Sigma

That Was Then This Is Now

| paulamyes
The Sigma 105mm f2.8 EX macro compared to its newer variant the Sigma 105mm f2.8 DG DN macro lens. Both lenses have their lens hoods attached.

Back in the annals of time, well 1999 to be precise, Sigma released the Sigma 105mm f2.8 EX Macro lens. Twenty one years later they released the Sigma 105mm f2.8 DG DN Art Macro lens. So let’s see what has changed in macro lens design.

As always click on the images to see them larger.

TLDR

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Physical Attributes

Sigma 105mm f2.8 EX Macro

The Sigma 105mm f2.8 EX macro lens in Canon EF mount. The lens has no weather sealing.

 

As I said above this lens was introduced back in 1999 and it was well received by reviewers and users alike. In fact it cemented Sigma’s reputation for producing excellent macro lenses. One of my photography lecturers reckoned that this was one of the best lenses he’d used so I bought the lens new in 2003 to use with my then Canon EOS 3 and 30 and it remained in regular use until 2016. I’ve used it for macro, product shots, still life, portraits, fine art reproduction and copywork and of course close ups of flowers.

The lens was designed with film use in mind and was made available in the following mounts:

  • Canon EF
  • Minolta A
  • Nikon F
  • Pentax K
  • Sigma SA

Pick up the lens and it feels very well made. It is light by modern standards but it has a nice heft to it. The lens barrel is metal – none of your plastic composites here – and the lens mount is a chrome plated brass affair. The front lens element is recessed 25mm into the lens barrel and it is ribbed to prevent reflections and acts as shallow lens hood. Combine it with the included metal lens hood and it is virtually impossible  to induce flare. The lens hood screws firmly into place on the lens’ front filter thread and is threaded to take 77mm filters which is a neat idea as it makes it possible to quickly attach filters without having to take the lens hood off.

The finish is the peculiar matt black finish that Sigma had for all their EX range of lenses with a gold ring at the end of the focus ring and the text done in a mixture of white and gold. The focusing ring is 35mm wide and has ribbed rubber to aid grip. In autofocus mode the ring spins freely, but pull that ring back and flip the AF switch and it has a nice smooth 270º throw taking you from infinity to 31cm. The lens barrel extends as you focus closer by 50mm and there are magnification scales marked on the barrel extension for both manual and auto focusing. This means you can quickly set the lens to a desired magnification ratio. It is to my mind still one of the best implementations of manual focus on an autofocus macro lens. The lens motor makes quite a bit of noise and it can’t be called quick by any stretch of the imagination, however, macro lenses are not noted for their speed of use.

 

The Sigma 105mm f2.8 EX macro lens at full extension to give 1:1 magnification. Note the magnification ratios marked on the lens barrel. This makes manual setting of the lens for specific ratios a breeze.

 

Behind the focusing ring is a clear panel over a focusing scale in both feet and metres. There are two switches on the right side of the lens. The first is a focus limiter which speeds up auto focus by preventing the lens racking back and forth through the whole focus range. The second switch is the previously mentioned focus mode switch. Both are very positive in their action.

Sigma 105mm f2.8 DG DN Art Macro Lens

Sigma’s 105mm f2.8 DG DN macro lens attached a Sony A7Rii.

 

Announced in September 2020 the DG DN is available in Sony FE and Panasonic/Leica/Sigma L mounts. It is part of Sigma’s Art series and so shares the same gloss black finish with understated white graphics and lettering. No 1990’s gold bling here, just a minimalist workman like appearance. The body is a combination of metal and Sigma’s Thermally Stable Composite a kind of plastic with thermal expansion properties the same as aluminium. There are a number of ribbed panels to facilitate a secure grip. It’s great to see that Sigma has not abandoned the chrome plated brass  lens mount – it’s a proven method and lasts a long time. Pick the lens up and the first thing you notice is the weight. It is very heavy for its size. The 17 lens elements really make their presence felt when compared to the EX’s 10.

 

Both lenses are focused at their minimum focusing distance to give a maximum magnification ratio of 1:1. The DG DN focus internally and remains the same length while the EX’s barrel extends.

 

So weight and appearance aside how else does the DG DN differ from its distant ancestor the EX? Well the DG DN is 40mm longer, but it is important to remember that it is made for mirrorless cameras with a shorter lens flange distance than DSLRs. Put a Sigma MC-11 on the EX and they are virtually the same length. Another difference is that the new DG DN focuses internally – there’s no extending barrel and this will help with the weather sealing. The large ribbed focusing ring is of the fly-by-wire type, there’s no pulling it back to engage a manual focus mechanism. Consequently there are no hard stops and you get no feedback as you focus other than the image in the EVF or on the back panel. Macro photography is an area where you do use manual focus a lot and using it on the DG DN is not a very pleasant or positive experience to my mind. 

