Adding custom lines on focusing screen

[k0diak]

Hi,

I've just got a spare focusing screen for my FM3A and would like to add custom frame lines (I'm running a project with a wider frame and I find I need more precise framing than I can achieve with the 3:2 aspect ratio).
I'm thinking about something similar in visibility to the light meter indicator circle, so I can still use the full frame without disctracting too much and having to swap screens in the field.

I have 2 questions though:

-how to determine the exact area being used on the screen (to be able to determine the aspect ratio in the height, I need the width). Or is it the entire surface?
-how to create the lines? Should I attempt it with a razor blade or laser engravers are better (can they deal with this?)

Did anyone do something like this before?

Thanks,
Andras

 

[Xmas]

HiAndres

Getting a line on a Fresnel screen will be difficult is your spare screen plain glass?

Noel

 

[AgX]

It's a FM3A, thus it is a plasctic screen.

-) scratching

-) transfer line

-) a seperate sheet with those lines

 

[richard ide]

Why not use an extra fine water base marker. You could remove it with a damp Qtip.

 

[Trask]

Back in the 60's and 70's, when artists mocked up magazine or advertising layouts by hand (and maybe they still do), you could by rolls of very thin cut black line, in varying widths, that the artist could use. Hard for me to explain, as I'm sure there's a technical term for this stuff, but essentially it's a roll of black film that you'd roll out wherever you wanted a black line to appear. Being manufactured, it created a black line that looked a lot better than anything you'd draw by hand.

The closest thing I can find in a quick search is here:

https://www.magnatag.com/page/TP/supply/whiteboard-chart-tape.asp?gclid=CNPBuMq9lsMCFQsDaQodbqkApQ

The 1/16 inch black tape solid color, though I recall that even narrower tapes used to be available.

 

[AgX]

Trask, that is what I refered to above as "transfer lines". I once have set complerte texts this way...

The term of the trade is "rub-on lettering".


To my knowledge lines are no longer produced.
(The link you gave is blocked for people outside North-America.)

 

[paul_c5x4]

Rub-down transfers are still available. Letraset still make a few products, but don't appear to do lines. However, other types are still available, see: http://www.jprelec.co.uk/store.asp/c=686/Etch-Resist-PCB-Transfers - Might find Radio Shack (do they still exist ?) stock something similar.

 

[frank]

I have glued single hairs to the edges of the focus screen to create lines. This was a long time ago and I don't think it worked because the hair was sensitive to humidity and would lengthen.

 

[Xmas]

Dead Link Removed

 

[cowanw]

Is there room to lay a piece of mylar on top which if the required hole is cut out would be seen.

 

[E. von Hoegh]

I have glued single hairs to the edges of the focus screen to create lines. This was a long time ago and I don't think it worked because the hair was sensitive to humidity and would lengthen.

I've used spiderweb from webs of globe spiders to replace crosshairs in rifle scopes. You can cement (Ambroid if it's still available) one end, stretch it a bit, then cement the other end and it will remain taut.

 

[E. von Hoegh]

Back in the 60's and 70's, when artists mocked up magazine or advertising layouts by hand (and maybe they still do), you could by rolls of very thin cut black line, in varying widths, that the artist could use. Hard for me to explain, as I'm sure there's a technical term for this stuff, but essentially it's a roll of black film that you'd roll out wherever you wanted a black line to appear. Being manufactured, it created a black line that looked a lot better than anything you'd draw by hand.

The closest thing I can find in a quick search is here:

https://www.magnatag.com/page/TP/supply/whiteboard-chart-tape.asp?gclid=CNPBuMq9lsMCFQsDaQodbqkApQ

The 1/16 inch black tape solid color, though I recall that even narrower tapes used to be available.

Called "Charttape", it came in rolls as thin as 1/32", maybe thinner. I still have some but the stickum has gone bad and migrated.

I guess it still exists!! http://www.amazon.com/Graphic-Black-Matte-64-648/dp/B000CCJPCA

 

[AgX]

No, that is something different. You are talking about solid Vinyl (or so) tapes, whereas that rub-on material is a varnish printed on a sheet of plastic for transfer with the varnish again printed with sticky glue at its open side.

