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Old Jun 25, 2007, 11:50 PM   #21
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John Hill wrote:
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Whatever..:?

Just wait until I get my pukka 'adapter' and we will have more to go on.
Hey John,

Glad no one caught me on this in the past few hours.... I must apologize though....

I checked the an A lens before I said that but not in great light. Then shortly later was out shooting sunset and went to use one of the A lenses.....

And again humbly apologize.... the plastic pin insulators are there on an A lens, but are absolutely flush, and clear plastic are hard to see but in bright contrast light vs the obvious protrudting A contact.

So yes on an A lens the max/min aperture is done that way.... but still a K/M which would not touch the recessed A camera contact, does focus trap none the less.

And though grounding the A contact may work, I sort of wonder if that might not be possibly damaging eventually over time as on no K lens is that contact intended to be grounded.

Just eiither a connected or isolated hot contact to the aperture control electronics.


And On a KAF or (2) camera, grounding one/some of the other pins does the same thing of enabling the AF shutter inhibit until AF, if cam in AF mode.... again maybe the paint on a M42 prevents happening.

Now a little more food for thought.....

Author of that articles says....

Early Pentax lenses can be modified to allow you to use the sophisticated multi-segment (matrix) metering capabilities of many modern Pentax cameras. Note, however, that this does not include any of the new digital SLR's or any of the film cameras like the ist or ZX-60/MZ-60 that require lenses with an "A" aperture setting.
"
If grounding the A pin is not damaging, might it not also fool a modern camera into thinking does have an A/AF lens on it, and therefore read that moded insulator/ground code and allow multipoint AE?

PS I did just confirm that a bare metal flanged M42 adapter will allow focus trap.....

No lens on the camera shutter will trip in AF (Just like a M42 making no contact).

Adapter on, shutter IS inhibited from tripping, yet again it is in no way contacting that recessed A contact.
So if absolute INF focus is not madatory that is clearly the easiest solution.
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Old Jun 26, 2007, 2:32 AM   #22
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OK Hayward, no problems there. Funny thing is I dont seem to be able to get focus trap on my ist DS EXCEPT by grounding the A contact. Though it sounds like you can on your camera?

I tidied up my hacked teleconverter and can report that focus trap operates with the camera set to "Auto Pict" and Auto Focus. I used a basic screw mount lens (Takumar 200/3.5) and get nice focus trap under modest artifical lighting.



I notice that the camera still detects the lens as manual focus so although the button is set to AF the camera reports the lens as MF.

I think I have only destroyed one lens with the 'A' setting and I dont recall any electronics, not even a resistor inside so I dont think I need be concerned at grounding the A contact causing damage as apparently that is exactly what the most simple lenses do.

The TC I am using had been fitted with all pins to pass through lens configuration but those pins are all removed, except the one for the 'A' on the camera end of the TC and that is grounded.

Just to make sure that the 'new' contact, the one nearest the bottom of the camera, was not playing a part I put tape over that and nothing changed.


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Old Jun 26, 2007, 2:49 AM   #23
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Might just be a K - *ist difference..... not really sure what "Auto Pic" is, 10D has no such thing.... its just if you leave it in AF with a MF lens K/M/or A. it just defaults to needing AF confirmation for the shutter to trip. You can if DOF deep enough/you stay still enough do it in advance and then take pics or you can start OOF, and fully hold the shutter and trap it as you bring it into focus.

"I think I have only destroyed one lens with the 'A' setting and I dont recall any electronics, not even a resistor inside so I dont think I need be concerned at grounding the A contact causing damage"

Well there has to be some sort of little servo or something in there that tells/sets the iris how far to stop down in the A mode.

Edit..... OK just did a little experiment with a K/M lens.... covered all pins with masking tape no trap,shutter or AF conferm in AF. Then all but the DATA (right bottom most contact looking at cam mount) pin and it still focus trapped...... did that through the rest of the pins with only one open and worked on all, but for having them all covered.


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Old Jun 26, 2007, 3:09 AM   #24
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You mean you cant take out of focus shots?

The DS goes to MF is I mount a manual lens while the button is on AF.

Of course, I have not really explored all the various options and that might be a consequence of the way something is set.



Auto Pict is the fully auto position of the camera mode knob.


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Old Jun 26, 2007, 3:14 AM   #25
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No not if you are in AF..... but if you can stay still enough and DOF is not critical you can half press do it in advance, and then take pic(s) or you can full press and and trap shot as you focus

" The DS goes to MF is I mount a manual lens while the button is on AF."

Ahhh might be phisical construction of the AF drive shaft on the *ist then.... solid... so it forces it out of AF on mount.... on the 10D it is spring loaded, so it just flatens to the mount surface. With no lens on and cam in AF, can you depress the shaft and its springy?

