Nikon F3 light meter illuminator bulb mods

[Sierra Club]

Has anyone ever tried replacing the F3's tiny incadescent light bulb with something more energy efficient and providing more uniform illumination like a micro LED od EL (electroluminescent) panels?

 

[PKR]

Has anyone ever tried replacing the F3's tiny incadescent light bulb with something more energy efficient and providing more uniform illumination like a micro LED od EL (electroluminescent) panels?

Micro LEDs are a SMD and may be hard to use. A small leaded LED could work. Most are 2-2.4VDC and may require a dropping resistor, taking additional space if 3VDC is delivered at the site.

https://www.mouser.com/ProductDetai...s/TLHY4400-AS12Z/?qs=nQ9vpdMXC6D7BUjVD5tUJw==

 

[Sierra Club]

Sorry if this is a dumb question but wouldn't it be possible to solder two wired to SMD to make it easier to use in this case?

I did find some really small LED's such as these (especially Nano and Pico size) which have operating voltage of about 3V.

They say that 10 of these chip-size LEDs (largest ones) will run for about 12 hours on a coin cell battery holder.
3 chip-size LEDs will run for about 40 hours on a coin cell battery holder.
One chip draws approximately 20 milliamps.
I'm guessing that both Nano and Pico will take less than that.

Standard LR44 battery seems to have about 125 mAh.
F3 uses two of these for a total of 250 mAh capacity (they primarily power shutter mechanism and light meter).
Assuming the smallest (Pico) LED will drain 5-10 miliamps (possibly even less) this would allow the illuminator to work *constantly* for over 30 hours.

Unless I fail miserably with electronics which is more than likely 😀

Do you think that changing incadescent bulb to LED would impact the light meter functionality in any way?

 

[monopix]

Yes you can solder wires to an SMD if you want and have a small enough soldering iron to do it. But there's a risk of overheating them.

The small LEDs you've linked to talk about voltage rather than current and don't mention the use of a series resistor so I guess they have a resistor built in somewhere. You have to have a resistor to limit the current to whatever the rating of the LED is.

The two batteries in the F3 are in series so you don't add the capacities together. The voltages get added together. So the total capacity will be whatever the capacity of a single battery is.

 

[PKR]

Yes you can solder wires to an SMD if you want and have a small enough soldering iron to do it. But there's a risk of overheating them.

The small LEDs you've linked to talk about voltage rather than current and don't mention the use of a series resistor so I guess they have a resistor built in somewhere. You have to have a resistor to limit the current to whatever the rating of the LED is.

The two batteries in the F3 are in series so you don't add the capacities together. The voltages get added together. So the total capacity will be whatever the capacity of a single battery is.

Using a Pro SMD work station a lot, i wouldn't attempt soldering leads to a micro SMD LED. The heat would likely kill it. Those devices are designed for solder flow placement on a board. A current dropping resistor is likely necessary too. I use F3 HP's for my film work. I have 3 in recent CLR condition. The little light works on all of them. If it failed, I would likely use a small flashlight rather than deal with an LED replacement. But, that's me. Nikon's little light was lacking from day one, IMO.


Friends of mine but, no $$ interest.
https://countycomm.com/collections/...nium-anodized-aaa-flashlight-by-maratac-rev-3

 

[Beemermark]

Do you think the LED draws too much power? Been a long time since I owned an F3 but I used to shoot a lot of film through it and I think the silver oxide battery lasting a couple of years.

 

[PKR]

Do you think the LED draws too much power? Been a long time since I owned an F3 but I used to shoot a lot of film through it and I think the silver oxide battery lasting a couple of years.

The F3 can also use a lithium battery. Just a guess but, I think the small LED would draw less current than a filament bulb, and likely deliver more light.

Snip
One 3V CR1/3N lithium battery, or Two 1.55V SR44 silver-oxide batteries, or Two 1.5V LR44 alkaline batteries

https://imaging.nikon.com/lineup/filmcamera/slr/f3/spec.htm

 

[Sierra Club]

The incadescent bulb Nikon mounted in F3s is draining power quite quickly and is a bitch to operate (I like to shoot at night with my F3 and N35 1.4)

I'm looking to replace currently used SR44s with one lithium CR1 which apparently has greater capacity - 160 mAh vs 125 mAh.
Only thing I'm worried about is whether this will impact meter readings in any way (something to do with discharge curve I think).

