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View Full Version : Shooting with HV20 + 16mm or 35mm anamorphic projector lenses?



Barry L Cohen
08-16-2007, 12:53 AM
Hello,

I'm shooting with an HV20 and I'd like to add an anamorphic projector lens to the front of it to achieve a ridiculously wide aspect ratio. The camera has a single, 1/3" 16:9 CMOS sensor to start with, so adding a 2X anamorphic would potentially give me a ratio of 3.55:1. Sounds good to me.

A Mr. Nathan Snyder has a website ( http://owyheesound.com/anamorphic/anamorphic.html ) with multiple examples of stuff shot through, I believe, a Bausch & Lomb 35mm Cinemascope Attachment I projector lens into a Canon GL2. His stuff looks great.

It surprises me that he was able to focus on objects only a few feet from the B&L Cinemascope Attachment I when, if I am not mistaken, said attachment is intended to focus a projector image onto a screen a minimum of 50 feet away... I'd thought that was the reason shooters intending to shoot through projector lenses opt for 16mm anamorphic projector attachments over 35mm ones--because the 16mm anamorphic projector attachments can focus a projection on screens a mere 6 feet away rather than 17 to 50 feet away as is the case with many 35mm anamorphic projector attachments.

I thought, if, say, an Iscorama 54 can't focus a projected image on a screen less than 6 feet away, then it probably can't focus on an object less than 6 feet away while shooting through it. But Nathan Snyder seems to have been achieving focus on objects about 6 feet away or so shooting through a 7" long, 8 lb. 35mm B&L Cinemascope Projector Attachment I...

If this is possible, why would I want to shoot through 16mm attachments over 35mm ones? Wouldn't barrel distortion, and CA likely be superior in a quality Isco 35mm attachment than in a quality Isco 16mm attachment? I suppose the extra length of most 35mm attachments over 16mm ones could increase the likelihood of vignetting, but certainly the size of the front and rear elements in any given attachment would also affect this, and, generally, 35mm attachments have larger diameter front and rear elements... Finally, because of the demand for quality, large-diameter 16mm anamorphic attachments, they are often sold for much more than quality, large-diameter 35mm anamorphic attachments.

Of primary concern to me in my decision as to whether to shoot through 16mm or 35mm attachments is focal length. I want to be able to shoot with as wide angles as possible. The HV20 has a 10X 6.1mm-61mm zoom yielding a widest focal length of 43.6mm, in 35mm still photography terms. The camera's front filter threads are 43mm, though its front optical element looks to be no more than 25mm or so in diameter... If, with any anamorphic projector attachment, I would be forced to zoom in a whole lot to avoid vignetting, I might reconsider the whole thing...

Where do the "Drive-in" attachments fit in to all of this? The Hilux Val and such. The ones that squeeze a projection vertically rather than expand it horizontally? What about shooting through one of those?

I greatly appreciate any information anyone can provide about any of this.

Thanks a lot,
Barry

Bob Gruen
08-20-2007, 09:25 PM
Why? Who could show it?

A theater screen has a maximum width that the anamorphic projection lens is designed to fit. If it worked all you would accomplish is to have a thin strip of an image with letterboxes above and below.

Bob

Ian-T
08-21-2007, 06:50 AM
Would it not give him more resolution working with more pixels? He would be able to shoot in 4:3 instead of 16:9 and take advantage of the cams full range of pixels....no? Just asking.

Bob Gruen
08-21-2007, 09:54 AM
No. There are specific standards for video, and there is no 4:3 standard that has more pixels than a high def 16:9. From the data below it is obvious that Canon uses a full resolution band for the 16:9 while using the whole sensor to read then downconvert to SD for 4:3.


From Canon's website:

Image Sensor
1/2.7" CMOS Sensor, RGB Primary Color Filter
Total Pixels
Approx. 2,960,000
Effective Pixels
Movies: HDV/DV (WIDE): approx. 2,070,000
DV (NORMAL): approx. 1,550,000
Still Images: 16:9 still images: approx. 2,070,000
4:3 still images: approx. 2,760,000


Ultimately, Anamorphic is a way to squeeze widescreen onto a 35mm film, which is 4:3. If you are shooting 16:9 digital there is no need for such technology. Attempting to use such technology will result in something that is simply unplayable.

Bob

Ian-T
08-21-2007, 05:04 PM
Sorry you are right..I guess i was thinking more in terms of an SD cam like the DVX.

Barry L Cohen
08-21-2007, 05:15 PM
Ultimately, Anamorphic is a way to squeeze widescreen onto a 35mm film, which is 4:3. If you are shooting 16:9 digital there is no need for such technology. Attempting to use such technology will result in something that is simply unplayable.





The camera has a single, 1/3" 16:9 CMOS sensor to start with, so adding a 2X anamorphic would potentially give me a ratio of 3.55:1. Sounds good to me.



You ever watched Abel Gance's 1927 epic, Napoléon, on the big screen? He shot three academy-ratio cameras simultaneously for a cumulative aspect ratio of 4:1. 3.55:1 is conservative.