Zeiss Ikon Meter

[anerjee]

I'm beginning to notice that my 1.5 yr old ZI is consistently under-exposing by a bit.

While I can fix this by adding +1 to the EV compensation dial, I'd like to know if others have faced a similar problem. Is it because of the batteries (I use super cheap chinese LR44)? Any other possible reasons?

[jpskenn]

No noticeable ender-exposure on my two ZI (Silver + Black), and never had such a problem.
Also when low battery, no problem.

I don’t have any good idea, but I’m thinking of lens problem.
Using only one lens or not?
(I’m using 2/50 planar ZM and 2.8/28 biogon ZM.)

[thegman]

Never had a problem on my ZI, got to be worth trying some new batteries before considering a service.

Also, a wide angle lens can sometimes meter on more of the sky than you'd probably like, leading to under exposure. If you're using 28mm or wider, that could easily be the problem.

[whitecat]

Never had a problem. What type of film are you using? Development?

[alexandru_voicu]

Hi,

I also think my ZI meter tends to underexpose a bit (one third of a stop or so), but I can't say for sure, yet. I have to make more tests.

[thegman]

I read somewhere, not sure where, that the ZI meter is calibrated for accurate exposure on slide film. That means that on some negative film it may appear to under expose, as we are so used to over exposing negative film.

[kossi008]

Hard to say really, but are you sure it's the camera and not you? I'm not trying to insult here, but when I got the Zeiss Ikon first, I under-exposed a lot. Later found out that it was due to my not being acquainted with the slightly asymmetric metering pattern, so I was holding it the "wrong way" for portrait orientation.

Here's the link to the old thread, for what it's worth:
http://www.rangefinderforum.com/foru...+ikon+metering

[Moriturii]

Something something battery? When the voltage goes down you usually get wrong exposure. Try a proper kind batteries.

[bensyverson]

In backlit or flare-inducing scenarios, I've had some very underexposed Ikon shots. I think it has to do with a ghost from the flare hitting the metering area. I suppose that's one downside of through-the-lens metering.

[135format]

Ever heard of a personal film speed? Part of determining that is your metering technique. If it's consistently a 1/3 of a stop underexposed then adjust film speed by 1/3 stop less for that type of film. Problem solved.

[alexandru_voicu]

Originally Posted by 135format

Ever heard of a personal film speed? Part of determining that is your metering technique. If it's consistently a 1/3 of a stop underexposed then adjust film speed by 1/3 stop less for that type of film. Problem solved.

I guess your message is a follow up to mine (as I was the only one talking about a third of a stop). I guess *I've "heard* of personal film speed, that's why I was saying I need to make more tests.

[EdwardKaraa]

The metering of the Zeiss Ikon is extremely accurate. Maybe too accurate. It is calibrated for 18% grey, as it should be. However, it just happens that nowadays we are more likely to face rather light environments, light walls, light clothing, not so many people are dressed in medium grey suits anymore. So in order to get the right exposure, one has to estimate the light reflectance of the scene, and adjust the meter reading accordingly. White walls are +2, Caucasian skin is +1, dark suit on dark background -1 2/3.

Most film cameras I have used are adjusted to give a +1 reading. Nikon, Canon, Olympus...etc. The only exception is Contax, and Leica.

[anerjee]

My experience is from C41, E6 and B&W -- and across a range of situations.

I'll try to measure things carefully this weekend, but I suspect this could be a battery issue. If not, I'll just dial in +1 and move on.

[Joakim Målare]

I have a different question that could use the same thread title...

I'm using filters; yellow, orange, red, green and some neutrals. For some reason, the ZI shows a two stop difference with the red filter on and off, but my Sekonic lightmeter measures three stops.

The red filter is just an example - the others are also "wrong" with the ZI meter...

Anyone else noticed the same?

[Bob Michaels]

I am reading an implicit assumption in many of the replies that a light meter will tell you the "correct" exposure. It just is not so. The meter will tell you the overall luminance of a scene. It will usually get you close enough so that the latitude of negative film will give you a good print. But you, the user, must make the final determination if the exposure indicated by the light meter serves your needs or not.

Similarly, different meters react differently to scenes with an emphasis of one color as resulting from use of a colored filter. As well, a scene with a lot of blue sky will indicate a different factor with a red filter than one with a preponderance of red.

