Soderbergh & Red Zoom

[PaulClements]

Thought it was worth posting in the lens section as well as the thread about Soderbergh in the main section. Excerpt from Red.com about Soderbergh:

"The RED 18-55mm T3 (f2.8) CF lens and many RED accessories were also chosen by Soderbergh for these movies. Shooting begins in Spain July 24th"

Hopefully we'll get to see something of the lens quality before it's available.

[planet e]

i've read this in a few places now and find it confusing...isn't the RED lens spec 18-50mm, not 18-55mm? did something change while i was asleep at the wheel? or is this a now-widely-circulated typo?

[Steve Gibby]

The "55" should be "50" - it's just a typo. The "CF" in the quote tells you that. The RED 18-50 CF zoom was the one originally announced. If you're wondering if the typo was meant to be RED 18-85, again the 18-85 was never announced as a "close focus" (CF) zoom.

I'm hoping the RED 18-50 CF zoom is available when the first cameras ship. I reserved one and if it's available the same time as RED #8, we'll test the heck out of it in the LART sessions. I also reserved a RED 300mm prime, and that should ship the same time as my camera, so we'll also test that at LART.

[planet e]

exactly what i was wondering. thanks for the clarification....

[edgar01]

Wouldo you please explainme what it mean; Close Focus

Sorry Im a Beginner

Edgar 01

[PaulClements]

Hi Edgar,

Basically the distance from the lens that an object can be positioned and still be focused upon is small on a close focus zoom, therefore an object can go right up close to the lens and remain in focus (I.E. you're focusing close to the lens). Most of the time lens specifications will list distance from the sensor or film plane that represents exactly how close you can get.

Some Zooms suffer because they cannot focus on objects within a few feet. As such a focus that can close focus offers greater potential.

Primes don't suffer as much with this problem. Wide angle lenses typically have nearer close focus distances than telephotos and macro lenses are of course optimized for near close focus distances for getting right up to the object you are shooting.

Cheers

Paul

[Craig Schober]

Hi Edgar,

Basically the distance from the lens that an object can be positioned and still be focused upon is small on a close focus zoom, therefore an object can go right up close to the lens and remain in focus (I.E. you're focusing close to the lens). Most of the time lens specifications will list distance from the sensor or film plane that represents exactly how close you can get.

Some Zooms suffer because they cannot focus on objects within a few feet. As such a focus that can close focus offers greater potential.

Primes don't suffer as much with this problem. Wide angle lenses typically have nearer close focus distances than telephotos and macro lenses are of course optimized for near close focus distances for getting right up to the object you are shooting.

Cheers

Paul

how is this different from a macro lens? is there a technical difference between the two or is it just a marketing term difference?

[Steve Gibby]

how is this different from a macro lens? is there a technical difference between the two or is it just a marketing term difference?

In general terms, macro lenses are designed for very close focus, sometimes as close as a few centimeters from the end of the lens - great for scientific shots, nature shots, etc. A close focus lens, focused to infinity, at stopped down F or T stops, will have extremely deep DOF, sometimes ranging from less than a foot from the end of the lens out to infinity.

For my work, a close focus zoom is great for mobile hand held, shoulder held, or stabilizer mounted shots where you want to have the aperture stopped down for deep DOF and move the camera all around the subjects - and have everything stay in focus. Alternately, I like a CF zoom for certain types of establishing shots or natural world stock footage where there are things framing the foreground that I want in focus, but I want the DOF deep enough for everything out to infinity to be in focus. Then, having the lens be a zoom, rather than a prime, allows the quick re-framing of alternate framings and b-roll shots. I generally use my zoom lenses as variable primes, moving the camera around or to the subject, then also for re-framings. I rarely zoom during a shot unless that is the best choice to express what I need to get across to the viewers.

I've reserved a RED 18-50 CF zoom. I'll look forward to testing it out...

[Stephen Williams]

A close focus lens, focused to infinity, at stopped down F or T stops, will have extremely deep DOF, sometimes ranging from less than a foot from the end of the lens out to infinity.

out...

