john_hill4

Whatever you do dont just 'try' any unidentified K mount lens on a *ist body without carefully checking. Certain Ricoh, and possibly others, have an extra pin that will foul the body auto focus drive and possibly jam the lens on becoming almost impossible to remove without dismantling camera and/or lens. Whatever this pin does in its native environment the Pentax camera cant use it but once it is removed the lens can be safely mounted and operates normally.

Hmmmm... autofocus? Now you have me thinking, are those autofocus lenses? I cant see the mechanical autofocus drive that the Pentax lenses have.

 

My lens is a manual 75-200 zoom, I cant remember the brand (Vivitar maybe) and of course it did not have auto focus.

 

When using a manual lens on my *ist DS I can select auto or manual focus, naturally I have to select manual to use that particular lens.

OK, hold the lens so you are looking into the back of it and rotate until it is in the normal use position, i.e. red dot at 12:00 o'clock, the pin will be in about the 7:00 o'clock position.

Oh yes Justin, the lens works fine without that pin. I dont know the function of the pin but apparently it "tells" the intended camera something as it just connects to a resistor inside the lens.

DO NOT PUT THIS LENS ON YOUR *IST!

 

See that little shiney pin on the lens? That looks just like the pin than jammed the lens on my *ist! Fortunately I was able to get the lens off but I have heard that sometimes this in impossible without taking the camera or lens apart! The pin fouls the auto focus drive on the camera.

 

 

You can carefully take the mounting flange off the lens and remove that little pin then you can use the lens on your *ist. Otherwise you could super glue the pin in its retracted position but I felt much happier with total removal.

 

 

Once the pin is out of the way you can use the lenses AOK, as far as I know.

Thanks for clarification Franklin, from other sources it appears I would need to take about 1mm off the lens barrel, I think I may be going cold on this idea!

Thanks Franklin, by 'shorter' I assume you mean I will need to pack the K mount out somewhat? I was afraid of the opposite which would have meant milling something off the body of the lens. Did I understood you correctly?

My local junk shop has a very battered 300MM 5.6(?) with what I think is a

Minolta auto focus mount. At least I think that is what it is, it has a few

(5?) square electrical contacts and an auto focus drive.

 

Considering its condition I expect I can get it for just a few dollars but

could I ever get it onto my Pentax cameras?

 

I am thinking to abandon any notions of auto focus and probably camera control

of the aperture. The general idea is to remove the Minolta(?) mounting ring

and fix a 'K' ring on there.

 

My camera bodies are K1000 and *istDS.

 

P.S. I am not afraid of failure after attempting the impossible, in fact I am

quite used to doing that! :-)

I think you can make something like Vinny describes by choosing an old filter you dont need anymore and taking the 'glass' out of it

I had difficulty finding an AC adapter for mine, it was not a challenge to find a suitable voltage but a plug to suit was the problem. While I was searching for this I was offered a Kodak adapter which is rated at 6.5 volts rather than the desired 6.0 volts and had a plug of exactly the right size! I cut the cable and put a single diode in series to get the voltage drop and everything works as desired.

Further to my above. The flash I have is a Cosmos 35AF which was really cheap. ('cheap and nasty really') But it does have the infra-red illumination. Maybe it would be practical to buy something like that and have someone disable or remove the actual flash, heck you could even blacken or put a hood over the flash tube itself.

Regarding auto focus difficulty in low light conditions. I wonder if some sort of infra-red attachment could be used to help the auto focus system? My "auto" flash puts out an infra-red grid pattern as part of its range finding process and with this flash unit mounted the camera certainly does appear to auto focus more readily. Maybe you can get some sort of infra-red light to do this without the whole flash unit.

 

Camera ia *istDS

Some Ricoh lenses have an electrical connection that fouls the auto focus drive, at least thats what happened to me. By careful examination of the lens and the camera mounting ring you may be able to decide if this is an issue for you. In my case I just took the pin out of the lens and all is well although it did rather prematurely age me when it first got jammed on and until I was able (fortunately) to free it.

I am not sure what they would be called but I assume they go to the Pentacostal Chruch!

Hi

I have a *ist DS and quite a jumble of K and screw mount lenses. Everything works without problem but I did have to read the manual and take advice on here to make minor changes to the settings of the camera. Once that was done things work quickly and conveniently.

 

Some things are not quite compatible, for instance my Pentax bellows could no longer focus the slide copier and I had to make up another extension tube (about 8 inches!) to bring it back to focus.

 

 

WARNING! Do not try to mount any lense with the extra pin (electrical contact) that fouls the auto focus drive! I think this is a Ricoh feature and is associated with their 'P' mode. It is possible to get a lense jammed on that cannot be removed without dismantling either the camera or the lense. In my case I was lucky and was able to get the thing off and two minutes with a screw driver prevented that lense ever causing that problem again!

No, there is no cable control for aperture on the 'bellows' lens.

 

I went out and bought a very cheap Helios lens which fits the thread of the bellows unit.

