Esteban.Media Free guide · 2026 @esteban.media1
Gear guide · Sony mirrorless

The Budget B4 Lens Setup

How to put an old TV broadcast zoom on your mirrorless camera, and get a 20x zoom at f/1.8 for the price of a kit lens.

13–20xzoom range on a single lens
f/1.8constant aperture through the zoom
~$550what my rig cost, shipped
Shop my exact setup ↓
Why this works

A TV lens on your camera

TV news cameras use lenses with a B4 mount, built for small 2/3" sensors. Stations replace them all the time, so used ones pile up on eBay for a fraction of what they cost new. With the right adapter they fit Sony E-mount bodies like the A7 series, FX3, FX30 and A6000 series. Adapters also exist for Canon RF, Nikon Z, L-mount and Micro Four Thirds.

You get huge reach, a zoom that stays in focus as you zoom, smooth motorized zoom on many units, and a vintage look with soft flares and rich color. No modern photo lens offers that range at f/1.8.

Read this first

What you're signing up for

The lens is cheap. The full working rig costs $550 to $800. Know these five things before you buy.

Manual focus only

There's no autofocus. Zoom and iris can be manual or motorized.

A small image circle

On a full-frame body you'll shoot in APS-C crop mode, or add a glass adapter to fill the whole frame.

1.5 to 3 kg of glass

A lens support on rods is mandatory. Without it you can bend your camera's mount.

A vintage image

Softer at the extremes, more flare, less contrast than modern glass. That's the look people buy them for.

Used and often imported

Many listings are "as-is". Buying from abroad can add 20% or more in import fees.

Step 1

Read the model code

Every lens name is a spec sheet. Learn to read it and you can judge a listing in seconds.

Format

Decides how much of your sensor the lens can cover. Only buy 2/3".

Zoom and focal length

20x from 8.5 mm means 8.5–170 mm.

Extender

An I or IE on Canon, an E on Fujinon (BERM, BERD). A K means none. It's a lever marked 1x/2x on the lens.

Servo

R is motorized zoom, S is motorized iris. M/A switches let you run both by hand with no power.

Buy: 2/3" lenses

JYJHJKJAAhHAXA

Canon J-series and Fujinon A-series. The largest image circle, the best documented, and the easiest to adapt.

Skip: 1/2" and 1/3" lenses

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They look like bargains, but their image circle is too small for a mirrorless sensor.

Also skip remote lenses: codes with PX, or a boxy unit with cables instead of a handgrip. They're built for robotic camera heads. Canon and Fujinon made over 90% of these lenses; Angenieux and Nikon versions work the same but are rare and rarely cheap.

Step 2

Pick a lens

The sweet spot is a standard-definition Canon J/YJ or Fujinon A lens with a built-in 2x extender, at about $400 to $700. I paid $399 for mine. Without the extender they cost a bit less. HD versions (HJ, KJ, HA, XA) start around $1,000.

LensRangeBuilt-in 2xAsking price
With extender: pair with a pass-through adapter
Canon J16ax8B IRS Mine8–128 mm, 16xYes$399 paid
Fujinon A18x7.6BERM7.6–137 mm, 18xYes~$600
Canon J22ex7.6B4 WRSD7.6–168 mm, 22xYes~$600
Fujinon A18x7.6BDERM7.6–137 mm, 18xYes~$650
Fujinon A20x8.6BERM8.6–172 mm, 20xYes~$700
Canon YJ12x6.5B4 IRS6.5–78 mm, 12xYes~$700
Fujinon A17x7.8BDERM7.8–133 mm, 17xYes~$720
No extender: pair with a glass 2x adapter
Canon J15x9.5B KRS9.5–143 mm, 15xNo~$300
Fujinon A20x8.6BRM8.6–172 mm, 20xNo$300–400
Canon YJ18x9B / YJ19x9B9–171 mm, 18–19xNo$400–480

Asking prices on eBay.com, checked in early October 2026. Most sellers accept offers 10–20% lower. "For parts" listings go for $150–250, but they're a gamble.

