ND filter for Bolex

Jon O'Brien · April 11

Hi, I'm filming down at the beach soon, for a website banner loop reel. I need some good shots about 30 seconds each of the surf rolling in, maybe seagulls flying past, that sort of thing. I only have 250D at the moment and was hoping to film in full sunlight. Last time I went into a camera store to ask do they have gel filters I can cut up and put in the Bolex the salesperson said those things we stopped selling back when the dinosaurs were still around. What can I do? If necessary I can film in lower light at the end of the day but interested to hear any ideas. I could buy filters on ebay but that will take ages to arrive.

aapo lettinen · April 11

Likely the best solution would be to find a local (in the same country) fellow cinematographer or photographer who still has gel filter material around. You only need a tiny bit or two (one for use and one for backup if the original gets scratched or too dirty) so someone might give it for free if them having any.

Other than that, you may need to use normal glass filter in front of the lens as lighting nd gels likely dont work well on cameras for other than artistic effects.

I used to buy leftover gel filters lots off of ebay for cheap and store them into a small box in original packages. Have lots of usable nd there too but does not help with you situation because shipping would take forever from here.

But just a reminder that you will want to wait for a good deal on ebay to pop up and then hoard the rest of your life worth of cheap nd scraps. I think my box full of gel filters cost something like 80 bucks total and likely I will never need to buy more even if I would use the bolex and the cp16r every week

Jon O'Brien · April 12

Good advice Aapo. Yes longer term I will have to locate some gel filter material (soon!). For now I'm wondering if I should pop into a local camera store and buy a stills lens ND filter and gerry rig it to the front of the lens with gaffer tape. Anything to get the shot. Can't wait until I have more 50D.

I do have ND filters for a matte box but that's a huge outfit more along the lines of a Hollywood production.

Edited April 12 by Jon O'Brien

Jon O'Brien · April 12

Won't look pretty, and the filter will be permanently damaged by contact with the front of the lens. And they're expensive.

Yesterday I finished a roll of 50D down at the beach and people were coming up and asking about the camera (yesterday it was a Kodak K100 with 25mm lens). Very polite and curious and looked obviously cheered to see someone filming with real film. When I said the camera was 16mm they seemed to know exactly what i was talking about. General knowledge of film and film cameras seems to be rising in the community. It's a good vibe when people come up and ask interesting questions and seem really keen about film. Very encouraging.

Doug Palmer · April 12

5 hours ago, Jon O'Brien said:

Won't look pretty, and the filter will be permanently damaged by contact with the front of the lens. And they're expensive.

Yesterday I finished a roll of 50D down at the beach and people were coming up and asking about the camera (yesterday it was a Kodak K100 with 25mm lens). Very polite and curious and looked obviously cheered to see someone filming with real film. When I said the camera was 16mm they seemed to know exactly what i was talking about. General knowledge of film and film cameras seems to be rising in the community. It's a good vibe when people come up and ask interesting questions and seem really keen about film. Very encouraging.

That's interesting. Maybe The Fablemans has helped 😀

I expect you're already going to be cutting down as much light as possible using the variable shutter, if fitted. Also maybe some slo-mo ? Cheap square ND filters on ebay etc for putting in front of lens, as long as they're well shaded.

Gregg MacPherson · April 12

6 hours ago, Jon O'Brien said:

... the filter will be permanently damaged by contact with the front of the lens......

You can wrap some black paper camera tape over the edge of the lens front and then you won't scratch the filter.

I have used CTO lighting gel in a jam, worked ok. When you have time you could test a lighting ND and see what happens.

Maxim Lequeux · April 12

Getting a filter sampler from Lee or somewhere is pretty good, you get clean and size appropriate filters for the Bolex filter holder, and all different varieties in case of CTO, CTB, and accordingly with ND in each.

I just filmed a bunch of 250D, in late summer, constantly using ND 1.2, 0.9, and 0.6 (out of said sample book) and am very happy with the results, got to around f4 (overexposing a stop or so).

Swatchbook2.jpg?v=1679576751

Joerg Polzfusz · April 12

Hi!

Kodak is still selling gelatine filters (including ND): https://www.kodak.com/en/motion/page/wratten-2-filters

Maybe there’s a company close to you that is selling them?