 

[E. von Hoegh]

No, that is something different. You are talking about solid Vinyl (or so) tapes, whereas that rub-on material is a varnish printed on a sheet of plastic for transfer with the varnish again printed with sticky glue at its open side.

The stuff Trask is talking about is the stuff I posted the link to, not Letraset or other rub-on stuff. I remember both the tape and Letraset being used ca. 1970 to mock up magazine layouts which were then photographed so plates could be made.

 

[k0diak]

Thanks guys, plenty of ideas to try!

I wonder if it's possible to have them engraved by one of the laser engraver shops.
I will give the tape/spider web techniques a go first as they're easy to experiment with but if that fails, I would prefer a machined line over me hand scratching it.

 

[frank]

Find extremely thin wire and glue it to the frame. Won't stretch with humidity.

 

[Arklatexian]

I've used spiderweb from webs of globe spiders to replace crosshairs in rifle scopes. You can cement (Ambroid if it's still available) one end, stretch it a bit, then cement the other end and it will remain taut.

During World War ll, there were people who raised black-widow spiders for their webs which were used in bomb-sights. I think I remember seeing pictures in "Life Magazine" showing how it was done. If I were doing this today, I would most probably use any web other than black-widow or brown-recluse as a bite from either might make you seriously contemplate giving up photography.............Regards

 

[rdg]

Thanks guys, plenty of ideas to try!

I wonder if it's possible to have them engraved by one of the laser engraver shops.

You can etch glass in a laser. I have experimented doing so with a 40W CO2 laser. But it will be different than what you likely expect.

From what I have read, and I am in no way about to gaurantee it is correct, the glass contains very small bubbles that the laser heats up and burst causing the glass to create very small shards. I have seen the results and the shards are very small but big enough to just cut your skin. I was not able to use the laser to cut through the glass even with multiple passes. The line is not as sharp and well defined in the glass compared to any other material I have ever used. I would experiment with another piece of glass befor doing it with your focusing screen to ensure you are getting the results that you want.

Another solution might be to etch the glass with an acid. I have seen where parts of a vehicle's VIN (Vehicle Identifiction Number) has been etched into the various windows on a car, usually from a car rental shop, to be used for theift prevention. Anyone replacing windsheilds should have the capicity to etch your glass for you. The width of the etch will be by how small a line you can mask for it.

There are a lot of other solutions that are going to provide a finer line for you than either using a laser or acid to etch the line.

Richard

 

[Jim Jones]

I scribe grids in view camera glass focusing screens with a sharp scribe or needle. The lines appear bright against the image, but not obtrusive like lines penciled or inked in, or worse yet, Chart Tape or wire glued to the ground glass. The glue tends to make the line wider than the wire.

 

[AgX]

You can etch glass in a laser.

This is not about a glass,but a plastic screen.


(That laser treatment of glass is nout about bubbles, but about induced cristallisation.)

 

[AgX]

If there is chance to place a sheet of clear foil between the screen an the prism or fied lens, and with sufficient sharpness, this sheet should be tried at with lining.

 

[frank]

I scribe grids in view camera glass focusing screens with a sharp scribe or needle. The lines appear bright against the image, but not obtrusive like lines penciled or inked in, or worse yet, Chart Tape or wire glued to the ground glass. The glue tends to make the line wider than the wire.

The glue is only at each end of the wire, on the frame.

 

[M Carter]

If it's plastic, I'd just scratch it in with a needle and straight edge.

As far as accurate aspect ratio... I do a lot of green screen shoots, where the perspective of one shot needs to match the perspective of another. I open a frame grab of the background plate in photoshop, scale it so the on-screen size is the same as the field monitor I'll be using on set, and trace perspective lines or details on static-cling material. Those get shot numbers and go in a binder - on the green screen set, I cling the clear plastic to the monitor and make sure the people match the perspective.

I've also done this just to make aspect ratio masks - you could print a sheet with the outline of the focusing screen and the outline of the aspect ratio or lines you want, tape it to a light box, put the screen over it and etch away. Dunno if that applies!

 

[cliveh]

If you can't compose the image within the format you are using, then you are using the wrong format.