Bottom line: you need to use you brain just a little bit. This is not complex stuff but there is more than simply reading a dial.

[EdwardKaraa]

Originally Posted by Joakim Målare

I have a different question that could use the same thread title...

I'm using filters; yellow, orange, red, green and some neutrals. For some reason, the ZI shows a two stop difference with the red filter on and off, but my Sekonic lightmeter measures three stops.

The red filter is just an example - the others are also "wrong" with the ZI meter...

Anyone else noticed the same?

What does the filter coefficient read?

[Joakim Målare]

Originally Posted by EdwardKaraa

What does the filter coefficient read?

It doesn't say on the colored filters :/

Tiffen 8 Yellow 2 (Wratten #8 I suppose) would be a factor 2, so that's a one stop difference. The ZI does that "properly" while the Sekonic says 1/2 a stop.

Tiffen Orange 21 is factor 3 according to Wikipedia, so what's that.. 1 1/2 stop difference? The Sekonic reads that and the ZI too, sort of.

Hansa G53 - have not found any info on that yet. It's 1 1/2 on the Sekonic and two on the ZI. It might be 1 1/2 on the ZI too, I'm not extremely scientific when it comes to testing.

The red though is a Milo 25a, which is a filter factor 5. Where between 2 and 3 stops that would fall is beyond me, but the ZI says two, while the Sekonic says 3. That's a one stop difference between the two...

These are all reflective readings of the same white-ish background.

I don't really care about the different readings from different meters when it's about half a stop, I just didn't know colour would matter the way it seems to.

My confusement remains, when it put the red filter on my M3, should I add two or three stops?

[Moriturii]

Originally Posted by Joakim Målare

My confusement remains, when it put the red filter on my M3, should I add two or three stops?

You should download the .pdf from the film you are using (TriX for example), and see how much exposure compensation you should use on that specific film then run your own test and see what you come up with.

http://www.kodak.com/global/en/profe...4017/f4017.pdf

Page 3, upper right corner.

[Araakii]

I actually feel that my Ikon gives better metering than my M7 does.

[EdwardKaraa]

Joakim, your ZI meter seems more accurate. Factor 5 is 2 1/4 stops not 3.

[Sparrow]

I always thought it was my job to decide on the exposure, all the meter ever does is measure the light.

If you simply follow it without applying any reason to the reading I'd not be surprised if the results were variable.

[Joakim Målare]

Originally Posted by Moriturii

You should download the .pdf from the film you are using (TriX for example), and see how much exposure compensation you should use on that specific film then run your own test and see what you come up with.

Right, that makes sense. Thanks.

Originally Posted by EdwardKaraa

Joakim, your ZI meter seems more accurate. Factor 5 is 2 1/4 stops not 3.

Cool. Do you know the math? I understand that the factor is 2 ^ stops, but can't figure out how to do the reverse equation

[EdwardKaraa]

Originally Posted by Joakim Målare

Cool. Do you know the math? I understand that the factor is 2 ^ stops, but can't figure out how to do the reverse equation

Pretty simple really.

1x, 2x, 4x, 8x, 16x... etc correspond to 0, 1, 2, 3, 4 f/stops.

I don't know the formula but it's easy to interpolate the in between values.

[Joakim Målare]

Originally Posted by EdwardKaraa

Pretty simple really.

1x, 2x, 4x, 8x, 16x... etc correspond to 0, 1, 2, 3, 4 f/stops.

I don't know the formula but it's easy to interpolate the in between values.

That's only valid for linear series. Which is why a factor of five is more like 2.322-something stops (trial and error on the calculator ). Too bad I forgot most of the math I did in school... All sorts of weird stuff, but what we don't understand is easy to forget.

Who cares really, 2-2.5 stops works for me

Thanks Edward.

[kossi008]

The math is pretty easy:
The number of stops n is the logarithm to the base of two of the filter factor N:
n = log2(N)

Most calculators don't have log to the base of 2, so you can use log to the base of 10 by:
log2(x) = log10(x)/log10(2) = 3.32 * log10(x)

So, a factor of 5 is log2(5) = 2.32 (or 2 1/3) stops.

But if you are in doubt of your meter readings, wouldn't it be smarter (faster) just to do some test exposures instead of doing math and searching for internet links?