But I don’t know why you’ll have to tape a „ND filter for still cameras“ to the Bolex?! There should be step up rings for every filter thread. And (designed for digital cameras without filter thread) there are magnetic systems and special filter holders that get screwed into the camera’s tripod socket…

https://www.ebay.de/itm/285232015206?mkevt=1&mkcid=1&mkrid=707-53477-19255-0&campid=5338722076&customid=&toolid=10050

https://www.ebay.de/itm/354683697198?hash=item5294cbb82e:g:5YQAAOSwE1dkIbmm&amdata=enc%3AAQAIAAAA8CQk7I7aLW3eF44TfGkx8TSaANZYnToPiy9XYweQhGG7riOgJlpnvWcmreZsulMQ5fxnyvZNIR%2Fujrb52Iuz5dqRUUThLKv16lBao7ekDJwxKqjTMJCu66CVuM4VdgS7w2Y8qZEYCkgDW8b9peBEnIXMKcWE%2BIHmzYQhaAWOP5brllyvSSpl%2FxpULjtfi4bnGln9sqeMYBzZtJWgZaVYGD%2Bzpxl1fyDnQIJ6LPe9AYONCEi7T3LvEO8xH7znbGXUKA3K8DqCFg7ulFLFYIKzHT7xmKvg1mrlZg44yqFpce4LJuIkOeOxTx3IiiDjH1Yoaw%3D%3D|tkp%3ABFBMxOXI9e5h

Jon O'Brien · April 13

Some great ideas here. Doug, yes I might end up filming at 48 fps and that will take an extra stop off the light input. Waves at half speed should look good. The camera I will be using, a Bolex Rex-5, does have the variable shutter so that is a definite option. When filming at 48 fps does a slightly closed down shutter make much of a difference in terms of motion blur? I don't have much experience of this yet.

Good idea, Gregg. I will get some of that black paper camera tape. I don't currently have any. I have heavy and sticky black gaffer tape but I guess that will do for now if I can find a suitable ND filter (see below). Lighting gels I don't currently have, but will look into experimenting with that.

Maxim, also a great idea. I checked out the book of Lee sample filters and they seem to be currently out of stock in Australia but I will keep looking.

Joerg, yes will have to track some Wrattens down, probably on Ebay. I needed something quickly, in the next day or two, but it looks like I can't actually get anything quickly. So I'm going to have to film in lower light and do some of the other tricks mentioned above, such as film at 48fps.

I went out today to get some more footage but this time not so much luck. I first went to two camera shops but both had absolutely nothing I could use. Both had just really dark ND filter, such as ND1000! That is virtually pitch black. I was looking for something around ND 8 or 16. They did have variable ND filters that went from something like 2 to 6 stops (can't remember) but either way these were unusable as obviously I need to know exactly what ND number they are so I can figure out the exposure.

Back out there again tomorrow to get these shots. I will figure something out.

Doug Palmer · April 13

Filming at 48 with the shutter half-closed I'd think should look OK for waves, depending on what you're planning. You'd get sharper details. Seagulls maybe slightly jerky, I'm not sure.

Joerg Polzfusz · April 13

What about „pull processing“ the 250D?

Jon O'Brien · April 14

14 hours ago, Joerg Polzfusz said:

What about „pull processing“ the 250D?

That's a very good idea, but I will leave that for a future experiment.

I briefly went to the beach again today, with my loyal camera assistant, my wife, who came along. I shot 100' of 250D. The sun was getting low and the light was just a bit warm, but the colours at the beach were pretty good . The ISO on the light meter I set 2/3 back from 250 because the prism takes a third and the Bolex shutter angle another third of the light. That won me a bit of extra f-stop space to move; not that it ended up that there was too much light. I set the camera to 48 fps and left the shutter open at the normal angle. The light meter was saying f22 (with the High Slide in) but I opened up one stop more because of the slo-mo speed. So set the aperture to f16.

The only thing is that I had committed the great mistake of leaving the tripod sliding plate on the Kodak K100 from the other day. So I couldn't use the tripod today, with the Bolex! I won't make that mistake again. Always, always, always put the tripod sliding plate back on the tripod, as soon as you get home. Don't leave it on the camera.

I hope the shots turn out fine. One never knows with film until you get the footage back. Next thing is order some more 50D. And get a ND8 or 16 filter for the Bolex and the Kodak.