Zoom Lenses for Scarlet?

[Michael Olsen]

Hello,

I apologize for asking what must seem to many an obvious question, but:

Will there be zoom lenses offered for the non-fixed 2/3" Scarlet? If not from RED, then what are the options?

Best,

Michael

 

[Joel Chu]

Check the FAQ , they offer just about any mounting option. You can get 35mm still lens (Nikon/ Canon) B4, C-mount, PL

 

[Michael Olsen]

Hello!

Check the FAQ , they offer just about any mounting option. You can get 35mm still lens (Nikon/ Canon) B4, C-mount, PL

Thank you for your reply, that certainly makes sense. Based on what I've read about here, using 3rd party zoom mounts may lead to reduced image resolution because the image they produce may not match the 2/3" sensor in size (namely, being too small and covering only a portion of it) and would essentially be like shooting 2K instead of 3K. Is that true?

Best,

Michael

 

[Stephen Gentle]

Hello!



Thank you for your reply, that certainly makes sense. Based on what I've read about here, using 3rd party zoom mounts may lead to reduced image resolution because the image they produce may not match the 2/3" sensor in size (namely, being too small and covering only a portion of it) and would essentially be like shooting 2K instead of 3K. Is that true?

Best,

Michael

These are 1st party mounts - RED make all of them so far. The thing that may lead to reduced quality is that if you use 35mm glass (eg. 35mm PL lenses, Nikon lenses and Canon lenses), it will look far more telephoto than they are (you need something like a 6mm lens to get the same field of view as a 35mm focal length lens), because the lens is designed to cover a far larger area, and you'll be just using a very small portion of the lens in the centre. You still get the full 3K though. If it's a good lens, you should be alright, just you will never be able to shoot wide.

Far better is to use lenses designed for 16mm cameras, such as 16mm PL and C mount lenses, the Mini-primes on the Mini-RED mount, or 2/3" HD lenses with the B4 converter mount.

 

[Dan Hudgins]

2/3" zooms

2/3" zooms

2/3" is not what the sensor is, its 11mm diagonal so regular 16mm lenses should cover, but do not use Bolex RX lenses without testing since they are undercorrected for use with a prism behind the lens.

Fujinon video TV lenses may be usable, more so if you stop down to f/5.6 or like between f/4 and f/8. You don't want to shoot past f/8 most of the time.

I got a Fujinon 12.5 to 75mm f/1.2 for less than $30 that does not look as bad as you would think even wide open, if you adjust the sharpen in post and shoot tighter than you would for 35mm film it could give good results. The backfocus adjustment is critical, without adjusting the backfocus and the lens focus it will be too soft, think of it as a vairable prime rather than a zoom when used wider than f/8. With a zoom you need good diopter lenses to shoot closer than three or four feet, in a pinch you can put a 5mm CS to C ring on the back of a C mount zoom and stop down to get closer, but only stopped down wide open the extension will make for some soft focus effect.

 

[Michael Olsen]

These are 1st party mounts - RED make all of them so far.

I'm sorry, I haven't quite gotten the terminology down so far. I meant 3rd party lenses which are definitely not the same as mounts.

Far better is to use lenses designed for 16mm cameras, such as 16mm PL and C mount lenses, the Mini-primes on the Mini-RED mount, or 2/3" HD lenses with the B4 converter mount.

Thank you for the suggestion - this really helps!

2/3" is not what the sensor is, its 11mm diagonal so regular 16mm lenses should cover, but do not use Bolex RX lenses without testing since they are undercorrected for use with a prism behind the lens.

Fujinon video TV lenses may be usable, more so if you stop down to f/5.6 or like between f/4 and f/8. You don't want to shoot past f/8 most of the time.

I got a Fujinon 12.5 to 75mm f/1.2 for less than $30 that does not look as bad as you would think even wide open, if you adjust the sharpen in post and shoot tighter than you would for 35mm film it could give good results. The backfocus adjustment is critical, without adjusting the backfocus and the lens focus it will be too soft, think of it as a vairable prime rather than a zoom when used wider than f/8. With a zoom you need good diopter lenses to shoot closer than three or four feet, in a pinch you can put a 5mm CS to C ring on the back of a C mount zoom and stop down to get closer, but only stopped down wide open the extension will make for some soft focus effect.

Thanks a lot Dan. That helps clear things up too.

One last question: Why is it called a 2/3" sensor if it is 11mm diagonal?

 

[Dan Hudgins]

Video tube sizes vs. sensor real sizes...

Video tube sizes vs. sensor real sizes...

One last question: Why is it called a 2/3" sensor if it is 11mm diagonal?

The old tube video cameras were rated by the diameter of their tubes, I guess the OD.

The scaned area was maybe half the width of the tube, so the image diagonal is smaller than the tube size.

2/3" lenses can cover less than regular 16mm lenses. Because the sharpness of lenses is in part in ratio to the size of the image circle 2/3" lenses which cover less area than Super16 lenses may have a higher resolution, and in particular the newer "5 MegaPixel" type lenses. Few lenses are rated better than 120lp/mm (240 video lines per mm) many older movie lenses might be 60lp/mm or less wide open since film was not as sharp as newer sensors per mm of image area. When looking at lens spec sheets, watch out for lenses rated in lines per mm rather than line pairs per mm, since 100 lines per mm is really only 50lp/mm or half as sharp, so 180l/mm is not as sharp as 120lp/mm.

Here is some image size info, it is approximate since film has both camera and projector size images,

8mm film (from web), 4.8mmx3.5mm, 5.5mm diagonal

1/3" sensor (from web), 4.8mmx3.6mm, 6mm diagonal

Super8 film (from web), 5.30mmx4.0132mm, 6.647 diagonal

2/3" lens (from web) 8.8mmx6.6mm, 11mm diagonal

For 2/3" the diagonal is the same for 16:9 sensors, the height is smaller and the width a little wider, but the image circle is the same.

16mm (from web)=10.4mmx7.5mm, 12.82mm diagonal

Super16 (from web)=12.4mmx7.5mm, 14.49 diagonal

KAI-02150 sensor (from pdf) 10.56mmx5.94mm, 12.01mm digonal (used in Acam dII camera)

1" sensor (from web) 12.8mmx9.6mm, 16mm diagonal

From this you can see that 2/3" is about twice the image circle of regular 8mm, but since the sensor pixels are smaller than what color film could resolve you get more image detail in those small square mm...

 

[David Rasberry]

Actually 2/3" lenses also cover 11mm circle. Same as normal 16mm. Super 16mm covers larger diagonal.
2/3" became the most accepted broadcast camera standard because it closely matched the TV projection aperture for 16mm film. Early black and white vidicon cameras could use the same lenses as 16mm cameras with no change in FOV compared to 16mm from a telecine.