Proof of concept regarding self coding of lenses

[stan98103]

Originally Posted by butter71

i don't think this is correct for the latest ASPH model (4th gen?)

working clockwise, it would be 0XXX0X

most of the others in this thread are counter-clockwise. we should standardize.

Thanks for the correction on my typo. I've edited the original to correct it as well.

Stan

[marknorton]

Excellent - I assume a Sharpie is some sort of pen. Better than any sort of label on the back of the lens and the marking can easily be refreshed. Just sent three more lenses off for coding, better not say how much I have spent on lens coding LOL.

All we need now is a template to fit over the lens bayonet so that you could mark the lens directly.

Keep in mind that the lens will only be recognised if it brings up the correct frame-set as well as having the coding.

[marknorton]

Sean, with Mike's elegant coding solution, that kind of removes the need for user lens selection, doesn't it?

[mike prevette]

Sorry for the late reply, i had to leave right after I posted this.

Yes the tape is over the front is merley to prevetn a floating "Leica" in all the shots I do through glass and car windows. That and i refuse to be anyones walking bilboard unless they pay me to be one.

The tape on the back is to pretect against weather. If you look closely you will se a seme between the topplate an when the screen begins. It totally looks like a place rain would collect. So I covered it. I am alo going to cover the 360degrees of the bevel of the screen itself, as I already have a few dut particles under the protective plastic.

I was so amazed that this worked even though the Zeiss has a screw directly under one of the coding points. Still not sure if the coding is matched to the frame lines but I seriously doubt it.

None of my screw mount to M adapters were a possibility for this as they have a cut away shape where the lens sensor is. i.e. there is no material on the mount to draw on.

Thanks so much for those of you who posted codes. I will do a complete test tomorow regarding the effective ness of all this.

No telling how long sharpie (magic marker) will hold up on a lens mount. Using an end mill and grinding an indent + using enamel paint is a much more permenant method. But also more hazordess.

I do not think this is an excusse for Leica to get away without providing us with manual contorl over the vignetting corection. That should be manditory. and please head Sean's advice about writting Lieca and telling them.

this whole coding system is bunk anyway. Any correction system that doesn't take into account shooting aperture can cause more harm than good. Imagine shooting with a lens that the firmware corrects for 1 stop of vignetting, at f8 when the lens renders no noticable vignetting. The camera wil still automaticly correct for it, and to your RAW data none the less. Thats unacceptable.


_mike

[mike prevette]

As far ar trying by eye. I don't recommend it, Look at my original file an how I set up a guide with tape on the body. The IR leds and sensors are VERY small, and accuracy is key here. Its not hard, but it does take some attention to detail to get it right. Also placing tape or a label between the lens and the body is a very bad idea. It will throw off your focus, and possibly bend or distort the very important flange to focal distance.

_mike

[masjah]

Mike

According to the review in LFI (though some dispute this) the "blue dot" gives the camera a metering which is compared with the "stopped down" TTL metering to enable it thereby to calculate the set aperture to within +/- 1 stop - which is good enough for vignetting correction purposes.

SOme people do dispute this, but I'm inclined to believe it - they wouldn't make up a story complete with specified tolerances, so I thing they got it from the horse's mouth.

[scott kirkpatrick]

The LTM to M adapter that Cameraquest provides is missing material around the bottom half of the mount, including in the area where the dots are picked up by the LEDs in the M8. However, it looks as if the part of the mount which remains is sufficient to cover the LEDs. So there's a prize for the first successful hand-coded CV lens. And if this can't be done, it is a serious setback for the under $10,000 full lens kit M8 purchaser scenario.

Here's another scenario. Take out the sharpie and an uncoded M-mount lens, and step through all the 64 possible codes. Install each time on an M8 with current firmware and see from the LCD on the back what it thinks is installed. Report the result, and accept the cheers of all the readers of this thread.

regards to all,

scott

[andybarton]

Originally Posted by sdai

I suspect this thread will be quickly locked down or simply disappear because it's obviously offending the forum sponsor's business interest.

Given that the vignetting and other characteristics of Zeiss lenses are likely to be completely different to those of Leica ones, the only advantage that I can see of this operation is to add the focal length to the EXIF data.

I can't see Leica objecting to that.

[mike prevette]

Vignetting is vignetting. Its a circular progressive decrease in luminance transmission. Even if the leica 21 doesn't vignette like the zeiss 21, possibly the leica 35 vignettes like the zeiss 21 or etc etc. ts just a matter of testing a little. I am willing to bet the math behind the M8's lens correction system is far simpler than you think.

_mike

[mike prevette]

Originally Posted by masjah

Mike

According to the review in LFI (though some dispute this) the "blue dot" gives the camera a metering which is compared with the "stopped down" TTL metering to enable it thereby to calculate the set aperture to within +/- 1 stop - which is good enough for vignetting correction purposes.