 

The controls on the Sigma 105mm f2.8 DG DN macro lens include an AF/MF switch, a reprogrammable focus lock button, a focus limiter switch and a switch to de-click the aperture ring.

 

There are a lot more controls on the newer lens:-

  • an AF MF switch
  • a focus lock button that can be reprogrammed
  • a focus limiter switch with 3 settings – 0.295 to 0.5m, 0.5m to infinity, full range.
  • a switch for de-clicking the aperture ring
  • an aperture ring
  • a locking switch for the aperture ring

 

The aperture ring on the Sigma 105mm f2.8 DG DN macro lens. Not only can it be de-clicked it can also be locked in the auto position for those who would prefer to chasnge aperture using camera dials.

 

The focus limiter switch has three settings. 0.295-0.5m macro, 0.5m to infinity normal range, and a full range option.

 

So let’s have a quick gander at the specs for both lenses.

 

 

Sigma 105mm f2.8 EX Macro lens Sigma 105mm f2.8 DG DN Art Macro lens
Focal length 105mm 105mm
Angle of view 24º (on full frame) 23.3º
Maximum aperture f2.8 f2.8
Miniumum aperture f45 for Canon, Sigma, and Minolta

f32 for Nikon and Pentax

 f22
Filter size 58mm on the lens body

77mm on the lens hood

 62mm
Stabilisation No No
Maximum magnification 1:1 1:1
Minimum focusing distance 31cm from the film plane 29.5cm (from the sensor plane)
Focusing modes Auto and manual Auto and manual
Optical construction 10 elements in 9 groups with 3 special low dispersion elements 17 elements in 12 groups with 1  special low dispersion element
Aperture blades 8 9 (rounded)
Weather sealing No “Dust and splash proof construction”
Weight 456g (Canon EF mount) 710g
Dimensions 95mm (h) x 74mm ⌀ 135.6mm (h) x 74mm ⌀

Optical Performance

Sharpness

A comparison between the 1999 Sigma 105mm f2.8 EX macro lens and the 2021 Sigma 105mm f2.8 DG DN macro lens. Aperture: f 2.8

This is where we really start to what has changed in terms of lens design over the years. Wide open at f2.8 the DGDN is sharper and more contrasty in the centre of the frame. The corners are sharp but the contrast is lower. The EX on the other hand is softer and has less contrast in the centre and the corners are not only softer but display prominent chromatic aberration and have a warm tinted vignetting. Older Sigma lenses were known for having a warmer look than other brands and it is clearly visible.

 

A comparison between the 1999 Sigma 105mm f2.8 EX macro lens and the 2021 Sigma 105mm f2.8 DG DN macro lens. Aperture: f 4

 

A comparison between the 1999 Sigma 105mm f2.8 EX macro lens and the 2021 Sigma 105mm f2.8 DG DN macro lens. Aperture: f 5.6

By f5.6 the corners of the DGDN have improved considerably and the centre is even sharper. The centre of the frame for the EX has improved but not to the same extent as that of the DGDN. The corners of the EX are still quite soft and still exhibit vignetting.

 

A comparison between the 1999 Sigma 105mm f2.8 EX macro lens and the 2021 Sigma 105mm f2.8 DG DN macro lens. Aperture: f 8

 

At f8 the DGDN really hits its stride and produces its best optical performance with both the centre and the corners having excellent sharpness and contrast. The EX has reached its best centre performance but it is still not as good as its younger sibling. The corners have improved slightly but vignetting is still present.

At the aperture of f11 the DGDN’s performance remains the same as it was at f8 in both the centre and the corners of the frame. The EX now turns in its best performance but some vignetting remains.

 

A comparison between the 1999 Sigma 105mm f2.8 EX macro lens and the 2021 Sigma 105mm f2.8 DG DN macro lens. Aperture: f 32

At f16 diffraction is taking effect on both lenses. Interestingly the EX will stop down to f45 but you wouldn’t want to use it as it looks like someone has smeared vaseline over the front lens element.