Hi Gibby,

Wouldn't a normal lens of the same focal length focussed at the hyperfocal distance would have more DOF than a close focus lens focused at infinity. Am I missing something?

Stephen

[explosive]

Hi Gibby,

Wouldn't a normal lens of the same focal length focussed at the hyperfocal distance would have more DOF than a close focus lens focused at infinity. Am I missing something?

Stephen

Well to be fair, he never said it had the most DOF. And, anyway, that really wasn't his point.

He was demonstrating how the CF Zoom is a good all round lens for his purposes...

[explosive]

For my work, a close focus zoom is great for mobile hand held, shoulder held, or stabilizer mounted shots where you want to have the aperture stopped down for deep DOF and move the camera all around the subjects - and have everything stay in focus. Alternately, I like a CF zoom for certain types of establishing shots or natural world stock footage .....


My question is, given that this is an engineered CF lens, pushed in to 50mm, aperture flung open(ish), will we be able to get a nice shallow DOF if we so wish?

I mean, that it is a CF zoom, will it effect the DOF on the shallow end too? (i am guessing so)

Given that the new 18-85mm zoom is not CF, at that same 50mm flung wide open(ish), would you guess that the DOF would be more shallow?

Ta mate...

[Antoine Baumann]

So Stevan Soderbergh is using the RED 18-50 zoom lens, but does he use other lenses? That would be interesting to know how well image shot with RED lens will blend with image shot with an other brand and which one.

antoine.

[Stephen Williams]

My question is, given that this is an engineered CF lens, pushed in to 50mm, aperture flung open(ish), will we be able to get a nice shallow DOF if we so wish?

I mean, that it is a CF zoom, will it effect the DOF on the shallow end too? (i am guessing so)

Given that the new 18-85mm zoom is not CF, at that same 50mm flung wide open(ish), would you guess that the DOF would be more shallow?

Ta mate...

Hi,

If the image magnification size on the sensor is identical, the DOF will be identical at the same F stop regardless of the lens being a prime, zoom or CF.
(or for that matter focal length!)

Stephen

[Steve Gibby]

Hi Gibby,

Wouldn't a normal lens of the same focal length focussed at the hyperfocal distance would have more DOF than a close focus lens focused at infinity. Am I missing something?

Stephen

Busy and I missed your comment. The answer to your question/statement is yes. I simply wasn't clear in the wording of my post.

[Steve Gibby]

Well to be fair, he never said it had the most DOF. And, anyway, that really wasn't his point.

He was demonstrating how the CF Zoom is a good all round lens for his purposes...

Yes, you caught the essence of what I was saying. The CF can be a good all around lens, especially for a limited kit. IMO if the RED 18-50 CF checks out well, it will sell well.

[Steve Gibby]

Hi,

If the image magnification size on the sensor is identical, the DOF will be identical at the same F stop regardless of the lens being a prime, zoom or CF.
(or for that matter focal length!)

Stephen

That's correct...

[Costelloe Michael]

Guys,

I think if you want to split hairs that zooms and primes will differ in their depth of field. This will surely be true in as much as the circle of confusion will differ and even if you calculate the prime and zoom as the same focal length you must allow for the optical differences, there being more glass and therefore more diffraction and therefore less resolving power and an apparent difference in depth of field.

Or have I just drunk too much Rioja?

Just back from a night out :usd:

Mike C

[Stephen Williams]

Guys,

I think if you want to split hairs that zooms and primes will differ in their depth of field. This will surely be true in as much as the circle of confusion will differ and even if you calculate the prime and zoom as the same focal length you must allow for the optical differences, there being more glass and therefore more diffraction and therefore less resolving power and an apparent difference in depth of field.

Or have I just drunk too much Rioja?

Just back from a night out :usd:

Mike C

Hi,

For lenses to cut well, both primes & zooms have to match in quality, one reason that Cooke & Zeiss zooms are fairly large, heavy and expensive relative to still camera lenses.

