Nikon F Photomic FTN Service

[ic-racer]

Back to the camera body and lenses.

Infinity focus checks perfect:

 

[ic-racer]

Shutter curtain travel time is spec'd at about 14.5 sec (without indicating the distance). So I assume about 35mm distance.

My Opening Curtain averaged about 14.8 and closing curtain about 14.9 msec across 35mm.

 

[ic-racer]

That chart tells me the CdS cells are likely weak, which is what I feared. You can only adjust the meter for strong light or low light. There is no compromise.

Yes, good call. One of the CDS cells was bad. I was able to salvage two working CDS cells from a parts camera. Gold ones are the 'new' ones.

 

[ic-racer]

Original has the green insulation. The 'new' ones were fixed up in a similar fashion.

 

[ic-racer]

New CDS cells in place. Too bad the leads on the 'new' ones are not long enough. I'll have to make some jumpers.

 

[F4U]

This is nice work, considering available parts. My only remaining question is what camera the parts cells came from. Some of those cells have built-in lenses that were engineered to mske a meter center weighted, or full frame averaging, or whatever. But in this day and time, just being able to use your noodle and hands to at least bring the meter back into compliance is about as good of a feat as can be hoped for. Some time back I believe I saw somewhere Sover Wong was sourcing new correct F2 cells. But 4 or 5 years hence is a lot of time for people to retire, die, or lose sources. Sometimes you have to just be happy with good enough. Recently I was lucky to find a nice F with motor drive, battery pack, FTN and prism finders, and a 35mm 2.8 Nikkor. and everything works dead on the money, and clean as a whistle. Not a soul has ever raised a screwdriver to it. How lucky was THAT?

 

[ic-racer]

These CDS cells are from a Rolleiflex SL35, of which I have quite a few spare parts and cameras.
Based on the configuration of the PC board and the potential to change all the components as needed, the FTn meter should be amenable to quite a range of CDS cells, either new or recycled.

I was able to get the value for R1 spot on with a combination of resistors, testing them externally like this.

 

[ic-racer]

Based on the external resistor testing above, in my case, a resistance around 270 ohm gave the most linear response. I used a 330 ohm and 1.8k I had laying around to get that value.

 

[ic-racer]

All ready to go back together for the last time.

 

[ic-racer]

Final results:

Battery: 2.7v
R1: 275 ohm
Ro: far to the left, not quite all the way (can't measure exact ohm in circuit)
K: 14.02
Lens: NKJ 50mm 1.4 non-AI
CDS cells: from Rolleiflex SL35 with working meter
ND filters over cells: No

Light Source EV	Exposure Error EV
5	+0.5
6	+0.5
7	+0.5
8	+0.3
9	0.0(calibration point)
10	0.0
11	0.0
12	0.0
13	0.0
14	0.0
15	0.0
16	0.0

 

[Andreas Thaler]

Good work!

 

[ic-racer]

Looks like the flash synch is not working. Time to open it up and have a look. The flash synch contacts are dirty. I cleaned them with deoxit and now the flash synch works great. No adjustment needed.

 

[ic-racer]

While I was in there, I also cleaned the 'safety' contacts. These open when the shutter button is released (because when the main flash contacts strike, they stay together after the exposure).

I also did some routine lubrication and greasing.

None of this is covered in the Richard Haw tutorials; apperatnly he does not use flash. Perhaps he lives where they don't have the time change that makes it dark on the way to work and dark on the way home. Without flash, I'd have to stop photography 4 months out of the year

I don’t think it’s practical to fix the flash-sync [on the F] because I believe that nobody uses this function these days - R.H.