Foil

I heard somewhere something about "The foil trick", something to do with the use of old lenses on digital cameras; new to me.
Any of you good folk able to enlighten me, please?

Regards, Larry.

You don't really need the foil...... you need loads of sunshine or UV light It eventually removes the yellow cast in old glass. We don't get enough sunshine in the UK and UV lights can be dangerous. The foil reflects the rays back again.

This might be something to do with that dubious mod I've seen to convince the camera that it's dealing with an A series lens (involved shorting body contacts with foil IIRC?)

I've never bothered. My old lenses work perfectly well in M mode with stop-down metering and I'm not inclined to fiddle about.

Excuse me, "stop-down metering"?

Amazing! the things I learn here!
( honest, I'm not being facetious)

The camera close the aperture down to take a metering, it only does that when the camera doesn't know the aperture.

Some old lenses have radioactive elements in them which can cause the glass to fog yellowish. I've been researching into the old Kodak Aero Ektar lenses.

http://home.earthlink.net/~michaelbriggs/aeroektar/aeroektar.html

If you do have a radioactive lens don't keep it under your bed

I think we've all misunderstood Larry's question. There is a mod done on the contacts with foil, but I can't remember the reason for it. There's also another mod where at least one contact is insulated.

I seem to remember it being so that you could use Av instead of manual and the green button?

Stop down metering is when the camera stops the lens down to the selected aperture, then takes a light meter reading and suggests a shutter speed on that basis. In my experience it's accurate down to about f11, smaller apertures tend to produce bad underexposure.

To use it you fit a manual lens, select "M" mode, set your chosen aperture on the lens and then press either the green button or the exposure compensation ( +/- button) depending on which camera you have. You'll hear the swish as the camera stops down and the viewfinder will go dim, then brighten again as the lens opens back up. After that you can use digital preview to check the exposure will be correct or just try a shot.

[quote:3496ace15f="Bobbinalorry"]I heard somewhere something about "The foil trick", something to do with the use of old lenses on digital cameras; new to me.
Any of you good folk able to enlighten me, please?

The foil trick is used with M42 lenses where the base of the lens does not cover the contact pins on the camera, the same applies to those PK lenses and converters which are painted black and therefore non-conducting. By using the foil or scraping away the paint the contacts are shorted by the foil inserted between the lens and mount. If the contacts are not shorted you can not get MF focus confirmation or catch in focus.

Greg

I've been using MF focus confirmation since I first got an MEF in the 80's I've never had a problem with any lens so I don't think that's what the foil was for.

That's very interesting

I've had no experience with the Aero lenses, but the Kodak Ektar lenses were among the best ever made and the QC was supposed to be better than the German companies. I've got a 202mm Ektar which is excellent used on a bellows (infinity focus possible). Very nice bokeh.

This is a 100% crop at wide open (f/7.7 and f/22

Algi, you sent me back to the test bench and you are correct, the focus confirmation light comes on without shorting out the contacts BUT catch in focus does not work unless the contacts are shorted, this for M42 and K mount lenses.

Thanks for the exercise.
Greg

Maybe catch is focus was the reason

WoW! All you guy's are GreaT!

Thank you all, what a font of knowledge we have here,