Lens Questions

Some Sigma lenses are designated "DG". What does this mean?
The DG designation indicates that the lens has been optimised for use with digital SLR cameras. The DG lenses feature improved (more even) light distribution from image centre to edge, especially at maximum aperture, compared to conventional fast wide-angle lenses. This is important in digital photography, but is also useful in 35mm photography, especially when slide film is used. The lens elements also utilise Sigma’s super multi layer coating which reduces flare and internal reflections from the highly sensitive surface of image sensors.

What is the difference between DG and DC lenses?
The designation DG indicates that the lens has been optimised for digital SLRs but is equally compatible with film SLR cameras. These will work on digital SLRs with a small (APS-C size) image sensor, digital SLRs with a full frame sensor and film SLRs. DC lenses are designed specifically for digital SLRs with the small, APS-C size image sensor. These are not suited for full frame digital or film SLRs as heavy vignetting will occur.

There are many abbreviations used by Sigma in the name of your lenses, such as APO and DG. Can you explain what these mean?
Each abbreviation has its own meaning and is an important part of the lens' construction and design. For detailed descriptions of each abbreviation, please click here to visit the lens technology page on this website.

I have just purchased your 18-125mm OS lens which I am very happy with however there is a buzzing noise which occurs even when the OS is switched off. This also remains for about 1 minute after the camera is switched off. Is the lens faulty?
It is normal for this lens to make a slight buzzing noise. Please refer to the lens' instruction leaflet for further details.

I would like to purchase a new camera of another brand, is it possible to change the mount of my previous Sigma lenses?
Sigma produces lenses with exclusive fixed mount systems; therefore it is not possible to change the mount of your previous lenses.

I understand Sigma make 1.4x and 2x tele-converters. Do these converters work on all Sigma lenses?
Our tele-converters are matched to work with a few Sigma EX telephoto lenses and are therefore not compatible with all our lenses. For a full chart of compatible lenses, click here.

What are the differences between the 70-300mm F/4-5.6 DG Macro and the 70-300 F/4-5.6 APO DG Macro zoom lenses?
The major difference between these two lenses is the optical performance. The DG model features a more conventional, achromatic optical design and uses one element of Special Low Dispersion glass (SLD). Its sharpness and contrast are rated very highly, however it is not quite as good as the APO model, which uses an apochromatic optical design and uses three SLD glass elements. This model has been top-rated by independent photo magazines. The APO DG model is also somewhat more expensive than the DG model. If you plan to make very large enlargements from your negatives, slides or digital files, the APO DG lens may be your better choice.

What is the difference between built-in HSM lens and DC-motor lens?
With conventional auto-focusing, auto-focus is driven by electromagnetic force of a DC-motor, gear and shaft mechanism. However, Ultrasonic Oscillation Energy operates the HSM lens and creates high-torque drive. Since this motor has no reduction gears, it has much quicker response to start and stop compared to DC- motor lenses. HSM system has virtually silent auto focus function, very quick responsive auto focus function and "full-time" manual focus, wherein AF can be overridden without disengaging the AF mode altogether.

What is the meaning of W and T symbols on the depth of field scale?
W indicates wide focal length and T indicates telephoto. For example on a 28-80mm zoom lens W is equal to 28mm and T is corresponding to 80mm. Depth of field region can be determined by combination of depth of field scale and distance scale. The depth of field scale is printed on depth of field scales on the right and left sides of the centre index line. These figures show the depth of field for each aperture setting. The range between numbers of the same f-number is the depth of field. For instance, choose the aperture, f22 and rotate the zoom control to the wide position until it stops and focus the lens on a subject. The distance from the camera to the subject will be shown on the distance scale by the centre index line. Therefore, the region between the right and left sides of the centre index, which will be in the range of the same f-number at the chosen aperture, will be in-focus. The same process also can be applied for tele-position. Set the focal length to tele-position, choose the aperture, f22. You would see the range on the distance scale, which corresponds to the depth of field.

I have just purchased a new Sigma optically stabalised lens and notice that the lens makes a slight noise when I half press the shutter button. Is that normal?
OS lenses do make a soft noise upon start up. This noise emits whilst the OS system is setting into position. Once the OS is set, generally after one or two seconds, the noise will stop. This is completely normal for OS lenses.

Where are Sigma lenses made?
All Sigma products, lenses, cameras and flash units are manufactured exclusively by Sigma in Sigma’s own factory in Aizu, Japan. No Sigma Corporation product - lens, camera or flash - is manufactured outside of Japan. This is very unusual these days, as most companies have at least some of their products produced outside of Japan because of cost considerations.

I am looking to buy a macro lens and I notice Sigma offer different types. How do I choose between them?
Each of the Sigma prime macro lenses offer up to 1:1 (Life-size) reproduction images, but at different working distances. For example, the 50mm lens provides the shortest working distance and the 180mm lens the longest working distance. Therefore, if you are looking to do copy or reproduction work, the 50mm is likely to be your best choice. If however you photograph small insects, the 150mm or 180mm may be better suited as these allow you to stand a little further away from the subject whilst still giving you the same image. This may prevent disturbing the insect. All provide excellent optical performance, and are fully compatible with current 35mm AF and digital SLR cameras.

