Topics

Short range zoom..

 

Hi all...

I need a short range lighter zoom for a shoot with no time to really test. 

I’ve used the Optimos DPs and was quite happy, but not sure we can get them so might just be Optimos.  

Any thoughts from any one?

It needs to be able to zoom in shot (slow creep as we move).  I have got a Canon 17 to 120 but the camera will be on an arm so I’d like to shave weight where I can..

Thanks.

Michael

Michael J Sanders: Director of Photography 
  

Mobile: +44 (0) 7976 269818   
Linkline Diary: +44 (0)20 8426 2200

Daniel Bronks
 

30-80 ez zoom angeniuex



On Fri, 20 Jul 2018 at 13:05, Michael Sanders via Cml.News <glowstars=me.com@...> wrote:
Hi all...

I need a short range lighter zoom for a shoot with no time to really test. 

I’ve used the Optimos DPs and was quite happy, but not sure we can get them so might just be Optimos.  

Any thoughts from any one?

It needs to be able to zoom in shot (slow creep as we move).  I have got a Canon 17 to 120 but the camera will be on an arm so I’d like to shave weight where I can..

Thanks.

Michael

Michael J Sanders: Director of Photography 
  

Mobile: +44 (0) 7976 269818   
Linkline Diary: +44 (0)20 8426 2200

--
Dan Bronks

Director of Photography
www.danielbronks.com   
THIS SITE IS ALSO ACCESSIBLE VIA iPHONE

AGENTS EUROPE:

Wizzo & Co.

47 Beak Street

London W1F 9SE

+ 44 (0)20 7437 2055

lee@...

http://www.wizzoandco.co.uk/


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UTA (UNITED TALENT AGENCY)
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PHONE: (310) 860-3741
EMAIL: ARAKELIANR@...
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WWW.UTAPRODUCTION.COM



nacamera
 

It’s actually 30-90mm and that would be my choice also.
Angenieux EZ-1 T2

Sent from 
Bob Donnelly's iPhone

On Jul 20, 2018, at 7:07 AM, Daniel Bronks <dbronx@...> wrote:

30-80 ez zoom angeniuex



On Fri, 20 Jul 2018 at 13:05, Michael Sanders via Cml.News <glowstars=me.com@...> wrote:
Hi all...

I need a short range lighter zoom for a shoot with no time to really test. 

I’ve used the Optimos DPs and was quite happy, but not sure we can get them so might just be Optimos.  

Any thoughts from any one?

It needs to be able to zoom in shot (slow creep as we move).  I have got a Canon 17 to 120 but the camera will be on an arm so I’d like to shave weight where I can..

Thanks.

Michael

Michael J Sanders: Director of Photography 
  

Mobile: +44 (0) 7976 269818   
Linkline Diary: +44 (0)20 8426 2200

--
Dan Bronks

Director of Photography
www.danielbronks.com   
THIS SITE IS ALSO ACCESSIBLE VIA iPHONE

AGENTS EUROPE:

Wizzo & Co.

47 Beak Street

London W1F 9SE

+ 44 (0)20 7437 2055

lee@...

http://www.wizzoandco.co.uk/


CREDITS AND RESUME

US: ROBERT ARAKELIAN
UTA (UNITED TALENT AGENCY)
9560 WILSHIRE BLVD., STE. 500
BEVERLY HILLS, CA 90212
PHONE: (310) 860-3741
EMAIL: ARAKELIANR@...
WWW.UNITEDTALENT.COM
WWW.UTAPRODUCTION.COM



 

Thanks guys...  we see if I can find one.

M

Michael Sanders: Director of Photography.  London based but works globally.

reel/credits/kit: www.mjsanders.co.uk    m: +44 (0) 7976 269818

On 20 Jul 2018, at 13:28, nacamera <bob@...> wrote:

It’s actually 30-90mm and that would be my choice also.
Angenieux EZ-1 T2

Sent from 
Bob Donnelly's iPhone

On Jul 20, 2018, at 7:07 AM, Daniel Bronks <dbronx@...> wrote:

30-80 ez zoom angeniuex



On Fri, 20 Jul 2018 at 13:05, Michael Sanders via Cml.News <glowstars=me.com@...> wrote:
Hi all...

I need a short range lighter zoom for a shoot with no time to really test. 

I’ve used the Optimos DPs and was quite happy, but not sure we can get them so might just be Optimos.  

