I call Hot Rod Cameras Bluff with a $10,000 Bet (for Sharpest PL RF for Komodo)

[GrahamClark]

You've diverted to this issue many times.

There's a massive fleet of very beloved PL mount lenses out there already existing that do not have this function, so making a product that assumes they're all adjustable and promoting that seems naive.

John, you said this at the end of your jab:

"Now if you work out a way to make it user adjustable in the mount adaptor itself with a degree of precision you might have a unique and compelling product."

how else could I have said "how about a user adjustable lens mount to make life easier? 3 moving targets, how to reduce that to 1 seems like fun"?

(of course this assumes the PL lens is collimated to spec, but i won't mention that again)

 

[GrahamClark]

Zeiss made the Master Primes, but they also made a whole equivilent set of B4 mount primes and zooms called Digiprimes and Digizooms. They had a novel back focus adjustment complete with a scale on the back.

It was brilliantly implemented. No one ever copied this or used it. Cinema work for the large screen requires a much higher level of precision than the average landscape photographer needs. Unless you have a field collimator then making it user adjustable will never be precise enough for super critical work.

this is awesome! it's inventions like this which could now be considered "vintage", that prove the practicality of something so simple yet effective.

when I was designing tripod equipment (www.aspenballhead.com) I found the greatest inspiration from vintage tripod and ballhead designs, 1887 - 1950's.

for some reason when there was no frame of reference for what was possible the inventions were falling from the sky.

everything was outside the box because there was no box.

this vintage back focus adjust by Zeiss was one of them, which is not unlike macro photography rail sliders invented before prior, around the same time macro lenses were invented.

to a photographer like myself I can see how a macro rail can be applied to a lens mount, when this open source patent you showed proved it was done once, but why not again?

as for the technical aspects image quality between photography and cinema when these inventions came about, I think Group f/64 (1932) would disagree on that one

(The original 11 members of Group f/64 were Ansel Adams, Imogen Cunningham, Edward Weston, Willard Van Dyke, Henry Swift, John Paul Edwards, Brett Weston, Consuelo Kanaga, Alma Lavenson, Sonya Noskowiak, and Preston Holder)

 

[GrahamClark]

You were fair, and let Graham know what's been done, what's hasn't, and what CAN be done (and needs to), in a way that's really encouraging and clear.

So John Brawley ASC - kudos to you sir for seeing the potential is this thread/convo, and pushing it in the right direction.

Filmmaking and its community has always been a team sport - we're at our best when everyone comes together (as opposed to knocking heads haha).

what I find really great about this thread is the uncovering of a brilliant solution which I assumed could be possible yet was already done, but has been forgotten.

so here's to open source patented vintage "user adjustable back focus adjust" for the modern filmmaker

 

[GrahamClark]

So who's the victor?

in my opinion Mr Hot Rod defaulted this bet by not accepting the terms of sending "as-is" units (Denz) within 48 hours after this thread began.

yes I suggested the terms, as to my mind any mount beyond that timeframe could have been made specifically for the "bet".

even though he defaulted on his own bet, at least a user-adjustable backfocus mount came to realization (again) throughout this thread, and that's going to be way more fun than screwdrivers, screws and shims.

 

[GrahamClark]

What will be the rear clearance space for PL protrusion on the breakthrough drop-in filter system? Most are okay, but revolva having some issues with some older and wider lenses.

that's entirely unrelated to this thread, but like user adjustable back-focus adjustable lens mounts, just as fun

 

[Ericsson San Pablo Chu]

Correct me if I'm wrong but was the essence of this whole thread that Breakthrough is releasing a pl rf adapter that is pre-shimmed for the Red Komodo's mean flange depth (I imagine despite heresay there has still got to be some variance camera to camera, whether out-of-factory or over time or enviromental factors)? I guess the main audience for this adapter is people who don't have the tools, time, need, experience or patience to shim the adapter themselves? But if you do shim and test such things yourself there is essentially no difference vs other quality adapters in terms of fine-tuning back focus? Seems to me that in that case the Vocas is a better design as the mount is more secure.

