Radar 12” on Betax 5

**rmdorman** · 22-Feb-2021, 23:03

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Hi all,
Recently I separately obtained a Radar 12” barrel with an iris diaphragm, and a broken betax 5. After getting the shutter going again, I was looking forward to mounting the Radar, as I had heard it fit natively. Unfortunately the rear cell fits fine, but the front shutter threads are a couple of mm shy in diameter of fitting the front cell threads. The shutter is marked for f/5, so I assume it originally fit a Vesta?, but it actually came with a single element mounted to the front via what I think is a bit of a custom rig, although well-done. My question is whether the shutter as originally built should have fit the radar, and now I just have to figure out how to get an adapter ring loose (if so it’s well fit and very tight), or if the shutter originally came with different-size threads on the front depending on the lens it came with, meaning I just found the wrong shutter to work with the radar.
Thank you!

**Tin Can** · 23-Feb-2021, 06:23

I have seen 3 variations of 300mm 'Radar' types

all were different in barrel and flange

This is why I use Packard shutters

**rmdorman** · 23-Feb-2021, 08:52

Thanks. It just seems strange cause the rear cell fits just fine. I usually use a sinar copal but the rear cell come back too far for mounting.

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**Dugan** · 23-Feb-2021, 09:15

I have a Radar 8x10 f4.5 in Betax #5, and another #5 Betax...I will compare fit when I get home from work today

**rmdorman** · 23-Feb-2021, 17:57

Originally Posted by Dugan

I will compare fit when I get home from work today

Thanks kindly Dugan! Do they both have name plates for 4.5 max aperture?

**malexand** · 23-Feb-2021, 18:19

I have a 12" f4.5 Radar in a Betax 5 - the front and rear cells have identical threads. I can put either cell in either position in the shutter.
I also have a Velostigmat f4.5 in a Betax 5 - same deal. Both cells identical threads.

Matt

**rmdorman** · 23-Feb-2021, 18:48

Ok thanks everyone! Your answers gave me the confidence that I was looking at a stuck insert so I got busy with the vice grip and hammer. Booyah-defeated!! Fits nicely now. Looking back at the original attachments I cast off in a hurry I’m pretty sure this was set up as a front-mounted shutter with a ring and tri-screw setup on the back, with an insert to hold a protective glass filter to shelter the blades on the front. A nice machining job too.