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Dealing With Lens In Frame

Published :  2nd February 2007

Dear CML,

Background :

Short film, S16, defective lens showing up in the corners of the frame at its widest. The film was one light telecine'd for SD on DigiBeta and an offline was made.

As it was a very low budget production (hence the defective lens...) possible solutions are being considered now, and include zooming in and printing from the scan that was made which should be cheaper than doing it optically.

Now, it seems to me that printing for 35mm from a one light SD scan is not an option, but please do correct me if I'm wrong.

Also, is it that a big deal to zoom in optically during printing from S16 to 35mm which will, in a low budget project, probably get the best result?

Are there any other options to consider?

Thanks for your help,

Tal Lazar
Cameraman
Tel Aviv, ISRAEL
http://www.talazar.net


What is wrong with a slight zoom in during optical blow-up to 35mm? Most optical printers can do that easily. If the whole film is shot with the same lens/camera combination this should be straight forward.

If you frame for 1.85 you will already get rid of some of the vignetting in the corners.

When we do blow-up from standard-16 to 1.85 there is a lot more cropping than from S16 with vignetting corners.

Dirk DeJonghe
www.color-by-dejonghe.com


There is nothing wrong with the optical zoom, these were my thoughts exactly.

It appears that the difference in price of either "running" on the negative without corrections or stopping for zoom corrections is so big that they are considering printing from video, in this case from DigiBeta so I feel that I need to get involved before they actually go and do it...

The negative is now at Synchro film lab in Austria, and as it turns out they don't do the blow-up so I guess we are looking for a place, as well.

Tal Lazar
Cameraman
Tel Aviv, ISRAEL


class="style15">>Short film, S16, defective lens showing up in the corners of the frame at >its widest

Were you using a S16 lens? ...or is it a Regular 16 lens that is not covering the corners.

Zoom in on the Optical and zoom in on the grain.

David Rakoczy
DP/Dir
La/Florida


Zooming in on the transfer is going to look like shit even a tiny 1% zoom noticeably softens the image. If it's only a small # of shots you might be able to get away with it. But it will need a variety of effects, sharpen filters, etc. and it will still stand out from the other footage.

Optical is the only reasonable way to go if there are many shots to be fixed. If you re-frame for 1.85 you might be able to do such a slight optical zoom that you could print the whole film that way without needing to fix individual shots (which sounds too $$).

Jim Eagan
NY shooter/editor


>The negative is now at Synchro film lab in Austria, and as it turns out >they don't do the blow-up so I guess we are looking for a place, as well.

Am I missing something ? How were you going to get from S16 neg to 35 print without a blow up ?

I don't see how 35mm print from d-beta is cheaper either, let alone the quality hit...

Sam Wells
film/.../nj


If you framed for 1.85 in Super16 then most of your problems will disappear when the film is blown up optically. I suggest you take the worst shot (most noticeable) and have it blown up to 35mm. When it's projected with a 1.85 mask, trouble is likely to go away or be so far at the edge that only you will notice it especially if the story is any good.

The SD transfer shows off the problem. Transferring from an SD DigiBeta one light to 35mm Film is UTTER STUPIDITY when you shot S16. The cost of reframing a shot or two is not cost-prohibitive at least in the US. The producers need to shop around for a quality blow-up house that can do the job right for your budget.

New York has several options and I'm certain with a little digging you can find options throughout Europe.

Robert M. Goodman
Author/Filmmaker
Goodman's Guides
www.goodmansguide.com
718 S. 22nd Street
Philadelphia, PA 19146
215-546-1448


I doubt very much that the lens was defective. Also why was this not determined in camera prep?

Sounds like you had a lens that was not designed for Super 16mm, OR, you focused closer than the minimum range at wide angle, causing the vignette. Even with true S16 zooms we are sometimes forced to use them outside their normal operating range and this vignetting takes place.

However, the vignetting is very obvious when you are doing non-linear edit on a computer, because the display shows you the entire video frame. This won't be seen on a TV monitor unless the vignetting is extreme.

Real life example: Look at the trailer for "Heavy Southern Nights":

An obvious lens vignette on the two shot of MD Selig and Lisa Robert. Near the end, just after a shot panning Selig shooting a rifle, then the wide shot of a woman looking into dark water and saying "Oh, no!". It goes by quick so hit pause when you see it.

http://heavysouthernnights.com/movie.swf

It looks like it's only vignetted on the left side but it goes all around. The darkness of the right side of the frame hides it. That was a real S16 zoom (Angenieux 11.5 - 138mm HR) but I was shooting in a trailer home and I was forced to focus closer than 5 feet on the wide end of the zoom. I wish I had some primes on that shoot....

Then look at the same scene in the DVD release version "Southern Justice". You won't see the vignette. TV overscan obscures it.

I hope this won't seem like a shameless plug. I've already plugged the movie enough on my website. It's just one real word example that I can come up with.

And, by all means AVOID punching in digitally on the transferred footage. It will look HORRIBLE, especially if you don't de-interlace the entire movie first.

I would also not waste the money to print to 35mm from DigiBeta. Re-transfer to HD or just project the DigiBeta on a digital projector.

Jorge Diaz-Amador
Designer / Technician
CinemaTechnic, Inc.
Miami, FL USA
http://www.cinematechnic.com


If you have only six shots or so that need reframing during the blow-up, I would suggest to keep them in a separate roll. We would blow-up to Interpositive, and intercut the reframed shots with the normal shots in the interpositive.

This is supposing you want an IP/DN blow up for theatrical release. If you want a direct blow-up there are other solutions.

From there we make a duplicate negative and from there normal contact prints on 35mm positive.

By the way, we did Amos Gitais film last year 'Free Zone'.

