Nikon F unPhotomic

[Mark777]

Photomic FTN heads are big, heavy, and after 50 ish years, many of them have worn out carbon tracks or aged CDS cells. Plain prisms can cost a lot of money now, so wouldn't it be great to rebuild a cheap, broken FTN head, maybe make it smaller and lighter?

Ideally I'd use the bottom half of the prism housing and create a new top half from brass sheet, making it almost as small and light as a plain prism. That's pretty complex for me, maybe a future project... Instead I decided to see what I could do with the existing top and bottom halves of the housing.

The mechanics and electronics were removed. There's a load of parts in the front of the head for aperture linkage. Those were stripped out to save weight, leaving only their mounting plates which help add to the finders rigidity.

I couldn't reduce the overall height of the finder without totally ruining the top cover. Instead I decided to get rid of the section that includes the battery compartment/meter switch and the shutter speed dial linkage. That meant sacrificing the speed indicator in the finder. Out came the Dremel and lots of cutting ensued.
https://flic.kr/p/GiujkY

1mm thick aluminium sheet was shaped to create a new side cover. It's epoxied to the upper part of the housing with a little epoxy putty behind it to add extra strength.
https://flic.kr/p/24niojd

Finally it's painted with matt black enamel, and a rubber edge trim. The trim is just for a bit of detail (and hides my shoddy metalwork). The big finder release lever was cut off leaving a small stub. It's still easy enough to remove the head.

The shutter speed dial is properly accessible, and overall the finder is about 100 grams lighter than it was originally. If I had to do it again I'd use 0.5mm brass sheet instead, being easier to bend into shape and still reasonably strong.

So here it is, the Nikon F unPhotomic.
https://flic.kr/p/EMboNZ

https://flic.kr/p/234YvYT

 

[Timmyjoe]

Would be interested in seeing the pictures. Unfortunately nothing is showing up on my end.

Best,
-Tim

 

[Joe Jesus]

If you follow the first link you can see all the images on flickr.

 

[Shac]

flikr links worked for me. Interesting project

 

[johannielscom]

Maybe a coincidence but just earlier this week in another thread somebody suggested 'liberating' the prism and mounting plate from an Photomic or Photo-eye finder, and subsequently 3D-printing a new housing for it to mount it on the camera.

I thought that was a pretty cool idea and might be a budget-shortcut to a usable finder in 'eye-level' style.

 

[Mark777]

Apologies, it's been a long time (years) since I used a forum and looks like photobucket doesn't allow embedded links any more. Hope the flickr links work better and I'll try to work out how to embed them properly on future posts!

I've also seen a couple of projects where people are talking about 3d printing prism covers. Seems like a good idea, though CNC'd aluminium would be nicer.

 

[Ronald M]

I bought camera just to get plain prisms, one black, one silver. DP1 & DP2 are in storage.

 

[zuiko85]

Often wondered about this myself. Although is the prism contained in the metered head the same as a unmetered head? I thought there were sub prisms cemented to it to divert light to the meter cells or some such, not sure though.

 

[farlymac]

That was a pretty cool mod. I'll have to keep it in mind as I've got some dead finders. If you do ever come up with a new covering, make sure to put the big F on it.

PF

 

[Mark777]

Often wondered about this myself. Although is the prism contained in the metered head the same as a unmetered head? I thought there were sub prisms cemented to it to divert light to the meter cells or some such, not sure though.

One of my plain prisms was chipped and badly desilvered, replaced it with a prism from an early Photomic, the one with the eye and meter on/off button. This only has a small sub prism at the front which pulled away easily without it affecting the image, good idea to score around it first with a sharp knife. Then it's a straight swap with the plain prism.

I've experimented with various silver paints, or products designed for restoring mirrors to repair prisms. None of them worked for me, was better to just clean the damaged area/s of the prism leaving the polished glass. Depending where the damage is, it may still reflect light due to internal reflection with a little more glare in that area of the finder.

The FTN prisms have a couple of extra bits of glass cemented each side of the eyepiece area, never tried taking those off and not sure if that prism is the same size anyhow.

 

[kshapero]

Photomic FTN heads are big, heavy, and after 50 ish years, many of them have worn out carbon tracks or aged CDS cells. Plain prisms can cost a lot of money now, so wouldn't it be great to rebuild a cheap, broken FTN head, maybe make it smaller and lighter?

Ideally I'd use the bottom half of the prism housing and create a new top half from brass sheet, making it almost as small and light as a plain prism. That's pretty complex for me, maybe a future project... Instead I decided to see what I could do with the existing top and bottom halves of the housing.

The mechanics and electronics were removed. There's a load of parts in the front of the head for aperture linkage. Those were stripped out to save weight, leaving only their mounting plates which help add to the finders rigidity.

I couldn't reduce the overall height of the finder without totally ruining the top cover. Instead I decided to get rid of the section that includes the battery compartment/meter switch and the shutter speed dial linkage. That meant sacrificing the speed indicator in the finder. Out came the Dremel and lots of cutting ensued.
https://flic.kr/p/GiujkY

1mm thick aluminium sheet was shaped to create a new side cover. It's epoxied to the upper part of the housing with a little epoxy putty behind it to add extra strength.
https://flic.kr/p/24niojd

Finally it's painted with matt black enamel, and a rubber edge trim. The trim is just for a bit of detail (and hides my shoddy metalwork). The big finder release lever was cut off leaving a small stub. It's still easy enough to remove the head.

The shutter speed dial is properly accessible, and overall the finder is about 100 grams lighter than it was originally. If I had to do it again I'd use 0.5mm brass sheet instead, being easier to bend into shape and still reasonably strong.

So here it is, the Nikon F unPhotomic.
https://flic.kr/p/EMboNZ

https://flic.kr/p/234YvYT

Looks nutty to me but I admire your creativity.

I'll take mind with creme and sugar.

 

[x-ray]

Doing an actual resilver of the prism seems pretty easy if you're really careful with the chemicals. Here's a company that sells kits.

http://angelgilding.com/kits-chemicals/pouring-silver.html

If I had an old prism I'd give it a try.

 

[Fred R.]

Mark777,
The head rises up 1mm in the front of my modification. How do you keep the head flush to the body without the handle and its grip?

 

[Mark777]

Mark777,
The head rises up 1mm in the front of my modification. How do you keep the head flush to the body without the handle and its grip?

Check the clamps are still fully locking under the nameplate when you attach the head, and that nothings fouling the clamp mechanism. If they are properly locking then you shouldn't have a gap as those clamps pull the head down snugly,. There is a spring in the clamp mechanism, so maybe that's come adrift?

This pic, with the front of the head removed, shows how the clamps lock right under the nameplate-
https://flic.kr/p/EUpeKa

 

[Fred R.]

Thanks, Mark777. That was a brainfart error on my part!