Step 3

Choose the adapter

The rule is simple: you need one 2x to fill an APS-C crop, and two to fill a full frame. That 2x can come from the lens's built-in extender or from a glass adapter.

My pick · what I use

Pass-through adapter + APS-C crop mode

I shoot a Canon J16ax8B IRS on a full-frame body with a simple pass-through adapter (no glass). I turn on the lens's 2x extender and set the camera to APS-C / Super35 crop, and the lens covers about 95% of the frame with very good quality. A 1.1x punch-in, in camera or in the edit, removes the last bit of corner shading. I like that slight vignette, so I usually keep it. It's the cheapest setup, it adds no extra glass between the lens and the sensor, and for most people it's the best choice.

Most Sony bodies still record 4K in APS-C crop, so a 1.1x punch-in leaves plenty of resolution.

Image circle coverage on a full-frame sensor Three panels. The bare 2/3 inch lens covers only a small center area. With one 2x it covers the APS-C crop. With two 2x it covers the full frame. Lens alone pass-through adapter Tiny center crop One 2x extender + pass-through ~95% of APS-C: my setup Two 2x extender + glass adapter Full frame

Rectangle: full-frame sensor. Dashed: APS-C / Super35 crop. Yellow: what the lens projects, roughly to scale. A lens without an extender plus a glass 2x adapter lands in the same place as the middle panel.

AdapterWhat it doesBest forApprox. price
Pass-through RecommendedJust a mount, no glassLenses with a 2x extender, shot in APS-C crop$35–100
Glass 2xDoubles the image circleLenses without an extender (APS-C crop), or full frame without crop~$200
Corrected 2x (7 elements)Same, with sharper cornersFull frame, better quality~$300
Pro optical 2.6x–3.6xClean full-frame coverageOutside this budget$2,400+

Go for a glass adapter only if you need the full frame. Each extra glass element costs some light and sharpness, and the lens's own extender is better glass than a cheap adapter.

Step 4

Build the rig

Plan $100 to $250 on top of the lens and adapter for support and power.

Side view of the complete rig From left to right: a 12V power bank, the camera, the B4 adapter, and the long broadcast lens with its servo grip. Two 15 mm rods run under everything from a baseplate under the camera to a lens support under the front of the lens. A cable runs from the lens grip back to the power bank. Power bank Camera Adapter B4 lens Lens support 15 mm rods Servo grip 1x/2x lever 12-pin to DC 12V cable 12V out on baseplate $35–300 $300–720 $35–55 $45–75 + plate $20–40

The rods carry the lens weight through the support, so nothing hangs off the camera mount. Add B4 lens caps ($15–30): most used lenses arrive without them.

Power: the servo runs on 12V. I use a phone power bank that outputs 12V over USB-C. A plain USB-C cable only gives 5V, so you need a USB-C PD trigger cable set to 12V, ending in a DC 5.5×2.1 mm plug. A V-mount battery with a D-Tap cable ($90–150) also works and lasts longer.

Going fully manual? If the grip has M/A switches, set zoom and iris to M and you can skip the cable and power bank. You lose the smooth motorized zoom, so keep the servo if you want slow push-ins.
Budget

Three builds

My build is exactly what I paid. The other two use mid-range prices from this guide, before import fees.

Recommended · my setup
$550

Exactly what I paid, shipped to Spain from China. Lens with 2x extender on a pass-through adapter, APS-C crop mode, servo powered from a phone power bank with 12V output. Support, rods and power bank added about €120 more: see Shop my setup.

  • Canon J16ax8B IRS (2x)$399
  • Pass-through B4 to E adapter$34
  • 12-pin to DC 12V power cable$22
  • Shipping + VAT$83
No extender
~$620

Found a good lens without a built-in 2x? The glass adapter supplies it. APS-C crop mode.

