Bolex-Paillard M8 Lens Comparisons 15 - 33mm focal lengths

[Francis Meetze]

I've been running a 33mm lens on my M8 at around a 14ft distance. I have a chance to maybe nab a 20mm or 15mm lens and wonder if it would be worth it for a better focus to size comparison? At around 14ft it can be a challenge sometimes to focus the picture, and even then the definition isn't great at a 3ft screen width.

Would it make any difference purchasing a 15 or 20mm lens to pull the projector closer to the screen? Will it make it easier to focus and get a clearer image?

[Maurice Leakey]

Francis
It sounds as if the 33mm lens which you are using may not be designed for the Bolex M8. The early models were supplied with a Kern 20mm f1.6 lens, later models progressed to a Kern 20mm f1.3. Both probably selected as being entirely suitable.
If the 20mm you have a chance to acquire is one of the above which I mention, then go for it. It will give a bigger picture for a given throw than your 33mm.
http://www.bolexcollector.com/projectors/m8.html

Maurice

[Francis Meetze]

Thanks for responding. Somewhere along the line I was confused. What I have is the 20mm f1.3.

I was looking at the projection graph in the manual which has stats for 33, 25 and 20mm. Right now we are projecting at an aprox. 3ft width from around 14ft and finding a focus is really touchy. I guess I was just curious why they have such a spread in focal lengths and if that had any bearing on the issue?

[Shane C. Collins]

Standard 8 has a much smaller diameter frame wise. As you enlarge this small frame the resolution decreases. I have found Standard 8 and Super 8 look better, and sharper when the film is projected with a smaller image on screen. I use a Da-Lite silver screen and when projecting Super 8 I leave the main frame in the center of the screen. Not super small but small enough that the film resolution is very sharp. I am also using a Bolex 1.3 prime 20mm lens.

[Maurice Leakey]

Francis
I agree with Shane. Try having a smaller picture and see if your focus problem improves. On the other hand, perhaps the film itself is slightly warped and doesn't lie perfectly flat in the gate,
Does this problem exist with all your films?

Maurice

[David Roberts]

The very best picture quality I ever achieved on 8mm(,st 8 or super 8),was with the M 8 and 20mm prime lens.It should produce a lovely picture 3 feet wide with no focusing issues,if the film is ok.
My film was a kodachrome original,shot on a bolex D8L with prime lenses,so it couldn't get much better!