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09-07-2012, 07:28 AM   #31
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QuoteOriginally posted by Lowell Goudge Quote
They made the change starting with the *istD film camera because the lenses no longer even had aperture rings,
The *istD film camera ???

First camera with crippled mount was the MZ-50.

FA-J lenses existed already for the crippled entry model MZ camera's

09-07-2012, 07:39 AM   #32
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QuoteOriginally posted by glasbak Quote
The *istD film camera ???

First camera with crippled mount was the MZ-50.

FA-J lenses existed already for the crippled entry model MZ camera's
sorry meant *ist, but you may be correct, *ist was the first I knew of, but if it was earlier it only reienforces the fact that the absolute need was no longer there.

however, having said that, and even tough I am happy with the performance of the green button for metering (at least with *istD and K5D) i strongly believe that there should be at least one top of the line body that supports open aperture metering with K lenses, and also supports TTL flash.

there are valid uses for both these things, and a lot of people would make use of the features if supported. In fact, I think the inclusion of these functions would lilely increase pentax total sales even considering it may reduce slightly lens sales.

The fact is, even considering the current level of support for K lenses, the market is largely depleted.
09-07-2012, 02:55 PM   #33
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QuoteOriginally posted by Lowell Goudge Quote
sorry meant *ist, but you may be correct, *ist was the first I knew of, but if it was earlier it only reienforces the fact that the absolute need was no longer there.
Not entirely correct, pentax did have the auto extension tubes in their program at the same time as the MZ50 with the crippled K-mount.
These tubes lack the A contacts, when used, the camera had to rely on the aperture simulator for correct lens open exposure measurement.
09-07-2012, 09:42 PM   #34
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QuoteOriginally posted by Lowell Goudge Quote
no this is not quite correct or perhaps accurate enough. The coupling we are talking about allows open aperture metering of Non A lenses, on A or later bodies,
I didn't realize that some bodies do not allow open aperture metering when using non-A lenses. The K-5 does allow open aperture metering with all lenses, including K and M. Which is great when shooting wide open. At least this is one improvement towards allowing better use of legacy lenses.
Edit: Comment retracted.

QuoteOriginally posted by Lowell Goudge Quote
This is why pentax has elected to delete the coupling from the bodies .... How long do you retain a function for which you do not produce any longer, lenses or bodies that require it.
That is a marketing decision, not one based on technical constraints or manufacturing cost.


Last edited by Tanzer; 09-07-2012 at 10:56 PM.
09-07-2012, 10:08 PM   #35
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QuoteOriginally posted by elliott Quote
I know how they work on film bodies, they do quite well on the K1000 and Super Program. I'm talking about a modern DSLR though, which is what this thread is about. If I'm using 40 year old lenses with a new body, I expect some limitations, the green button happens to be a very minor limitation that is easy to live with.

Wonder how many Spotmatic owners complained when the K series came out, even though they could get a cheap adapter to use the old lenses, they didn't have the convenience of the lever to actuate aperture pin. Maybe Pentax should add this to the next DSLR to make M42 users happy.
Sorry, I didn't mean to sound condescending. Didn't know if you had actually tried the coupling since there weren't any bodies in your sig (not that I have any listed either).

Your point is well taken, when considering that, depending on what one is shooting, it is not necessary to re-meter between every shot. Doing so is perhaps a bad habit on my part.

Regarding M42 support, that is a poor analogy because the entire mount and hardware changed, for good reasons. Whereas the crippled KAF2 mount offers no user benefit compared to the proper KAF2 mount, and it could be easily uncrippled using a few existing parts.

I agree that Pentax does a better job of supporting old lenses than anyone else, but as far as "100% support" for old lenses, I would prefer to say that Pentax supports offers 100% of the lenses, but only 90% of the way on recent bodies. Otherwise it wouldn't be called a crippled mount.
09-07-2012, 10:14 PM   #36
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Nobody in this thread has mentioned the problem of stop-down metering errors on the newer bodies, with their non-linear focusing screens. Not sure when those focusing screens were first introduced, but a stop-down coupling would eliminate that.
09-07-2012, 10:26 PM   #37
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QuoteOriginally posted by Tanzer Quote
The K-5 does allow open aperture metering with all lenses, including K and M.
Can you tell me how my K5 can measure correctly with K and M lenses at open aperture, when the lens is not at open aperture ?
This is not possible without the aperture simulator, which is absent in every 'crippled' camera body.
09-07-2012, 10:47 PM   #38
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QuoteOriginally posted by Tanzer Quote
Sorry, I didn't mean to sound condescending. Didn't know if you had actually tried the coupling since there weren't any bodies in your sig (not that I have any listed either).
They don't get a lot of use, just some flea market and thrift store finds that came with nice lenses. Hard to accumulate a good selection of manual glass without a half dozen or so manual bodies kicking around too.