Any thoughts from any one?

It needs to be able to zoom in shot (slow creep as we move).  I have got a Canon 17 to 120 but the camera will be on an arm so I’d like to shave weight where I can..

Thanks.

Michael

Michael J Sanders: Director of Photography 
  

Mobile: +44 (0) 7976 269818   
Linkline Diary: +44 (0)20 8426 2200

--
Dan Bronks

Director of Photography
www.danielbronks.com   
THIS SITE IS ALSO ACCESSIBLE VIA iPHONE

AGENTS EUROPE:

Wizzo & Co.

47 Beak Street

London W1F 9SE

+ 44 (0)20 7437 2055

lee@...

http://www.wizzoandco.co.uk/


CREDITS AND RESUME

US: ROBERT ARAKELIAN
UTA (UNITED TALENT AGENCY)
9560 WILSHIRE BLVD., STE. 500
BEVERLY HILLS, CA 90212
PHONE: (310) 860-3741
EMAIL: ARAKELIANR@...
WWW.UNITEDTALENT.COM
WWW.UTAPRODUCTION.COM



Matthew Clark
 

"It’s actually 30-90mm and that would be my choice also Angenieux EZ-1 T2

I’m baffled by that lens.  It is a “tweener.”  Never wide enough, never long enough for my needs.  I really don’t get it.  It looks OK.  But nothing amazing, IMO.  I’d reach for a Canon zoom, something like the 14.5 -  60mm 2.8.  You are on an arm, maybe wide is good?  Mated with a microforce, you’ll be golden.  Also, the 19-90mm Cabrio 2.9 is also a good option.  I’ve not fallen in love with the 17-120mm.  For me, it doesn’t balance well and the ramping is a no go.  And, another option with budget in mind is the Ang. HR 25-250mm 3.5.  I still love that lens and if you can afford a little more weight (about the same as the 17-120) you might have a match.  

Let us know where you land with your optics.

-m

Matthew J. Clark  //  Director/DP //   StraightEIGHT Films  //  www.str8films.com  //  206.200.3621

 

Thank for the thoughts Matthew.

Image wise I like the pictures out of the Canon 17 to 120, but no it wouldn’t be my first choice but It was bought to match two other camera kits for long running show so it’s here at my disposal.

The shot needs to creep from around 35 to 24 mm. I say about as we haven’t been able to access the location.  Camera (f55) needs to be on an arm so we don’t reveal the tracks as it’s not a smooth surface.  We’ve now managed to get a peewee and panther short arm (as it’s the only way we can get another more crucial shot) so weight isn’t so much of an issue.

And of course the shoot was only confirmed on Friday pm as I was shooting and budget is reasonable tight.  Shooting Tuesday so might have to some time to play on Monday.

Direction from client “it’s got to look good” ......

Mmmm.

Michael Sanders: Director of Photography.  London based but works globally.

reel/credits/kit: www.mjsanders.co.uk    m: +44 (0) 7976 269818

On 20 Jul 2018, at 23:48, Matthew Clark via Cml.News <str8films1=me.com@...> wrote:

Canon zoom, something like the 14.5 -  60mm 2.8.  You are on an arm, maybe wide is good?  Mated with a microforce, you’ll be golden.  Also, the 19-90mm Cabrio 2.9 is also a good option.  I’ve not fallen in love with the 17-120mm.  For me, it doesn’t balance well and the ramping is a no go.  And, another option with budget in mind is the Ang. HR 25-250mm 3.5.  I still love that lens and if you can afford a little more weight (about the same as the 17-120) you might have a match.  

nacamera
 

15-40mm Angenieux EZ-2 T2

Sent from 
Bob Donnelly's iPhone

On Jul 21, 2018, at 10:04 AM, Michael Sanders via Cml.News <glowstars=me.com@...> wrote:

Thank for the thoughts Matthew.

Image wise I like the pictures out of the Canon 17 to 120, but no it wouldn’t be my first choice but It was bought to match two other camera kits for long running show so it’s here at my disposal.

The shot needs to creep from around 35 to 24 mm. I say about as we haven’t been able to access the location.  Camera (f55) needs to be on an arm so we don’t reveal the tracks as it’s not a smooth surface.  We’ve now managed to get a peewee and panther short arm (as it’s the only way we can get another more crucial shot) so weight isn’t so much of an issue.

