Astron Reflex 500mm.. Anybody knows anything about this lens?
Recently, I bought it on ebay, $40... Mechanically it is very solid.
Over weekend I tested it, optically it is quite good, but suffers from some fungus.
I didn't try to open it yet (there are some grab screws under the rubber ring, probably this will be the starting point).. does anybody have experience with it, who is manufacturer etc.
I couldn't find any info on web, so any hint is most appreciated.
Today, I tried to unscrew those screws to dismantle the front part where the fungus is, but it seems they are too tight or even glued (locktight?). Tried to apply the acetone (this usually helps) but no joy. Has anybody idea how to proceed? I don't want to damage the screw heads (philips at the back, slot beneath the rubber band).
Any idea/suggestion is much appreciated
Other than acetone or heat (not recommended on lenses) I know of nothing else which will help.
It's not that there likely isn't anything else it's the risk of damaging the glass and mechanisms, perhaps some isopropyl alcohol may loosen them, I do not know but it won't destroy the lens.
Actually, I might.
Recently while trying to remove a battery cover from an old Miranda camera I recently came into possession of, I found a hint online. I already knew cans of compressed air are just refrigerant but I read about it on a camera site where someone suggested using a little of the liquid (turn can upside down and gently press nozzle to get liquid) and try and spray it directly (sorry, drip it) on the screw heads. After a few applications the screws MAY shrink enough to loosen the binding on the threads. Worth a shot. Maybe put a small ring of double sided tape or plasticine or anything to form a small reservoir for the refrigerant to pool.
It worked on the battery cover.
It's funny, my son and I had already played with making a full octave set using empty water bottles and this liquid. The bottles have to be struck with a small hammer (from my xylophone) but they sound amazing.
If it helps with these little things I buy the packs of diabetics syringes at the local pharmacy, cheap and convenient when you need precise control to apply oils and solvents in small quantities though I'm sure you'd probably already know this. Yes, I stab myself nearly every time I use the rotten things too no matter how careful I am, I'm surprised I haven't caught some nasty infections up to now.
I managed to loose the screws on the focus collar without heating/cooling, using the better screwdriver, the tip was filed on grindstone, to be just right fit for the slot in the grab screw.. there was the click sound when the glue cracked inside the thread.
However, the back screws (4x philips, a gateway to mirror, I hope) I left for now, the fungus cleaning is the first task.
The next problem is dismantling the front end .. despite the grab screws are out, the barrel is tightly screwed in.. hopefully not glued.
The reason I am trying this first is because I suspect there may be grab screws for the front lens retaining screw ring (I had this when dismantling MTO1000A).
Today, with the help of acetone, the retaining ring is loosened, it is free but it doesn't go out of the barrel.. it seems the thread can't pass over the anti-reflex grooves.
The people who designed that lens body are not making it easy for you.....
Nope :-)
It was a good mental gymnastics though (with some good suggestions from other forums).. and not too much damage done (couple of scratches on rings, a touch of black paint will cover those).
This lens body is very well made..
DO you have an adjustable tool for removing the rings?
I have one with twin horizontal bars and twin vertical bars (like goal posts sort of) but it's not the best, I designed a better adjustable tool some time back but can't remember where I put my drawing or the actual design. Mine would also double for opening watches.
I think some of these things are built from the back forwards, put the primary lens in from the rear, locking ring goes in first, I've seen stuff made like this and it's always a brain fizzle (not my first choice of words) figuring it out.
Going further, I think this lens could be similar to Soligor on this link (5'54").
There are traces of glue visible between large washer and front plate (with text) that holds the secondary mirror.. so I am guessing the acetone soak will help gain to dismantle this assembly and free the front lens for proper cleaning.
Quote:
Originally Posted by Leo.G
DO you have an adjustable tool for removing the rings?
Usually I make the tool (from old handsaw blade), but for this job I am using caliper...
Astron Reflex 500mm.. Anybody knows anything about this lens?
