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  1. Sigma Sd Quattro and 150 f2.8 OS, the power of...

    My new experience withe the Sigma SD Quattro, this time equipped with a true macro, the excellent  Sigma 150mm f2.8 Macro OS enabled me to experiment something new, along with usual "scientific" or documentaitve photos, I tried to look for unusual, tighter shots,  with the aim  to transform  reality into something more creative, a sort of abstract photography.
    First, user impression



    It has to be clear that the Sigma 150 macro cannot be used in Af with the SD Quattro. It hunts endlessly and frustratingly, whatever light or subject contrast you have. It has to be focused manually. And so I did. looking at the display, with 4x enlargement and focus peaking I could get sharp photos. Indeed, at 4x the focus peaking looks "feeble", rather hard to see, at 1x it is more visible, but focusing is less precise.
    These are the limits.
    That said, the good thing is that with a true macro lens you can make ... true macros (with astonishing sharpness)!
    please click on the images to appreciate how this kit works!



    How  little is that dark critter?


    But with the 150 macro you can get this without having to crop at all:



    A curled up trilobite, I have stacked eight photos to get enough depth of field.



    I had two shooting session in two different muesums with different purposes: In the first I tried to get appealing, but still informative, images of  interesting objects or specimens, in the second instead I wanted to make photos more artistic than documentative.
    In the first session I had problems with flimsy supports and less than ideal lights, that caused some shake and slight focusing problems,   however I succeeded to get some satisfactory results:
    A stone  arrowhead  made by ancient Native Americans nearly ten thousands years ago. Wow.



    It was crafted by chipping  a flint stone made by silicified corals, going closer with the 150, I could show the corals at full frame  without any crop:



    You can see the corals, how cool , really.



    As in my previous article, I tried to take photos in UV light (UVA lamp 380nm wavelength)



    An eel 100 millions year old, in visible light





    Here you can see it had eaten a mantis shrimp, again visible light





    And that's what sorts out in UV light. It is simply awesome. Look how the  different composition of the shrimp exoskeleton and the eel bones (black) is  made evident and how both are tremendously sharp. Also a colleague that was with me was really amazed.



    • nov 14 2016 09:21
    • da Silvio Renesto
  2. Sigma Sd Quattro, applications for Palaeontology

    Main features, pros and cons of the Sigma SD Quattro have already been extensively described in many sites and here on Nikonland byMauro Maratta in his  articolo, that I recommend reading (it's in Italian Language by the way) . 
    I will not repeat them  here. I will instead show how this unusual camera surprised (and enthralled) me as a tool for my work, giving me a very special user experience.
    I am a vertebrate Paleontologist and my field of interest are fossil reptiles of the Triassic (roughly 250-200 million years ago) . I published over sixty scientific papers and also have a lot of teaching and popular education activities in my University Department. 
    No need to say that photography  plays a fundamental role in Palaeontology both for illustration of one's studies and for didactic purposes.
    Since fossils are amongst the most quiet things (along with rocks) in the natural world, the main shortcomings of the Sigma Dp Quattro, concerning ISO, reaction times and so on, become irrelevant. With a good stand or tripod and right lights, one can take photos at 100 ISO with proper apertures and exposure time,s without any worry. Thus, the shortcomings are gone, but the good qualities are still there.  Mainly, as we will see later, the richness of detail and the perception of three-dimensionality that  the camera gives to images. Something I believe can be obtained only with much more expensive or bulky (or both) equipment.



    A Jurassic Ammonite

    However, what renders the photos taken with the Sigma Dp Quattro really different (and useful)  for my work,  does not concern photographs of complete specimen to be published on scientific journals (where, given the requested sizes, any good or decent DSRL will do the job) but rather the great sharpness of fine details, and the usability of even the biggest crops.  This is a plus both for research and for teaching. 
    I take a photo of this Ammonite that still has the shell preserved. a rather uncommonevent. The specimen is about 4-5cm in diameter. I photographed it with the Sigma  50mm f1.4 ART and the Achromatic close up lens Marumi 3x, because a 105mm macro Sigma wasn't available for the test. Note: all photos have been taken with the 50mm f1.4 ART with or without the Marumi according to need.




