Lens less Pin Hole NBTV camera?

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Lens less Pin Hole NBTV camera?

Postby Viewmaster » Mon Jun 25, 2007 5:03 am

There is a big following for taking photographs with pin hole cameras, (without any lens)...some even have multiple pin holes! .........
http://pinhole.stanford.edu/ur.html

Some of the photos obtained are amazing although exposure times are long. The pin hole cameras are even made out of paint tins :shock:
A one gallon camera :lol:

I wonder if anyone has ever heard of a NBTV camera using a pin hole lens?
Probably the light obtained would be insufficient for any kind of photosensor behind the Nipkow.
It needs a very, very, very slow rotating Nipkow to get a long time exposure, record it, and then play it back at normal 12.5 revs per sec speed....
Just a thought.
Albert.
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Re: Lens less Pin Hole NBTV camera?

Postby Steve Anderson » Mon Jun 25, 2007 12:55 pm

Viewmaster wrote:I wonder if anyone has ever heard of a NBTV camera using a pin hole lens? Albert.


As a concept this is entirely possible, it's just the roles are reversed. Instead of a stationary pinhole and a large area of film, we would have a point sized photosensor and a moving pinhole. As you say this could well require a lot of light and a very sensitive detector.

In the early 80s I wanted to generate some pictures for SSTV, remember this is before the days of digital cameras, scanners and for most people the PC.

At the time I had an Amstrad PCW9512 (stop laughing!), it ran c/pm and booted from a single floppy. It was basically a word-processor, there was third-party software available for it, but it was like trying to get a dog to walk on its hind legs. (Sorry Gromit, I know you can do it).

It came with a daisy wheel printer (remember those? So noisy), to which I attached a pinhole sensor. It was the business end of a Rotring propelling pencil, a very small bore tube behind which I mounted a phototransistor. From there the usual A-D...the rest is as normal.

It worked and produced the files I wanted, I still have them, but they're on 3" floppies, not the familiar 3.5" There's little chance of recovering them.

So, yes, it can be done!

Steve A.

One chap I know still has 8" floppies which stored an amazing 100kB!
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Postby Viewmaster » Mon Jun 25, 2007 6:40 pm

I'm not laughing at your Amstrad, Steve. We all started with bits of string and sealing wax! Interesting about your experience with SSTV though.

I can see that a highly geared very slow speed Nipkow could only take static images and not face Grand Prix racing images!
Conversion to digital as you say, storage, then fast play back via D/A.

So a form of gearbox is required for slow recording and normal playback.....no reverse though! :lol: Gears might introduce patterning, so a big flywheel for inertia. But then motor control gets prickly.

Imagine a NBTV camera/viewer with a gear change lever on the side...bet even Baird never had that. :) ............or did he?
Albert.
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Re: Lens less Pin Hole NBTV camera?

Postby Dave Moll » Mon Jun 25, 2007 9:34 pm

Steve Anderson wrote:It worked and produced the files I wanted, I still have them, but they're on 3" floppies, not the familiar 3.5" There's little chance of recovering them.

If you wish to recover files from 3" Amstrad discs, I have the means to do so - though whether it's worth shipping the discs from Thailand to Britain is another matter altogether.
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Re: Lens less Pin Hole NBTV camera?

Postby gary » Tue Jun 26, 2007 11:07 am

Viewmaster wrote:There is a big following for taking photographs with pin hole cameras, (without any lens)...some even have multiple pin holes! .........
http://pinhole.stanford.edu/ur.html

Some of the photos obtained are amazing although exposure times are long. The pin hole cameras are even made out of paint tins :shock:
A one gallon camera :lol:

I wonder if anyone has ever heard of a NBTV camera using a pin hole lens?
Probably the light obtained would be insufficient for any kind of photosensor behind the Nipkow.
It needs a very, very, very slow rotating Nipkow to get a long time exposure, record it, and then play it back at normal 12.5 revs per sec speed....
Just a thought.
Albert.


I thought I had seen something about a Pin Hole device in a News Letter so I had a look through my collection and found a reference by Dave Buddery C30EP. Unfortunately he refers back to another article by Alan Short in Newsletter Vol 11 which I do not have. Maybe someone else could look this up?
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Re: Lens less Pin Hole NBTV camera?

Postby Steve Anderson » Tue Jun 26, 2007 12:23 pm

Dave Moll wrote:If you wish to recover files from 3" Amstrad discs, I have the means to do so - though whether it's worth shipping the discs from Thailand to Britain is another matter altogether.


