Zeiss Ikophot - whats the transluscent screen?

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who?

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I bough a cheap lightmeter, Seems a good buy - a Zeiss Ikophot.

Comparing with the results from a digital camera it seems to be well calibrated.

In the case there is a slide in translucent screen which fits over the light sensor.

What is this for? How would I use it?

Thanks
 
Brilliant!

Thanks Carl
 
My example is I think older than those instructions but the operation is the same.

The answer (for anyone else) is that the diffuser is used to take a reading from the subject pointing towards the camera when you are shooting into the light.

Also great is that the instructions include calibration info, although as I say the one I've got seems to match my digital camera anyway.
 
I'm sure I read somewhere it dates from the early 1950s, so I'm glad it's working OK for you.
 
Its always nice to pick up something which is well made, isn't it?

The whole feel of the case, strap and the actual meter are very nice.

Form & Function in harmony. (y)
 
The diffuser is used to take a light reading of the light falling onto the subject rather than the light reflected off the subject and is a much better way as it ignores bright spots which may effect the reading. Attach the diffuser and point the diffuser at the camera from the subject position, you can use it from the camera position as long as the light is the same.
SIMPLE "tch"
 
I have one of these and I have found it is accurate enough to use for transparency film.


Steve.
 
Oh cool, I've got several old light meters like this, my dad seemed to like collecting them from all sorts of places before he popped. I was wondering if they go out of kilter after many years or good forever?
 
Hi. The only way to tell is to suck it and see. Some do seem to lose their way after years of use and others found in a deplorable condition at car boot or charity are as accurate as the day they were made. Comparison with a meter known to be spot on is the only way I know to test them, but be careful that they are measuring the same angle of view.
 
DUNKS said:
Hi. The only way to tell is to suck it and see. Some do seem to lose their way after years of use and others found in a deplorable condition at car boot or charity are as accurate as the day they were made. Comparison with a meter known to be spot on is the only way I know to test them, but be careful that they are measuring the same angle of view.
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Cheers Dunks, only trouble is I don't have a modern light meter at all, just the one built into my 400D - does anyone know of any way I could use this?
 
I tested against a digi camera. Pointed the camera and the light meter at the same thing, checked what the camera was recommending (camera in Aperture mode) and compared to the light meter. Good match so I'm happy. Incidentally I alsoi checked against a Zenit film camera and that was also about the same.

The Zeiss can be adjusted, its in the manual Carl pointed me at.. I've also seen threads on mflenses where people have talked about calibrating westons by turning one of the screws.
 
who? said:
The Zeiss can be adjusted, its in the manual Carl pointed me at.. I've also seen threads on mflenses where people have talked about calibrating westons by turning one of the screws.
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Does that actually adjust the calibration or is it just a zero set?

EDIT: Just had a look, it is just a zero position set.

The cells on these meters have a finite life but it is generally related to the amount of light they have seen in their lifetime.

If you have one which has been kept in its case in a drawer for years, it stands more chance of working accurately than one which has spent the last thirty years out of its case, on a window sill.



Steve.
 
There is one thing not quite right with these meters though. Set it to 100 ASA and it will tell you it is also set to 22 DIN.

As we all know, 100 ASA is actually 21 DIN.

I always use the ASA settings for mine and it seems o.k.


Steve.
 
Actually mine shows about 20.5 for 100ASA, or 11 and a bit of something else, I know not what.
 
Yours is closer than mine then (but still not right).

The manual in the link above also shows 100 ASA as 22 DIN.


Steve.
 
I think mine is older that the manula one - I dont have a scale for the needle. just a ring that I adjust. I'll take a pic and pop it up tomorrow
 
Steve Smith said:
As we all know, 100 ASA is actually 21 DIN
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Yeeeessssss, we all knew that! Actually, I do just about remember ASA v DIN from when I did half a term of photography at school, I seem to remember using the DIN for some reason? That's back when men were men and cameras had lots of cogs inside...
Anyway, is the ASA number the same as the ISO number?
 
Pippy_Neville said:
Anyway, is the ASA number the same as the ISO number?
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ISO (International Standards Organization) is more commonly used now than ASA (American Standards Association) and is the same scale.

DIN (Deutsche Industrie Norm) is the German system.

You are quite correct, 100 ASA/ISO is the same as 21 DIN.
 
Just realised the ikophot i paid a premium for cos its calibrated its minus the diffuser, it must have dropped out somewhere :crying: gutted
 
Pippy_Neville said:
Anyway, is the ASA number the same as the ISO number?
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Yes... and no.

Whilst what is generally known as ISO 100 is the same as 100 ASA, the actual SI convention is to use both numbers in the designation.

i.e. ISO 100/21°

Fairly pointless really but I suppose it kept all countries involved happy!


Steve.
 
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