FWIW a soft lens will have more apparent DOF, it's not obvious what is actually soft / sharp.

Stephen

[Costelloe Michael]

Stephen,

I think you have misunderstood my point.

That post had nothing to do with 'matching' lenses or the 'softness' of a lense, from which I think you mean poor colimnation, ie lack of ability to focus at the right point.

It was merely pointing out that a zoom, any zoom not dependant on make, due to the extra glass elements present, at the same focal length as a prime, (for instance zoom at 50mm and a 50mm prime), will not show the 'same' dof characteristics.

Mike C

[Matthew Rogers]

It was merely pointing out that a zoom, any zoom not dependant on make, due to the extra glass elements present, at the same focal length as a prime, (for instance zoom at 50mm and a 50mm prime), will not show the 'same' dof characteristics.


So are you saying that a zoom has a shallower DOF?

Matthew

[Stephen Williams]

Hi,

I have not misunderstood your point, I disagree with what you are saying.

DOF calculations are a best guess of what might be acceptable, not more or less. You must test any lens you use & decide what YOU are happy with.

I did not mean poor collimation. Take any 1950's lens such as a Cooke SII or Super Balitar & test against a Master Prime @ T2.8. You will notice the Master Prime is much sharper with a far quicker drop off in focus. The older lenses will seem to have a greater DOF, if they have been rebuilt with large focus markings, they will be easier to pull focus with.

As always TEST TEST TEST

Stephen



Stephen,

I think you have misunderstood my point.

That post had nothing to do with 'matching' lenses or the 'softness' of a lense, from which I think you mean poor colimnation, ie lack of ability to focus at the right point.

It was merely pointing out that a zoom, any zoom not dependant on make, due to the extra glass elements present, at the same focal length as a prime, (for instance zoom at 50mm and a 50mm prime), will not show the 'same' dof characteristics.

Mike C

[Costelloe Michael]

Matthew,

No. I don't know how you came to that conclusion from my post.

Ask yourself the question also that does a lense with more apparent contrast and therefore 'bite' have the same dof characteristic as a lense with less contrast, within the same make? Between different glass manufacturers?

I was merely addressing the point someone made that a zoom and a prime at matching focal lengths would exhibit exactly the same depth of field.

MIke C

[Costelloe Michael]

Hi,

Take any 1950's lens such as a Cooke SII or Super Balitar & test against a Master Prime @ T2.8. You will notice the Master Prime is much sharper with a far quicker drop off in focus. The older lenses will seem to have a greater DOF, if they have been rebuilt with large focus markings, they will be easier to pull focus with.


Stephen,

This is my point! Lenses will show different characteristics and it is not just as easy as to say a zoom and a prime will show the same at the same focal length.

I'm going to stop reading this and replying as I seem to be repeating the same thing!

Mike C

[David Mullen ASC]

I've done some simple eyeball tests on this in the past and I couldn't see any significant differences caused by the type of lens -- the "classic" issues (f-stop, distanced focused, focal length) -- are far more significant in determining depth of field characteristics.

With big zooms, you do get into some issues with the fact that the front of the lens is physically closer to the subject than the focal plane.

So, no, it's not exactly the same (50mm prime vs. 50mm on a zoom), but it's nearly the same. I suppose if the lens characteristics were radically different, really milky let's say, then it would have more of an effect, but at that point, the lenses aren't really intercuttable anyway and you've got bigger problems than depth of field.

[Jordan Schroter]

Would someone in the know please oblidge me as i've never heard the term milky before. What does this phrase refer to?

[David Mullen ASC]

"Milky" as in low-contrast, washed-out.

[Costelloe Michael]

Good reply as usual David, seeing the whole of the subject and analysing it quite succinctly.

I do remember as a 1st AC on jobs we used to favour Panaflex dof calculators over the Kelly as it allowed for use of zooms instead of primes and an interpretation of COC.

Sometimes in replying to these things one gets caught in a small world of micro detail which is only interesting in a transitory way, or musings that others take exception to.

I trust your film prep is going well BTW.

Mike C