And of course the shoot was only confirmed on Friday pm as I was shooting and budget is reasonable tight.  Shooting Tuesday so might have to some time to play on Monday.

Direction from client “it’s got to look good” ......

Mmmm.

Michael Sanders: Director of Photography.  London based but works globally.

reel/credits/kit: www.mjsanders.co.uk    m: +44 (0) 7976 269818

On 20 Jul 2018, at 23:48, Matthew Clark via Cml.News <str8films1=me.com@...> wrote:

Canon zoom, something like the 14.5 -  60mm 2.8.  You are on an arm, maybe wide is good?  Mated with a microforce, you’ll be golden.  Also, the 19-90mm Cabrio 2.9 is also a good option.  I’ve not fallen in love with the 17-120mm.  For me, it doesn’t balance well and the ramping is a no go.  And, another option with budget in mind is the Ang. HR 25-250mm 3.5.  I still love that lens and if you can afford a little more weight (about the same as the 17-120) you might have a match.  

Keith Jefferies
 

For slow creeping zooms, I really like the built-in motor on the Cabrio 19-90 T2.9

Keith Jefferies
DP/operator, Los Angeles


On Jul 21, 2018, at 10:04 AM, Michael Sanders via Cml.News <glowstars=me.com@...> wrote:

Thank for the thoughts Matthew.

Image wise I like the pictures out of the Canon 17 to 120, but no it wouldn’t be my first choice but It was bought to match two other camera kits for long running show so it’s here at my disposal.

The shot needs to creep from around 35 to 24 mm. I say about as we haven’t been able to access the location.  Camera (f55) needs to be on an arm so we don’t reveal the tracks as it’s not a smooth surface.  We’ve now managed to get a peewee and panther short arm (as it’s the only way we can get another more crucial shot) so weight isn’t so much of an issue.

And of course the shoot was only confirmed on Friday pm as I was shooting and budget is reasonable tight.  Shooting Tuesday so might have to some time to play on Monday.

Direction from client “it’s got to look good” ......

Mmmm.

Michael Sanders: Director of Photography.  London based but works globally.

reel/credits/kit: www.mjsanders.co.uk    m: +44 (0) 7976 269818

On 20 Jul 2018, at 23:48, Matthew Clark via Cml.News <str8films1=me.com@...> wrote:

Canon zoom, something like the 14.5 -  60mm 2.8.  You are on an arm, maybe wide is good?  Mated with a microforce, you’ll be golden.  Also, the 19-90mm Cabrio 2.9 is also a good option.  I’ve not fallen in love with the 17-120mm.  For me, it doesn’t balance well and the ramping is a no go.  And, another option with budget in mind is the Ang. HR 25-250mm 3.5.  I still love that lens and if you can afford a little more weight (about the same as the 17-120) you might have a match.  

Mitch Gross
 

With the required focal lengths, perhaps the Sigma 18-35 T2. There’s a cine style version available. 

Mitch Gross
Cinema Product Manager 
Panasonic Systems Solutions Company of North America
New York

On Jul 21, 2018, at 11:50 AM, Keith Jefferies <keith@...> wrote:

For slow creeping zooms, I really like the built-in motor on the Cabrio 19-90 T2.9

Keith Jefferies
DP/operator, Los Angeles


On Jul 21, 2018, at 10:04 AM, Michael Sanders via Cml.News <glowstars=me.com@...> wrote:

Thank for the thoughts Matthew.

Image wise I like the pictures out of the Canon 17 to 120, but no it wouldn’t be my first choice but It was bought to match two other camera kits for long running show so it’s here at my disposal.

The shot needs to creep from around 35 to 24 mm. I say about as we haven’t been able to access the location.  Camera (f55) needs to be on an arm so we don’t reveal the tracks as it’s not a smooth surface.  We’ve now managed to get a peewee and panther short arm (as it’s the only way we can get another more crucial shot) so weight isn’t so much of an issue.

And of course the shoot was only confirmed on Friday pm as I was shooting and budget is reasonable tight.  Shooting Tuesday so might have to some time to play on Monday.

Direction from client “it’s got to look good” ......

Mmmm.

