 3D printers now? I thought they only had them at Discovery Channel exhibits?
Posted 05 January 2017 - 06:47 PM
You can buy a cheap one for about $400. The better ones go up to around $4000
Posted 05 January 2017 - 08:07 PM
There's a website somewhere (edit: here) that has 3D files of lens gears in a selection of outer diameters and with inner diameters every half millimetre or so. As an alternative, Google's Sketchup 3D design software accepts scripts and plugins, one of which is capable of plotting gears. It would be possible to set the gear plotter up to draw correct movie lens gearing, but I took the quick route and downloaded them. I made some changes to the file for other reasons, but I think to get a really cast iron result, you're going to need to be in the room with the printer and a computer running the Sketchup software, with which you can trim the dimensions until they're a nice solid push fit.
It's not beautiful, but it works. You can get black materials.
I had to print them fractionally small and rub down the inner surfaces of the gears with abrasive, taking off the sharp corners with an x-acto knife, until they'd just barely slide over the rubber grips on the lenses. I think my good results are at least partially due to the rubbery focus grips on the Nikon Es, which provide just enough elasticity to keep things really solid.
We printed some test gears at reduced thickness to establish the required tolerance, comparing the micrometer measurements over the rubber with the ideal printed size. You could probably trial and error it, with a bit of time.
We printed them in PLA, not ABS, because PLA is harder. The geometry of the gears is... j... just about okay. The common plastic deposition printers start to run out of resolution at the size of a lens gear tooth. Stereolithography is more precise and would look more professionally presentable, but may be more expensive. I also can't advise on the suitability of the materials used in stereolithography, beyond "I suspect it'd be fine." Both techniques, and others, are available as bureau service, but as I say, I found a rapid prototyping approach worked.
Disclosure: I know someone who owns an Ultimaker 2, which sort of guided my choices.
Posted 10 January 2017 - 05:30 PM
I have a full set of Nikkor AIS lenses and I LOVE them. I recommend doing it, especially because, in the SLR world, they have the longest focal flange distance and have been somewhat adaptable to any camera (short of PL of course).
I cinemodded them myself, much like Phil, and they've treated me well. However, Duclos does superb work.
Pull the trigger, get the AIS! Great character, sharp images, and cost effective.