PS see edit to last post if you didn't notice it.

Oh that is another thing the 10D will do it in any mode, only the lens AF/MF lever matters. (Though on a M lens all modes but M and B will default to wide open aperture priority) In M/B mode they will auto stop down as set on exposre or DOF/AE preview. M42's have to be manually stopped down, but then again will work at any stop in the Aperture Priority mode (though they say maybe prone to error at small apertures).

Think I'll download an *ist manual and see what the differences are operationally.
Though even the 10D manual doesn't really document the AF trap, but does mention the assist confirm with MF setting (just confirms doesn't inhibit without in MF).

Now the difference in focus trapping on different models is suddenly making much more sense.
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Old Jun 26, 2007, 5:53 AM   #26
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Well that was an interesting night's read/scan.....

Download both the DS and 100D manuals.....

Scanning them got me comparing the 10D manual, and made me notice some things I had over looked and then going into the Custom Setting to change some things, noticed some things the Firmware upgrades had added I hadn't noticed before.

So all in all a productive endeavor and now I have a much better grasp of the *ist's particularly DS, and also the 100D's workings. As well as a better configuration of my 10D.


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Old Jun 26, 2007, 2:28 PM   #27
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You read the books Hayward? You really are taking this serious!

Yes, the focus drive is springy. Mounting a manual lens causes the camera to display 'MF' in the viewfinder but the button does not move.

Regarding covering the pins, I dont know how the camera knows a lens is mounted, perhaps insulating all pins shows as 'no lens' whereas a contact on all pins is interpreted as 'dumb lens' and a contact on at least one but not all is interpreted as a 'smarter' lens? I expect the camera logic looks for three states of the 'data' contact, ground, open and data present.



I just tried a few more observations: (All with Auto Pict mode)

Turn camera on with a M42 lens and the lcd display shows 'Av - -'

With kit lens, lcd shows Av4.0.

My modified TC with 'A' contact grounded and 'data' contact grounded, lcd shows Av2.8 (all other pins not grounded)

The 2.8 is not really what the lens was set to but it isthe data read from the 5 pins and corresponds to the table at the page I linked to. Presumably the only difference between the first and the last test is that having the 'A' contact grounded has signalled the camera to read the aperture pattern from the five contacts, in neither case was there anything to read on the data pin.



Off to work now...
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Old Jun 26, 2007, 10:19 PM   #28
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I never thought a little piece of tin foil would make me sooo happy.

So with a piece of foil covering those contacts, the focus trap work flawless.

No, John is right, there has to be a better way than the foil.

I'm thinking of everything, but always open to some suggestions.

This new M42 Vivitar Series One 70-210mm f3.5lens is awesome. I figured that liked the Kiron 105mm macro so much that i'd find another Kiron lens as well.

Took a little while to make sure that it was the version 1 copy. Then really disappointed when the focus trap didn't work, but all is well now.

This whole thing started when a friend of mine's brother in law just bought a canon 70-200mm f4lens for around $1000 usd. I thought that's a lot of money. More than I've spent probably on all the lens I now own. His lens might have IS, but so will I once I upgrade to the k10d. On all my lenses!

Just a little rant. Thanks for listening.

Thanks for all the support here, thanks to Pentax as well.

Fred
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Old Jun 26, 2007, 11:32 PM   #29
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John Hill wrote:
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You read the books Hayward? You really are taking this serious!
Sure WHY NOT?????? A few min of DL time and some scan reading of pertainent sections.... knew just where to look and how Pentax manuals are organized.

And again doing so also got me to understand my K10D better and get it configured better for stuff I had overlooked in the now several FUNCTION NOT JUST FIX firmware upgrades, I had over looked.

Interesting to know it is springy (*ist) but still kicks it out of AF inhibit mode from what you have said.

Yes on the 10D it is impossible to take an out of focus shot if cam still in AF EXCEPT maybe if you were focusing faster than the AF could trigger the shutter, and again in any mode. ( the basics none of the "don't really know what I am doing" scene modes on the 10D)

Also on the 10D AF-C is a third positionof the AF -MF lever set vs having to choose the preset MOTION SCENE to do tha (you do on *ist AND K100Deven).... and again in any Mode AUOTO.P, AV, TV. SV, M, or B.

OK if shaft is still springy and doesn't physically knock the lever out of AF, could have to do with the "scene modes" all but the K10D have.... In AF mode the 10D will plain inhibit the shutter in any of the modes (Auto, P, Tv,Av, Sv, M, B, X) .... no mater what unless the cameras sees AF confirmation. And yes VF shouw MF, but the inhibit is still active if lever is in the AF position.

PS John did't want to divert this thread too far off..... but, again from the manual researching see..... for yet more food for though

http://www.stevesforums.com/forums/v...mp;forum_id=80

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