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ARRI Macro lenses, periscope and diopers


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#1 Valentina Caniglia

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Posted 11 December 2005 - 01:07 AM

Hi all,

I am shooting a miniture commercial in 35mm.
I am ordering the Arri macro 50mm and the arrimicro 100mm.
I would like to know how many stop do I loose using a 50mm macro or 100 micro? How do you calclute the T stop when you have these lenses on?
Do you just measure the light with lightmeter and calculate the stop loss in relationship?

I would like to use a periscope lenses. How do I calculate the T stop with the periscope?

If I use diopers +1,+2,+3,+4,+5 how much T- stope I loose?

Thank You to all

V.
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#2 Daniel Stigler

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Posted 11 December 2005 - 05:23 AM

You can download info on exposure compensation for macros here:
http://www.arri.de/s...am/ti/index.htm
Use your lightmeter like you always do and then correct the stop according to the lens settings. (or have your AC do that....)

You don't have to change your stop when using diopters.

What periscope do you plan to use? You'll need a lot of light. At least a T8.

Edited by Daniel Stigler, 11 December 2005 - 05:24 AM.

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#3 Stephen Williams

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Posted 11 December 2005 - 07:55 AM

Hi all,

I am shooting a miniture commercial in 35mm.
I am ordering the Arri macro 50mm and the arrimicro 100mm.
I would like to know how many stop do I loose using a 50mm macro or 100 micro? How do you calclute the T stop when you have these lenses on?
Do you just measure the light with lightmeter and calculate the stop loss in relationship?

I would like to use a periscope lenses. How do I calculate the T stop with the periscope?

If I use diopers +1,+2,+3,+4,+5 how much T- stope I loose?

Thank You to all

V.


Hi,

The newer Arri Macro lenses are self compensating.
As a rule of thumb 1:1 is always 2 stops.
I often shoot watches, for a watch and strap packshot about 1/3 Stop, watch face in 1:185 about 1 stop.
Periscopes usually lose about 1 stop but you should ask the rental company and ideally test!

Stephen
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#4 Valentina Caniglia

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Posted 12 December 2005 - 01:18 AM

Thank You to all for your response.

I am not still clear though how much I have to open for Arri 50mm macro and arri 100mm macro.

I would like to undertand the arri chart when it says 1:1 or 1:2 ect.

Thanks a lot

V.
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#5 Adam Frisch FSF

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Posted 12 December 2005 - 02:03 PM

As Stephen says - the newer Macro lenses compensate themselves. This means that when you focus normally the lens has it's speciefied stop, say T4. When you go into macro-range, the lens automatically opens up the stop to compensate for the light loss, for example to T2.8. This will be clear to you when you see such a lens.

The older ones don't compensate themselves. But that doesn't matter because clearly printed on them are a diagram that say how much you should open up the stop at this and that focus range to compensate. It's all printed on the barrell, so you can't go wrong.

Diopters don't need compensating, but they also remove the lens possibility for infinity focusing, so you can't pull very much focus when you use them.

And as a last resort - you can always overexpose when you're at normal focus and then let it go "darker" and arrive at the correct exposure when you're in macro. Then all you do is a dynamic in telecine to darken the image in the beginning - easy pie. Film can handle at least 2 stops of overexposure, even more, if need be.

I've always argued that every lens should be a macro lens anyway. Don't need complicated compensating stops and such - all I need is close focus capability when I need it. It' such a hassle with diopters that never fit and get smear marks and thumbprints all over them. All the lens manufacturers have to do is make the lens have longer focus threads and that's it.

Edited by AdamFrisch, 12 December 2005 - 02:09 PM.

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#6 Stephen Williams

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Posted 13 December 2005 - 03:31 AM

Thank You to all for your response.

I am not still clear though how much I have to open for Arri 50mm macro and arri 100mm macro.

I would like to undertand the arri chart when it says 1:1 or 1:2 ect.

Thanks a lot

V.


Hi,

For the same image size you would open a 50mm or 100 mm lens the same amount. At the same F stop the DOF is also the same!

1:1 is when the image size on the negative is the same size as the object being filmed. 1:2 the object is twice the size of the image on the negative.

Stephen
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Media Blackout - Custom Cables and AKS

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Aerial Filmworks

Opal

FJS International, LLC

Tai Audio

CineLab

Wooden Camera

Glidecam

Metropolis Post

Gamma Ray Digital Inc

Abel Cine

Ritter Battery