I like to tinker with things and thought it would be cool to improve a bit on the, admittedly, poor illuminating solution Nikon has used in this camera.

 

[PKR]

The incadescent bulb Nikon mounted in F3s is draining power quite quickly and is a bitch to operate (I like to shoot at night with my F3 and N35 1.4)

I'm looking to replace currently used SR44s with one lithium CR1 which apparently has greater capacity - 160 mAh vs 125 mAh.
Only thing I'm worried about is whether this will impact meter readings in any way (something to do with discharge curve I think).

I like to tinker with things and thought it would be cool to improve a bit on the, admittedly, poor illuminating solution Nikon has used in this camera.

See the post above your last.

The Illumination is poor at it's best. Any LED would be an improvement. It's only on briefly and I think, using a CR-1 might be wise. If you expect to do a lot of extended camera timed exposures, then expect replace batteries more often.

When I make long exposures, the camera is on a mount so, the T shutter setting is used. It's completely mechanical and the camera's battery isn't involved. I use my digital watch to time the exposures. The watch display has a back light but, it times off quickly so, i use a small flashlight. I don't rely on the camera's metering for these exposures.

 

[Beemermark]

I wonder if a DL-1 illuminator would work. Made specifically for the Nikon F2 DP-1 finder to illuminate the VF exposure meter. Attaches by installing between the DP-1 housing and VF eyepiece. Most, if not all, Nikon eyepieces are about the same diameter. I use one my F2 for night shooting.

 

[Sierra Club]

See the post above your last.

The Illumination is poor at it's best. Any LED would be an improvement. It's only on briefly and I think, using a CR-1 might be wise. If you expect to do a lot of extended camera timed exposures, then expect replace batteries more often.

When I make long exposures, the camera is on a mount so, the T shutter setting is used. It's completely mechanical and the camera's battery isn't involved. I use my digital watch to time the exposures. The watch display has a back light but, it times off quickly so, i use a small flashlight. I don't rely on the camera's metering for these exposures.

Thanks and agreed, the poor VF data illumination is the reason why I started thinking about replacing bulb with LED since it gives more light while being more energy efficient and being immune to filament damage.

I like to shoot street photography at night so it's not the same as landscape or astro photography where a flashlight would be a good alternative. Granted, it's easier to just use very high ISO film, max aperture and 1/60s or 1/30s shutter for all shots but it's still nice to know the meter readings anyway. It would be ideal to have something similar to LED indicator system like in FM2n.

I wonder if a DL-1 illuminator would work. Made specifically for the Nikon F2 DP-1 finder to illuminate the VF exposure meter. Attaches by installing between the DP-1 housing and VF eyepiece. Most, if not all, Nikon eyepieces are about the same diameter. I use one my F2 for night shooting.

Sounds like an interesting idea for SS dial illumination from the top, assuming it would fit the F3 eyepiece thread and won't come in the way of the prism housing.
The prism construction is significantly different between F2 and f3 and the white plastic daylight illuminator "window" is located in a different place so I don't think it would illuminate the viewfinder data.

 

[Calzone]

SC,

I shimmed the contacts closed with a tiny rectangle of cardboard on my F3P so the light is on anytime I activate the meter. Even in daylight this makes reading the LCD easier.

The drawback is that the F3P depletes fresh batteries after 5-7 rolls.

The wotkaround for this is use the MD-4 motordrive as your source of power.

Because I own a 58/1.2 Noct-Nikkor this works for me. The added weight helps steady the camera.

Cal

 

[Sierra Club]

SC,

I shimmed the contacts closed with a tiny rectangle of cardboard on my F3P so the light is on anytime I activate the meter. Even in daylight this makes reading the LCD easier.

The drawback is that the F3P depletes fresh batteries after 5-7 rolls.

The wotkaround for this is use the MD-4 motordrive as your source of power.

Because I own a 58/1.2 Noct-Nikkor this works for me. The added weight helps steady the camera.

