Film-Tech Forum ARCHIVE: FP20 with short focal length lens

This is topic FP20 with short focal length lens in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=008335

Posted by Matthew Taylor (Member # 2310) on 10-27-2006, 05:47 PM:

I am considering buying a Philips FP20 with a turret. it has occured to me that there might be a problem using my 32mm lens with this. Does anyone know if the projected beam will clear the projector with out obstruction if used with this lens?

Posted by Brian Guckian (Member # 1678) on 10-28-2006, 05:32 PM:

Check the front of the FP20 and see if the front corner of the main frame has been cut away immediately beside the turret.

Some of Philips'/Kinoton's models had(?)/have this feature to accommodate the greater angle of divergence produced by short focal length lenses.

But you should really try to aim for c.50mm on 1:1.85. Is this something you could look at?

Posted by David Graham Rose (Member # 1450) on 10-29-2006, 05:45 AM:

Greetings Matthew

To put it bluntly, you are buggered. I tried using a 45mm lens the other day and even that was still clipping the left hand side of the image. Return the projector to the supplier, and tell him/her that it is of no use. Since it is not. Then go out and buy a nice new Century. That will work. The Century projector - the workhorse of the cinema industry.

Regards

David

Posted by Matthew Taylor (Member # 2310) on 10-29-2006, 06:33 AM:

Oh...that's a real shame. I can't really use another lens because this is a home screening room and I have no more room to move the projector back and if I get a smaller lens, I will have an even smaller image than I do now [Frown]

I have this FP20 lined up for purchase (not from a dealer) and due to the reputation the Philips/Kinoton FP20's have, I've been looking forward to getting it. I think a century is going to be out of my league - I only have a hobbyists wallet!

I appreciate the info though.

Posted by Stephen Furley (Member # 1277) on 10-29-2006, 07:02 AM:

quote: Brian Guckian
Check the front of the FP20 and see if the front corner of the main frame has been cut away immediately beside the turret.

Some of Philips'/Kinoton's models had(?)/have this feature to accommodate the greater angle of divergence produced by short focal length lenses.

Can we assume that this is the old FP-20, and not the fairly recently introduced FP-20A? If it is the old FP-20, then I don't think you'll find the cut-out in the corner of the column, this was on the later machines. However, the older machines had smaller columns than the current ones do. I'm doubtful that you'd get away with a 32mm, that's a very short lens.

David, I'm quite surprised that you couldn't use a 45mm; I don't think I've ever used anything shorter than a 50 in one, but the beam was well clear of the column. Maybe even within the older projectors there was some variation in the column size? I've never actually measured it.

I've never used a machine with a turret, but the lens would still have to be in the same position, so that shouldn't make any difference to the shortest lens which can be used.

Posted by Scott Norwood (Member # 30) on 10-29-2006, 07:14 AM:

How about using a slightly longer lens with a magna-com attachment? This would at least extend the front of the lens by a few inches and may allow you to get the picture size that you want. The downside, of course, is the image-softening and light-eating properties of the magna-com.

Posted by Louis Bornwasser (Member # 3063) on 10-29-2006, 10:17 AM:

I would follow Scott's advice exactly. (It does help to know that this is not a commercial theatre where money is concerned.) Louis

Posted by Matthew Taylor (Member # 2310) on 10-29-2006, 11:06 AM:

Thanks guys. Do the Magnacoms eat loads of light? What sort of price are they on the second hand market?

Posted by Louis Bornwasser (Member # 3063) on 10-29-2006, 11:19 AM:

Should be PLENTY around. They do reduce the light; unfortunately on FLAT where you don't need any reduction. Should be OK for home, though. Good projector otherwise. Louis

Posted by Pete Naples (Member # 761) on 10-29-2006, 12:14 PM:

Maybe in the US, but over here they were never popular, and have all but dissapeared. I last saw one about 12 years ago.

Posted by Steve Guttag (Member # 268) on 10-29-2006, 05:07 PM:

I'm not as anti-magnacom as others are. I would advise a curved screen with one htough since they will introduce a pincushion.

Alternately, I would look for what ISCO called their Spezial lens. It used a .52X magnifiier with Ultra prime lenses...it was what followed their T-Kiptikon lenses. These lenses were available down to 31.3mm for 35mm projection.

The current generation are sold as an attachment like an anamorphic. They are available for flat field and curved and will carry the "F" or "C" stamp on their barrel, respectively.

I've used these lenses on my AA2 installations in IMAX theatres due to their ability to put out an excellent image without vignetting on the AA2's body.

Steve