Thanks for the offer Dave, but I doubt that the disks would be any good. They've been frozen whilst I was in the UK, and stored here here in very hot and very humid conditions at this time of year. They are 25 years old! I don't know why I keep them. The data on them is nothing special anyway.

I have found that new brand-name 3.5" floppies fail here after a couple of years, even if they've had hardly any use.

VHS tapes if not stored properly go 'green', you look through the window and the edges of the tape have gone green (mildew).

But thanks again for the offer.

Steve A.
Last edited by Steve Anderson on Tue Jun 26, 2007 12:47 pm, edited 1 time in total.
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Step right this way Sir....

Postby Steve Anderson » Tue Jun 26, 2007 12:37 pm

Viewmaster wrote:I can see that a highly geared very slow speed Nipkow could only take static images and not face Grand Prix racing images!


The ideal motor for this application would be a stepper motor, perhaps pulled from old printer. They are quite simple to drive with a little bit of logic, and they run in either direction quite happily.

The downside is they a intrinsically slow speed devices and might find it hard to go at 750RPM even with direct drive.

So it would have to be pinhole camera and separate conventional display.

Steve A.
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Re: Lens less Pin Hole NBTV camera?

Postby Viewmaster » Tue Jun 26, 2007 6:17 pm

gary wrote:I thought I had seen something about a Pin Hole device in a News Letter so I had a look through my collection and found a reference by Dave Buddery C30EP. Unfortunately he refers back to another article by Alan Short in Newsletter Vol 11 which I do not have. Maybe someone else could look this up?


This goes back to previous threads...if only we could obtain all the back numbers of the NBTVA News letter. I for one, would be prepared to pay for copies to cover printing etc.
When I was a member of the Eddystone Radio group one could obtain all previous issues.
But I suppose it's all a question of time and everyone does it all on a voluntary basis.
Maybe a small print over run each time to keep a few back for newcomers to buy in the future?
Albert.
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Re: Lens less Pin Hole NBTV camera?

Postby gary » Tue Jun 26, 2007 8:16 pm

Viewmaster wrote:
gary wrote:I thought I had seen something about a Pin Hole device in a News Letter so I had a look through my collection and found a reference by Dave Buddery C30EP. Unfortunately he refers back to another article by Alan Short in Newsletter Vol 11 which I do not have. Maybe someone else could look this up?


This goes back to previous threads...if only we could obtain all the back numbers of the NBTVA News letter. I for one, would be prepared to pay for copies to cover printing etc.
When I was a member of the Eddystone Radio group one could obtain all previous issues.
But I suppose it's all a question of time and everyone does it all on a voluntary basis.
Maybe a small print over run each time to keep a few back for newcomers to buy in the future?
Albert.


My understanding was that you CAN buy back copies, certainly I have bought back copies in the past from the late Les Robotham, whether or not this has been stopped I am not sure, I wouldn't have thought so.
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Re: Lens less Pin Hole NBTV camera?

Postby Steve Anderson » Tue Jun 26, 2007 10:47 pm

gary wrote:[This goes back to previous threads...if only we could obtain all the back numbers of the NBTVA News letter. I for one, would be prepared to pay for copies to cover printing etc.


Here's an extract of an e-mail I sent to Andrew not so long ago..

Scans of all the back issues of the newsletter would be most welcome, but quite a task! All (every single one) of the back issues of CQTV are downloadable from the BATC web site, issue No. 1 is dated October 1949, so why not the NBTV newsletter?

I have to qualify that a little as they don't post them until they're a year old, it's a 'teaser' to get you to open your wallet and get the latest issue. It works well, and I'm happy with the arrangement.

I have the time and the facilities to do the same, I just don't have the back-issues!

Steve A.
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Postby Dave Moll » Wed Jun 27, 2007 3:15 am

If a project were started to get back issues of NBTVA newsletter into machine-readable format (e.g. PDF), I would also be willing to do some of the scanning. If the task were shared around, it would more managable.

I feel that it would be polite, and the best way to source copies for scanning, for someone here to approach the committee with what is proposed. Judging from discussions at the last AGM, there may even be funds available to assist if the project is adopted by the NBTVA - though that may have to await the next AGM in April 2008.

Incidentally, the moderators may wish to consider splitting off these last few posts into a separate thread on this subject.
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Postby Steve Anderson » Wed Jun 27, 2007 12:22 pm

Dave Moll wrote:Incidentally, the moderators may wish to consider splitting off these last few posts into a separate thread on this subject.


Agreed.

Steve A.
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