Olympus, Independent Lens Makers, Tamron, Sigma

Perhaps the most backward-compatible camera brand, a new Pentax digital SLR camera will accept a lens made for one of the first Pentax K bayonet-mount 35mm cameras back in the mid-1970s. If the lens has auto aperture control (Pentax KA) and autofocus (Pentax KAF) capability, those features will couple to the D-SLRs controls. A Pentax digital SLR will even accept old Pentax screw-mount lenses made for cameras in the 1960s and early ‘70s, provided a Pentax Lens Mount Adapter B is used.

Pentax is now collaborating with Samsung on digital SLR design, so present (and most likely, future) Samsung digital SLR cameras use the same lens mounting system as Pentax.

OLYMPUS

Unlike the other 35mm camera brands, Olympus was never successful with their 35mm autofocus SLR system so they didn’t have a legacy lens system to use with digital SLR cameras. Thus they created a new lens system open to other camera makers as well, called the Four Thirds system, after the 4:3 aspect ratio of the sensors used by Olympus D-SLRs. The size of sensors used in Olympus D-SLR cameras measure 17.3 x 13mm, much larger than commonly used in “point & shoot” style cameras, but smaller than the approximately 23 x 16mm sensors used by other D-SLR makers. One significant difference is Olympus focal lengths are one-half the equivalent of 35mm format lenses (a 2X factor) for the same field of coverage. So a new 25mm lens is equal in view to a 50mm lens on a 35mm camera, a 14mm wide-angle is equivalent to a 28mm film camera lens, etc. These lenses are designed specifically for digital SLR cameras.

Olympus made an earlier manual-focus 35mm camera system called the OM system. While Olympus makes a lens mount adapter to attach OM lenses onto their D-SLR cameras, there is a significant loss of features.

INDEPENDENT LENS MAKERS

Lenses made by independent lens makers usually have the same compatibility characteristics as camera-brand- ed lenses. For instance, a Tamron lens made for a Canon EOS film camera will work on a Canon digital camera in the same manner as a Canon brand lens. Independent lens makers have often kept mechanical aperture rings on Nikon and Pentax-mount lenses long after those two camera makers have dropped them from all but select series of lenses.

TAMRON

Tamron’s latest generation of lenses is called the Di-II series. These digital-only lenses cover digital sensors, without the covering power needed for film. Tamron also has Di lenses that will cover film and digital formats and they have been optimized in their design and multi-coatings to perform better on digital cameras than earlier lenses made only with film photography requirements in mind.

SIGMA

Sigma makes several lines of lenses, with DC format lenses their digital-only line. Sigma’s DG lenses are opti- mized for better performance with digital cameras, but will work fine with 35mm cameras and will cover the full image size.

TOKINA

Pro DX lenses from Tokina are digital-only and won’t cover full size sensors or 35mm film. Some Tokina lenses are designated ProD and will work fine for both film and digital cameras and have the improved multi-coatings for excellent digital performance.

Courtesy of Porter’s Camera Store

Phone: 1-800-553-2001 www.porters.com

CAN 35MM specifications

The Sigma 35mm F1.4 DG HSM Art lens has established itself as a versatile masterpiece in the world of photography. Designed for both full-frame and APS-C cameras, this prime lens is a member of Sigma's prestigious Art line, emphasizing exceptional optical performance, outstanding build quality, and innovative technology.

One of the key features of the Sigma 35mm F1.4 is its fast maximum aperture of F1.4. This large aperture allows for excellent low-light performance, making it suitable for indoor photography and night-time scenes. It also provides a shallow depth of field, allowing photographers to create stunning bokeh effects, isolating subjects from their backgrounds with unparalleled precision.

The lens incorporates advanced optical technologies, including aspherical and special low dispersion (SLD) glass elements. These elements work together to minimize various optical aberrations, such as spherical and chromatic aberrations, resulting in sharp, clear images across the entire frame. With an emphasis on edge-to-edge performance, the Sigma 35mm F1.4 delivers exceptional sharpness even at wide open apertures.

Another notable characteristic of this lens is its Hyper Sonic Motor (HSM) technology, which ensures fast, quiet, and precise autofocus. This feature is particularly beneficial for capturing spontaneous moments or shooting video, where noise can be a distraction. The lens also includes a rounded 9-blade diaphragm, enhancing the quality of out-of-focus highlights for pleasing bokeh.

The build quality of the Sigma 35mm F1.4 DG HSM Art is robust, featuring a rugged, weather-sealed construction that can withstand various shooting conditions. A high-quality thermally stable composite (TSC) material is used, which helps in maintaining optical performance under temperature fluctuations.

In addition to its impressive optical performance, this lens also supports Sigma's USB Dock, allowing photographers to update firmware and fine-tune autofocus settings according to their preferences. This feature offers a level of customization that is appreciated by serious photographers.

Overall, the Sigma 35mm F1.4 DG HSM Art lens stands out due to its impressive array of features, including a bright aperture, excellent build quality, and advanced optical technologies, making it an essential tool for professional photographers and enthusiasts alike.