Dirk DeJonghe
www.color-by-dejonghe.com


class="style15">> First, it's a converted 12-120 lens, if I'm not mistaken.
> Tal Lazar
> Cameraman

The converted 10-100 T2 Zeiss (it becomes 12-120 T2.4) does vignette when focused below 5 feet at focal lengths below about 25mm. The problem is worse with the old version (80mm front) and much improved with the newer version (87mm front, called Mk.II).

The vignetting does actually get worse when you zoom in slightly which is why you notice it more at 14mm (which used to be 12mm).

This problem is an optical compromise of front external focus zooms of 10:1 or 12:1 range, which by necessity must have enough focus displacement to focus the lens at maximum focal length. This means the displacement is excessive at short focal lengths causing the dreaded "breathing".

Does the lens have an Optex branded conversion kit installed on it?

Jorge Diaz-Amador
Designer / Technician
CinemaTechnic, Inc.
Miami, FL USA
http://www.cinematechnic.com


Tal,

You have been given some good (and some not so good) suggestions. But before this happens to you again and for future reference for yourself (and for us) you have not answered the critical question. Did you use a S16 zoom or a regular 16 zoom on this project??? What were you give'em? One phone call could clear the cause of all this.

Please share your findings.

David Rakoczy
DP/Dir
LA/ Florida


Thanks for your replies.

First, it's a converted 12-120 lens, if I'm not mistaken. I actually shot a different project on the same lens, but after extensive testing I found the lens limitations (the lens is in frame more at 14' than on 12' for example). Sometimes you just have to work with what's given…

Anyway, the project is intended to go to 1.85, but there are about 6 shots that it's really noticeable. The idea of zooming a it in on all the movie will be checked, although it's a bummer. Do you think that the difference in price when blowing up could be so different because of 6 corrections?

Tal Lazar

Cameraman

Tel Aviv, ISRAEL


class="style15">> rather than finding a solution with a lab.

One US optical house I know would charge ~ $ 20 USD per reposition (sometimes called a 'scan' here).

6 of them = $ 120. A _bit_ cheaper than film out from D-beta, hell it's cheaper than a single DigiBeta tape ;-)

If you as per Dirk DeJonghe put them on a single roll with the same repos maybe you could pay one setup charge only. Even single strand it won't hurt to much though...

-Sam Wells
film/.../nj


Not sure how accurate it would be, but I guess you could take your sd scan and apply a mask with a 1.85 aspect ratio on final cut, to have a preview of how much vignetting will be in the final copy without zooming.

Daniel "Chewie" Sanchis
Editor and DF
Brazil


Ok,

First of all thank you all for your replies. Some of the information here I already knew but needed to confirm for the film's director.

Anyhow:

1/. The lens is exactly as you described, Jorge. It's a converted 10-100 Zeiss lens, I guess the old version. At 14mm it's actually worse than 12mm. Some of it has to do with close focusing, and some with the fact that the markings on the lens were a bit blurry. I guess this only proves what is obvious - equipment should be tested before use. In this project the attempt to save money ended up spending some more.

2/. The intention is to blow up of course, final aspect ratio 1.85. The problem was that the director considered blowing up from the beta rather than finding a solution with a lab. I needed to illustrate how stupid this idea is, and in that your replies helped...

Thanks for all the help; I'll post what the final solution was when we do it.

Tal Lazar
Cameraman
Tel Aviv, ISRAEL


Tal Lazar wrote :

class="style15">>1/. The lens is exactly as you described, Jorge. It's a converted 10-100 >Zeiss lens, I guess the old version. At 14mm it's actually worse than >12mm.

If it is a lock off shot - in the future - perhaps focusing to infinity to clear the vignetting, and using a proxar to bring the focus in, might work. Again, only in a lock off. It seems that my 10-150 Angenieux lens covers Super 16 at 10mm, when focussed to infinity, but not when focusing closer.

Steven Gladstone
New York Based Cinematographer
Gladstone Films
www.gladstonefilms.com


Tal,

Zeiss "cut some corners" (sorry, couldn't resist) on the 10-100 T2 design. I guess they (or ARRI) did not want to have a front housing larger than 80mm so the same accessories could be used on the Mk.2 primes and the T2 zoom.

The justification was that the vignetting would only affect full aperture R16mm for 1.33 projection when focused closer than 5 feet [1.5 meter], but would not affect TV safe. I read that somewhere in an old ARRI brochure for that lens. There are NO focus marks on that lens below 1.5m.

When shooting wide shots with this type of lens, I recommend calculating the depth of field and avoiding any shot focused closer than 1.5 meters. In most cases at wide angle 10mm or 12mm, the depth of field will allow you to go closer than 1.5m and maintain focus.

Remember to calculate DOF with a circle of confusion no larger than 1/1667 inch (0.0006 in) [0.015 mm or 15 µm]. This gives a cut-off at 33 line pairs per millimetre. This is the COC that the ASC 16mm tables are based on. It will give good results for transfers to SD video (not more than 480 p)

DO NOT use the 1/1000 in COC from the old circular slide rule calculators. That's unsuitable for today's sharp lenses and high resolution film. You can see through the SR viewfinder that this is inadequate.

For more critical work 1/2000 in (0.0005 in) [ 13 µm] is a better choice that puts the cut-off at 40 lp/mm. This is adequate for 720p transfer and possibly acceptable for 1080p. Focus splits will become difficult to justify unless small apertures are used.

It's possible that with the new high resolution primes from Cooke and Zeiss for Super 16 we may have to consider using a 12 micron (0.00047 in) COC for 1080p transfer, putting the cut-off at 42 lp/mm. This is almost like saying there's "no depth of field".

Jorge Diaz-Amador
Designer / Technician
CinemaTechnic, Inc.
Miami, FL USA
http://www.cinematechnic.com



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