Lynx update and 2 new scores :)

[bspeed]

Hi all;
A little while back I greeted you all, with my 1st RF since decades ago.

just a little update/conversation

So the Yashica Lynx shutter speeds are pretty close. almost perfect, 1s thru 1/30, a little wee bit slow at 1/60, and
then:

125 = about 100
250 = 166
500 =285 <- so I have a 250 setting haha.

Used a phototransistor, Oscope. flashlight pointed into the lens, apeture mostly wide open. works real neat just happend to have an old RC propeller tachometer, the case was perfect with its hood for the phototransistor.

today I found a Yashica GS 35 electro ($20)
and a Canonet Ql 19 I think it is. Will see/get the Canonet tonight, Yashica is in the mail.

so thats whats going on over here,
hope you all have a great RF day.

 

[Dave Wooten]

The Lynx has a nice 1.4 45 mm lens! How do you like it?

 

[Nicholas Lindan]

Used a phototransistor, Oscope.

You may need a ~470 ohm resistor between the base and the emitter - without it the phototransistor may be too slow to measure high speeds accurately.

 

[Phillip P. Dimor]

I've always wanted one, myself. Let us know!

The Lynx has a nice 1.4 45 mm lens! How do you like it?

 

[bspeed]

The Lynx has a nice 1.4 45 mm lens! How do you like it?

Awww, shucks, mine has the slower lens have to get it light sealed first.
on my to do list.



the Canonet is a wee bit rough, but it is mostly funtional. just got it 30 minutes ago. can't get the speed ring to go slower than 1/4.
and of course no working 1.3v battery. And it needs film door seals.
But it's all good.

 

[bspeed]

You may need a ~470 ohm resistor between the base and the emitter - without it the phototransistor may be too slow to measure high speeds accurately.

I will look into that.
My initial testing of the "unit" , for rise and fall times, was done with a many- bladed muffin fan, and a flashlight shining through it. the rise and fall times were much faster than the top end of the camera (1/500).
even taking them into account did not get me much closer to the shutter's set speed. kinda wish it did, eh ?

I have not spent any time with phototransistors.
I am taking the signal off of the collector, have a 4.7k collector to +3vdc.
at this resistance and voltage, the phototransistor appears to be fully off, to the lights in the lab.

Nice to have something work, without a "lot of work" lol.
esp since you dont want to get caught playing around. too much anyway. hehe.

I like "switching stuff" though. My prior positon was at a High Voltage power supply company.

 

[bspeed]

I just need to "watch" myself though.....already thinking of dragging out a PIC programmer, my pic board and lcd and searching the net for some pulse duration measuring code...:rolleyes:

 

[Ralph Javins]

Good morning;

David Wooten, there were two versions of the Yashica Lynx; the standard Lynx with the 45 mm f 1.7 lens, and the Lynx 14 with the 45 mm f 1.4 lens. I had the standard back in the very early 1960's and I now have the Lynx 14; the camera I wanted back then. I am not really sure now why I wanted it. It made no difference in focusing. Only occasionally did I use it wide open.

Nicolas Lindan, nice to see that there is another electronics technical type around. I will need to watch what I say.

BSpeed, your test setup for measuring the camera shutter timing almost matches the one I first set up back in the near middle 1960's. I used a Tektronix 545B with a Type L plugin to watch the waveform and a Hewlett-Packard 5245L Frequency Counter in period mode to measure the pulse length coming out of the Texas Instruments 1N2175 photodiode. The light source was a collimated light source (expensive flashlight) on the optical bench. It is amazing what a lab rat can do with all kinds of toys around him at lunch time. Oh, that TI 1N2175? That was an opto-electronic device from TI that was intended for use in computer systems that read the data on Hollerith cards. You guys might remember Hollerith cards better by their common description; an IBM punch card. (Oh, the number of hours sitting in front of an IBM Model 26 Card Punch.) BSpeed, good luck with the PIC project.

 

[bspeed]

Fortran and Punch Cards. Tried that once. once.was.enough.

 

[bspeed]

currently the Canonet:
has rear lens element removed.
bottom palte off.
front covering matl. peeled back.
2 screw on plates, each side of lens removed.
Guess(ing) I have to remove the top now, to remove the lens and its assembly.

I am juuuuustt stupid enough to try and clean this thing myself, you see
looking at it under the low power lab microscope, it is really filthy. probably should not have looked at it that close!

 

[Ralph Javins]

Good morning, BSpeed;

Yup. FORTRAN 2.4, a version not too different from the classical FORTRAN IV that McCracken wrote about. (FORTRAN; FORmula TRANslation, a computer programming language intended for lots of scientific data reduction.) The guys at CDC developed it for us. Had to do it many times in the lab. As mentioned, lots of time up on the second floor of Building 46 in front of an IBM Model 26 Card Punch.