Chromatic Aberration 

Chromatic aberration is the failure of a lens to focus all colours at the same point and there are two types:-

  1. Axial or longitudinal chromatic aberration – this where different wave lengths of light are focused at different distances from the lens. Generally it can be reduced by stopping down thereby increasing the depth of field so that all the wavelengths fall with acceptable focus. This is very hard to remove in post processing.
  2. Transverse or lateral chromatic aberration – different wavelengths of light are focused at different positions in the focal plane. It does not occur in the centre of an image and increases as you move out to the edges. It is not effected by stopping down, but can be removed in post.

The DGDN is exceptional well controlled for both kinds of chromatic aberration and even at magnifications of 200% I could not observe any. The EX is really showing its age here as both types can be seen. The transverse chromatic aberration is very prominent.

Flare

 

The Sigma 105mm DGDN shows good resistance to flare. In this extreme case we can see some evidence of veiled flasre and a little reflection.

 

The EX despite having that recessed front element that acts as a de facto lens hood suffers badly from halation, veiling flare, and reflections when specular light sources were in the frame. The DGDN has better lens coatings which means that the halation and reflected glare is minimal and there is no halation. This means that there’s little loss of contrast.

Bokeh

Sigma 105mm f2.8 DGDN Macro lens bokeh test.

 

 

 

 

 

Both lenses at f2.8 have nice round bokeh balls in the centre of the frame and at the edges exhibit that elliptical cats eye effect. The tonal transitions are nice and smooth, there is no busyness or swirly effect. At f4 the EX is starting to develop polygonal balls while those of the DGDN are still nice and round. At f11 the bokeh balls in the corners of the DGDN are starting to develop into sun stars and the effect on the EX is more profound. The 9 rounded aperture blades are producing much more pleasing bokeh effects than the 8 straight ones of the EX.

Autofocus

Continuous autofocus with the Sigma 105mm f2.8 mounted on a Canon EOS 6d.

 

Autofocus is where there has been an enormous improvement in performance over the last 22 years. The EX when mounted on the Sony A7r ii with either the Metabones V Smart Adapter or the Sigma MC-11 just won’t autofocus. When you switch the camera on the lens racks through its entire focus range (depending on where the limiter is set) and then does nothing. So to test the AF performance I had to mount it on a Canon EOS6d which wasn’t known for its blistering AF speed. I shot several sequences with the focus limiter on at f2.8 of me walking slowly towards the camera with it set Continuous AF and obtained a nit rate of between 70-75%. Video AF was a non starter and it just would not find focus. To be fair the CAF of the 6d in video mode is pretty lacklustre. With the DGDN mounted on the Sony A7r ii the stills burst rate for AF averaged out at 94% which is pretty impressive. The DGDN handled the video AF test with aplomb, it was smooth and positive keeping up with me moving about in the frame. The AF was noisy and was picked up by the shotgun microphone mounted in the camera hot-shoe. Speaking of noise the EX was incredibly noisy.

 

Continuous auto focus using the Sigma 105mm f2.8 DG DN macro lens on a Sony A7rii.

 

Conclusion

Both lenses mounted on Sony bodies. The EX is mounted via the Sigma MC-11 lens adapter.

 

This should really come as no surprise, time has marched on and the advances in lens design are easily apparent.The Sigma 105mm f2.8 EX macro was considered a very good lens in its day, and even now it is remembered fondly on photographic forums. The DGDN is just at another level of performance both in terms of optics and auto focusing. The EX while being optically suited to a number of tasks its AF performance let it down when it came to anything that moved quickly or erratically. The DGDN on the other hand can be confidently used as a general purpose short telephoto with a wide variety of subjects as well as being a dedicated macro lens. The only area in which the EX is superior to the DGDN is in the handling department. The manual focusing experience and the ability to pre-set specific magnification ratios makes the lens a joy to use manually. The DGDN is clearly aimed at the autofocus only photographer. A great shame.

So if you have a Sony FE or one of the  offerings from the “L mount alliance” then the lens is worth a look at. Well it is your only option in L mount. It is also a worthy competitor to the Sony 90mm f2.8 FE macro OSS G at a cheaper price.

 

Sample Images

 

Looking through the Olympus OM Zuiko 135mm f2.8 lens at an Olympus OM 40.

 

Lime slice oozing juice.

 

Cream runs down over a strawberry.

 

Where there’s smoke there’s fire.

 

Australian one and two dollar coins.

 

Sigma 105mm f2.8 DG DN Macro lens auto focus test. Auto focus tracking a subject walking towards the camera while the lens is wide open at f2.8.

 

Darth Vader divided by the light.

 

Bee feeding on lavender flowers.

