Noctilux @full aperture *:: is Lightroom Exif data of 0.95 recorded as 0.95 or 1.0!?

[Sekander]

Advertisement (gone after registration)

My lens is only 18 days old and I have observed the following: **

 

1) Up to now, when I use the Noctilux fully open I have not been able to record from my photos Exif data at 0.95 even though the diaphragm is wide open. At most I get F values of magic value 1.0 *or 1.2 while the lens is at maximal aperture.

 

Is this normal?

Exposure metering/calibration issue?

 

2) There is a click-stop position of the aperture setting ring which is spot on in front of the 0.95 index (white dot) for diaphragm setting and another position which is the extreme click-stop position where the 0.95 label is slightly towards the right of the white dot.

 

I am not quite sure whether the extreme click-stop position is normal. In both cases, I am unable to get photos at 0.95 while looking at Exif data. At most, I get 1.0 values at wide open aperture.

 

Do you guys have any idea whether this is ok. Some kind of glitch? Am just wondering...

Am using the latest M typ 240 firmware 2.0.1.5 and Lightroom 5.6

 

Thanks

[k-hawinkler]

Welcome to the forum!

Yes, it's normal.

The recorded f stop number is an estimate by the camera.

There is no electronic communication from the lens to the camera.

Edited September 17, 2014 by k-hawinkler

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[FlashGordonPhotography]

Leica lenses do not transmit any exif data to the camera body during exposure, except for focal length via the 6 bit code. The aperture value in exif is from a small sensor above the lens mount and is a guess at best and often not what you set on the lens. Filters are also not taken into account so things can and will get more "interesting" with exif.

 

If you really need it to be accurate there are programs to change exif data manually.

 

It's just part of the fun of owning a digital Leica.

 

edit: beaten by K-H :-)

 

Gordon

[Sekander]

Thanks K-h & Flash Gordon, cool to know and definitely not an issue for me anymore. Guess I'll have better dreams tonite - knowing this.

[k-hawinkler]

Sleep well!

[indergaard]

Completely normal. All my 0.95 shots are detected as 1.0 if they are correctly detected. Some are detected as f/1.4, f/2, f/2.8 and so on as well.. It's all approximations made by the electronics as there is no way for the lens to pass correct aperture information to the camera body. So ignore the detected aperture values, cause they basically mean nothing.

[Michael Geschlecht]

Advertisement (gone after registration)

Hello Sekander,

 

Welcome to the Forum.

 

An interesting question.

 

The difference between a lens opening of F1.0 & F0.95 is 1/7 of a stop.

 

When film speeds were being standardized & represented with numbers: One of the systems that was developed was for Deutche Industrie Norm. The film speed numbers using this system are acompanied by the acronym DIN.

 

DIN numbers are a logarithmic progression with each succeeding number representing a 1/3 of a stop increase in film sensitivity .

 

Example: A film which is rated at DIN 24 (Equivalent to today's ISO 200) is 1 stop faster than a film rated at DIN 21 (Equivalent to today's ISO 100).

 

The reason for choosing 1/3 of a stop as the dividing line was that the average person viewing different negatives taken of the same subject at different exposures required a minimum of 1/3 of a stop difference in exposure to see a detectable difference in 2 different negatives.

 

Best Regards,

 

Michael

[Herr Barnack]

Welcome to the forum!

Yes, it's normal.

The recorded f stop number is an estimate by the camera.

There is no electronic communication from the lens to the camera.

I have been wondering why my M240 thinks my pre-ASPH 50mm Summilux is set at f/1.6 or f/1.7 when I m shooting wide open at f/1.4...

[Sekander]

Completely normal. All my 0.95 shots are detected as 1.0 if they are correctly detected. Some are detected as f/1.4, f/2, f/2.8 and so on as well.. It's all approximations made by the electronics as there is no way for the lens to pass correct aperture information to the camera body. So ignore the detected aperture values, cause they basically mean nothing.

That's exactly what's going on. Thank you Indergaard. Good advice!

Thus instead of getting excited about Exif data exposure parameters, I may want to concentrate more on Pre-Treatment.

 

Cheers,

Sekander

[Sekander]

Hello Sekander,

 

Welcome to the Forum.

 

An interesting question.

 

The difference between a lens opening of F1.0 & F0.95 is 1/7 of a stop.

 

When film speeds were being standardized & represented with numbers: One of the systems that was developed was for Deutche Industrie Norm. The film speed numbers using this system are acompanied by the acronym DIN.

 

DIN numbers are a logarithmic progression with each succeeding number representing a 1/3 of a stop increase in film sensitivity .

 

Example: A film which is rated at DIN 24 (Equivalent to today's ISO 200) is 1 stop faster than a film rated at DIN 21 (Equivalent to today's ISO 100).

 

The reason for choosing 1/3 of a stop as the dividing line was that the average person viewing different negatives taken of the same subject at different exposures required a minimum of 1/3 of a stop difference in exposure to see a detectable difference in 2 different negatives.

 

Best Regards,

 

Michael

Hello Michael,

 

Thank you for taking the time to provide a captivating answer.

 

So that's neat to know::

Wow : 1/7 of a stop!

When comparing F1.0 & F0.95, the 1/7 stop would appear to be barely noticeable/"translatable for a healthy human eye(maybe not a falcon's)" in terms of shutter speed repercussions. Correct me if I misunderstood.

So, in this lens the available click-stops are F0.95 - F1.2 - F1.4... etc. and the stop difference implemented by Leica is a 1/2 stop between each?

For more details, I guess I'll have to delve into Erwin Putts' publications - according to Thorsten.

 

Years back when I started photography - I became familiar with the DIN / ASA nomenclature - At the time, I would have been pretty happy to get the explanation you provide in the last paragraph. So thanks again.

I guess this piece of knowledge is not necessarily anchored in the minds of many of us!

 

The 1/3 stop increment / decrement is well implemented by the 3 click-stops of the aperture setting ring for instance in Carl Zeiss lenses - which is very practical indeed.

 

Best regards,

Sekander

[ninicholas]

perhaps, the estimation is correct, there is no 0.95 in existence, just a myth or a number engraved on the aperture ring.

[k-hawinkler]

perhaps, the estimation is correct, there is no 0.95 in existence, just a myth or a number engraved on the aperture ring.

 

:D

[mjh]

perhaps, the estimation is correct, there is no 0.95 in existence, just a myth or a number engraved on the aperture ring.

That must have been what the designers of the Exif standard thought as there is no way one could represent f0.95 – or indeed any f-stop value < 1.0 – in the Exif metadata. The standard doesn’t allow it and although it has gone through many revisions, this restriction has never been lifted.

[DickieT]

Bringing this back to life this thread as I picked up a mint f1.0 (78-82) Nocti and it has the same pre-f1 and post f16 click-stop positions that do open/close the aperture just a tiny bit. None of this gets recorded properly with LR of course.

 

When I took off the cap for the first time, I almost unscrewed the lens in 2, but I understand that's normal too ?

 

Thanks! Dick

[IWC Doppel]

Is your lend a built I hood model ?

[DickieT]

No - it has 2 small steel pins on the side on which you push/slide the lens cap - bajonet style..

[Surge]

So it seems like many Noctilux aperture rings do move slightly past the end of the range (f/0.95 / f/16), correct?

[adli]

I assume this kind of questions is why Leica removed aperture from the exif data on the M10