SIGMA Lenses - Why buy one instead of the genuine OEM version ?
1stcameras buying team are tasked with selecting a full range of imaging products that offer our customers new technology, value for money and a real benefit for them when used with the cameras they have selected. This isn’t a simple process as there are constant changes in camera designs with camera features and the electronic interface. Whatever camera system has been selected by the customer, it is the lens that should be the most critical part of the buying process. Whilst a camera body is very much based upon its feel (rather like a sports car in its handling and balance) it is at the end of the day a light tight box with a sensor (and yes sensor type, size / and number of pixels on the sensor are important) but it is the lens that makes or breaks getting pin sharp pictures. A bad lens cannot give perfect results.
That in simple terms is why 1stcameras buyers have selected SIGMA lenses as an option for our customers. As the World no.1 independent lens designer and manufacturer with over 50 years of producing lenses in their facilities in Japan, SIGMA offer consumers and retailers three impressive buying reasons. These are QUALITY, RELIABITY and AFFORDABILITY.
Quality is based upon the SIGMA record of designing and producing lenses that produce results every bit as good as the OEM camera brands and that are fully compatible with the camera systems. This is evident in the number of industry and test body awards from institutions such as TIPA & EISA plus top “best buy” reviews in specialist magazines. These awards and accolades are based upon product performance and design innovation (offering more useful features) and value for money.
Reliability is a very important issue. No one wants to buy a product that cannot be relied upon and that gives variable results. SIGMA quality control (and they only manufacture in their own Japanese production facilities) are so good that in the UK they offer the consumer a 3 year UK warranty when their lenses are bought through one of their authorised resellers. This warranty offers the buyer great piece of mind and we can report that it also makes us confident when selling SIGMA lenses.
Affordability, the value for money element is very important to us and our customers.
SIGMA lenses are generally less expensive than the camera companies equivalent product. The reason for this is simple. SIGMA manufacture their lenses in all popular D SLR camera fittings covering Canon, Nikon, SONY and Pentax as well as their own SIGMA lens mount. They have also produced 4/3rds lenses and are designing for release soon a range of micro 4/3rds lenses for the new CCS camera sector. Because of this range the economy of scale of production with low overheads means SIGMA are extremely competitive and good value for money. SIGMA are a family owned company that cares about the products they produce and the customer they are making them for. (Their designers in the R&D division in Japan are keen and enthusiastic photographers themselves!)
What are the features and descriptions / designs that SIGMA use in comparison to the other brands on the market? Whilst these designs and features are replicated in most other brands every manufacturer seems to use their own designation – so here follows a quick guide as to what these acronyms stand for:
IMAGE STABILISATION
This is where camera shake (the main cause of blurred images) can be countered by use of gyroscopes in the lens. Located in the body of the lens these sense the movement. They remove shake by adjustment of the optics in the light path to the sensor. (This can be sensed both visually through the viewfinder of the camera and a physical sensation through the lens body) Whilst It sounds complicated it offers the real benefit of hand holding a lens and camera up to 4 stops better than normal. Most top designs of image stabilisation have three setting – OFF for when you are using a tripod or don’t want the stabilisation, position 1 for general use and position 2 for panning where you don’t want the stabilisation to attempt correction of sideways movement.
SIGMA call image stabilisation OS (optical stabilisation) whilst Canon call it IS (image stabilisation) and Nikon use the designation VR (vibration reduction).
SENSOR SIZE specific designs
Because lenses are designed to match the sensor / film size they can vary in size and weight based upon whether the lens has to cover a full frame (24x36mm) sensor or the more compact APS-C or smaller sensor used in S SLR cameras. Lens designers will identify their products by using a code that indicted the coverage of that particular lens. Do bear in mind that full fame coverage lenses do work with all sensor size cameras but in the case of smaller sensor D SLR’s the camera would only use the central are of the lens capability.
SIGMA call full frame coverage lenses their DG series and these are optimised for use on all digital SLR (D SLR) cameras. Canon describe their full frame lenses as their EF range whilst Nikon use FX to describe the sensor but accept that any of their lenses will be useable of any of their D SLR’s. For use only with APS-C and smaller sensor D SLR cameras SIGMA produce their DC series range. Canon call their smaller sensor design lenses EF-S and Nikon describe theirs as DX
AF Motors for fast and quiet focussing
All modern SLR camera designs tend to have autofocus (AF) systems that can detect and lock focus on to the chosen subject. The AF motor that drives this can however vary and older AF designs did use a mechanical link to alter the focussing of the lenses where the more modern designs will have a system controlled by ultrasonic/hypersonic waves. With SIGMA the latest AF designs are designated HSM (hypersonic motor) whilst Canon use USM (ultrasonic) and Nikon use AFS ( S for silentwave).
TYPE of OPTICAL GLASS
The glass used in lenses has a bearing on image quality and this can be identified by specific acronyms used by any optical glass manufacturers. These are: LD (low dispersion glass) ELD (extra low dispersion glass) APO (apochromatic glass) SLD (super low dispersal glass) and the best of all FLD (fluorite glass). All these acronyms are where the performance of the glass in terms of light transmission and correction of aberations is better than ordinary glass elements. SIGMA and HOYA jointly developed a mass production of fluorite glass lens elements. This is now being used in many of the SIGMA professional award winning lens designs without a dramatically increased cost in the product. Finally ASP identifies aspherical designs where the surface is complex having the ability to give the best performance with one element rather than two or three individual lens elements. An extension of this is - hybrid aspherical lens design is where the lens element surface comprises of two materials - glass and optical resin – where these are bonded together at high pressure and heat to give high performance lens elements at an affordable price.
LENS COATINGS
All optical lens surfaces are coated so that light transmission and reflections / flare is reduced to a minimum. Modern lenses for the digital market use MC and SMC to identify the latest generation of multi and super multi layer lens coatings. This gives dramatically better images than the single layer coating used in the past.
ENGINEERING DESIGNS
In lens terms there are some engineering designs that do offer benefits in terms of speed and compactness and these are often identified by the following symbols: RF indicates rear focus where the lens rear group actually moves to adjust focus and this means the length of the lens doesn’t rotate or extend. IF (internal focussing) is a similar principal but could be a lens grouping in the middle of the design allowing balance when the lens is mounted on a camera body.
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