M9 minor issue

[Daniel Leung]

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Hi,

 

A friend of mine bought the M9 last week. with the 50 f/2, the f-stop in the camera is consistently indicated as one half stop too high (i.e. At f/2 the camera reads f/2.4, etc.).

same issue with the Noct F1, it reads F1.7 instead of F1. the camera does have the latest FW.

 

any comments?

 

Tks

DL

[gravastar]

If you are referring to the f stop reported in the EXIF data, then that is only an approximation. There is no coupling between the lens aperture ring and the camera body. What the camera does do is to compare the reading of it's internal exposure meter to that of the small photocell just above and to the side of the Leica red dot in order to estimate the aperture set. The estimate is used to improve the in camera vignetting (M8 and M9) and corner color cast corrections when UV-IR filters are used (M8).

 

Bob.

[delander †]

The F-stop used is not directly transmittted to the camera. The number you see in the RAW convertor is an estimate based on the exposure and the light level read form the little sensor on the front.

 

This has been discussed many times on this and the M8 forum.

 

Jeff

[250swb]

Its similar to calculating the wind direction by licking your finger and sticking it up in the air, it gives a rough idea of direction, not an exact direction. Likewise the aperture reading can sometimes be way out, sometimes spot on, but its all calculated guesswork.

 

Steve

[zeitz]

If you really need to know the aperture that you used, so some reason, get out a piece of paper and write it down.

[REberhard]

Thank you all, particularly to Bob. I am actually the friend Daniel is referring to.

 

For coded lenses the exposure in the EXIF data is reported correctly. Thus, if I coded the two lenses mentioned would the camera then read the data from the lens?

 

Roland

[delander †]

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Thank you all, particularly to Bob. I am actually the friend Daniel is referring to.

 

For coded lenses the exposure in the EXIF data is reported correctly. Thus, if I coded the two lenses mentioned would the camera then read the data from the lens?

 

Roland

 

If you are referring to the aperture you actually used I'm afraid not. All my lenses are coded and the aperture number in the EXIF is still a guesstimate. Sometimes its near sometimes not. But I do find it useful because it tends to guesstimate apertures slightly smaller than used. Some lenses are more accurate than others.

 

Jeff

[Ario Arioldi]

The purpose of the 6 bit code is only to let the camera know which lens is mounted on.

Cheers,

Ario

[REberhard]

So, just to be crystal clear, whether the camera reads the lens from coding or whether I input the camera manually has the same effect?

[mby]

So, just to be crystal clear, whether the camera reads the lens from coding or whether I input the camera manually has the same effect?

 

Yes.

[Daniel Leung]

The purpose of the 6 bit code is only to let the camera know which lens is mounted on.

Cheers,

Ario

 

Just curious to know. the 50mm F1 that I own is not coded. I heard that the F1 was original designed for film camera. the coding will minimize the vignetting as well as improve the white balance. is this true? it it worth it to send it to do the coding?

Tks

DL

[jaapv]

Not if you are comfortable with selecting the lens in the menu.