Question for the lens designers on RedUser

[david farland]

Been thinking how you can future proof any recent/upcomimg s35 cine prime lens purchase to ensure it has maximum compatibility with Red's FF35s cameras with an image circle of 43mm or 41.3mm (16x9).

Been checking Matt's "image circle database' http://matthewduclos.wordpress.com/2009/06/02/lens-image-circle-database/#more-68
And noticed that UniqOptics has the following image circles....
25mm - 36mm
35mm - 38mm
50mm - 43mm+
85mm - 43mm+
100mm- 43mm+

And with Red RPP not too far behind....
25mm - 34mm
35mm - 36mm
50mm - 41mm
85mm - 43mm+
100mm- 43mm+

All this means is that the if the wider lenses (25mm/35mm) were 'redesigned' to provide an image circle of 41mm/43mm, the world would keep on spinning when the FF35 Epics are released..

Question...how difficult would this be to redesign these the 25mm & 35mm wide lenses so they cover a 43mm image circle?

Even an 18mm if you wanted a 12mm s35 FOV lens. Guess these new wides would be added to the Red lens arsenal shortly after the FF35 camera release.

anyone?
Dave,

 

[Pawel Achtel]

It would be a major change, Dave. It would affect both, the lens size and the design because an 18mm on S35 can not perform outside its angle of view (FF35).

I think the best combination to cover FF35 would be the Rubby on the wide end and primes at medium and long end. Fast glass covering FF35 is not widely available and, if it was, it would be very large and heavy...and expensive.

Personally, I'm sticking with S35 for the most part. I would rather see the development of higher resolution, less noisy, etc... S35 sensors rather than going into non-standard sensor sizes.

The only use for larger sensors that I have is for night-time/low-light work and this is not frequent enough to justify investment in a new format.

 

[lensmaster]

Distortion on a lens (third order) goes as h^3 so that's alot of stress on the distortion correction. Especially since distortion and astigmatism fight each other with increasing field.

The focal length is short but lateral CA also increase as h^2 (h is image height). So again, you are using up your variables (radius, thickness, glass type) to correct the lateral color.

Looking at the pictures of the RPP's they probably have very low angle of incidence to the sensor (Jim called it Red centric).

These types of designs make going to a 43mm circle VERY tough. It's a totally different design issue with FF35 lenses since the angles to the sensor can be alot greater.

Also, I don't know if RPP's use aspherics but many of the modern FF35 lenses do. This makes the distortion control easier since the asphere is the extra variable required. However, I have to imagine FF35 camera lenses are made in MUCH higher quantities and can jutify the use of the aspheres. I'd be surprised if the RPP's used aspheres, especially given the size.

 

[david farland]

I understand lens manufacturers use aspherics particularly for wide/large aperature lenses to correct various chromatic/seidel aberations.

Would using aspherics be the key difference in approach for reducing aberations on wide lenses (<35mm) with low f-stops (<F2.0)?
I also understand manufacturers use different glass/coating materials to reduce dispersion/glare.

Are aspherical lens elements only used by large volume lens manufacturers (canon, nikon) or expensive lens manufacturers (zeiss, cooke) due to setup costs?
Or is this within the bounds of smaller lens manufacturers (Red, UniqOptics).

Are there any other optical issues besides breathing to consider when designing a cine lens over a still lens?

I'm hoping lens manufacturers will take up the challenge of producing wide/low f-stop lenses for the FF35 cine market like they did with PL mount lenses once Red hit the market.
Considering UniqOptics took the time/money to produce a complete range of lenses to rival RPP lenses and they wouldn't be selling >500 units, I'm hoping a few thousand FF35 Epic/Scarlets will produce a similiar demand for FF35 cine lenses.....over and above Red's electronic hybrid FF35 lenses.

If Red/UniqOptics/other manufacturers ensured their wide angle lenses covered a FF35 sensor it would make their entire range more attractive as it would cover both s35 & FF35 sensors for cine (& still) use.

Dave,

 

[david farland]

bump...opps

 

[Christian Edwards]

bump...opps

bumpings not allowed dave didnt your mother ever teach you netiquette LOL... come to think of it it may not have been around then .carry on as you were