[timw4mail]

1. My thoughts on build quality / functionality

• K lenses - the most well-built Asahi K-mount lenses
• M lenses - cheaped out and compacted K lenses
• A lenses - In between K and M in quality, adds auto aperture in the "A" setting, otherwise same as K and M lenses in functionality

2. As far as A lenses go: Aren't they just as annoying to use on a DSLR if you set the aperture manually? The aperture doesn't seem to get communicated to the camera except in the 'A' setting.


3. Is there a good fix for an M-series rubber grip that is loose? I have two lenses with this problem.



4. The Sears Auto MC 50/1.7 seems to be better in build quality and ergonomics than the Pentax M 50/1.7, with the exception of the aperture ring.

[jatrax]

As far as A lenses go: Aren't they just as annoying to use on a DSLR if you set the aperture manually?

That is sort of the point of having the 'A' setting. On a DSLR there is no reason to use any setting except 'A' if the lens has it. Except possibly with a bellows or some other exotic application.

[pepperberry farm]

That is sort of the point of having the 'A' setting. On a DSLR there is no reason to use any setting except 'A' if the lens has it. Except possibly with a bellows or some other exotic application.

I'm not sure why you wouldn't use the 'A' setting if it were available - just simplifies the process...

[jatrax]

I'm not sure why you wouldn't use the 'A' setting if it were available - just simplifies the process...

Me either. Main reason I have mostly obtained 'A' versions instead of 'K' or 'M', I don't want to mess with the aperture ring.

[timw4mail]

That is sort of the point of having the 'A' setting. On a DSLR there is no reason to use any setting except 'A' if the lens has it. Except possibly with a bellows or some other exotic application.

I'm not sure why you wouldn't use the 'A' setting if it were available - just simplifies the process...

Me either. Main reason I have mostly obtained 'A' versions instead of 'K' or 'M', I don't want to mess with the aperture ring.

Obviously I have a rather unpopular option on the matter

I just think its easier to turn the lens ring than bother with camera settings in this case.

[aremmes]

It should be noted that while the aperture ring on an A lens allows one to change the aperture only in half-stop increments, while a DSLR can adjust it by thirds as well -- or whatever the firmware chooses, really -- giving another benefit to controlling the aperture through the camera's controls.

[Adam]

2. As far as A lenses go: Aren't they just as annoying to use on a DSLR if you set the aperture manually? The aperture doesn't seem to get communicated to the camera except in the 'A' setting.

Just don't use the aperture ring, rather the dial on the camera. If you use the aperture ring, then yes you have to stop-down meter. But aperture rings are pointless in the digital age

As for the lens series comparison, generally image quality goes up over time. Also, the focus of the M series was compactness, whereas many K lenses were simple K-mount conversions of M42 lenses, and hence big.

Adam
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[jatrax]

Obviously I have a rather unpopular option on the matter

Not unpopular, just different. I shoot with a lot of M42 lenses so I do use the aperture ring. But if its k-mount I would rather use the camera dials. YMMV.

[timw4mail]

Not unpopular, just different. I shoot with a lot of M42 lenses so I do use the aperture ring. But if its k-mount I would rather use the camera dials. YMMV.

I have more K mount lens than K-A or K-AF, so I see it as closer to the film days, I guess.

[stevebrot]

My thoughts on build quality / functionality

K lenses - the most well-built Asahi K-mount lenses
M lenses - cheaped out and compacted K lenses
A lenses - In between K and M in quality, adds auto aperture in the "A" setting, otherwise same as K and M lenses in functionality

Those are rather unique conclusions. IMHO:

• K-series -- build was typical for top-tier optics of the time and essentially equivalent to the Super-Takumar lenses that came before
• M-series -- equivalent build to the K-series, but compact
• A-series -- Introduction of plastic build in some models, but otherwise similar to M series

I own or have owned Ex+ examples of all four series (K-mount + Taks) and was in the market to buy when all four types were new. In my opinion, the A-series is the first Pentax product where build was a disappointment. This was obvious when the cheaper A-series bodies were released.

2. As far as A lenses go: Aren't they just as annoying to use on a DSLR if you set the aperture manually? The aperture doesn't seem to get communicated to the camera except in the 'A' setting.

Ummmm...you are correct, that is how it works and the behavior was the same on K-mount film SLRs. What is detected by the body is whether the aperture ring is in the "A" position and if so, the maximum aperture and aperture range are read from the contact pattern on the mount. The logic tree for A-series and newer bodies goes like this:

Code:

Does the body support body aperture control?
 |
 |-- No --> Modes limited to Av and M modes using the aperture ring
 |
Yes
 |
Can the aperture be controlled by the body (aperture ring in A position)?
 |
 |--- No --> Disallow P and shutter priority automation
 |
Yes --> Read the maximum aperture and aperture range from the mount
        and allow all supported exposure automation modes

3. Is there a good fix for an M-series rubber grip that is loose? I have two lenses with this problem.

Trim to fit and fix with glue.

