Using 8mm movie camera lens in enlarger

radiant · Jul 19, 2021

warden said:
Considering how close your lens is to the negative I imagine if you touch the focus control at all it makes a huge difference! I know my Beseler is not designed for focusing in that minute of increments. And if your negative moves at all (from heat, etc) that will throw off focus more than it would with a normal enlarging lens. It's a fun experiment!

Yes. Even letting go of focusing knob changes the focus However it is totally doable but it is a bit extreme sport. I really need to consider adding a motorized focus control for larger prints ..

Donald Qualls · Jul 19, 2021

vedostuu said:
I really need to consider adding a motorized focus control for larger prints ..

Or perhaps a gear-reduced fine focus capability...

warden · Jul 19, 2021

Donald Qualls said:
Or perhaps a gear-reduced fine focus capability...

That sounds ideal. I've been experimenting with a 6mm lens on a Beseler 23C and if you touch the focus knob at all, giant things happen. ;-)

radiant · Jul 19, 2021

Donald Qualls said:
Or perhaps a gear-reduced fine focus capability...

It is not the resolution, it is the distance When doing large prints it is impossible to reach to the knob AND view through grain focuser at the same time.

warden · Jul 19, 2021

vedostuu said:
It is not the resolution, it is the distance When doing large prints it is impossible to reach to the knob AND view through grain focuser at the same time.

It's both I think.

I was wishing for orangutan arms last night for focusing, or maybe just an assistant.

last year I was trying to make large enlargements and was projecting horizontally 12 feet or so, and had the dual problems of dim enlarger light and impossible to verify focus when working alone. Using an itty-bitty enlarger lens certainly helps both of those problems, assuming you want to use only a tiny part of the negative, which is fine by me.

Donald Qualls · Jul 19, 2021

vedostuu said:
When doing large prints it is impossible to reach to the knob AND view through grain focuser at the same time.

There's a two word solution for that: flex shaft. Check your thrift stores for an equatorial tripod made for a cheap "toy" reflecting telescope (ideally one that's lost the actual telescope or its optics). Those usually have flex shaft knobs on the azimuth and right ascension controls, for the same reason: you can't reach those adjustments while looking into the eyepiece.

radiant · Jul 19, 2021

warden said:
It's both I think.

Well yes, eventually But it is undoable if you cannot reach the knob in the first place

Donald Qualls said:
There's a two word solution for that: flex shaft.

Good idea but how to attach that (if I find any) to my enlarger.. And is the resolution enough on these?

One idea: CCD/CMOS (backing/reversing auto camera) and small monitor to attach to grain focuser. Maybe the light levels aren't enough, altough the cameras I have are pretty sensitive..

Donald Qualls · Jul 19, 2021

The equatorial mounts have the flex shaft mounted to a worm gear; that gives a pretty large reduction. You'd have to fabricate a clutch system (else the worm would prevent back-driving), so you could rough focus with the regular knob, get the flex shaft knob in hand, then look into the grain focuser and fine focus from there.

If you could lift the coarse and fine focus parts off a microscope, and then put a flex shaft on the fine focus knob, that would give you everything already built.

radiant · Jul 19, 2021

Thanks @Donald Qualls for the ideas. I have to think something. I'm really tempted to add stepper motor to the fine adjustment wheel, probably with a gear reduction. That would be so cool to focus with two push buttons.

But technics aside. I've been on summer holidays and shooting lot of frames just with a thought of this method. Autumn will be interesting in terms of printing. I have done few prints already which I haven't posted anywhere and I just love those already. I feel I have found a new photography home. I've shot also some other projects in mind too simultaneously, on same film+camera+lens. Just fantastic.

warden · Jul 19, 2021

vedostuu said:
One idea: CCD/CMOS (backing/reversing auto camera) and small monitor to attach to grain focuser. Maybe the light levels aren't enough, altough the cameras I have are pretty sensitive..

I was thinking along this line too:

https://www.amazon.com/Inspection-M...ocphy=9007217&hvtargid=pla-569726362960&psc=1

Maybe attach something like this to the grain focuser?

radiant · Jul 19, 2021

warden said:
I was thinking along this line too:

https://www.amazon.com/Inspection-M...ocphy=9007217&hvtargid=pla-569726362960&psc=1

Maybe attach something like this to the grain focuser?