Michael Sanders: Director of Photography.  London based but works globally.

reel/credits/kit: www.mjsanders.co.uk    m: +44 (0) 7976 269818

On 20 Jul 2018, at 23:48, Matthew Clark via Cml.News <str8films1=me.com@...> wrote:

Canon zoom, something like the 14.5 -  60mm 2.8.  You are on an arm, maybe wide is good?  Mated with a microforce, you’ll be golden.  Also, the 19-90mm Cabrio 2.9 is also a good option.  I’ve not fallen in love with the 17-120mm.  For me, it doesn’t balance well and the ramping is a no go.  And, another option with budget in mind is the Ang. HR 25-250mm 3.5.  I still love that lens and if you can afford a little more weight (about the same as the 17-120) you might have a match.  

 

Hey Mitch.

I did think about them but a friend whose got them says they are more like variable primes than parfocal zooms.

Is that your experience?

Michael Sanders: Director of Photography.  London based but works globally.

reel/credits/kit: www.mjsanders.co.uk    m: +44 (0) 7976 269818

On 21 Jul 2018, at 20:00, Mitch Gross <mitchgrosscml@...> wrote:

With the required focal lengths, perhaps the Sigma 18-35 T2. There’s a cine style version available. 

Mitch Gross
Cinema Product Manager 
Panasonic Systems Solutions Company of North America
New York

On Jul 21, 2018, at 11:50 AM, Keith Jefferies <keith@...> wrote:

For slow creeping zooms, I really like the built-in motor on the Cabrio 19-90 T2.9

Keith Jefferies
DP/operator, Los Angeles


On Jul 21, 2018, at 10:04 AM, Michael Sanders via Cml.News <glowstars=me.com@...> wrote:

Thank for the thoughts Matthew.

Image wise I like the pictures out of the Canon 17 to 120, but no it wouldn’t be my first choice but It was bought to match two other camera kits for long running show so it’s here at my disposal.

The shot needs to creep from around 35 to 24 mm. I say about as we haven’t been able to access the location.  Camera (f55) needs to be on an arm so we don’t reveal the tracks as it’s not a smooth surface.  We’ve now managed to get a peewee and panther short arm (as it’s the only way we can get another more crucial shot) so weight isn’t so much of an issue.

And of course the shoot was only confirmed on Friday pm as I was shooting and budget is reasonable tight.  Shooting Tuesday so might have to some time to play on Monday.

Direction from client “it’s got to look good” ......

Mmmm.

Michael Sanders: Director of Photography.  London based but works globally.

reel/credits/kit: www.mjsanders.co.uk    m: +44 (0) 7976 269818

On 20 Jul 2018, at 23:48, Matthew Clark via Cml.News <str8films1=me.com@...> wrote:

Canon zoom, something like the 14.5 -  60mm 2.8.  You are on an arm, maybe wide is good?  Mated with a microforce, you’ll be golden.  Also, the 19-90mm Cabrio 2.9 is also a good option.  I’ve not fallen in love with the 17-120mm.  For me, it doesn’t balance well and the ramping is a no go.  And, another option with budget in mind is the Ang. HR 25-250mm 3.5.  I still love that lens and if you can afford a little more weight (about the same as the 17-120) you might have a match.  

Mitch Gross
 

On Jul 21, 2018, at 3:47 PM, Michael Sanders via Cml.News <glowstars=me.com@...> wrote:

I did think about them but a friend whose got them says they are more like variable primes than parfocal zooms.

Is that your experience?

Not at all. In my experience the 18-35 has behaved as a parfocal. While Sigma is conservative in not calling it a technical parfocal, if it walks like a duck and quacks like a duck then it’s a parfocal lens. 

Mitch Gross
Cinema Product Manager 
Panasonic Systems Solutions Company of North America
New York


 

Thanks Mitch - I think the recordist might complain about the quacking but hey, what’s new.

Michael Sanders: Director of Photography.  London based but works globally.

reel/credits/kit: www.mjsanders.co.uk    m: +44 (0) 7976 269818

On 21 Jul 2018, at 21:17, Mitch Gross <mitchgrosscml@...> wrote:

Not at all. In my experience the 18-35 has behaved as a parfocal. While Sigma is conservative in not calling it a technical parfocal, if it walks like a duck and quacks like a duck then it’s a parfocal lens. 

Matthew Clark
 

I agree with Mitch. It certainly behaves like a parfocal. And if looks alright. The complimentary long zoom 50-100 is good too it just happens to breathe a bit. But seems to be parfocal.