That said, the Breakthrough filter is probably a better product for the general mass market who will never bother to worry too much with collimation (camera, lens or adapter) as long as things generally work.....this is likely because they rarely or never use their focus marks anyway (so as long as infinite or past is achievable). But if that is case, ironically most of them wouldn't benefit from the pre-shimmed adapter for the most part anyway. I guess there is peace of mind for someone owning a Komodo that they can worry more about shimming the lens if needed.

While I like the idea of having back focus adjustable lens mounts and Red's sensor adjustment I'm in the school that that just adds more moving parts/things that can break.

 

[Jacek Zakowicz]

Correct me if I'm wrong but was the essence of this whole thread that Breakthrough is releasing a pl rf adapter that is pre-shimmed for the Red Komodo's mean flange depth (I imagine despite heresay there has still got to be some variance camera to camera, whether out-of-factory or over time or enviromental factors)? I guess the main audience for this adapter is people who don't have the tools, time, need, experience or patience to shim the adapter themselves? But if you do shim and test such things yourself there is essentially no difference vs other quality adapters in terms of fine-tuning back focus? Seems to me that in that case the Vocas is a better design as the mount is more secure.

That said, the Breakthrough filter is probably a better product for the general mass market who will never bother to worry too much with collimation (camera, lens or adapter) as long as things generally work.....this is likely because they rarely or never use their focus marks anyway (so as long as infinite or past is achievable). But if that is case, ironically most of them wouldn't benefit from the pre-shimmed adapter for the most part anyway. I guess there is peace of mind for someone owning a Komodo that they can worry more about shimming the lens if needed.

While I like the idea of having back focus adjustable lens mounts and Red's sensor adjustment I'm in the school that that just adds more moving parts/things that can break.

Not only that- it now puts the camera flange and lens back focus into the "unknown' realm. I've seen ACs go so lost so quickly.... going nuts adjusting back focus with every lens change...not a good way to make AC friends ;-)

 

[Satsuki Murashige]

Not only that- it now puts the camera flange and lens back focus into the "unknown' realm. I've seen ACs go so lost so quickly.... going nuts adjusting back focus with every lens change...not a good way to make AC friends ;-)

Agree with this. The back focus adjustment on the DigiPrimes were a necessary evil at the time, due to the variable quality of many B4 mounts. I had a DP who used to love them on his Panasonic HPX500 back when they came out. I learned the hard way that due to that camera’s cheap mount and thermal expansion characteristics, the back focus had to be checked with every lens change, and sometimes a few hours into the day after the camera had warmed up. Easy enough with a zoom, but a nightmare on primes - especially if you were shooting a lot of Steadicam. This was before we started relying on large focus monitors for Steadicam shots and were pulling off the lens marks. God help you if the Zeiss Sharpmax wasn’t available. There were no such issues with the Sony F23, with its mount made out of Anvar.

There should be no reason to return to those dark days anymore.

 

[Björn Benckert]

A 16mm camera needs much tighter tolerances for backfocus then 35mm camera. Like twice. As the distance between the lens nodal point and sensor plane is shorter.

 

[Jacek Zakowicz]

A 16mm camera needs much tighter tolerances for backfocus then 35mm camera. Like twice. As the distance between the lens nodal point and sensor plane is shorter.

Ah I see- you mean the FL/speed of the lenses. Yes maybe but we never really adjusted them to tighter tolerances than 35mm...

 

[Kemalettin Sert]

John, you said this at the end of your jab:

"Now if you work out a way to make it user adjustable in the mount adaptor itself with a degree of precision you might have a unique and compelling product."

how else could I have said "how about a user adjustable lens mount to make life easier? 3 moving targets, how to reduce that to 1 seems like fun"?

(of course this assumes the PL lens is collimated to spec, but i won't mention that again)

Graham do you really think that nobody thought about making a user-adjustable lens mount adapter before ?

