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Forum: Pentax SLR Lens Discussion 09-07-2022, 11:41 PM  
Need Help with Pentax Auto Focus Extension Tube for K mount
Posted By donhon1928
Replies: 44
Views: 1,930
Years back I purchased a set of VivitarAT-23 extension tubes for K mount. They were screw drive AF and had the contacts for lens/body comunication. They worked perfectly for me with *ist DS and later Pentax bodies and AF lenses.
Probably out of production now, maybe available S/H.
Good luck, Don.
Forum: Pentax Q 02-20-2022, 04:36 PM  
Macro with a Q10?
Posted By donhon1928
Replies: 2
Views: 1,136
G'day Bob256.
Seems that the bug had departed leaving just the fluffy "nest". I'd like to know what it might have been.
The brush was made from animal hair, very soft. I've had it for over 40 years!
Thanks for your interest.
Don.
Forum: Pentax Q 02-18-2022, 08:30 PM  
Macro with a Q10?
Posted By donhon1928
Replies: 2
Views: 1,136
One of my lens brushes began shedding hairs. Seems that a little bug of some sort had made a nest and done some trimming.
Not being set up for micro photography, I made use of a 10X Lupe to help my Q10 and 5mm -15mm lens to take photos of the nest, which was approximately 1.5mm in size.
Although not perfect, the result was OK as far as I’m concerned.

Re this post.
I realize now that I overcooked the operation. I didn't need the tripod, it only made things more difficult. I've just found that I can sit the Q10 lens directly on top of the Lupe and get a better result.
Sorry if I misled any one. It seems so obvious now
Forum: Vintage Cameras and Equipment 12-02-2021, 07:59 PM  
Sticky: About the Vintage forum
Posted By donhon1928
Replies: 19
Views: 2,147
G'day Arnold.
Here's another. Same little fella but some time later, definately prior to Christmas 1955. Leica IIIc. I'm not sure, but lens could have been a Steinheil Culminar 85mm f2.8 coupled for the Leica. Flash used.
Don.
Forum: Pentax DSLR Discussion 12-01-2021, 09:25 PM  
The Six-Megapixel Club
Posted By donhon1928
Replies: 4,312
Views: 395,262
Here are a couple of shots from my *ist DS with Sigma 18mm - 125mm Zoom lens, taken in 2005 not long after I'd bought it.
The photos are from Flagstaff Hill Maritime Museum in Victoria, Australia.
The Peacock was on a slowly rotating base, in a glass case.
Forum: Vintage Cameras and Equipment 11-29-2021, 10:06 PM  
Sticky: About the Vintage forum
Posted By donhon1928
Replies: 19
Views: 2,147
It was 1952.
My first flash unit was made in England by a company which was still making studio flash equipment many years later, Clive Courtenay!
It was called the Courtenay Speedflash and Its output was rated as 100 Joules
It consisted of two parts, a flash gun and a power unit.
The flash gun was the size, and looked very much like those used by the press in old Hollywood movies. It connected to the power unit by cable and plug. It These very early units were based on flash tubes much the size of a radio valve, 6V6GT perhaps, and operated at very high voltages 1200 Volts DC or thereabouts.
The power unit was built in to a polished wooden case, the top of which had two opposing lids, hinged in the middle of the case. One lid covered the control panel, the other covered the battery compartment. The battery was a small 6 Volt lead-acid unit in a clear plastic casing.
All up it weighed around 14 pounds!
Despite much Internet searching I haven’t been able to find any reference to my unit.
The Courtenay Speedflash was a very early design, certainly too early, as it used technology (and I use the term loosely) that existed pre WW2.
To provide the required high voltage from the 6Volt battery, a Vibrator similar to those used in early car radios was used. The vibrator interrupted the DC current and allowed the use of a transformer to increase the voltage to the level required. It was then rectified and used to charge a capacitor, usually an oil filled paper type in a metal housing, with ceramic insulators to cope with the high voltage. For the 100 Joule output the capacitor only needed to be of a small value, because of the high voltage involved.
The high voltage used in these units had a plus and a minus. The plus, was the very short flash durations, perhaps up to 1/10,000 of a second. No camera shake here.
The minus was that, due to film emulsion latency, a sizeable part of the light was wasted.
Owners of this type of unit felt it imperative to take at least one photo to demonstrate the short duration of their flash.
Of course, so did I, with this very crude shot.
As electronic flashes developed, they became more efficient. For a given output the capacitor became larger and the operating voltage lower. Flash duration became longer, hundredths of a second now, film emulsion latency no longer a problem.
To get back to my Speedflash. It worked for about one year then died. No warranty, I couldn’t find anyone among the camera shops who would take on the repair. Eventually I was able to trade it in on a lighter more modern Blaupunkt Ultrablitz flash running on D cells.
A number of flash units followed, becoming smaller, more refined and easier to use (If you still have the user manual).
I hope you found this of interest, Don.
Forum: Vintage Cameras and Equipment 11-29-2021, 08:21 PM  
Sticky: About the Vintage forum
Posted By donhon1928
Replies: 19
Views: 2,147
G'day Arnold.
Here's another 10 ASA Kodachrome shot. My wife and first born taken in early 1954. He was one year old and had just taken his first steps that day.
Leica IIIc and standard Elmar 50mm f3.5 lens.
Don.