  • Fujinon A20x8.6BRM$330
  • Glass 2x adapter$200
  • Support + rods$90
Full frame, servo
~$770

Fills the whole full-frame sensor, with motorized zoom. About $730 if you already own a power bank with 12V output.

  • Canon J16ax8B IRS (2x)$400
  • Glass 2x adapter$200
  • Support, rods, cables$130
  • 12V USB-C power bank$40
Shop my setup

Everything in the video

These are the exact products and sellers I bought from. Prices are what I paid in August–September 2026.

Lens and adapter
Canon J16ax8B IRS · B4 lens with 2x extender · my exact lens is sold; this seller (xuanwusky) has more B4 lenseseBay ↗
B4 (2/3") to Sony E pass-through adapter · no glass, used with APS-C cropeBay ↗
Support
SmallRig 5609 baseplate + 15 mm carbon rods (20 cm) · holds the rods under the cameraAmazon ↗
SmallRig BSL2681 15 mm lens support · carries the weight of the lensAmazon ↗
Power for the servo
12-pin Hirose to DC 12V cable · plugs into the lens gripeBay ↗
USB-C PD trigger to DC 5.5×2.1 mm, 12V · makes the power bank output 12VAliExpress ↗
INIU MagSafe Qi2.2 25W power bank, 10,000 mAh · my phone power bank, with 12V output over USB-CAmazon ↗
Extras
Zivacate reusable cable ties (120 pcs) · to keep the power cable tidy along the rodsAmazon ↗

eBay and AliExpress links go to the exact listing or seller. Amazon links open a search for the same product.

Buying used

Find a bargain, dodge the duds

Where the deals hide

  • Search the exact model code: A18x7.6, YJ20x8.5. Mislabeled listings only show up this way.
  • Try other words: "TV zoom lens", "ENG lens", "BCTV", "2/3 zoom".
  • Filter by your own region to avoid import fees.
  • Look at whole TV cameras sold with the lens. The bundle can cost less than the lens alone.
  • Make an offer. 10–20% under asking is normal.
  • Save your search to get an alert when a cheap one is listed.

Red flags

  • "Lens only, no motor" or "motor only". Some sellers split one lens into two listings.
  • "For parts" or "not working" with no returns.
  • Photos that never show the glass or the 1x/2x lever.
  • A 1/2" or 1/3" prefix listed as if it were 2/3".
  • Remote (PX) lenses sold as handheld ENG lenses.

Check the glass without a camera

Ask the seller to hold the lens up to a bright light and look through it. Here's what they might see.

Fungus

Thin threads like a spiderweb. Walk away.

Haze

A milky fog over the glass. Costly to clean.

Scratches

Fine lines. Small ones on the front rarely show.

Dust

A few specks inside. Normal and harmless.

Setup

Put it together

Assembly takes about 20 minutes. Back-focus is the step people skip, and then their zoom goes soft.

  1. Mount the camera on the baseplate and slide in the two 15 mm rods.
  2. Attach the adapter to the camera, then the lens to the adapter.
  3. Clamp the lens support under the front of the lens so it carries the weight. Nothing should sag.
  4. Using servo? Plug the 12-pin cable into the lens and the DC end into a 12V source: a power bank through a 12V USB-C trigger cable, or a V-mount battery.
  5. Flip the lens lever to 2x and set the camera to APS-C / Super35 crop mode. Want clean corners? Punch in 1.1x. With a glass adapter on a full-frame body, you can leave crop mode off.

  6. Set back-focus so the image stays sharp through the whole zoom.

    1. Put a focus chart or any detailed printout a few meters away. Open the iris fully.
    2. Zoom all the way in and focus with the focus ring.
    3. Zoom all the way out. If it's soft, fix it with the back-focus ring (marked F.B, near the mount), not the focus ring.
    4. Repeat 2–3 times until it's sharp at both ends.

With back-focus set, you can zoom during a shot and stay in focus. That's the real reason to own one of these.

Before you pay

The checklist

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