-m

Matthew J. Clark
Seattle, Wa
(sent from my tiny pocket computer)

Timur Civan
 

No lens is truly  Parfocal.  Duclos showed me the tests against the angeniuex who claim to be parfocal.   They results were nearly identical.   The  Japanese have a strong sense of honest conservatism with regard to the capabilities of they products. 

Just like the Sigma Cine Primes are officially supported to cover 43.3mm image circle. But illuminate far beyond that. The just say 43.3 because it’s the circle where the optical performance is perfect.   I mean, Duclos just posted a photo of a 100MP hassleblad medium format stills camera with Sigma Cine lenses on it.   According to him they cover great. 

On Sat, Jul 21, 2018 at 5:44 PM Michael Sanders via Cml.News <glowstars=me.com@...> wrote:
Thanks Mitch - I think the recordist might complain about the quacking but hey, what’s new.


Michael Sanders: Director of Photography.  London based but works globally.

reel/credits/kit: www.mjsanders.co.uk    m: +44 (0) 7976 269818

On 21 Jul 2018, at 21:17, Mitch Gross <mitchgrosscml@...> wrote:

Not at all. In my experience the 18-35 has behaved as a parfocal. While Sigma is conservative in not calling it a technical parfocal, if it walks like a duck and quacks like a duck then it’s a parfocal lens. 

--
Timur Civan
Director of Photography 
www.timurcivan.com
917-589-4424

 

Thanks Matt/Mitch.

I ended up buying the pair as I couldn’t find any.  So far so good.  

Looking forward to seeing how well they work.


Michael

Michael J Sanders: Director of Photography 
  

Mobile: +44 (0) 7976 269818   
Linkline Diary: +44 (0)20 8426 2200

On 22 Jul 2018, at 07:08, Timur Civan <timurcivan@...> wrote:

No lens is truly  Parfocal.  Duclos showed me the tests against the angeniuex who claim to be parfocal.   They results were nearly identical.   The  Japanese have a strong sense of honest conservatism with regard to the capabilities of they products. 

Just like the Sigma Cine Primes are officially supported to cover 43.3mm image circle. But illuminate far beyond that. The just say 43.3 because it’s the circle where the optical performance is perfect.   I mean, Duclos just posted a photo of a 100MP hassleblad medium format stills camera with Sigma Cine lenses on it.   According to him they cover great. 

On Sat, Jul 21, 2018 at 5:44 PM Michael Sanders via Cml.News <glowstars=me.com@...> wrote:
Thanks Mitch - I think the recordist might complain about the quacking but hey, what’s new.


Michael Sanders: Director of Photography.  London based but works globally.

reel/credits/kit: www.mjsanders.co.uk    m: +44 (0) 7976 269818

On 21 Jul 2018, at 21:17, Mitch Gross <mitchgrosscml@...> wrote:

Not at all. In my experience the 18-35 has behaved as a parfocal. While Sigma is conservative in not calling it a technical parfocal, if it walks like a duck and quacks like a duck then it’s a parfocal lens. 

--
Timur Civan
Director of Photography 
www.timurcivan.com
917-589-4424

Mark Kenfield
 

Hi Michael,

I'd highly recommend that the first thing you do with the Sigmas, is take them to a lens tech to confirm that backfocus is as good as it can be.

I got the first two Sigma 18-35mm zooms into Australia, tested the first one, and discovered that while the witness marks were accurate at 35mm. They were unusably far off at 18mm (4' was 6' etc.). 

I'd heard various reports from trustworthy sources online that the lens was parfocal, so I assumed it must be a case of sample variation, returned the first one, and got the second... And had exactly the same issue again. 

So I took the lens into Panavision bere in Melbourne to get it looked at. And after an hour or two of fiddling we learnt that you could use regular Zeiss shims to reshim the lens (if you punched some fresh holes in them), and that the lens was well outside of tolerance for backfocus (about 0.05mm out from memory, which I was told was substantial) once it was reshimmed though the lens was fine, and witness marks held through the zoom range.

So definitely get them checked first thing. If you don't get a well set copy, you'll be in trouble otherwise.

Cheers,

Mark Kenfield 
Cinematographer 
Melbourne 

0400 044 500

On 24 Jul 2018, at 2:40 am, Michael Sanders via Cml.News <glowstars=me.com@...> wrote:

Thanks Matt/Mitch.

I ended up buying the pair as I couldn’t find any.  So far so good.  

Looking forward to seeing how well they work.