 

[Björn Benckert]

Ah I see- you mean the FL/speed of the lenses. Yes maybe but we never really adjusted them to tighter tolerances than 35mm...

Basically you use a wider lens for the same fov on 16mm and the wider the lens the more crucual is the tolerance for backfocus to no offset the marks, no?

 

[Jacek Zakowicz]

Basically you use a wider lens for the same fov on 16mm and the wider the lens the more crucual is the tolerance for backfocus to no offset the marks, no?

Theoretically yes but with the grain on the film the same size as 35mm essentially limiting the resolution, the deeper field as well it did not require different tolerances. Maybe with an 8k sensor on 16mm size would need it...

 

[John Brawley]

A 16mm camera needs much tighter tolerances for backfocus then 35mm camera. Like twice. As the distance between the lens nodal point and sensor plane is shorter.

Not really ?

Yes wide lenses for both formats are always more critical for having the lens be set to the correct FFD.

JB

 

[Jacek Zakowicz]

Many factors influence actual tolerance. With film the specs were easier to determine as the recording medium was the same, no matter what format, size. With electronic sensor you look and format size, pixel pitch, debayer(or no debayer) algorithm, compression just to name a few. It's time to start looking at the image acquisition as a complete system from image creation to storage, playback, display. I hope we all can agree this is not a job for the camera crew.

 

[Björn Benckert]

Not really ?

Yes wide lenses for both formats are always more critical for having the lens be set to the correct FFD.

JB

No as if you want the same FOV for both cameras then the 16mm camera has almost half the nodal to back plane distance. Which gives it half the tolerance span when you colimate it. Basically a smaller camera demands higher tolerances.

 

[John Brawley]

No as if you want the same FOV for both cameras then the 16mm camera has almost half the nodal to back plane distance. Which gives it half the tolerance span when you colimate it. Basically a smaller camera demands higher tolerances.

Who said anything about matching FOV between lenses on cameras? Last time I shimmed a pl mount in 16mm it was the same depth for 35mm and both were measured and shimmed to .000mm.

JB

 

[Björn Benckert]

The reason for digiprimes being user adjustable is
1. they came out when mounts for 16mm digital cameras where all over the place.
2. When shoothing 16mm / smaller sensor you naturally use a range of lenses that is much shorter lenghts, short focal lengths are more demanding in terms of backfocus.


A 50mm lens on a s35mm camera simply gives more slack to backfocus adjustement than a 20mm on a 16mm camera still both gives the same fov. And for a large format 8/10 camera you need a 520mm to get the same image. The using such large camera your backfocus is far less crucial.

So backfocus distance simply gets more and more important the smaller the sensor you work with as the tolerances naturally narrows in.


I doubt lens and mount stay colimated to .000mm for long. sensor move with temperature, mount swells up etc.

 

[John Brawley]

T.

I don't think you're thinking about this the right way.

Lenses are set to a set depth, no matter what focal length they are. If it's PL then it's 52mm. No matter what focal length, what format.

Cameras are also set to a 52mm Depth, be it actual or virtual (using a FFD like the Denz).

Both are set to the same FFD. Focus marks work. Lenses hit infinity. they are treated seperate. Sometimes home users, people that don't have collimators would maybe collimate a lens to a camera, but that's pretty poor practice.

JB

 

[Björn Benckert]

I don't think you're thinking about this the right way.

Lenses are set to a set depth, no matter what focal length they are. If it's PL then it's 52mm. No matter what focal length, what format.

Cameras are also set to a 52mm Depth, be it actual or virtual (using a FFD like the Denz).

Both are set to the same FFD. Focus marks work. Lenses hit infinity. they are treated seperate. Sometimes home users, people that don't have collimators would maybe collimate a lens to a camera, but that's pretty poor practice.

JB

All im saying is that for a large format camera the tolerances is far bigger than for lets say a super 8 camera. The tolerances scale with the sensor. If you want to achive the same fov image with both. So the shorter focal lenght you want to use the more critical is your mount. On 16mm you use lenses half as long compared to s35mm so yes mounting the lens gets twice as critical.