QuoteOriginally posted by Tanzer Quote
Regarding M42 support, that is a poor analogy because the entire mount and hardware changed, for good reasons. Whereas the crippled KAF2 mount offers no user benefit compared to the proper KAF2 mount, and it could be easily uncrippled using a few existing parts.
Alright, what about the old TTL flash? Bodies newer than the *istD don't have TTL flash anymore, so the awesome old Pentax AF 280T is crippled on the newer bodies. What about the AF lens that came on the Pentax ME F? These crippled mounts don't have the contacts for that either. I sometimes wish my DSLR supported the old cable releases for the shutter, is my shutter button crippled? They could easily support these features in a new DSLR, the reason they don't is because a large majority of buyers wouldn't know or care one way or the other that they do, similar situation with the aperture coupling.

QuoteOriginally posted by Tanzer Quote
I agree that Pentax does a better job of supporting old lenses than anyone else, but as far as "100% support" for old lenses, I would prefer to say that Pentax supports offers 100% of the lenses, but only 90% of the way on recent bodies. Otherwise it wouldn't be called a crippled mount.
Pentax clearly states that M lenses require stop down metering.

09-07-2012, 10:57 PM   #39
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QuoteOriginally posted by glasbak Quote
Can you tell me how my K5 can measure correctly with K and M lenses at open aperture, when the lens is not at open aperture ?
This is not possible without the aperture simulator, which is absent in every 'crippled' camera body.
Comment deleted. I misunderstood Lowell's comment.
09-07-2012, 11:31 PM   #40
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QuoteOriginally posted by elliott Quote
Alright, what about the old TTL flash? Bodies newer than the *istD don't have TTL flash anymore, so the awesome old Pentax AF 280T is crippled on the newer bodies.
I recall others bemoaning the loss of TTL support as well, but I don't know enough about Pentax flash compatibility to really comment.

QuoteOriginally posted by elliott Quote
What about the AF lens that came on the Pentax ME F? These crippled mounts don't have the contacts for that either.
Not a good analogy, because that system was dropped for good reasons. And I thought the hardware (i.e. contacts) are used differently, which renders them incompatible. And you're talking about one single lens that was ever manufactured, compared to all the K and M lenses, c'mon.

QuoteOriginally posted by elliott Quote
I sometimes wish my DSLR supported the old cable releases for the shutter, is my shutter button crippled? They could easily support these features in a new DSLR, the reason they don't is because a large majority of buyers wouldn't know or care one way or the other that they do, similar situation with the aperture coupling.
Dare I say it ... Yes, it is a crippled shutter button! So they can sell you a wireless remote, of course!

QuoteOriginally posted by elliott Quote
Pentax clearly states that M lenses require stop down metering.
Exactly, but this doesn't mean the situation can't be improved, whether by uncrippling the mount, or by improving the stop-down metering support in firmware. Maybe a job for hacker community. Pentax would probably start supporting this only if there were a Magic Lantern.
09-07-2012, 11:44 PM   #41
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Lets try looking at this from a business perspective. Do you actually believe adding an aperture coupling would lead to a measurable increase in sales? I somehow doubt it. I have a feeling a great majority of bodies sold never see more than a kit lens, let alone anything manual focus. So you're asking Pentax to spend the engineering time on something that offers them little to no return, when they could be improving other aspects of the body that will lead to increased sales. Adding the coupling isn't exactly something that can be designed and implemented from napkin drawings.
09-08-2012, 12:05 AM   #42
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QuoteOriginally posted by Tanzer Quote
Nobody in this thread has mentioned the problem of stop-down metering errors on the newer bodies, with their non-linear focusing screens. Not sure when those focusing screens were first introduced, but a stop-down coupling would eliminate that.
Tackling this light metering problem requires communicating absolute aperture values to the body, and the aperture simulator only simulates relative values to an unknown open aperture on K and M lenses.
09-08-2012, 12:16 AM   #43
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Agreed elliot. I do not believe it will increase sales measurably, and could potentially hinder new lens sales, which is why they won't do it.

As far as putting the coupling back in, they have all their original engineering designs. It's just a plastic tab/ring and some electrical contacts to read the position. A very simple and elegant solution which has been intentionally obsoleted, for business reasons, not technical reasons.
09-08-2012, 12:24 AM   #44
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QuoteOriginally posted by glasbak Quote
Tackling this light metering problem requires communicating absolute aperture values to the body, and the aperture simulator only simulates relative values to an unknown open aperture on K and M lenses.
Are you saying that the K-1000 cannot meter correctly?
09-08-2012, 12:37 AM   #45
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QuoteOriginally posted by Tanzer Quote
Are you saying that the K-1000 cannot meter correctly?
I won't say this is the case with every camera with the aperture coupling, but my Super Program isn't the most consistent when switching from aperture priority mode to shutter priority mode.

For example:
With the lens in the A position and body in M mode it is in shutter priority mode, I change the shutter, it changes the aperture. The aperture coupling is not doing anything in this mode. I might set 1/125s, it picks f8.

Now I put the lens at f8 and change the body to Auto, which is aperture priority and it is determining the aperture position with the coupling. In this mode it might pick 1/60s for the shutter under the exact same light.

Won't happen every time, but it does happen on my body in some conditions.
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