B4-Mount Parfocal Soom Lenses Instagram Made Me Buy
Intro
Parfocal zoom lenses are really expensive. Too expensive for me right now. But when I saw these 2/3” B4 zoom lenses on instagram, I immediately went to eBay and set up some deal alerts.
These lenses range from $50 all the way up to a few thousand dollars a piece, I managed to get 3 B4 broadcast zoom lenses for around $60 to $80 a piece, and then I had to figure out how to use these things.
There is some setup that goes into these lenses.
I ran into 5 major problems with these lenses, I wrote them down, and let’s go over how I solved those problems and set up my Sony cameras with these B4 zoom lenses.
Note: Lens Sharpness
Also, a quick note about sharpness and image quality, since this lens was made for much smaller sensors, there is going to be a big hit to image quality. These broadcast lenses are also on the cheaper side, so I went into this knowing the image quality and sharpness wasn’t going to be as good as a g-master lens or something, but for me, I kind of like that. There are better quality zoom lenses that are rated above “broadcast” quality, but they start at $500 to a few thousand dollars. So the broadcast-quality for $50-$100 seemed like a good trade off for me.
If I need a high quality parfocal zoom lens, I’m probably going to rent one, but this is more of a fun lens for me, so I don’t mind some wild abberations, soft edges and vignetting.
Problem #1: Adapters and sensor coverage
B4 to E Adapter
Getting into the problems, the first problem here was sensor coverage. These b4 broadcast zooms were made for 2/3” sensors, so when you adapt them to anything larger, like aps-c or especially a full frame sensor, you’re going to get some vignetting.
The first adapter I bought was a standard b4 to e mount adapter, and I was going to clear image zoom through the vignetting. Kind of worked on the FX30, didn’t work at all on the FX3 or 6.
2x B4 to E Adapter
After sorting the adapters by price, I noticed that there was a 2x b4 to e adapter - so I bought that one from rare adapters on ebay and waited another week. I had to buy this doubler, since my lenses didn’t have the doubler built in.
When this one came in, the coverage on the lens was much better. It almost covers the FX30 on the wide end. Zooming in a little clears the entire sensor, but using clear image zoom to 1.1 to 1.5x gets rid of the vignetting on the wide end.
On the FX6 and 3, you’ll need to clear image zoom into 1.5x and you’ll still get some vignetting on the corners. It’s worse on the wide end, but in post, I’d rather zoom in, than go into the camera’s digital zoom.
So that solved the adapter and sensor coverage problem.
Problem #2: Parfocal
The next problem I ran into was the lens being parfocal. All of these lenses were not parfocal out of the box. But there is a way to adjust the focus of the lenses, I’ll just show that really quick.
If your zoom in, set your focus, then zoom back out and it’s out of focus, then you’ll have to adjust your back focus. Adjusting this is pretty simple, zoom in, set focus, then zoom out and adjust focus with your back focus ring on the back of the lens. Then zoom in, focus again, and repeat this until you’re in focus.
This is really easy, but it took me a few days to figure this out, then I came across a video from James and camera that went over this. He actually commented on one of my videos, then I reached out to him and he answered a few questions of mine. He’s way more knowledgable about B4 lenses than I am. If you still have questions after this video, check out his channel. He has some great stuff.
Problem #3: Smooth Zooms & Servo Motor
My third problem was getting smooth zooms. My first J15 lens had a broken servo motor, so I took it off and was trying to zoom around with it, and you can get some smooth faster zooms, but consistent speed slow zooms are pretty tough.
On the video on Instagram, I saw these lens gears with handles on them, so I ordered a set off of ali express, waited two weeks, and got these in, they work really great for crash zooms. But not so great for slow zooms. Better than on the barrel of the lens, but still not great.
Then my Canon YJ17 servo to d-tap cable finally came in, and this is by far the best way to get consistent slow zooms. The servo on this lens isn’t very fast for crash zooms, but it’s fantastic for consistent slow to medium speed zooms.
I’ll leave the cable I purchased for my YJ17 in the description. It tooks me so much forum crawling, and googling, and zooming in on product photos to finally find this one. And it was actually on amazon with 2-day shipping somehow.
Problem #4: Camera Rig
Right when I put this lens on the camera, I knew I needed some kind of rig to support this huge lens and adapter. I also wanted to use a monitor, so I could accurately pull focus, and the servo motor also has to be powered with d-tap. So I’ll need a battery on this, so I decided to make a bit of a rig for this setup.
Lets quickly go over it (This is more in-depth in the video segment)
Baseplate
Rails
Dovetail
Lens support
Battery adapter
Battery
Monitor
Lens caps, because the most b4 lenses do not come with lens caps. Bought these separately on amazon
Lens straps with handle, allow for easier crash zooms if you’re not using the servo motor
ND filters, maybe? Since you have to use these lenses at F8 to get a sharp image, you may not need ND filters
Problem #5: Stability
My fifth problem was stability. I tried to go out and hand held crash zoom this camera, but it’s way too distracting. In my opinion, if you want this footage to be usable, you’re going to need a solid tripod. The more you’re going to crash zoom, the more you’ll need to think about a solid tripod.
Problem #6: I Broke my Canon J15 Lens
Since making this list, I actually have a new problem, I was using the Canon J15 and it actually broke. The Iris blades fell apart and are no longer working and covering half of the lens.
Kind of a bonus though, it stuck at F/8 - and the image is kind of warped and ghosting on the wide end, however, whenever you zoom in the ghosting goes away, and you zoom past the broken iris blades and the image is sharp. So one of my J15’s broke while using it, but it’s actually kind of an awesome look if the right quirky project comes along. I kind of like how this looks.
Future to-do list
By no means is the my final and exhaustive test with these lenses, I have a few more tests to do, when I can save up a little more money to do them. First one is to buy a B4 to PL adapter with a 2x adapter. The 2x adapters are on ebay for about $250. Kind of a lot of money and I’m mostly using my Sony cameras for now, so I’m just going to stick with this.
I would really love to use this lens on the Komodo though, thats a super fun camera, and this lens would be sweet to use it with, but the FX30 is fine for now.
Quick tips
For the most effect while zooming, put as many things between your final frame and your zoomed in frame. The more things you have passing by the camera, the higher the impact of the zoom will be.
These lenses are best around f8, they need a lot of light
Even at f8 there is a lot of chromatic aberration, and soft edges. My yj17 has marks on the inside, that blooms out even more
Very soft, the 2x adapters to help clear the sensor, clear image zoom, the additional cropping in post probably doesn’t help
These old lenses are delicate. Treat them very kindly
The color cast can be pretty wild. I found that a matte box that can flag off light helps cut down on color cast and flaring but these lenses still have a lot of “character”
I wouldnt shoot an entire project in this lens, but it’s great for specific shots or adding an attention-grabbing crash zoom
Conclusion
If you don’t mind the soft image, setup and rig you need to build to get these lenses working, they are really fun to shoot with.
I definitely see myself continuing down the rabbit hole of 2/3” B4 lenses, and always trying to keep an eye out for a good deal on these.
I remember looking at these lenses earlier this year and this j15 was selling for around $50-$100, now they are selling for about double that. I blame instagram for that, and I’m sure I’m not helping now, but if you can get your hands on one of these lenses, they are a lot of fun to use.
Very unique and need the right project that needs this look, but still a good tool to have for the price.
This was my experience with these B4 lenses so far. Will make another video in the future if I learn more about these. If you have any other questions about these B4 lenses, let me know in the comments and I’ll do my best to answer them.