Michael

Michael J Sanders: Director of Photography 
  

Mobile: +44 (0) 7976 269818   
Linkline Diary: +44 (0)20 8426 2200

Patel, Snehal
 

Hello All,

 

I’m glad that Mark mentioned the importance of shimming your lenses for your camera system.  This is very much the case for any lens, but especially lens with variable focal lengths (zooms).  Rental houses do a very good job of balancing their lenses to match with various cameras.  Keep in mind that when projecting an image from the rear of the lens onto the film plane, you have to take into account the thickness of the low pass filter.  That is the actual plane the lens must project onto.  So if your low pass filter is thicker than expected, you have to move the projecting forward a bit (remove shims).  If the low pass filter is thinner than expected or non-existent, than you may have to move the projection back towards the sensor (add shims). The only way to really tell is by putting on your camera and testing the focus marks.  Do a search for “shim lens zeiss” to see some videos about this process.  This works for any manufacturer and it not very difficult or time consuming – all you need is a camera, your lens, a set of shims and a focus chart on a stand.

 

Zeiss, for example, currently ships lenses with shims set to the correct distance for a 3mm OPLF (Flange Focal Depth of 53.06mm), like the kind found on Alexa sensors.  If you project the lens without compensating for the OPLF, the lens may seem to not hit its focus marks or stay parfocal through the zoom range.  You would have to use an adapter with your projector that adjusts for the 3mm OPLF to see it correctly.  Jon Fauer did FD Times has a great article about the Gecko-Cam system which takes this variation caused by film vs. digital cameras: https://www.fdtimes.com/2015/04/06/gecko-cam-ims-olpf/

 

You may have to shim your lens for a number of reasons:

1.      You are using a different camera than what the new lens was specified for when it shipped – like filming on a RED or BlackMagic Ursa instead of Alexa, Amira when using a new Zeiss lens.

2.      Your camera has seen some wear and the lens mount is not perfectly aligned anymore but it pretty solid in place.

3.      Your cinema zoom is not behaving parfocal even though most of the focus marks seem to fall into place correctly.

4.      You are renting or subrenting a lens and using it on your camera for the first time.

5.      At your rental house, you have already balanced all your various camera sensors to have the same projection distance (52mm) as your lens projector sans low pass adapters. Yes even camera sensors can be shimmed or adjusted!

 

So for your DIY owner/operators out there – it would help keep things in focus if you learned how to shim.

 

Best regards,

__________


Snehal Patel

Sales Manager, Cine & Applications Specialist
Consumer Optics Business Group

Camera Lens Division

Carl Zeiss SBE, LLC
15260 Ventura Blvd., Suite 1200
Sherman Oaks, CA 91403

Office: 
(818) 582-2363
Mobile: 
(818) 259-0559
snehal.patel@...
www.zeiss.com/cine

 

From: cml-glass@... <cml-glass@...> On Behalf Of Mark Kenfield

 

Hi Michael,

 

And after an hour or two of fiddling we learnt that you could use regular Zeiss shims to reshim the lens (if you punched some fresh holes in them), and that the lens was well outside of tolerance for backfocus (about 0.05mm out from memory, which I was told was substantial) once it was reshimmed though the lens was fine, and witness marks held through the zoom range.

 

Cheers,

 

Mark Kenfield 

Cinematographer 

Melbourne 

 

 

Ben Rowland, Yonder Blue Films
 

This is a perfect example of why I recommend CML. Always something to be learned. A sincere thank you to Mr. Patel for taking the time to post. 

All the best,
Benjamin Rowland, Director, Georgia, USA

On Tue, Jul 24, 2018 at 11:43 PM Patel, Snehal <snehal.patel@...> wrote:

Hello All,

 

I’m glad that Mark mentioned the importance of shimming your lenses for your camera system.  This is very much the case for any lens, but especially lens with variable focal lengths (zooms).  Rental houses do a very good job of balancing their lenses to match with various cameras.  Keep in mind that when projecting an image from the rear of the lens onto the film plane, you have to take into account the thickness of the low pass filter.  That is the actual plane the lens must project onto.  So if your low pass filter is thicker than expected, you have to move the projecting forward a bit (remove shims).  If the low pass filter is thinner than expected or non-existent, than you may have to move the projection back towards the sensor (add shims). The only way to really tell is by putting on your camera and testing the focus marks.  Do a search for “shim lens zeiss” to see some videos about this process.  This works for any manufacturer and it not very difficult or time consuming – all you need is a camera, your lens, a set of shims and a focus chart on a stand.