4. The Sears Auto MC 50/1.7 seems to be better in build quality and ergonomics than the Pentax M 50/1.7, with the exception of the aperture ring.

Depending on age, that lens is either a rebadged XR Rikenon or Cosina product. I own a few XR Rikenons and their build quality is a notch below Pentax offerings with a few exceptions. The 200/4 is almost identical to the Pentax-M as is the 28/3.5. Whether Ricoh made them for Pentax or Pentax made them for Ricoh is not known. If you like the build, that is cool. Sears and Ricoh sold a ton of them.


Steve

[stevebrot]

As for the lens series comparison, generally image quality goes up over time. Also, the focus of the M series was compactness, whereas many K lenses were simple K-mount conversions of M42 lenses, and hence big.

Ironically, the M42 lenses they replaced were much more petite. I have long puzzled over this. The closest I have come is that the K-mount diameter is larger and the lens barrel follows. The SMC Takumar 55/1.8 is a scant millimeter shorter than the Pentax-K 55/1.8 from mount face to filter ring. The K is simply fatter.


Steve

[IgorZ]

Obviously I have a rather unpopular option on the matter

I just think its easier to turn the lens ring than bother with camera settings in this case.

I prefer the aperture ring too. Was rather disappointed that the irix doesn't have one...

[Jonathan Mac]

1. My thoughts on build quality / functionality

• K lenses - the most well-built Asahi K-mount lenses
• M lenses - cheaped out and compacted K lenses
• A lenses - In between K and M in quality, adds auto aperture in the "A" setting, otherwise same as K and M lenses in functionality

2. As far as A lenses go: Aren't they just as annoying to use on a DSLR if you set the aperture manually? The aperture doesn't seem to get communicated to the camera except in the 'A' setting.

3. Is there a good fix for an M-series rubber grip that is loose? I have two lenses with this problem.

4. The Sears Auto MC 50/1.7 seems to be better in build quality and ergonomics than the Pentax M 50/1.7, with the exception of the aperture ring.

I own quite a few K and M lenses, and a few A series too. I would regard the Ms as only slightly behind the Ks in build quality, and that's probably due only to the higher weight (more metal) of the Ks giving them a more robust feel. Ms are without a doubt better built than As, though you need to bear in mind that the A series lenses, like the M series cameras, were the first series to introduce variations in build quality across the series. As such, it's more difficult to generalise the build quality, because it depends on the lens. The A series 50mm f/1.7 and f/1.4 lenses are quite poorly built, while the 28mm f/2.8 and the 50mm f/2.8 macro are much better.

I always use the A setting on a DSLR when available, there's no reason not to, and some A series lenses' aperture rings break and become unusable or very gritty with age, so best not to move them unless really necessary. My A28mm f/2.8 over-exposes by at least 0.7 EV when in A mode on a DSLR but exposure comp works fine to solve the problem.

I have a few lenses which equal or beat the old K/M series build quality (namely a Vivitar 28/2 and an Auto-Revuenon 50/1.4) but most third-party lenses are not as good in that respect.

[Kerrowdown]

As far as A lenses go: Aren't they just as annoying to use on a DSLR if you set the aperture manually?

I just think its easier to turn the lens ring than bother with camera settings in this case

For me, the "Ladies" in my harem are all A series lenses.

I find these a joy to use, for example, in P mode... right hand, front wheel shutter speed (middle finger), rear wheel aperture (thumb), quick and efficient, my eye never leaves the viewfinder and the left hand stays on the focusing.

[timw4mail]

Those are rather unique conclusions. IMHO:

• K-series -- build was typical for top-tier optics of the time and essentially equivalent to the Super-Takumar lenses that came before
• M-series -- equivalent build to the K-series, but compact
• A-series -- Introduction of plastic build in some models, but otherwise similar to M series

I own or have owned Ex+ examples of all four series (K-mount + Taks) and was in the market to buy when all four types were new. In my opinion, the A-series is the first Pentax product where build was a disappointment. This was obvious when the cheaper A-series bodies were released.

Yeah, but the A-series doesn't have the tendency for the focus grip rubber to come loose like the M-series. (At least on the 50s)

The Takumar-As, at least judging by the zoom I had, were not as cheap as the SMC As.

Depending on age, that lens is either a rebadged XR Rikenon or Cosina product. I own a few XR Rikenons and their build quality is a notch below Pentax offerings with a few exceptions. The 200/4 is almost identical to the Pentax-M as is the 28/3.5. Whether Ricoh made them for Pentax or Pentax made them for Ricoh is not known. If you like the build, that is cool. Sears and Ricoh sold a ton of them.


Steve

Must be a Cosina. It has half-stop notches, and doesn't look like this: Auto Sears 50mm f1.7 MC (K-mount) Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database