Lens Size, Why so Big?

[Kevin Olsen]

This is just a matter of curiousity more than anything. Why are the RPP, or any cine lenses for that matter, so significantly larger than their photo counterparts?

Is this because Cine lenses are attempting to minimize breathing and distortion and thus require larger elements and housings?

Example, the Nikon 50mm f1.4 weighs 9.9oz and has a 58mm filter. The 50mm T1.8 RPP is 4.53 lbs and has a 110mm front element. Why so big?

KO

 

[Evin Grant]

Part of it is optics and part is mechanics. Ever since the Primos and S4s came out ACs have become very fond of large barreled lenses with the long (read accurate) focus throws they afford.
Also more size and weight mean more correction for optical aberrations like CA and coma. As well as breathing. To make the lenses perform as well and be light you'd need extremely sophisticated hybrid aspherical elements. That's reasonable in a 500,000-1M unit production like Nikon or Canon produce, but much less so in a low volume (under 10K) run like the RPPS. And in most situations the cam is already lighter than an equivalent 35mm film cam so you can afford the weight/performance trade off. A good comparison is either the Duclos/Tokina 11-16 or Focus Optics/Nikon 14-24. Both offer very high optical quality by leveraging the mass produced but very modern (aspherical) designs of the still lenses they are based on, but do not have as long a focus throw as the RPPs.

 

[Charles Angus]

Another thought - it is sometimes desirable to have both focus and iris motor-controlled. There is a certain minimum size to accommodate two motors.

 

[Evin Grant]

That is less of an issue, My standard speed Zeiss lenses can take two motors and they are about the same size as a still prime.

 

[Kevin Olsen]

interesting. yeah it makes sense, it's still amazing to me that the Nikon primes are so small and deliver some great results. Either way, I can't afford any RPPs. Hopefully the Mini-Primes will be quite economical.

KO

 

[Mike Prevette]

Also keep in mind Cine primes and zooms are made to be serviced and have a very long life compared to still lenses. With serviceability comes size.

 

[Steve Gal]

The larger diameter of the lens helps for more focus travel as well as more room for printing scales with much more markings.

 

[Kevin Olsen]

With more focus 'travel' then comes more precision? Meaning a 1/4" of rotation on a cine lens is less sensitive compared to a photo lens and thus allows more precision. That is a good thing, for sure.

KO

 

[Rick Darge]

The RPPs are anchors!! Especially the 25 and 35..

 

[Mark Pedersen]

The RPPs are anchors!! Especially the 25 and 35..

Which is a pain when you are hand holding, since you typically use a wider lens.

M