I would like to use a filter on my 15mm fisheye lens but I can only use a gelatine filter, why is this and where can I buy them?
Due to the ultra wide angle shooting capabilities of lenses such as the 15mm, front filter use simply is not possible. It would damage the front element of the lens and cause heavy vignetting on the images. Gelatine filters are available from the following website: http://www.galvoptics.fsnet.co.uk.

I recently purchased a new Sigma lens from a local dealer. When I received the lens I noticed that it came without a warranty. When I inquired to the dealer about this, he told me not to worry as Sigma will still honour the warranty. Is this true?
The lens you received has a serial number which has not been issued by Sigma’s factory in Japan. It appears that the lens you received is a "Grey Market" lens, and has been tampered with having its serial number changed. This would explain why you received no factory warranty card with the lens; the serial number printed on the warranty card at the factory, would not match the number on your lens. The Sigma lens should always be supplied with the factory warranty card, which is necessary to help verify the factory warranty. This altered serial number has implications for the Sigma one-year warranty. We suggest that you contact the dealer regarding this situation, immediately.

Auto Focus of HSM Lens for some Nikon Cameras does not work.
The AF control system for some Nikon Cameras does not work with HSM lenses. Sigma's HSM lenses have full compatibility with F5, F4 series, F100, F90/N90, F90X/N90S, F80/N80 F70/N70, u/F65/N65,Pronea 600 and Pronea S. With other Nikon cameras, Sigma's HSM version lenses can be only used in manual focusing mode.

Is it possible to use the OS function with a tripod?
A. The vibration caused by the firing of the shutter and the movement of the mirror is transferred to the tripod. The characteristics of these movements are different to those experienced during hand held photography and the OS system cannot compensate for them.
If you wish to use a tripod, please switch off the OS function.

You use the term ‘Minimum Focusing Distance’ on all your lens specifications. What does this mean?
This is the distance from the film plane/image sensor to the subject. Many people assume it is the distance from the front of the lens however it is measured from the film plane. The shorter the Minimum Focusing Distance, the closer you can focus on the subject.

How do I use the Macro Switch on my 70-300mm f/4-5.6 lens?
First, set the zoom control to its maximum telephoto position. Then, slide the Macro Switch to the "Macro" position. Now the focus ring can turn from infinity to macro range. (The macro switch cannot be changed to the "Macro" position if the zoom ring is set to other than the maximum telephoto setting.) While the Macro Switch is set to the "Macro" position, the zoom ring is locked in the maximum telephoto setting and zooming is not possible. To avoid damage to the lens, please do not force the zoom ring to turn. To return the normal mode, please then turn the focusing ring out of the macro range. Then slide the Macro Switch to the "Normal" position. If the focus ring is in the macro range, the switch will not move.

What is the difference between 50/2.8 EX macro and 105/2.8EX Macro with Life Size Magnification?
The image of the subject, which is taken by both lenses, will have same magnification, however the size of backgrounds will be different. The picture, which is taken by 50mm/f2.8 EX Macro Lens, will have wider background if compared with the 105/f2.8 Macro Lens. Further, lens to subject distance will be different for making life size pictures with both lenses. The subject to lens distance for 50mm/f2.8 is 40.5mm/1.7in., however this distance is 120mm/4.7in., for 105/2.8EX lens.

Is it possible to attach other manufacturers ‘drop-in’ filters into the filter holder of my 500mm f/4.5 lens?
The filter used in the 300mm f/2.8, 500mm f/4.5 and 800mm f/5.6 lenses have a 46mm filter size and there is no problem if you attach the filters of the other brands. However, if the thickness of the filter is over 5mm then you cannot attach this filter to its holder. In the case of polarising filters, you can only use the Sigma filters.

I have an Olympus E system camera with 4/3 technology. Which lenses in your range are suitable for this camera?
We produce a range of lenses in the Four Thirds fit. For details of these, click here.

I have just purchased a Nikon D40x camera and the auto focus of my Sigma lens will not work with it. Is the lens faulty?
Unlike most cameras, the Nikon D40x does not have an auto focus motor built into the camera. Therefore, auto focus will only work with our HSM lenses as these have a motor built into the lens.

Does your Sigma lens have an International warranty? I am looking to buy one of your lenses and I’m working overseas for a couple of months. I wanted to check whether Sigma UK will still cover lenses brought from outside the UK?
Sigma lenses do come with a 1 year international warranty, however, the warranty is only honoured if VAT and duty have been paid on importation into the UK, otherwise it is an illegal import. Once these taxes have been taken into account, our customers usually find it better value to buy an official UK imported lens. Sigma UK also offer an extended 2 year warranty on all EX lenses which have been imported through us. For further details click here.

Can I use different types of lens hoods on my Sigma lens?
No. All our lens hoods are matched exactly to the lens they are supplied with.

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