SOme people do dispute this, but I'm inclined to believe it - they wouldn't make up a story complete with specified tolerances, so I thing they got it from the horse's mouth.

Interesting, I hadn't read that. I only read that the blue dot was responsible for average ttl flash and viewfinder information brightness.

_mike

[carstenw]

Maybe you can use a purple one, Guy

I presume that the reading you did is counter-clockwise? Let's standardize on clockwise, it seems logical somehow. However, I would suggest that instead of 0 and X, where X means sharpie, we use binary. These are numbers. Standard in the computer industry is that 0 is black (like 'off'), 1 is white (like 'on'), and the easiest way to read the pattern is to place it at 12 O'Clock. Here are all the codes so far, read in this way (compared to previous chart 0 is 1 and X is 0).

16-18-21/4.0 Asph: 010101 = 21
21/2.8 Asph: 100111 = 39
24/2.8 Asph: 100110 = 38
28/2.0 Asph: 100101 = 37
28/2.8 Asph: 100011 = 35
28-35-50/4.0 Asph:
35/1.4 Asph: 100010 = 34
35/2.0 Asph: 100001 = 33
50/1.0: 100000 = 32
50/1.4 Asph: 011111 = 31
50/2.0: 011110 = 30
50/2.8: 011101 = 29
75/1.4:
75/2.0 Apo-Asph: 011011 = 27
90/2.0 Apo-Asph:
90/2.8: 011001 = 25
90/4.0:
135/3.4 Apo-Asph:

Still wanted: 28-35-50 T-E, 75 Lux, 90 Cron, 90 Macro, 135 Telyt.

[chetccox]

Decimal equivalent from binary codes-

21 f2.8 0XX000 = 24
24 f2.8 0XX00X = 25
28 f2.0 0XX0X0 = 26
28 f2.8 0XXX00 = 28
35 f1.4 0XXX0X = 29
35 f2.0 0XXXX0 = 30
50 f1.0 0XXXXX = 31
50 f1.4 X00000 = 32
50 f2.0 X0000X = 33
50 f2.8 X000X0 = 34
75 f2.0 X00X00 = 36
90 f2.0 X00XX0 = 38

Interesting? I would guess the 75 lux to be X000XX =35 (

[mhoutman]

Originally Posted by butter71

we should standardize.

a bit of "ISO coding for Dummies"

Michiel

[carstenw]

I have placed the entire list here:

Leica M8

I have taken the liberty to change the scheme slightly. I have kept the clockwise reading, which is a good idea. However, I have chosen 0 for black (like 'off') and 1 for white (like 'on'). This is more commonly used, and allows reading the codes as binary numbers, a convenient short-hand. I will add more codes as we find them.

Perhaps we should have a quick vote as to which way is more likely to be what Leica uses, and then settle on that. It is better for some of us to change the way we think (me included) than having two standards out there.

I vote for 0=black, 1=white.

By the way, although the numbering scheme is not obvious, it does allow to deduce some of the codes with high probability, for example, that the Elmarit-M 28mm f/2.8 (pre-ASPH.) is going to be 36 (100100).

[marknorton]

First generation TE is 010101 (0= black, clockwise) = 21. Are you sure about the 16-18-21 TE?

Mike - the frame selection lever definitely is used to qualify the coding - it allows the TE selected focal length to be displayed and if you use a normal coded lens, changing the frame selection lever to a different position causes the lens not to be recognised.

[Riley]

any sort of foil or paper would raise the lens from the body which should be avoided
the idea of using a marker pen is great, its handy that you dont need white

if an image was provided, a stiff card template would make the job quick and accurate

its nice to see people working together to get a solution from systematic tasking, rather different from some of the other threads here of late

Riley

[egibaud]

Originally Posted by sdai

I suspect this thread will be quickly locked down or simply disappear because it's obviously offending the forum sponsor's business interest.

Maybe not... if the sponsor start selling coded stickers ;-)

[blovitch]

What is a sharpie ?

[M'Ate]

Originally Posted by egibaud

Maybe not... if the sponsor start selling coded stickers ;-)

Suggest all we need is a clear plastic template with holes in the right places so a Sharpie, or a more permanent marker, can be poked through to mark the mount.

How about using a Dremel and filling it with paint ?

[marknorton]

Leica told me at Photokina that the lens coding is being done at cost or close to in order to maintain compatability. So the loss of revenue is unlikely to have the guys in finance jumping out of the window.

Mike's solution is better than mine - which used Scotch tape to avoid marking the lens or body - costs nothing and should remove at a stroke the complaints from people who do not want to have their lenses coded plus there's a route for Zeiss and CV users.