 

Zeiss, for example, currently ships lenses with shims set to the correct distance for a 3mm OPLF (Flange Focal Depth of 53.06mm), like the kind found on Alexa sensors.  If you project the lens without compensating for the OPLF, the lens may seem to not hit its focus marks or stay parfocal through the zoom range.  You would have to use an adapter with your projector that adjusts for the 3mm OPLF to see it correctly.  Jon Fauer did FD Times has a great article about the Gecko-Cam system which takes this variation caused by film vs. digital cameras: https://www.fdtimes.com/2015/04/06/gecko-cam-ims-olpf/

 

You may have to shim your lens for a number of reasons:

1.      You are using a different camera than what the new lens was specified for when it shipped – like filming on a RED or BlackMagic Ursa instead of Alexa, Amira when using a new Zeiss lens.

2.      Your camera has seen some wear and the lens mount is not perfectly aligned anymore but it pretty solid in place.

3.      Your cinema zoom is not behaving parfocal even though most of the focus marks seem to fall into place correctly.

4.      You are renting or subrenting a lens and using it on your camera for the first time.

5.      At your rental house, you have already balanced all your various camera sensors to have the same projection distance (52mm) as your lens projector sans low pass adapters. Yes even camera sensors can be shimmed or adjusted!

 

So for your DIY owner/operators out there – it would help keep things in focus if you learned how to shim.

 

Best regards,

__________


Snehal Patel

Sales Manager, Cine & Applications Specialist
Consumer Optics Business Group

Camera Lens Division

Carl Zeiss SBE, LLC
15260 Ventura Blvd., Suite 1200
Sherman Oaks, CA 91403

Office: 
(818) 582-2363
Mobile: 
(818) 259-0559
snehal.patel@...
www.zeiss.com/cine

 

From: cml-glass@... <cml-glass@...> On Behalf Of Mark Kenfield

 

Hi Michael,

 

And after an hour or two of fiddling we learnt that you could use regular Zeiss shims to reshim the lens (if you punched some fresh holes in them), and that the lens was well outside of tolerance for backfocus (about 0.05mm out from memory, which I was told was substantial) once it was reshimmed though the lens was fine, and witness marks held through the zoom range.

 

Cheers,

 

Mark Kenfield 

Cinematographer 

Melbourne 

 

 

--
Ben Rowland

Mako Koiwai
 

So for your DIY owner/operators out there – it would help keep things in focus if you learned how to shim.

*******************

While Shimming keep in mind that if you are Close Focusing you have Too Thick a Shim. Think in terms of Extension Tubes. Conversely if 6’ is coming up nearer to Infinity, you need a thicker Shim to bring focus closer.

Sometimes one needs to adjust a Tele-Xtender to maintain focus while zooming. Just make sure your Flange Focal Distance is correctly set first! Best to use a very wide lens, near wide open, to First Check your Flange Distance. (While making sure IT’S hitting it’s focus marks.)

That is one thing RED got right. An easy built-in adjuster for setting Flange Depth.

One of the Fun Things I got to do as an AC was making all these adjustments. Really, I kid you not! Well, during a Prep and not out in the field during a shoot!

Of course those of you with ENG experience know all about setting Back Focus ... adjuster built into the zooms, and the Zeiss Digi Primes.

Another thing to keep in mind when making these adjustments. Use a Siemens Star type Chart as your target. (As recommended by Arri.) NOT a PUTORA Sharpness Inducator Chart! See Attachment. The Putora chart is too coarse and will give you False Positives! Focus POPS in nicely but it’s actually giving you a bit of a “range of focus.”

For Focus Aid, Magnification is Better then Peaking. Again, Peaking can give you a range of what’s in focus. Focus Pullers need to watch out for that pulling off of monitors.

I use to try and find that focus point between red and blue fringing, but our lenses are getting so apochromatic that color aberrations are disappearing. Thank you ED glass, Fluorite elements and aspherical elements.

Makofoto, tool twiddler, Ret, S. Pasadena, Ca

Do NOT use this type of Sharpness Indicator Chart! Mr. Putora will Agree. We had that discussion.


Mako Koiwai
 

That last short message with the Sharpness Indicator Chart attachment was a mistake. Please Delete.

Thanks ... Mako