lenses

If you're new here, you may want to subscribe to my RSS feed or get my latest posts directly in your mailbox. Thanks for coming to the Foo!

Found a great paper by Canon on lens theory, which also explains the common terminology used in lens construction. The paper also includes an extensive collection of graphs showing the optical resolution of all Canon lenses, both wide open and at F8.

Great resource if you have a Canon stills camera, or a Red One with the very soon forthcoming Birger mount (video link).

Cooke make great film lenses with a passion. Back in the early 90s I went to one of their presentations of a new set of lenses, and they are designed with everyone involved in film production taken care of. For the DP they offer great picture quality. For the AC they have about the clearest markings in the market, which makes it much easier getting the right focus. Very smooth running mechanics. And they take literally years to develop a new lens.

So it was with great satisfaction that I read today that Cooke are launching a set of 4 lenses specifically for the Red camera.

The Cooke RED Set includes: a Cooke S4/i 15-40mm, T2.0 CXX Zoom and Cooke S4/i 50mm, 75mm and 100mm, T2.0 Prime Lenses, a protective glass cover for the CXX Zoom lens and a rigid carry case to hold all four lenses.

The RED ONE camera is fully /i compatible and will communicate directly with Cooke S4/i lenses via special contacts in the camera’s lens mount. There is no need for additional equipment.

No mention about the prices, but I would imagine that they are worth every single penny (as they are made in the UK). For more info on the Cooke zoom, click here. More data on the primes here. UPDATE: looks like the set of lenses will go for just under USD 100k. Ouch! Looks like more of a rental option…

Reds out in the field

Geoff Boyle, British DP of cinematography.net fame, is currently shooting a feature film in 3D, where one of the 3 camera packages is a Red camera. His crew has experienced some difficulties with the camera, but because of its excellent quality, the camera has gotten a – very rare – second chance. That the camera gets good comments from a critical voice such as Geoff is (owner of an ARRI 435, if memory serves right), means something. Read his blog here.

Maybe our next camera will be a Red?

Anyone familiar with photography knows about f-stops. Calculated as Focal Length divided by Diameter (of the front lens element). The smaller the value of the f-stop, the more light passes the lens, the shorter exposure time necessary, the narrower the depth of field, the lower ASA/ISO rating necessary.

Typical f-stop values are f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22 and f/32, but there are lenses with f-stops as low as 1 and as high as 128. With the arrival of automatic exoposure meters, fractional f-stops have also become the norm.

T-Stop

When you start using professional film lenses, you will come across the phrase T-stop. While the f-stop is a mathematically derived value, the T-stop is a calibrated value. Since lenses have optical elements, and each of these elements blocks a (tiny) amount of light, the actual amount of light coming through a lens is always lower than the f-stop value suggests.

Therefore most cine lenses are individually calibrated to give the actual amount of light transmitted, the T-stop (T standing for Transmission.) T-stops are always (slightly) higher than f-stops.

After it turned out that my old SLR got stolen on a recent shoot, I am now looking for a new one.

I’ve always liked Nikon, but since both cameras that were stolen from me were Nikons, I start to believe that they might have some sort of karma.

But seriously speaking, I took the chance - since both body and lenses are now gone - of looking into a different system. And here the Canon EOS 400D comes out as a very promising candidate. The natural competitor would be the Nikon D40. Here the Canon has a couple of advantages, namely

1. Higher pixel count
2. Self cleaning sensor
3. Wider choice of lenses (as the D40 requires lenses with built-in motor)
4. And, as it turns out, Canon offers some cash-back on selected equipment

Read the rest of this entry »