Leica 6bit coding vintage lenses

[stump4545]

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besides EXIF data, is there any benefit to coding older Leica lenses like the 50mm 2.8 elmar or 35mm cron v4?

 

or just turn off lens detection?

 

vignetting?

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[Ecar]

Yes, there is a benefit - mostly in the corners/edges and mostly for lenses wider than 50 mm. Then again, it varies by lens and it may not bother you or you may want to correct any issues in post-processing.

[Printmaker]

I use a 35 Summicron type 4 on my M9 and just dial in the lens. No big deal because I use that lens most of the time. If I were switching lenses a lot, I would either have it coded or buy a new flange on ebay that allowed me to self-code.

 

But now that you mention it, I better check my dial in. I was using my 50 Summicron yesterday and do not remember changing the setting back to the 35...

[hoppyman]

Disregarding the convenience of the EXIF, you are unlikely to gain any practical benefit for lenses longer than 35mm.

However the simple test for you with your 35 is to shoot a good representative sample with manual setting on and off and compare results.

Commenting from experience it is easy to forget to change the detection settings when you change lenses and that can be annoying. Manually correcting the EXIF of a couple of hundred frames loses its charm quickly ;-)

 

As an additional consideration you might elect to have a CLA at the same time on any lens upgraded to the 6 BIT standard.

[stump4545]

for say a 28mm lens what is the image benefit gained by setting the correct lens on an M9/MM?

 

is the image benefit limited to vignetting compensation?

[hoppyman]

Vignetting in the traditional senses, but also correction of "red edge" effects with some wides in some circumstances with some cameras.

The differences due to vignette correction are easily seen in a comparison. Whether or not the lack of correction will bother you will depend on your content and preferences. Also the firmware corrections are aperture independent (one correction per lens only) and based on best case (not wide open where largest vignetting can occur).

 

 

 

As mentioned you will inevitably forget to reset if you use manual selection.

[Leicaiste]

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Also the firmware corrections are aperture independent (one correction per lens only) .

 

Are you sure of that ?

A (guessed by the front cell) aperture is recorded in the exif.

[250swb]

Are you sure of that ?

A (guessed by the front cell) aperture is recorded in the exif.

 

The corrections only apply in a general way, so if you open the aperture up, or close it down you will probably still see some vignetting at the extremes. For instance the coding does not fully correct the vignetting on a modern 28mm Summicron, it just makes it a bit better at the medium apertures. I personally don't mind a bit of vignetting and some simple post processing corrections can remove it anyway. So it acts like the guess the camera makes for the aperture, it isn't totally accurate, but better than nothing given the digital sensor responds in a different way to film, for which most Leica lenses were designed.

 

Steve

[hoppyman]

Yes. To the best of my knowledge. As far as I recall that came from engineers at Leica Camera. My understanding is that, as far back as the M8 development, Leica Camera discontinued an initial plan to use that brightness sensor information for exposure adjustment as it proved insufficiently precise. Over correction might introduce new problems.

One instance that may be relevant is that there is only a single correction applied for all three focal lengths of the 16-18-21. That information was directly from Leica Camera to me.

 

However I am always interested in improving my understanding/knowledge. Do you have any evidence to the contrary? An experiment would be possible.

Can you contribute or comment on what the Original Poster asked about?

[01af]

One instance that may be relevant is that there is only a single correction applied for all three focal lengths of the Tri-Elmar-M 16-18-21 m Asph. That information was directly from Leica Camera to me.

I gave this information here on the forum three years ago.

[IWC Doppel]

I code as many lenses as I can to avoid the repeated problems with using a different lens with the wrong code.

[hoppyman]

I gave this information here on the forum three years ago.

 

Olaf I recall that there have been previous discussions including that topic and some varying opinions posted. What I said is still true. I emailed Leica Camera on this at that time and Jesko von. Oeynhausen responded to me, as he did on the "Red edge " topic too. I shared those answers here of course.

 

"...The manual setting to 16 / 18 / 21 mm only influences the exif data. The lens correction alogrithms is the same for all f-lengths, like in "auto"......."

 

You can be credited with agreeing with the M Product Manager if you like

[01af]

What I said is still true.

Yes, sure it is. I didn't disagree.

[algrove]

As someone mentioned above, if you often change lenses then for me it helped immensely as I forget to manually coded lens changes.

 

In addition to being some what accurate in my EXIF data, I find knowing which lens I used the most on a certain trip (or for a specific photo) is beneficial. I often use this information to decide on what lens or lenses would be best for another similar trip.

[bjornthun]

Another advantage to coding vintage lenses and indeed all lenses is that the raw converter can recognise the lens used. In the case of Lightroom this allows you to have profiles for correction of distortion and vignetting automatically applied. You can create your own profiles for Lightroom and teach Lightroom which profile should be applied to which lens in addition to or instead of default values. Coding will also make batching with software like Cornerfix easier, since one doesn't have to remember which len was used for each particular shot.

 

As a side example, I've put Dandellion cpus on my Leitax converted R-lenses so I can automatically apply Lightroom profiles for them, if I wish to.