FUJINON-TV ZOOM LENS – H6x12.5R 1:1.2/12.5-75
Like many GH1 users one of the challenges and the joys is experimenting and finding reasonably priced c-mount lenses. To get full coverage of the m4/3 sensor, you generally need to use a 25mm c-mount lens or higher otherwise you get a “peep hole” effect as well as vignetting because the image circle of the lenses that are smaller than 25mm will not fill the whole sensor. Despite these drawbacks people are still finding these lenses a lot of fun to shoot with. Many people have done a number of tests with c-mount prime lenses with both not so great and wonderful results. But not a lot of folks have explored c-mount zoom territory and it seems that more and more are finding ways to use c-mount zooms in a filmmaking capacity.
I have posted a few preliminary tests with an Angenieux and Schneider zoom here on this blog and despite the image circle not filling the sensor I still love the look of these lenses. Some folks have figured out a way around the issues with image circle size by converting the mount of the c-mount lens with a Nikon teleconverter but you lose the fast aperture as well as your wides. Converting the lens is one solution but you need to have some skill to be able to do that. So for those who are willing to live with the current limitations of c-mount zooms on a m/43 sensor I wanted to add some more initial findings of another zoom lens: The FUJINON-TV ZOOM LENS H6x12.5R 1:1.2/12.5-75 The advantage of this zoom lens is that it’s fast at f/1.2 and you can use your GH1 in low light situations. And for close range work, these lenses are quite sharp especially in the higher focal ranges and are reasonably priced so it’s worth a little experimenting especially if you can find a good deal on one. Many users who bought this lens found out they couldn’t use them because the lens mount cannot properly fit the c-mount to m 4/3 adapter.
After some brainstorming and experimentation, I figured out a very cheap and pretty solid solution to getting this lens to mount on my Hawk Peng c-mount to m4/3 adapter using the magic of Scotch Blue Painters Tape. I love this tape because it’s removable and thin and can be used almost anywhere. It’s like a poor man’s gaffers tape. Here’s what I’ve done in order to mount this lens:
1) Remove the threaded black cap on the back of the lens that holds the c-mount plate in place.
The c-mount plate is silver looking and removable.
2) Once you remove the plate, you’ll cut to size a 1 inch long tiny piece of blue painters tape and place it along the flat edge of the plate.
3) Place the c-mount plate back on the lens making sure it’s flat and snug.
4) Screw the c-mount to m4/3 adapter to the lens first making sure that it is not loose and sits evenly on the mount.
5) When you mount the lens, you can slowly twist the lens so that the scales are pointed up and where you want it to be.
6) Be aware, that the lens is snug but not permanent. It should really not go anywhere unless you twist it off.
7) Replace the tape when you feel it starts to jiggle out of place.
- When using this and most c-mount zooms you are still going to get a smaller image circle and a little bit of vignetting depending on your focal length but the lens will sit snugly in the mount. You can also adjust focus, aperture, and focal distance through out the zoom range with very nice results.
- You can use the 2x digital zoom on the GH1 in order to get a full frame picture for both still and video but be aware there will be a resolution loss that will be equivalent to SD resolution. For those who are producing web content or DVD content then this may not be so bad of a loss.
- One thing that I did notice with the FUJINON-TV ZOOM LENS is that when you are in digital zoom mode it is a little shy from infinity focus when using your widest focal range. With out digital zoom engaged you are able to focus to infinity.