If you are registered, you get access to the members only section, can participate in the buy & sell second hand forum and last but not least you can reserve your preferred username before someone else takes it.
Nothing optically. The AE lenses can't be used in shutter priority or programmed modes on those bodies that support them. Aperture priority or manual only. I wouldn't hesitate to buy a non-MM lens if a good deal comes along.
The difference between AE and MM lenses is just important, if you want to use Tv or P-mode. AE lenses are with 2-3 exceptions just the older technique.
All Contax Cameras before the 159MM, which means befor ca. 1984 offered just Manual Mode and Av. Therefore the lens barrel has had different requirements than for the Contax Cameras after 1984. All lenses produced after 1984 (with 2-3 exceptions) are MM lenses.
The 159MM was the first Contax Camera with the so called Multi-Mode (MM), which means you can use them also for the new introduced modes Tv and P. There is a little switch on The MM lenses, which makes the Tv and P mode possible.
Optically, there is no differences in lens design, it is just the mechanical connection part. You can recognize the newer MM-lenses on the smallest aperture, which is always a green number (i.e. 16 or 22).
If you do not use anyway Tv and P mode, it does not make any differences to you. Used prices for AE are cheaper.
There is another nice advantage of this mechanical change: you can use a kind of selective Tv-Mode with MM-lenses.
If you put in Tv mode the aperture i.e. on 8 and the speed on 1/125, the camera will react as follows:
If there is enough light, you will shoot with speeds of 1/125 and maximum aperture 8. If there is even more light available, the aperture will stay at 8, but the speed will go faster than 1/125. Why is this an advantage?
Because you can use the lens at the optimum optical performance i.e 5.6 or 8 for maximum resolution of the lens and the film. With the speed setting of 125 you know that this will be shake-free. A kind of "do not worry combination".
Unfortunately, this is just because of this technical modification of the AE lens to the MM lenses. Therefore the N-System does not have that advantage anymore, which is a pitty...
On the MM/AE subject, someone told me that if you use an AE lens and wedge the little switch on the body, with a little sliver of wood for ex&le, the result is the same as if you used an MM lens, so TV and P work. If this is true, the only difference in the lenses is the little piece which activates the switch on the body. Does anyone have any experience of this?
I've already pushed the switch with a swizzle stick with an AE lens was mounted and I got it into Tv and Programmed modes, but I haven't tried shooting anything yet. Does this mean it works? Any suggestions as to how I should test this hypothesis and what I should look for?
I just purchased a 135 F2.8 (s/n 6601049), and the mounting ring is black (not silver like my newer 50 1.4). In addition, the "22" f-stop is white, not green. Nonetheless, the camera (RTS III) appears to function in Tv mode (ie the aperature changes, the shutter speed stays constant).
Any idea whether any older MM models retained the white "22," or does the absence of the green "22" mean this is definately an "AE" model.
your 135 F2.8 is an old Ae modified in MM.????
All Ae model can be modified to MM.
The difference is that MM model (not modified) will have the diaphragm most precise and fast.
Also all bodies from 159MM and after can be modified for use with Ae lens in Tv and Program.
In this case I noted an overexposure of 1/3 of stop.
I have converted Planar 135F2 and Distagon 28F2
The differnce about Ae Lens and MM lens is e little metal part on the base of lens.
It activates a switch on camera near lens attach.
If you install (in the just position)in Ae lens this little metal part, it become MM lens.
You can obtain the same thing using a little part of a toothpick to stop a little switch (near lens attach)at the end of his limit.
This is possible with 159 MM and all bodies made after.
As Contax and Zeiss tells a conversion is not possible (Cause it would be much too expensive). They say that MM lenses are using a different diaphragm mechanism which is much smoother to operate than the one in AE lenses.
I moved the diphragm lever on my Tessar 2.8/45 AE and on my Distagon 1.4/35 MM with a finger. The one on the MM lens is moving much smoother and easier than on the AE lens which is quite stiff.
You told about a overexposure before. Maybe this is a result of the stiffer mechanism on the AE lens. So camera can't set aperture correct.
It definitely doesn't work. The AE Spring-Blade Mechanics is too heavy and not linearly closing down. At the time the AE design was made, it was only important to close the blades at all, without taking care of "intermediate positions".
Doing what was suggsted generates a very big likelyhood for wrong (mostly over-) exposure.
As said, the MM Diaphragm-blades are much smoother designed (to close faster and with less force) and they are designed to give a defined (most likely linear) closing curve so that the camera can control the actual value.
both cameras are only working in manual and aperture priority mode with AE lenses. For time priority and program mode a MM lens is needed.
MM lenses could be recognized by the green shortest f-number and a little pin on the lower left side of the lens (look at it from behind)
with the yashica 108 and 109 mp-cameras you can use non MM-zeiss in program mode too. but the contax mm-combination is quicker concerning the time between measuring and exposure. btw: sigma made mm-lenses with c/y-mount! i have seen this in an older prospectus.
a camera doesn't always expose the film with the time/f-stop combination shown in the viewfinder. Sometimes a 673 1/s is needed or a f stop of 7.3.
As I know Contax-cameras really set the diaphragm blades to any value which is needet while Yashice can only set the values given on the Aperture ring. The "rest" is done by setting the shutter to another value than selected in TV-mode.
So Contax cameras need lenses which can be set to each aperture value for TV and Program mode.
This can also be possible with lenses of third party manufacturers.
Thanks Matthias for your help. I have a 50/ 1.4 CZ lens now. However, the f16 figure is in white, not green. The CZ box indicates that this is a Multimode lens. How can I be sure this is an MM lens or have the boxes been switched. I know you have referred to a small pin on the lower left hand side and I can see (at about 8 o'clock) a small lever that sticks out from the back of the lens slightly. There is also a lever near the 12 o'clock position, but this doesn't stick out as far. Have any 50/1.4 MM lenses been made without a green painted f16?
in my opinion someone switched the box. It's a unique feature of the MM lenses to have the shortest f-stop printed on in green.
A picture says more than words. So I took out my digital p&s and took some pictures of the pin and the corresponding switch on my Contax for you. The pin may look a bit different on your Planar 1.4/50mm (If there's one) than on my Planar 1.4/85mm 'cause of the smaller diameter.
I numbered all the connecting parts on the camera and the lens mount:
1 Automatic diaphragm coupler
2 coupler for largest aperture setting
3 aperture linkage lever
4 mm (program + TV) coupling lever
I have a 50/ 1.4 CZ lens now. However,> the f16 figure is in white, not green. The CZ box indicates that this > is a Multimode lens. How can I be sure this is an MM lens or have the> boxes been switched. I know you have referred to a small pin on the> lower left hand side
Another difference between the AE and MM lenses is the shape of the diaphragm opening - the older AE lenses have a sort of "sawtooth"shape when you stop them down a bit , the MM's opening is "rounder"....... Steve