 

A bee feeding on a daisy.

 

A ladybird looking for aphids.

 

Clubbed Spider Orchid, Caladenia longiclavata. Mount Observation, Western Australia.

 

Custard Orchid, Thelymitra villosa. Mount Observation, Western Australia.

 

Known by a variety of names the dancing spider orchid (Caladenia discoidea) is also known as the antelope orchid and sometimes the bee orchid. St. Ronan’s Nature Reserve, Western Australia.

Optical Antithesis

| paulamyes

A review of the Sigma 16mm f/1.4 DC DN lens for m4/3

 

 

 

The Sigma 16mm f1.4 shown mounted to an Oympus OMD EM1 mk 1 which is one of the larger m4/3 cameras.

 

I’ve said many times on this blog that my favourite focal length is 35mm (35mm equivalent) which give a diagonal angle of view of 63.4º To me it is a relaxing normal view, I find 50mm a bit too tight and 28mm a bit too “loose”. So when I migrated from so-called full frame to micro four thirds in 2010 one of the first lenses I bought was the Olympus m.Zuiko 17mm f2.8 pancake lens. Actually at the time there were only three lenses in the system the 17mm, a 14-42mm kit lens and the 40-150 telephoto kit zoom and I ended up getting them all.

 

Olympus m.Zuiko 17mm f2.8 shown on an EP5. The lens was the first prime introduced for the Olympus’ m4/3 system.

 

The 17mm was equivalent to 34mm in in full frame terms and has a diagonal angle of view of 65º, so close enough as not to make any real difference. It wasn’t a well received lens despite being what initial advocates of the micro four thirds said they wanted – pancake lenses. It’s slow maximum aperture of f2.8, slow and noisey auto focus combined with less than stellar optical performance put many people off and they went for the much more expensive Panasonic 20mm f1.7 which had the virtues of being optically better, and having a faster maximum aperture. It still wasn’t great in the AF department though. But hey these were the early days of mirrorless technology and AF systems were not very quick and accurate then. But anyways I got the Olympus in a kit with my Olympus EP2 and I actually loved it. I could slip it mounted to the EP2 in my pocket which made it a great stealth camera combination and I used it to shoot my TransPerth-Transhumance project. I still use the lens today, mainly on my EP5. The area where I felt it was absolutely hopeless was video. The AF was too slow, too noisy (think angry wasp stuck in a jar) and I wanted a bit more subject isolation than the f2.8 aperture could give.

 

The Sigma 16mm f1.4 compared to the Olympus 17mm f2.8, 25mm f.1.8 and the 45mm f1.9.

 

The Sigma 16mm f1.4 is a physically large lens. Here it is shown with the Olympus 12-40mm f2.8 and 75-300 f4-6.3 zoom lenses.

 

So fast forward a few years and I’m shooting more and more video and I decide to get myself a better 17mm lens. In the intervening years Olympus had produced the very favourably received 17mm f1.8 and the eye-wateringly expensive f1.2 version. Panasonic had also come to the party with their Panasonic Leica Summilux 15mm f/1.7 lens. In fact I went to my local (if you can call 110Km away local) camera dealer to buy this lens and it was always out of stock which made me want it even more. But in the end I went for an outlier in the form of the Sigma 16mm f/1.4 DC DN lens. The reasons being that f1.4 is faster than f1.9, it was cheaper than the f1.2 and the difference between f1.2 and f1.4 is slight, and my dealer had it in stock. So what makes it and outlier? Well to put it bluntly it’s bloody huge. It has a 67mm ⌀ filter thread which compares to 37mm for the Olympus 17mm f2.8. It is bigger than the Olympus 12-40mm f2.8 and the Panasonic Leica 8-18mm f2.8-4 while being only a little shorter than the Olympus 75-300mm f4.8-6.7. The 16mm focal length equates to 32mm on full frame with a diagonal angle of view 68.1º so is a bit wider, but when used with the Panasonic G85 for 4K video this isn’t much of a problem as the camera crops in slightly. So how come this lens is so lardy I hear you all ask. Well this lens wasn’t designed for micro four thirds, it was initially designed for the Sony 6000 series cameras with an APS sized sensor where it equates to being a 24mm in full frame terms. To get a wide angle lens that’s fast and a good optical performance means lots of glass and glass is heavy, and this lens is large and heavy for APS format cameras. To get some additional return on their investment Sigma decided to offer the lens in micro four thirds mount hence it seeming a funny focal length and being bigger than necessary.

