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2x extender, will help Cover Super 16???


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#1 Gigi Forkon

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Posted 12 March 2011 - 11:51 AM

Hi all,
I like to ask,
if the Zeiss Mutar 2x for the 10-100 T2, will cover Super 16 format, or better.

Trying by hand with just the lens, a piece of paper (or real ground glass, or a brusched plexiglass) fixed at focus, it gives me a max.circle of 14mm, how much will be with the 2x extender?


:huh:

Edited by Gigi Forkon, 12 March 2011 - 11:52 AM.

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#2 John Young

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Posted 12 March 2011 - 05:44 PM

As far as I understand, the Zeiss Mutar 2x teleconverter is just that. It will turn your 10-100mm lens into a 20-200mm lens, effectively doubling the focal length.
I have not done any image circle tests, but the camera aperture for Super-16 is 12.5mm, so your 14 will cover that (in theory).

I am not thinking that a 2x converter will have any effect on the image circle. Just like when you zoom with your zoom. The physical image circle cast by the light leaving the rear glass, because it's stationary, will not change. The compression of distances perceived (perspection, I like to call it) will change. But you know all that.

A 14mm image circle should be able to cover Ultra-16 on down. Of course, I could be totally wrong.
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#3 Brian Drysdale

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Posted 13 March 2011 - 04:21 AM

X 2 converters have been used to increase the image area, the well known example being the 12mm to 240mm being converted from 16mm format to a 35mm format 24mm to 480mm. However, in this case I suspect you'll need to test the Mutar x 2 yourself, unless someone confirms they've actually done it with 10-100 T2.

I know you do need to get Super16 converter for the 10-100 T2 zoom, although it may cover Super16 at longer focal lengths without one fitted.
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#4 Mitch Gross

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Posted 13 March 2011 - 11:06 PM

The optics within the Mutar might allow it, but the mechanics may be designed to prevent it. The goal of the Mutar is to increase focal length, not expand image area coverage. So to stop stray light from causing other problems, it is likely the mechanical design prevents it from increasing the coverage much. This is standard in most such designs. If you use a 2x designed for 35mm then there should be no such issue, provided that the lens physically fits on the adapter.

BTW, the image circle for Super-16 is actually 14.7mm. One must use the diagonal of the frame, not the horizontal measurement. A2+B2=C2 anyone?
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#5 Dom Jaeger

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Posted 14 March 2011 - 07:50 PM

I've tested a Zeiss T2 10-100 with a Mutar 2X on projection and it covers Super 16.

The Mutar I tested was a bayonet mount version, but the optics are identical to the later PL mount model, which is compatible with both the 10-100 and the Super 16 converted 11-110. There may have been an even earlier bayonet version that masked the image circle as Mitch describes, but I'm not aware of it.

The coverage of zooms is smallest at the wide end (and at close focus). The 10 - 100 covers a Super 16 image circle at focal lengths of above about 32mm (and as low as 25mm at distances of 15 ft or more). So using the Mutar would be helpful for the 20 - 32mm range.
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#6 Gigi Forkon

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Posted 15 March 2011 - 04:54 PM

Late ....Thanks everybody :)

@ Mitch,
Like you say, I found that some 2x extenders (35mm fotography) enlarges image and some not, I wish for this mutar :rolleyes:

@ Dom
Wow :o
For curiosity, I need to know if over the Super16, it can cover other bigger stuff, like 4/3 sensors etc..., can you please measure the projected circle at focus?

This is the STD mount I have:
Posted Image

And I'll need to buy this: (any proposal?)
Posted Image
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#7 Dom Jaeger

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Posted 15 March 2011 - 07:17 PM

When used with the Mutar 2X the image circle of the 10 - 100 (20 - 200) is actually limited by the iris. As you stop down the coverage decreases, from about a 22mm diameter wide open to about 16mm at T16.

So you could theoretically use it on a 4/3 sensor camera if you only shoot at T2!
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#8 Gigi Forkon

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Posted 16 March 2011 - 10:02 AM

When used with the Mutar 2X the image circle of the 10 - 100 (20 - 200) is actually limited by the iris. As you stop down the coverage decreases, from about a 22mm diameter wide open to about 16mm at T16.

So you could theoretically use it on a 4/3 sensor camera if you only shoot at T2!


Thank you very much!

Stopping down :huh:.....how this could happen, for my understanding, seems like the iris is not centered with the focal intercection.

The Mutar you have tested, is the same of the photo up?? with same bayonet?

Well, anyway I'm still searching for one to buy, on ebay all gone :(
Only Mutar makes this extenders for Arri STD mount?
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#9 Dom Jaeger

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Posted 16 March 2011 - 10:31 PM

Stopping down :huh:.....how this could happen, for my understanding, seems like the iris is not centered with the focal intercection.

I guess the Mutar expands the image circle well beyond what the lens was designed for, and anything outside the 16mm diameter limit doesn't intersect at the iris. It's interesting that the image still projects sharply to the edges even over that limit when the iris is opened up. Maybe an optical engineer could explain it!

The Mutar you have tested, is the same of the photo up?? with same bayonet?

Yes, same one.

Only Mutar makes this extenders for Arri STD mount?

I don't know. It's the only one I'm aware of.
Your lens is actually an Arri bayonet mount, different to Arri STD (Standard) mount, which was an earlier design. Standard mount lenses will fit in a bayonet mount camera but not the reverse.
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