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focal length extender for 20x


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Hi Jean-Louis,

 

the Optex 2x extender for Bayonet mount has an optic that hits the rear of the 12-240 so it's no good.

 

I tested a Zeiss Mutar 2X (Bayo mount for 10-100) and it fits the 12-240, with no vignetting through the range.

 

You lose I think 2 stops, and wide open doesn't look so great, so realistically you're looking at a min of about T11! But it works.

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Hi Jean-Louis,

 

the Optex 2x extender for Bayonet mount has an optic that hits the rear of the 12-240 so it's no good.

 

I tested a Zeiss Mutar 2X (Bayo mount for 10-100) and it fits the 12-240, with no vignetting through the range.

 

You lose I think 2 stops, and wide open doesn't look so great, so realistically you're looking at a min of about T11! But it works.

 

 

 

Many thanks Don. I'll check out the Mutar.

 

Cheers,

Jean-Louis

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  • 1 year later...

Hello, on the same issue, I have a question about this accessory:

 

http://www.ebay.it/itm/Astro-Siriar-2x-Converter-16mm-Arri-Arriflex-Bolex-Beaulieu-/201019569249?pt=LH_DefaultDomain_77&hash=item2ecdb33461

 

is this another focal extender? does anybody have experience with this, so to tell if could it be used with Schneider old primes (cinegon 10 and 16, cine-xenon 25) with a protruding back? generally, is the image obtained with a combination of a prime lens and a converter better than an image obtained with a zoom lens?

Thank you for any help.

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Yes that looks to be a 2x extender, but I doubt it will work with the wide Schneiders you mention due to how far back they protrude. You could ask the seller to measure the distance from the front mounting surface to the first optic inside (carefully!) and then work out if a particular lens will fit.

 

Most of these older extenders were made to extend already long lenses even further, a cheaper way to get extreme telephotos. Since long focal lengths don't need to protrude behind the mount, the extenders usually have very little room to accommodate a protruding rear. This one is possibly made by Astro Berlin, who specialised in top class telephoto lenses.

 

A doubler on a 16mm Schneider for example would only make a rather slow 32mm, certainly worse than a comparable focal length prime and I would hazard to guess no better than most zooms.

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A doubler on a 16mm Schneider for example would only make a rather slow 32mm, certainly worse than a comparable focal length prime and I would hazard to guess no better than most zooms.

 

The seller assured he tried with a Xenon 16mm and it fits, the deepness being aroud 35 mm.

My aim is to have a discrete variety of focal lenghts, to cut with old Schneider primes' look. For keeping it cheap, I thougt to double some of them with the extender. Frankly, do you think is this latter the better solution, or to use some - adapted - Minolta Rokkor lenses instead?

(please excuse me for bouncing into the main discussion!)

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  • 5 years later...
On 1/10/2012 at 6:53 PM, Dom Jaeger said:

Hi Jean-Louis,

 

the Optex 2x extender for Bayonet mount has an optic that hits the rear of the 12-240 so it's no good.

 

I tested a Zeiss Mutar 2X (Bayo mount for 10-100) and it fits the 12-240, with no vignetting through the range.

 

You lose I think 2 stops, and wide open doesn't look so great, so realistically you're looking at a min of about T11! But it works.

Hi Dom, I'm new to old cameras so this might be a dumb question!

But I have a 12-240mm Angenieux I want to use with a Mutar 2X (Bayonet mount for 10-100 t2), but I can't get them to fit together... nor can I get ANY Arri standard mount lenses to fit inside the Mutar 2X.

I have one Bayonet mount lens but it's in a PL mount adapter atm so I haven't tried it out yet.

How do I make this work?

Edited by M Joel W
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Hi Joel,

that’s annoying!

As you’ve mentioned, some lenses won’t work if the rear protrudes too far, but if all of your Standard mounts won’t fit something is wrong.

It’s hard to diagnose without having the actual thing in front of me, but the black tab you pictured should retract if you push a button on the side (I think). It is meant to lock into the groove around the back of the lenses, and needs to be retractable to get the lenses in and out. 

Sorry it’s been some years since I looked at a Mutar.

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Thanks, Dom. When I rotate the mount the black tab retracts but not fully–pictured above is about is as far as it retracts:

https://www.dropbox.com/s/1pbhkko86tkrgnk/IMG_0520.MOV?dl=0

I think the black tab is poking forward just a bit too far and the lenses won't mount. I wonder if I could shave the tab down a bit or something, but have no idea what happened. The mutar is otherwise like new. Or maybe I'm missing something. I tried pressing the button but it seems to actuate a different tab, whereas rotating the ring moves the black tab.