Cal

Thank you for this information Cal!
Where exactly would the cardboard be placed to make the illuminator light activate together with the meter?
I think this would solve most of my problems 🙂

 

[Calzone]

Thank you for this information Cal!
Where exactly would the cardboard be placed to make the illuminator light activate together with the meter?
I think this would solve most of my problems 🙂

SC,

Dig into the F3 Tribute thread for extensive obsessive comments in a very-very long thread. This was the first "Tribute" thread.

Underneath the prism are two tiny phillips flathead screws. Be careful because as I remember there is a tab that retains one end.

You will need tweezers to insert a square from a matchbook cover about a 1/16"x 1/16" inbetween the button switch and a small metal strip that get pushed against contacts.

As I remember there is a flexible circuit board that you might have to work around.

The only difficulty is that somehow there is this tiny square of copper that you need to sandwich in-between the button switch and the contacts.

A word of warning: when your batteries run low if you are not using a MD-4 motordrive for power, at times your shutter might not fire and you will think that the camera is defective. This is not the case. Since the shutter is electronic this symptom is just indicating marginal power to trip the shutter.

Of course the F3 is a great camera, but for night shooting that LED button is not elegant. The Noct-Nikkor on a F3P is a wonderful rig, especially with an illuminated LCD.

Cal

 

[Phil_F_NM]

Sover Wong offers adding LED illumination as a service for DP12 prisms. While these are F2 specific, you may reach out to him to see what circuitry he's accessing and what he is using for the light itself. He may be interested in hearing of your project.
He's very reachable, extraordinarily personable, and a fantastic resource in the Nikon world.

Phil Forrest

 

[Sierra Club]

SC,

Dig into the F3 Tribute thread for extensive obsessive comments in a very-very long thread. This was the first "Tribute" thread.

Underneath the prism are two tiny phillips flathead screws. Be careful because as I remember there is a tab that retains one end.

You will need tweezers to insert a square from a matchbook cover about a 1/16"x 1/16" inbetween the button switch and a small metal strip that get pushed against contacts.

As I remember there is a flexible circuit board that you might have to work around.

The only difficulty is that somehow there is this tiny square of copper that you need to sandwich in-between the button switch and the contacts.

A word of warning: when your batteries run low if you are not using a MD-4 motordrive for power, at times your shutter might not fire and you will think that the camera is defective. This is not the case. Since the shutter is electronic this symptom is just indicating marginal power to trip the shutter.

Of course the F3 is a great camera, but for night shooting that LED button is not elegant. The Noct-Nikkor on a F3P is a wonderful rig, especially with an illuminated LCD.

Cal

Digging through that thread now! Lots of valuable knowledge shared there!
Thank you very much for the guidance provided it seems like a rather straightforward albeit delicate procedure.
Checked some pictures on the net and the drawings in the service manual.
Going to buy a junk F3 and will practice on it, possibly getting some spare parts in the process.

Sover Wong offers adding LED illumination as a service for DP12 prisms. While these are F2 specific, you may reach out to him to see what circuitry he's accessing and what he is using for the light itself. He may be interested in hearing of your project.
He's very reachable, extraordinarily personable, and a fantastic resource in the Nikon world.

Phil Forrest

I've never heard of mr Wong before, thank you for this info.
Checked his website - amazing stuff, he's passionate about keeping the old film gear going and even improving it.
I wish there were more pople like him nowadays...
Thanks again for pointing me in the right direction, I hope maybe he'll be willing to provide some expert advice.
It would be awesome!

Thanks again gents, I appreciate your help 🙂

 

[Calzone]

Digging through that thread now! Lots of valuable knowledge shared there!
Thank you very much for the guidance provided it seems like a rather straightforward albeit delicate procedure.
Checked some pictures on the net and the drawings in the service manual.
Going to buy a junk F3 and will practice on it, possibly getting some spare parts in the process.



I've never heard of mr Wong before, thank you for this info.
Checked his website - amazing stuff, he's passionate about keeping the old film gear going and even improving it.
I wish there were more pople like him nowadays...
Thanks again for pointing me in the right direction, I hope maybe he'll be willing to provide some expert advice.
It would be awesome!

Thanks again gents, I appreciate your help 🙂

SC,

Anytime.

Cal

 

[NicholasNicholas]

Did you ever get around to this mod?
🙂 I daydream about adding a -0+ diode to the interface instead of the LCD but that's just getting out of hand... and likely impossible!