Ryan Patrick O'Hara
Veteran
So my roommate and I were just messing around on the internet and decided to bid on an old S16mm PL mount Angenieux zoom for fun. We ended up having the winning bid, and now will soon own it!
We really don't care terribly much about the lens as far as using it on our films, but we just like old cinema gear, so I'll probably not use much at all except for the occasional film that requires that older vintage zoom lens look, and of course need to shoot it at 2k... but then again, I was curious about increasing the flange focus distance and perhaps squeezing the lens to 4k.
Technically, I'm asking this...
If I got a PL adapter, to something else, and back to a PL adapter (because both the RedOne and Lens are PL mount) would increasing the flange distance of the back element of the lens force the projection circle of the lens to increase? In doing so, I acknowledge that spreading the gathered light over a greater distance means less exposure, so a T/2.5 or T/2.8 lens would turn into a T/4 or T/5.6. And I know the barrel markings would become VERY unusable, losing the ability to focus that range. But for mid range focusing, such as 10ft away or something should stay available.
I'm not a lens tech, but just theorizing... if I increased the PL flange depth of 52mm to perhaps around 100mm, it should almost cover 35mm, yes? Twice the distance would be around 4-times the surface area of the projected image circle. This would also technically be a two stop loss, right?
I'm going off of the inverse square law of light. Double the distance of a light and it spreads to 4x the surface area, thus losing two stops.
I'm excited to at least try this out. I'd end up shooting at a T/5.6 but I figure I usually do that on day interior commercial work, so why not?
And again, I understand that changing the flange distance without changing the backfocus of the lens will result in a HUGE shift of the focus markings and thus I'll loose a big part of that scale. However, I do think there will be a zone still achievable to focus on and if I can keep subjects within that zone (unknown as of now) I can at least get critical focus on individual focal lengths. I understand many won't be possible anymore AND zooming through focal lengths will def not hold focus.
Thoughts??
ps: If I were to try this... does anyone familiar with adapters know a good combination to increase flange distance?
PPS: Holy crap, I am dumb. Isn't a Telephoto 2x extender ALMOST exactly what I am talking about, yet should not disrupt the focus scale? I kinda feel dumb.
We really don't care terribly much about the lens as far as using it on our films, but we just like old cinema gear, so I'll probably not use much at all except for the occasional film that requires that older vintage zoom lens look, and of course need to shoot it at 2k... but then again, I was curious about increasing the flange focus distance and perhaps squeezing the lens to 4k.
Technically, I'm asking this...
If I got a PL adapter, to something else, and back to a PL adapter (because both the RedOne and Lens are PL mount) would increasing the flange distance of the back element of the lens force the projection circle of the lens to increase? In doing so, I acknowledge that spreading the gathered light over a greater distance means less exposure, so a T/2.5 or T/2.8 lens would turn into a T/4 or T/5.6. And I know the barrel markings would become VERY unusable, losing the ability to focus that range. But for mid range focusing, such as 10ft away or something should stay available.
I'm not a lens tech, but just theorizing... if I increased the PL flange depth of 52mm to perhaps around 100mm, it should almost cover 35mm, yes? Twice the distance would be around 4-times the surface area of the projected image circle. This would also technically be a two stop loss, right?
I'm going off of the inverse square law of light. Double the distance of a light and it spreads to 4x the surface area, thus losing two stops.
I'm excited to at least try this out. I'd end up shooting at a T/5.6 but I figure I usually do that on day interior commercial work, so why not?
And again, I understand that changing the flange distance without changing the backfocus of the lens will result in a HUGE shift of the focus markings and thus I'll loose a big part of that scale. However, I do think there will be a zone still achievable to focus on and if I can keep subjects within that zone (unknown as of now) I can at least get critical focus on individual focal lengths. I understand many won't be possible anymore AND zooming through focal lengths will def not hold focus.
Thoughts??
ps: If I were to try this... does anyone familiar with adapters know a good combination to increase flange distance?
PPS: Holy crap, I am dumb. Isn't a Telephoto 2x extender ALMOST exactly what I am talking about, yet should not disrupt the focus scale? I kinda feel dumb.
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. I'd be better just building a bellows or extension tube.