That could work. I have this kind of cameras:

https://www.banggood.com/Foxeer-Raz...ehouse=CN&ID=5304995222376269620&rmmds=search

The camera is said to go to 0.001 lux.

and this style of monitor: https://www.banggood.com/5_8G-48CH-...-p-1364626.html?cur_warehouse=CN&rmmds=search - Not needed to be wireless at all. Just examples..

Nicholas Lindan · Jul 19, 2021

Donald Qualls said:
If you could lift the coarse and fine focus parts off a microscope, and then put a flex shaft on the fine focus knob, that would give you everything already built.

Building a projection microscope out of an enlarger. Using a microscope with a moderate 10x objective that you turn into an enlarger may be a better path.

According to the Thor Labs web site the EFL for a microscope objective is ~200mm/magnification. I am not sure how this is defined for a microscope objective but it seems they treat 200mm as 'infinity' as there is a lens in the tube that makes the conversion. Sophomorically, This leads to a 6.7mm lens being equivalent to a 30x microscope objective (which is something they do not make, 20x or 40x are the choices). The Thor Labs table gives a field of view for a 20x as 1.2mm for a 200mm image plane - it will only get smaller as you get farther from the lens.

A microscope with a 20x objective might make a starting point.

Another approach might be to mount a 35mm camera to a microscope to produce an intermediate negative (well, actually a positive...) that is then used to make the final print.

Reference: https://www.thorlabs.com/NewGroupPage9_PF.cfm?ObjectGroup_ID=1044

Nicholas Lindan · Jul 19, 2021

If a projector or camera lens is used then mounting the lens in a focusing helical might make life easier. Taking the whole lens assembly off a projector will get you the helical.

radiant · Jul 19, 2021

Nicholas Lindan said:
Reference: https://www.thorlabs.com/NewGroupPage9_PF.cfm?ObjectGroup_ID=1044

It seems I'm in holiday mode because it didn't click me at first what was this thorlabs again.. And I work with industry fiber lasers. I think I could find some interesting stuff from our dumpster if I could understand the possibilities

I really like that I can skip the intermediate stage with 8mm movie camera lenses. Enough magnification for me, for sure.

Nicholas Lindan · Jul 19, 2021

I just tried mounting a camera to a microscope (with the right adapter, even) and a 4x objective is too powerful. The camera has a 1.5mm field of view. The eyepieces have a 4mm view, and I'd wager it's the same for a projected image. To get a 15mm field of view on the camera it would take a 0.4x objective - if something like that even exists.

Scratch anything I said about using a microscope.

I looked at my 8mm projector and it has a 25mm/1" lens - not nearly short enough.

I worked at Gooch & Housego for few years. They made the components for lasers. The division in Cleveland made pockels cells and waveplates and various non-linear optical crystals. I developed their electro-optic pockels cell drivers: 5kV pulses with 5nS risetimes, a slew rate of a trillion volts/second - take that ECL!

warden · Jul 19, 2021

You guys are way more high tech than me. I found a 6mm C mount Pentax lens for CCTV and MacGyvered it to my lens board with a toilet paper core and gaf tape. It works but could use some improvement.

Nicholas Lindan · Jul 19, 2021

warden said:
It works but could use some improvement.

If it works that is all that matters - "Good enough is best." Remember, if you fix anything enough times you are sure to really break it.

radiant · Jul 20, 2021

warden said:
You guys are way more high tech than me. I found a 6mm C mount Pentax lens for CCTV and MacGyvered it to my lens board with a toilet paper core and gaf tape. It works but could use some improvement.

I approve this.

Nicholas Lindan said:
5kV pulses with 5nS risetimes, a slew rate of a trillion volts/second - take that ECL!

Nice, but how many kilowatts?

I like this thread, so good buzz going on! Makes my day.

Nicholas Lindan · Jul 20, 2021

vedostuu said:
Nice, but how many kilowatts?

They drive a ~15pf capacitive load and the output current is 15 A during the rise and fall. Power isn't really a thing here, but at 1mHz rep rates things do get nice and toasty and you need water cooling for the driver and sometimes for the Pockels cell itself.

Using 8mm movie camera lens in enlarger

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