Minolta MC and MD - Differences and a problem

I posted this last night in the Minolta Manual Focus group but it hasn't gotten any hits so I'll try it here.

I just got a MC Rokkor-PF 1:1.7 55mm on a SRT 101 and a MD Rokkor-X 1:1.7 50mm on a SRT 201. What are basic differences between these lenses other than the focal length?

There is a problem with the MC. Off the camera, the apperature stays at maximum when you turn the Apperature Ring to a smaller opening. On the camera, the Stop Down button will not close down the opening. I can get the opening to stop down only by removing the lens and moving the small lever on the back that couples with the stop down button.

Comparing the MD on both cameras, it looks like the 201 stops down when the button is pressed and opens back up when the button is released. The 101 appears to stop down and stay there until the stop down button is pressed again. The MC will not stop down on either cameera.

The MD lens works as described on both the 101 and the 201

Good morning, John;

This message has two (2) parts:

(1.) You may not like this answer. The MC ROKKOR-PF 1:1.7 f=55mm lens has a problem. Unless you have a manual for the lens that describes the disassembly procedure, and the tools for doing the work (including the JIS form of "Phillips" screwdriver tips), I do not recommend this lens as a subject for your first lens repair. The lens normally is known to be quite good, and is probably worth the effort of a repair. My personal opinion is that the 55mm lens is closer to 58mm and I find 58mm to be the optimum focal length for a normal lens. To me, the 50mm focal length is slightly wider angle in its field of view. I have discussed my reasoning why in previous posts, both here and in the Manual Minolta Forum. Again, your 55mm lens has an aperture control problem that will require the attention of a competent camera technician.

(2.) I am sorry that the Manual Minolta Forum or Group has not been as responsive as you might like. There have been a few noticeable changes in the "social groups" since the Great Migration to the "New System" a few months back. One of those changes is the loss of an indication that there has been a new posting in the Group. That previously available indication was very useful in showing us that there was something new in there, and we should go into the Group and see what it is. There are several people in the group who have great experience with Minolta, and they will probably give you a response similar to what is written just above, although probably without the comment about a 58mm focal length.

Agreed. Ralph's assessment, on the surface ('cause we're not there and pro techs we are not), would seem to be correct. As these systems are tanks, the gear does tend to go through its fair share of abuse and is exposed to more bangs and bumps and bruises. Hey, it can take it. But this one seems to have become unsettled. Repair, replace or saunter on in with mirco screwdrivers in hand.

As to the group, give it a couple of days. I check it regularly (though not hourly).

Thanks. The lens didn't cost aything so dollar wise it's not a great loss. There's a good shop here. I'll see what they say about the lens. If the estimate is too much I may try to locate some tools and instructions and look inside. That would have been a good task this winter after I got sick and tired of snow pictures.

Do you know the difference between MC and MD?

I'll keep checking the Minolta Group. I usuall forget to keep an eye out there.

Hi,
sorry to hear that your lens isn't working, but from what you describe, it certainly is an aperture problem. If the lens had sentimental value, you could have it repaired fairly easily, but honestly, it's probably just not worth the money.
Are you a project kind of guy? If so, you may have some fun opening it up and seeing how it works...

The difference between the MC and MD lenses are mostly just the extra lug on the MD series that allow the use of S mode and P mode on the X-700; although in my experience that lug is not necessarily required for those modes...just set your lens on max aperture and let the camera do the rest. I never shoot in S or P mode myself, though, preferring A or M modes.
There Are some other differences in the lenses as well, such as the coatings being newer (better at reducing flare) on the MD lenses, and the fact that the MD lenses are smaller, lighter, and use plastic in some areas that the MC lenses use metal. My favorite are the MD ROKKOR (-X) versions because they incorporate the metal bodies of the first versions with the better MD version coatings.
Best of shooting!
Your fellow Minolta Bro,
Jed

MD lenses tells x-700 and sucessor cameras that the lens is set at minimum aperture. THis allows that when the camera automatically tells the lens to stop down, it knows that it is possible to 'push the lever' far enough that it will go to the smallest aperture. {P}rogram mode auto exposure setting is the only setting that is programmed to do this for the given level of EV it has sensed in the scene.

Sometimes there is even a little locking mechanism to allow you to lock the aperture to the smallest setting.

There may also be differences in the cam action of the stop down pin movement. I am pretty sure that MD has constant distance between stops; prior to program mode no one would care about this.

Sometimes the MD lenses may have a dit more sophistocated multicoatings, but this is not universal against all MC lenses. There os much fine MC glass, and I am happy to use it on my minoltas that can takes MD and use it properly. Who really wants a camera to decide exposure all on its own?

Good morning, John;

As mentioned, there are actually two responses to your inquiry; one here and one over in the Minolta Manual Focus "social" group. The responses are not the same.

The main difference between the MC (Meter Coupled) and the MD lenses (no real abreviation, just a designation to follow the MC one) is the addition of the second tab on the lens (the one associated with the Green marking on the lens ring) that communicates to the X-700 the minimum aperture or opening of the lens diaphragm for its use in choosing an appropriate camera setting for shutter speed and aperture opening when it is in "P" or Program mode. The MD tab or second tab has no other useful purpose on any of the earlier cameras. Your Minolta SR-T 101 and SR-T 201 cameras will use only the original MC tab on the aperture ring of the lens. The even earlier Minolta SR series cameras do not care if the lens has any tabs. They are fully manual operation.

The other differences between the MC and MD lenses are ones that happened due to time and the advance of technology. The MD lenses received the advantage of later developments in lens coating technology, although all of the Minolta SLR lenses from the SR through the MD were multi-coated. The earliest ones were done with only two coatings, but that is "multi." The other real difference came in the increasing use of high density plastics in the later versions of the MD lenses. This is one of the things that has many people preferring the earlier MC lenses; what they call a difference in "build quality." The real benefit of this development in the use of plastic parts in the lenses came a few years later when Minolta came out with their AF (Auto Focusing) lenses for the Minolta Maxxum 7000 and later cameras. (By the way, I do have a Minolta Maxxum 9.) The lighter weight lens parts had less inertia and were easier and faster to move when focusing with the small electric motors used for that purpose. It also took less battery power to move those lens parts. I think that it is alright to talk about auto focusing in this forum; we are not in the Minolta Manual Focus discussion group.

I tracked down a repair manual in Japanese with lots of pictures. It looks like you can get to the aperature area fairly easy. If I can track down the itty-bitty screw drivers, I think I try it. No loss and I might learn something.

The stop down feature on the 101 is correct, one push to close, one push to open. I am not familiar with the 201 stop down operation.
With the MC lens, I would approach it from the back. If the blades work when you press the lever on the back of the lens, and the aperture blades are clean(no oily blades). The linkage at the rear of the lens may be oiled up & sticking on the rear mount. It's pretty simple to clean by removing the mount & wiping the grunge out.

FWIW, the stopdown feature on the SRT101 only works when the shutter is cocked. I have never owned an SRT201 so i don't know if it is the same.