 

I used an adapter ring to fit my *stDS to the bellows and even with neither lens could I get focus on the supplied slide copier the focus being found about 5 inches past the end of the rails.

 

Fortunately, slide copying is not my objective and with the bellows unit mounted on a rather cheap tripod I was able to photograph the insides of a point contact diode rather well, also a piece of old computer core ram and an early EEPROM chip. I need a bit more work before these would be good enough to post, mainly due to lighting issues I think. The width of these objects that I photographed is about 6mm ( 1/4 inch).

 

Not suprisingly the depth of field at those magnifications is only paper thin, am I right in thinking that if I can solve the lighting issues I may be able to close the aperture and increase the depth of field a little?

Thanks Thomas, now you have explained it I can see what I need to do. I have an old enlarger stand and if I can mount everything on that I will have the required second rack function.

Thanks guys..

 

Yes, I got the Pextax 55-200 when I bought the camera and I am very pleased with that too.

 

What I am looking for is something more convenient than the teleconverter and mirror lens combination. I would also like something a bit faster which would allow me to select a slower ISO setting on the camera and still operate hand held.

 

Thanks Douglas, from a quick look it seems Boz's site will have the information I am look for.

 

At the end of the day I expect I will have to accept that what I want is out of my budget.

 

P.S. Have you seen my car? :-)

Hi Jochen, the switch I removed was just a tiny pin that fouled the auto focus drive when putting the lens on. Although I took the bayonet ring off my lens and actually removed the switch I could have got the same effect by simply holding the pin flush with the metal surface and dropping some 'superglue' or something on it.

 

To find this pin hold the lens in front of you as if you were trying to look through from the back. Rotate the lense until the red dot at the 12 o'clock position. With the lens in that position the switch pin was at the 6:30 position. I hope this is clear?

 

John

I have a 'Magnon' auto zoom 75-200 that would not fit on my *istDS, I could engage the bayonet but only turn about half the angle required to mount the lens.

 

The problem is a switch inside the lens that fouls the auto focus drive. This switch (and I am not sure what function it served, maybe someone can tell us?) switched a resistor to ground apparently signalling something to the camera.

 

I removed the switch and the lense now goes on, I have not tested to see if it works though.

OK, I found what it is you need to change in the camera:

 

Go into the "custom setting" menu and change "Using aperture ring" from "1" to "2"

Denny, I use a 500mm mirror lens with my *istDS no problems (except holding it steady! :-) )

 

You do need to programe you camera somewhat, sorry I forget the details but I found it on one of the threads of this Pentax Forum.

 

For mine I have to set for manual focus (the switch on the front lower left of the body) and the mode knob to Av (aperture priority)

 

Hope that helps.

 

John

Before I bought my *istDS the shop people were tearing their hair out trying to find a set of batteries in the shop that the camera would accept! Eventually they got a set to work and I bought the camera.

 

Soon after I got it home I tried four alkaline AA and got the flat battery indicator. I tried inserting them again and everything was OK for 30 or so pictures until it gave me the warning again when I tried to use the flash.

 

My conclusions, Pentax are quite right when the discourage the use of alkaline batteries, secondly, the battery contacts are rather clever and if you look closely you will see how they are designed to prevent reverse polariaty unfortunately this appears to make the positioning of the batteries critical.

 

My suggestion is get some NiMh batteries and try putting them in a few times, if it is like my new, right out of the box, camera you will eventually hit that sweet spot and it will work.

Glen, I have the Remote Assistant software and it does appear to do some basic functions with my *istDS but I have not really played with the software to learn its full potential and limitations. I did note that nothing appears in the 'viewfinder' window but then I dont see how it could with the mirror down. I sort of imagined that the purpose of this screen was to review shots after they were taken.

 

The shutter release seems to work and the various other control screens that change the mode and various camera parameters at least appeare to be working.

 

The software can do interval and delayed shutter release as well as automatically uploading image to PC disk rather than camera memory. I did not try the interval or delayed but the upload works.

 

Again, this was just a few minutes playing with Remote Assistant and my *istDS.

 

Even with limitations I will be keeping the Remote Assistant and am confident it will getting used at times.

 

 

I was hoping for a system where the shutter could be triggered by an external event, model train entering the station, bird landing on the feeder [EVIL ON] or car passing a red light [/EVIL OFF] :-)

 

Thanks for information on the switch cable, I was unsure if the cable control was simple contacts or if the controller did something clever like switch in different resistances or a diode matrix for different functions.

 

The ideal for me would have been the technical information regarding both the remote socket and the protocol between the camera and the PC so that I could have played around with my own software.

I have my *istDS and am very pleased with it. I have also found the

Pentax 'Remote Assistant' software.

 

Remote Assistant will do a lot of what I want but I may want to do

more.

 

There is a cable remote available, called a 'switch' in the catelogue

but I see it has a three contact plug. Does anyone have the details

of this contact or any suggestions on where I may obtain

such 'technical' information? Does Pentax readily release such

details?

 

Thanks