M8 6-bit coding system - why is it necessary ?

[kingsley1]

Is there a reason why the lens information must be relayed through an expensive 6-bit coding on the lens and not fed in by

the user through the camera's set-up menu ? Can't the M8's firmware be made to accomodate this ?

[ronald_moravec1]

The firmware needs to know what lens is on the camera in order to make vignetting corrections etc.

 

The camera can tell the fstop in use by the difference in light meter reading , one outside, one inside.

[stuart_richardson]

Francis -- No, there is no reason that it couldn't be manually selectable through firmware, like how Nikon does it for non-

CPU lenses. For whatever reason, Leica has refused to do this. Probably to sell newer lenses and try to prevent Zeiss and

Voigtlander from gaining market share.

[kingsley1]

Stuart, that is exactly what I think. I use old "Ais" Nikon lenses on my Nikon D700 and all I have to do is to enter the lens information (i.e. its focal length and its maximum aperture) in the set-up menu and the camera will then allow its metering system to be used with the lens. I believe what the M8's sensor does when it reads the 6-bit code is the same thing i.e. picking out the lens information to be used by its firmware.

[anthony_brookes5]

So for a Leica dealer to say that your M6 lenses can be used is not telling the truth. What he means is that only modified M6 lenses can be used. Is that right ?

[kelly_flanigan1]

Anthony; One can add a LTM to M adapter and use any LTM lens; or just use a 1950's M lens too. Thus one can shoot with a Rigid 50mm F3.5 Industar LTM from a Zorki if one wants too; or a 15mm VC LTM lens; or a 1970's Noctilux; or The other brand thats making M mount lenses. If one gets vigneting one can use the raw converter in photoshop and force the image to have even illumination; even its its a pre WW2 LTM lens. One can also make ones own 6bit code with a sharpie (magic marker) too.

[kelly_flanigan1]

One can also use a Novoflex "LEM/NIK" adapter as use Nikon F mount lenses on a M body; here I use one with my Lweica M and Epson RD-1/s.

[kelly_flanigan1]

If camera companies didnt need the sell new lenses to stay afloat they could have a wheel to turn for lenses A; B; C and D; where one in software injected the vigneting signature for a 15mm VC lens; your 35mm F2.8 LTM Nikkor; your 50mm F2 DR Summicron; your 80mm F2.8 OhMyGosh Triplet; your 13.5cm Russian gem.

[larry_kincaid2]

I use Leica lenses from 75 Lux, 50 Lux, 35 Lux, and 24 f2.8 without any lens coding. I've never seen any problem with the images from any lens. It's supposed to be necessary from 35mm and wider, but I've taken many tests shot at blue skies and white walls and I have not seen any problems in the corners whatsoever. My advice is shoot without coding until you see a problem, and if you don't have any problems, forget about it. I don't need to pay that much money to have information automatically recorded. It also irks me that this issue is not resolved with software. Anyone else have the same experiences with wide, uncoded lenses?

[blakley]

Vignetting and color fringing (with filters) are only problems at focal lengths wider than 50mm, so lots of existing M lenses can be used, with or without filter, uncoded. Uncoded lenses wider than 35mm will exhibit (relatively mild) vignetting, which is an effect you might like, and which can easily be corrected in photoshop using an adjustment layer with a radial gradient. They will also exhibit "cyan corners" which can again be corrected in Photoshop, again using an adjustment layer and a red radial gradient.

 

So when your Leica dealer says you can use the lenses you've been using on your M6, he's telling the truth. Using modified lenses is a bit easier when you go wider than 50mm. It would certainly be possible to update the M8 firmware to allow entry of lens information through the menu system, but Leica seems very reluctant to do this.

[steve_swinehart]

I'm with Larry - I use an uncoded 35mm on my M8, and cannot see any vignetting, or cyan corners. My shorter focal length lenses (28mm, and 16-18-21mm) are coded, and of course, they works fine.

[john fleshin]

Some shops are machining the mounts, or adapters, to key in the data. I heard Dag is converting G2 16mm to M mount, with the coding. Am wondering when some one starts to sell stickers on ebay for them?

[a_y]

Does it really make a difference?

 

Any test/info on showing the difference between using a coded and a non-coded lens in M8?

 

Thank you very much.