 

Vital Statistics

Olympus 17mm f2.8

Sigma 16mm f1.4
Diagonal angle of view 65º 68.1º
Optical construction 6 elements in 4 groups 16 elements in 13 groups
Diaphragm 5 rounded blades 9 rounded blades
Minimum aperture f2.8 F1.4
Maximum aperture F22 F16
Minimum focusing distance 20cm 25cm
maximum magnification ratio 0.11x 0.07X
Filter diameter 37mm 67mm
Dimensions ⌀ 57mm x 22mm (H) ⌀ 72.2mm x 92.3mm (H)
Weight 71g 405g
Internal focusing No Yes

 

 

In the hand the Sigma 16mm feels very dense and substantial. The lens body is made out of what Sigma calls a Thermally Stable Composite (TSC) which is substantially stronger than conventional polycarbonates while having similar thermal expansion properties to aluminium. The lens mount is made of chromium plated brass which should ensure a long life. The Sigma 16mm is advertised as being dust and splash proof but on closer reading of Sigma’s spec sheet there is only one seal and that is at the lens mount. The lens comes with a bayonet mount petal lens hood which has a ribbed grip to make attaching and detaching easier. While it is good that the lens comes with a hood it’s not the best implementation and feels quite insubstantial and can be fiddly to attach as it can foul and not lock home. There is a ribbed rubber focus ring of the fly by wire type – it feels smooth and easy to use. There are no other controls or switches which means if you want to switch between AF and manual focus you will have to use the camera controls for that.

 

 

The Sigma 16mm has an optical construction of 16 elements in 13 groups with 3 FLD (“F” Low Dispersion) glass elements, which offers performance equivalent to fluorite which exhibits less chromatic aberration than those utilising a traditional flint glass. There are 2 SLD (Special Low Dispersion) glass elements which also help to minimise chromatic aberration and 2 ASPH moulded glass aspherical elements which work to reduce optical aberrations. According to Sigma’s website the ASPH elements are polished with a tolerance of under 10 nanometers or 0.000001 millimetres which according to Sigma reduces onion ring bokeh.

Performance

100 % crops showing lens performance wide open and then at the best performing aperture.

 

In terms of autofocus the stepping motor is fast and accurate and very smooth when shooting video. I tested the lens on the OMD EM1 mk ii which has on sensor phase detect AF and on the Panasonic G85 which uses DFD technology – a variant of contrast detect auto focus that requires the lens to provide a profile to the camera to ensure fast and accurate AF. The Sigma does not have such a profile as these are limited at present to only Panasonic’s own lenses. Despite that there were no problems and I could detect no discernible difference between the Olympus and the Panasonic. The only downside in the AF department is that I can’t use the Pro Capture Low setting which gives up to 18 fps with auto exposure and AF tracking. This is no fault of Sigma’s as the option is only available with Olympus lenses.

 

 

Optically – well straight from the get go the Sigma is impressively sharp wide open corner to corner. The performance improves slightly (and it is only visible on my 4K screen at 300%) as you stop down. Diffraction sets in at f16 and this does soften the image. In terms of chromatic aberration, well wide open in high contrast situations it is apparent albeit slight and it is easy to correct in post. The lens is reasonably resistant to flare – but if you have a specular light source in the frame you will experience some veiled flare and ghosting. If you turn off the built in lens profile you can observe a slight barrel distortion, but switch on the profile and it is not visible. The bokeh balls this lens produces are more or less round when shooting wide open even at the edges of the frame and the transitions are nice and smooth. There is some onion ring bokeh which is the result of using moulded aspherical lens.Vignetting is not a problem and is very slight in the region of 1/2 stop.

 

Chromatic aberration is quite apparent on this lens. It is also quite prone to flare even when using the included lens hood.

 

Verdict

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Being designed to have an image circle much larger than micro four thirds requires means that you are using the best performing part of the lens and this really shows. Just for giggles I compared the Sigma with my old Olympus. The Olympus is noticeably soft in the corners at all apertures and just average in the centre. It suffers badly from chromatic aberration. Vignetting is very apparent, in excess of 1 stop in the corners with the lens profile switched on and getting on for 2 stops when switched off. Physically, optically and figuratively the Sigma stands head and shoulders above the little Olympus. The only area where the Olympus wins out is its small size and that is why I’ll continue to use it when I want something small and compact. For every other occasion I’m reaching for the Sigma. The knock on effect is that I’m seriously wondering about replacing my Olympus 45mm f1.8 with the Sigma 56mm f1.4.