1.4x exposure question

[milan_moudgill]

Hi all. I just received a Mutar 1.4x.

 

Since it has contacts to link the lens ahead of it to the circuitry, I suppose it can

work the diaphragm, TTL etc.

 

Questions:

does the AF work with the 1.4 on? It did not seem to. But with 210 on (narrow

focus depth), it may have been that I did not have a textured subject I was

pointing at?

 

How do the exposure calculations work in the priority settings and in manual?

In manual mode, if I meter externally, I should open up by one stop to

comepensate for the 1.4?

Obviously if in (say aperture) priority, the camera will automatically add on the

extra stop, since this is TTL?

 

Is this asumption correct? Right? Only what really threw me was that I:

1. pointed the camera at a clear patch of sky, in Av with just the 210 on

2. pointed the camera at the same clear patch of sky, in Av with the 1.4 and

the 210 on....

and the readings were identical!

 

Please tell me what I am doing wrong. I am going a bit insane - I thought my

exposure basics were sorted out!!!

 

Thanks in advance

 

Milan

[mike_earussi1]

What camera do you have?

[lee hamiel]

Milan:

 

Here are the specs from the Contax site:

 

"Carl Zeiss has introduced a new Mutar Teleconverter, the Mutar 1.4x. This new Mutar is used exclusively with the Contax 645 lens system. The Mutar multiplies the focal length of the installed lens by 1.4 times, losing only one f/stop of light. The new converter is matched for use on the Sonnar T* 140mm f/2.8, Sonnar T* 210mm f/3 and the new Tele-Apotessar 350mm f/4. The Mutar offers a fully automatic diaphragm and the amazing ability to carry Auto Focus through itself to operate the Carl Zeiss T* lens".

 

Your first sentence is correct. I'm guessing that your readings will be different if you're metering a grey card & not the sky.

 

Good Luck

[milan_moudgill]

Sorry Mike... i thought I had posted this in the Contax 645 section - which is

what the camera is.

 

Lee, I read the same thing but was insettled when I OPERATED the Mutar+

210.

The AF should work through the 1.4x. But it did not. Obviously I should retry

this with a subject that has a strong contrasty pattern

 

Secondly, the meter shot off the same reading, with and without the 1.4x,

when covering a similar section of sky!!! Waz up? This should be a stop off?

 

Any clues?

 

Milan

[lee hamiel]

Milan:

 

With the 210 & the Mutar will it AF at closer distances?

 

My only thought now is that maybe the contacts need to be cleaned - even if they look clean they could need it. This is considering that you're having issues with both AF & metering.

 

Let me know