Steve Anderson wrote:A good quality magnifying glass might get you going, but you'd have devise some form of iris.
Steve A.
Steve Anderson wrote:Looking at the data for the 1848 tube you're going to need a lens with a focal length of at least 80mm, and that's from its rearmost part. not its optical centre. And it would need to be designed to cover the entire mosaic of over 3" x 2"...that's a big piece of glassware! A 35mm lens just ain't gonna cut it, whatever its focal length, whether for a projector or a camera.
You're into the realm of large-format cameras. Best try and find a 120 film based camera (usually 2" square negs) but the landscape version where you only got eight shots per roll of film. Rare. Expensive.
These lenses were not fast and simply may not be up to the task. Or you've gotta find a lens designed for this type of device.
A good quality magnifying glass might get you going, but you'd have devise some form of iris.
Steve A.
aussie_bloke wrote:I admit when it comes to designing the circuitry for this camera from scratch I don't have a clue, circuit designing has always been above my scope of knowledge, I can follow circuits, trace faults, make some modifications and of course I can construct any circuit provided I have the parts but sadly I don't know how to design circuits from scratch except very basic ones despite doing Certificate 3 and 4 Electronics at TAFE and working at an electronics company building power related equipment for over 5 years. .
Klaas Robers wrote:The plumbicon cameras like the Philips LDK3 have a target of 2.5 cm diameter. The lenses for them are designed for this size of picures, so say 35 mm film size. As far as I know the target of an iconoscope tube is much larger, so you need a much "longer" taking lens, a lens that is designed to have quite some space behind its glass ant the focal plane. I would try to find a better lens from a old photo camera that used roll films with a picture size of 6 x 9 cm or 6 x 6 cm, e.g Rolleiflex or Hasselblad.
Can you give an impression of the seize of the target and the distance of the target from the glass of the tube?
In the beginning of TV the cameras did not have a zoom lens, but different lenses on a rotatable disc, a so called Turret.
Viewmaster wrote:aussie_bloke wrote:I admit when it comes to designing the circuitry for this camera from scratch I don't have a clue, circuit designing has always been above my scope of knowledge, I can follow circuits, trace faults, make some modifications and of course I can construct any circuit provided I have the parts but sadly I don't know how to design circuits from scratch except very basic ones despite doing Certificate 3 and 4 Electronics at TAFE and working at an electronics company building power related equipment for over 5 years. .
Well Aussie, join my ignorant club.
You have described my lack of design talent too. I never had any electronic training at all.
It never ceases to amaze me how some folk here can sit down and put, in some cases, 100's of components, IC/C/R/diode/etc together to achieve a working system.
I just pinch bits of cct. from one chap and try to sew it onto another bit from someone else.
A kinda "Sew and grow."
BTW, I take it that you have seen this site all about old TV cameras. It will not help in your actual cct design but might spur you on to do great things with your project.
http://www.tvcameramuseum.org/pye/pyethumb.htm
aussie_bloke wrote:G'day Steve.
Yep I intend on making it do 625 lines 50 fields/sec to be compatible with the Australian PAL standard for best quality pictures and for convenience with signal output to my DVD recorder.
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