Difference between -X PG and PG

[jaimeb82]

I am looking at a Minolta 50mm 1.4 lens to buy and found two different codes. One is:

MC Rokkor PG 1.4 50mm

and the other is:

MC Rokkor-x PG 1.4 50mm

Is anyone familiar with this lens, and if so, what's the difference between those two?

any info will be appreciated,

thanks,

jaime.

 

[dougjgreen]

The main difference is that all of the Rokkor-x lenses were multi-coated, while only some of the Rokkor lenses were, and some were not. But actually, with the specific lens in the OP's question, both were multi-coated. The main difference is that the Rokkor-x lens is slightly more recent, and has a couple of cosmetic differences (a red dot for alignment of the mount, and some bright orange text instead of white text). Also, earlier examples of the Rokkor used a knurled metal focusing ring, but the later ones used the same rubber waffle pattern of the Rokkor-X lenses.

The main FUNCTIONAL difference in Minolta's lenses occurred between the MC-Rokkor-X and the MD-Rokkor-X lineup, when Minolta added dynamically balanced aperture blades and an extra indexing pin, so that the Camera (XD series and the X-700) could set the aperture automatically based upon the meter reading.

 

[AgX]

What is that aperture blade feature about? Making the lens faster in the meaning of enabling a higher exposure rate?

 

[dougjgreen]

No, it allows the aperture to be stopped down to a controlled stop via the diaphragm actuating lever by the camera body for Shutter-priority and program. In the MC lenses, the lens can only be stopped down to the setting that the aperture ring is set to, which puts a mechanical stop to the autodiaphragm action - it's 2 way mechanical setting. In MD lenses, the lens can be stopped down by the body through the actuating lever to any intermediate setting between maximum aperture and the setting on the lens - depending upon the meter reading - unlike the MC lenses, it's a continuously variable mechanical setting.

That's a complicated explanation, but all that you need to understand is that MC lenses require the user to set the aperture via the aperture ring on the lens. MD lenses allow the camera to set the aperture to any intermediate setting between the max aperture and the mechanical setting on the lens based upon the meter reading - and Shutter priority and Program modes require this capability.

 

[Ralph Javins]

Good morning, Jaime;

The main difference between any of the lenses without the -X engraving and those with the -X, is the destination. The ROKKOR-X lenses were those shipped to North America and were imported by the Minolta Corporation here, and they carried the Minolta Corporation "M-tag Warranty." The only difference in how the lenses were treated while in Japan was that the -X lenses did have some minor cosmetic differences (such as the "-X") and they received some additional quality control checking requested by the Minolta Corporation. This information was given to me originally by my local Minolta Camera vendor back in the late 1960's, who also explained that the "X" was associated with "Export." At least, that is what I was told, and there have been corroborating statements in books seen in recent years.

Functionally, you will not see any difference in the lenses with or without the "-X." Others have mentioned that there are some differences in the MD lenses, and the earlier MC lenses, which are functionally different mechanically from the even earlier SR lenses, all of which use the same basic bayonet mount. The differences in those lenses are related mainly to the meter coupling systems. MC on the lens refers to "Meter Coupled," not to "Multi-Coated," and came out with the introduction of the SR-T series of cameras. The "MD" variants appeared with the additional meter coupling lug for use on the "X" series of cameras, especially the X-700 with its Program Mode. Even the earliest SR lenses were coated, but the coatings improved, and became Multi-Coatings as time went on, and they were introduced on the production line when it was felt that the improved coatings would help. There was no point where the improved coating process change occurred with a lens series model change, such as the MC to MD. If the new coating process was better, they put it in.

Optically, there were small incremental improvements in the prime lenses over the years, but they were pretty mature by the time of the introduction of the Minolta SLR camera back in 1958. Yes, Minolta does predate Nikon in that regard. The main area where we have seen real improvement in lens quality has been with the zoom lenses. The ready availability of computers to aid in lens design has produced the major improvements seen there.

You might notice a slight difference in the price of a lens with the "-X." Sometimes it will be a bit higher, but with the Minolta Corporation M-tag Warranty program being over now, there is no longer any really significant reason for any price difference.

 

[dougjgreen]

But Ralph, the fact is that the earlier non-X designated lenses were also imported into the U.S. prior to the Rokkor-X, M-tag program. The fact is, in the U.S., an X designated lens will have been slightly newer than the non-X lenses as well. But you are right in that there is no functional difference between one set of MC lenses and the other. Just that as time went by, more of the lenses were multi-coated, and a few cosmetic details were added, including the red raised plastic alignment dot, and some of the text on the lens being painted in orange, rather than white.

The main functional difference occurred at the transition to MD mount, which was a few years after the Rokkor-X, and coincided with the XD series camera introductions.

 

[Ralph Javins]

Good morning, Doug;

Yes, and to make things even a little more confusing, toward the very end of the Manual Focusing Era for Minolta, they dropped the "-X" on the lenses and later they even dropped the name "ROKKOR" and went with just "MINOLTA." I guess the engraving guys' union really got to them.

In this particular case, the main question was about an "MC" lens, so I did not want to wander too far away from the original question.