Anyway, I appreciate the feedback. Yes I do have lenses that have rear elements that are too deep, so I am not using those. But even my telephoto zooms and long primes won't fit so I suspect it's that black tab protruding just a bit too far. Wish I could figure this out.... this are hard to find.

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My memory is that the ring locks bayonet mount lenses while the button is for Standard mounts.. 

Is there a tab for the Standard mount to locate into, to stop it rotating? If that isn’t lined up with the hole in the lens mount the lens won’t go in.

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13 minutes ago, Dom Jaeger said:

My memory is that the ring locks bayonet mount lenses while the button is for Standard mounts.. 

Is there a tab for the Standard mount to locate into, to stop it rotating? If that isn’t lined up with the hole in the lens mount the lens won’t go in.

That makes sense, thanks. I think you're right about the button being for standard mount and ring for bayonet.

Surprisingly, I don't see a tab to fit inside the standard mount. 

My impression is it's still something to do with the black tab (part of the bayonet mount locking system) not retracting fully. It seems to poke out a bit even when closed and something doesn't allow the lens to go deep enough. That said, I would expect a tab for the standard mount and don't see one so maybe I am missing something.

 

IMG_3895 v2.jpg

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Sorry, I wish I could remember better and I don’t work for the rental house that had Mutars anymore. 

I have seen adapters that have worn so that the button doesn’t work properly anymore, so it could be something like that. You may need to take the locking mechanism apart to check it.

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It's nearly unused so I doubt it's wear. Perhaps a lack of use.

Do you remember the silver tab and black tab both retracting when you press the button? Currently only the silver tab retracts.

When I push the black tab in when it's not extended (turning the ring extends it), it goes a bit deeper into the lens and I strongly suspect it's extending more than it should (unless I push it back) and is what's blocking the lens from mounting. But I'm pretty confused by this since my only Bayonet mount lens has a rear element too deep to even try mounting on the Mutar.

And I can't find a tab for the Arri Standard mount lens to lock it... so that's confusing, too. Aren't some mounts missing that tab to allow the lens to spin freely?

I lack the mechanical skills to take this thing apart. Might just return it, I guess.

Edited by M Joel W
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34 minutes ago, Dom Jaeger said:

Sorry, I wish I could remember better and I don’t work for the rental house that had Mutars anymore. 

I have seen adapters that have worn so that the button doesn’t work properly anymore, so it could be something like that. You may need to take the locking mechanism apart to check it.

Sorry to keep bothering. But how deep is the lens supposed to sit? Maybe it does fit, but it just doesn't lock? There's clearance between the lens and mutar but not a lot. Maybe the button is broken, not the black tab? 

IMG_5655.jpg

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38 minutes ago, Dom Jaeger said:

It should seat down to the flange behind the focus ring, so a bit deeper I think.

There may not be a tab, it was just a thought.

Thanks, Dom. Yeah I am starting to think it is the black tab not recessing sufficiently after all, or not engaging with the button properly. That would make up for the difference in clearance exactly, and I cannot focus close to infinity with this set up as-is.

Ah well. Mutar seems so cool... Perhaps this is a fool's errand.

Did you find the 12-240mm with mutar to cover S35mm (16:9 crop) btw? I remember Kubrick used it (apparently) on Barry Lyndon but I think it was academy 35....

Edited by M Joel W
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On 11/15/2019 at 8:37 PM, Dom Jaeger said:

It should seat down to the flange behind the focus ring, so a bit deeper I think.

There may not be a tab, it was just a thought.

Is it possible the 12-240mm you were using was converted to ARRI Bayonet? 

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Yes I think the 12-240 I checked was a Bayonet mount zoom.

I happened to be in my old workplace this morning and checked out the Mutar. A Standard mount lens fitted but wasn't held very well - it rotated in the mount and felt a bit loose.

The lock ring does two things, it tightens on the wings of a Bayonet mount and it moves that black tab in your photo out to lock into a Standard mount groove. The button is to unlock the ring once you turn it far enough with a Bayonet mount lens, I don't think it has any effect on Standard mount lenses. So I think you're right that the tab is sticking out too far and not being retracted enough by the lock ring.

Having said that, maybe try pushing in the button while undoing the lock ring in case it allows it to turn further and retract the tab a bit more.

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