Forum: Pentax Q 11-29-2021, 07:56 PM  
Fun with a Q10 and some old lenses.
Posted By donhon1928
Replies: 10
Views: 1,647
G'day kwb
The two threads are quite close to each other. My C mount lens will screw in to a Robot mount, but a Robot lens will only just enter my C mount adapter.
The C mount is 1 inch dia. X 32 TPI. This equates to 25.4 dia. X 0.79mm pitch.
The Robot mount in my case is 26mm dia. X 0.75mm pitch.
You can see that a lathe set up to cut a Robot mount thread will remove very little material from a C mount adapter. You need to set the threading tool accurately to the beginning of the existing thread.
As to the different registers (Film plane to lens flange), C mount register is 17.526mm. My Robot register, measured from flange to film plane (with film in the camera) measures 30mm, a difference of 12.474mm. I haven’t been able to find the official factory register on line anywhere.
I was lucky in having some Robot extension tubes which brought the Robot lenses close enough to the proper Register to take a few photos. More work would be needed to get to the correct register if you were serious about using the Robot lenses. The Robot lenses were of very high quality.
Unfortunately my modified C mount adapter has been lost and I no longer have my workshop and Lathe.
Thanks for the interest, Don.
Forum: Pentax Q 11-28-2021, 10:59 PM  
Fun with a Q10 and some old lenses.
Posted By donhon1928
Replies: 10
Views: 1,647
G'day i_trax.
The adaptors were cheap ones. Mine allowed the C mount to be rotated to position the lens inf mark to the normal (top) position, some might not.
You can see the set screws in the photos.
Don.
Forum: Pentax Q 11-28-2021, 09:00 PM  
Fun with a Q10 and some old lenses.
Posted By donhon1928
Replies: 10
Views: 1,647
Firstly, I must confess that this project was carried out some years back, I hope it will still be of interest to some.
I love my little Q10. It came with the two lens kit, and both lenses are very capable. I find it handy to use for photo records of projects and indoor shots, but for me the screen is difficult to see outdoors even when fitted with a folding hood.
Back to the fun.
Shortly after I bought the Q10, I decided to try a few lenses, a Taylor-Hobson Cine lens (C mount) and a couple of old Robot lenses (Very nearly C mount).
I bought two Q to C mount adapters. One I setup in my lathe and carefully re-cut the thread to suit the Robot lens.
The attached photos show the Q10 with the lenses fitted and a comparison between the Q10/150mm Robot lens and my K30 and a Sigma 600mm Miror lens.
The power pole was around 350 feet from the camera. The extra depth of field in the Q10/Robot 150mm is obvious and due to the very narrow angle of view.
Comments and questions welcome.
Don.
Forum: Pentax SLR Lens Discussion 11-21-2021, 07:23 PM  
Anyone Know 3D printing service for an M42 to 52mm lens filter adapter
Posted By donhon1928
Replies: 13
Views: 913
Hello Bob.
It seems that you need an adapter with M42 x 1 mm pitch (male thread) and a 52mm female thread to accept normal 52mm close-up lenses. This is pretty much a non-standard item, but if you are able to find someone with a small lathe it could be made.
It's the kind of work I did many years ago. If you wanted to go to the trouble you might be able to use a cheap M42 to some other camera mount adapter and attatch a suitable 52mm step-up or step-down ring (glue?).
Good luck, Don.
Forum: Welcomes and Introductions 11-20-2021, 09:11 PM  
Very old Newby
Posted By donhon1928
Replies: 21
Views: 988
Greetings from Eltham, Victoria, Australia.
My name is Don. I am 93 years old and reside in an Aged Care facility. My interest in cameras, photography and associated equipment began when I was about eighteen years of age when a neighbour, who had a small darkroom, showed me how to develop 120 roll film and make contact prints. This was during WW2, a period of mainly B & W photography. Colour film was yet to become commonly used. My neighbour had a large collection of English photographic magazines and I endlessly poured over the articles and advertisements for the many cameras written about at the time.
I had many cameras before I purchased my first Pentax in late 1960s. It was a second-hand, early Pentax Model K. It’s 55mm f1.8 Auto Takumar lens had to be cocked to fully open the diaphragm for framing and focusing prior to taking the photo. Pressing the shutter release button allowed the diaphragm to close to a pre-set aperture before the shutter operated.
Various Pentax cameras followed the Model K. SV, various Spotmatics, K1000, ME, ME Super and my last film camera the MZ-5. Only the MZ-5 was bought new, all the others were bought second-hand, none of them ever failed me or gave me trouble.
The gift of a Canon A40 introduced me to Digital photography. I was well set up with a computer, printer and scanner and I was immediately hooked.
When the Pentax *ist D was released, I lusted for it but it was beyond my reach. Later I was able to purchase the *ist DS with the Sigma 18mm – 125mm Lens. Despite some poor reviews, I liked the lens and it produced some fine results.
It was during this period that I first registered as a member of this forum and I made a few posts.
I was unable to retrieve that earlier registration but with Adam’s help I am now a Newby, despite my age and an interest in things photographic spanning seventy years.
I recently purchased an *ist D on Gumtree at a low price. It is in very nice condition and seems, so far to operate fully. The Compact Flash card in it had images taken in 2007. Maybe that was the last time it was used. I’m enjoying my time playing with it.
I must apologize for the lengthy introduction; I hope I’ll be forgiven.
Regards to all, Don
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