6 bit coding

[mctink]

I just bought the M8. Could someone please explain about the 6 bit coding. What does it do and do I need to have it done to my 50mm lens and my 90mm lens.

[Paul Hart]

If you have the instructions for the M8, you'll find some information about the coding on page 86. If you do a search for 'coding' on this site you'll find a lot more information.

[LeonardT]

Originally Posted by mctink

I just bought the M8. Could someone please explain about the 6 bit coding. What does it do and do I need to have it done to my 50mm lens and my 90mm lens.

First I'd like to welcome you to the forum. There is certainly a wealth of knowledge here on just about any Leica related subject you can think of going back over 70 years to the first 35mm film cameras to the present digital M8 and the latest lenses.

Now to your question. The only thing the 6 bit coding does is tell the M8 what lens is currently attached to the camera. This information is used to correct vignetting in certain lenses and color artifacts left in the sides and corners of the images when using the UV/IR correction filters. Since the M8 is very sensitive to Infrared, certain surfaces like synthetic black cloth will appear violet colored instead of black. It will also change the color hues of other objects to be different then what they actually are. You must use the UV/IR filters available from Leica and other vendors to correct these color changes.

Now to the filters. If you look through the filters directly head on the view will be clear with no apparent color shift. But if you start tilting the filter so you are looking at it at an angle the filter will appear to change color, to cyan, the more you tilt the filter. The amount you tilt the filter is equivalent to how the sensor in the M8 sees through various angles of wide angle lenses. The more you tilt the filter or the wider the lens will show up in the photos as cyan color at the edges. In order for the M8 to properly correct for this cyan coloration it needs to know how much correction to apply to the picture. This correction is different for each lens and that's why the camera needs to know which lens to correct for.

I hope this has been clear. But to answer your question, I don't code any of my lenses longer then 50mm. In the case of the longer lenses there is very little tilt angle to cause the cyan to appear.

Len

[@bumac]

I use all from 35 to 90 without coding, the rest I have coded it.

[LeonardT]

Originally Posted by mctink

I just bought the M8. Could someone please explain about the 6 bit coding. What does it do and do I need to have it done to my 50mm lens and my 90mm lens.

Just an additional comment. You can probably get away with not having your 50mm lens coded or your 90mm. But you do need to use the filters.

Len

[chris_livsey]

Originally Posted by LeonardT

Just an additional comment. You can probably get away with not having your 50mm lens coded or your 90mm. But you do need to use the filters.

Len

That depends on the 50 A post recently showed significant (IMHO) effect of coding on the Noctilux. Maybe less on the lux and less again on the cron but someone would need to prove that. My lux is too old for coding another consideration to add to the answer see the list of codable "heritage" lenses on the Leica site.

[LeonardT]

Originally Posted by chris_livsey

That depends on the 50 A post recently showed significant (IMHO) effect of coding on the Noctilux. Maybe less on the lux and less again on the cron but someone would need to prove that. My lux is too old for coding another consideration to add to the answer see the list of codable "heritage" lenses on the Leica site.

Here is a photo I took this past saturday with the current uncoded Noctilux at f1.0. It was in a dimly lit museum room and while the photo does show some vignetting or maybe it's just the lighting there is no cyan drift. I use maybe 5 or 6 50mm lenses with my M8 from the Noctilux to the 3 versions of the Summicron and Summilux asph. Only the Summilux is coded because I got the free coding of two lenses when I bought the WATE. I don't really see a need for coding on any of them. And I use filters on them all.

Len

L1009191.jpg

[innerimager]

I coded all my lenses (the last 2, 75/1.4 and 90.2,8 still in NJ) including those longer than 35mm for 2 reasons. First, I had vouchers to get them done for free. Even so, giving them up for 6-8 weeks made it hard. Reason 2 is that it seems possible that future advances of the firmware and even hardware capabilities of the M8 may use the lens coding for other reasons than corner color. Perhaps certain lens optimizations or something of that sort. But if I had to pay, especially the increased cost of the coding, I doubt I would have done it on the longer lenses. The wider ones are a must.. best....Peter

[chris_livsey]

http://www.l-camera-forum.com/leica-...tml#post442732
This is post I was referring to, I posted from work with limited time to search. Obviously the aperture used,lighting conditions and subject will all affect the difference,if any, seen between coded and non-coded in "real life" photography. Some are unhappy just knowing it's there, even if they can't see it I merely put it forward that coding a 50 is not a straight yes or no there are many factors to consider even down to just having the lens recorded in the exif.

[LeonardT]

Originally Posted by chris_livsey

http://www.l-camera-forum.com/leica-...tml#post442732
This is post I was referring to, I posted from work with limited time to search. Obviously the aperture used,lighting conditions and subject will all affect the difference,if any, seen between coded and non-coded in "real life" photography. Some are unhappy just knowing it's there, even if they can't see it I merely put it forward that coding a 50 is not a straight yes or no there are many factors to consider even down to just having the lens recorded in the exif.

Thanks, Chris.

Subtle but a difference, yes. I would love to have my Noctilux coded but I don't want to have it sitting in New Jersey for two months. That's what it took for my Tri-Elmar and 7 weeks for my current 50mm Summilux Asph. To me that's not acceptable. As long as my uncoded lenses give me the photos I like they'll stay that way.

Cheers,
Len

[chris_livsey]

Originally Posted by LeonardT

Thanks, Chris.

Subtle but a difference, yes. I would love to have my Noctilux coded but I don't want to have it sitting in New Jersey for two months. That's what it took for my Tri-Elmar and 7 weeks for my current 50mm Summilux Asph. To me that's not acceptable. As long as my uncoded lenses give me the photos I like they'll stay that way.

Cheers,
Len

Hi Len
I agree. I have fallen foul of the new Leica desire to rebuild any lens sent for coding. I sent a 90mm Elmar M newish lens working spot on on the M8 really for exif and any future corrections and I could live without it. Off to Germany,early Jan, reply was spend within £50 of what I paid S/H to 'repair'. I said no thanks works for me send it back and that was three weeks ago
As it was S/H although mint I had tested it extensively and was happy. Let them tamper, especially your noctilux, no way given the track record.

[mctink]

Thanks to everyone who has helped me to understand about the 6 bit coding. If I do decide to do it I am hoping that I am eligible for the pro-service status at Leica. If I qualify I can get a 3 day turn-around time. To be without my lenses for 4-6 weeks won't work for me.