    Below, the 100%crop:





    And here comes the first surprise:  You can clearly see the broken shell layers, the sutures (those arborescent lines) and the sediment that filled the shell cavity. I never saw it so well in a photo, especially in a huge crop, taken with a camera of this price level. Surely the crop can't be printed, but its more than good for didactic purposes, in fact I used it in my power point for my lesson on fossil cephalopods last Friday.
    Section of another Ammonite. This one is pyritized (that is, it is  encrusted by iron sulphide, due to a reaction that occurs in anoxic sea bottoms often by action of bacteria).




    Again, a 100% crop:




    Again, I was stunned by seeing the "step" in thickness between the black pyrite encrusting and the shell septa. This one has also been used  for my lesson.
    Now,  Bivalves:



    Would you like to see the growth lines? Here they are:





     Carboniferous Fern leaves:




    you can see the little creases of the leaflets:





    Please take in mind that all the photos have been taken with a standard (as focal lenght) lens, with a  true macro there may have been much less need of cropping, greatly enhancing image quality and usability. As for the following examples.
    [page 1][page 2][page 3][page 4]

    • nov 14 2016 09:21
    • da Silvio Renesto
  3. Sigma 150mm f2.8 Apo Macro OS in-depth review.

    I have just tried the new Sigma 150mm f 2.8 Apo Macro OS, a lens with excellent reputation not only among macrophotographers, but also among portrait shooters.  However I tried it only as a macro lens, comparing it with the Micro-nikkor 105 f2.8 AfS VR as well as with its main competitor, the legendary Nikon 200mm f4 micro-nikkor AfD ED.
    Years ago I had used for some time the Sigma 150mm f2.8 Apo Macro EX (non OS), and I found it had excellent quality for general photography, apart for a little warm rendition in some occasions, but it was somewhat short  for my needs, thus I replaced it with the Sigma 180mm f3.5 Apo macro Ex at first, subsequently  with  Nikon 200mm f4 micro-nikkor AfD ED. 
    Recently Mauro Maratta kindly offered me to try the new Sigma 150mm Apo Macro OS, to test its performance in macrophotography. As an enthusiast as I am, I accepted gladly, driven also by the curiosity to check if performances are on par with the reputation this lens has gained, and also if my attitude toward  shorter focal lengths in macro has changed.




    Lens and groups: 19 lens in 13 groups, 3 SLD elements
    Diaphragm with  9 blades
    Minimum focusing distance 38 cm (reproduction ratio 1:1)
    Size (width x length) 80x150mm
    Weight 1150g 
    Filter size 72mm
    Hood and tripod collar (rotatable and detachable) supplied.
    Focus limiter and (obviously) image stabilizer.
    Costruction and ergonomy.
    I would say it's exciting at least. For the first time I found in a Sigma lens  a pleasant tactyle feeling no more crackling or sticking/"greasy" coatings) joined with a sense of  sturdness. The Sigma 180mm f3.5 Macro was also quite sturdy while the last black version of the Bigma  (50-500mm) had a good coating , but with the 150 Os we are at the top for Sigma (at the time of writing, now the Sigma 180mm Macro f2.8 OS is on par, or even better, as are the other high-end lenses of the Art/Sport series).
    Another plus of the Sigma 150, as for the previous non OS model, is its compactness, perfectly suited for a mid-sized DSRL. In short, handling this lens is a pleasure. 
    The Sigma 150 Apo macro OS  is only slightly larger and heavier than the  105VR, and like the latter one can be used free handed, but when tripod is needed, the 150 is much more practical than the 105 Vr thanks to the tripod collar.
    With respect to the Nikon 200 micro AfD, the Sigma 150 is shorter (but slightly wider), however both show excellent ergonomy. 



    The three competitors, without (above) and with (below) the hood. Notice the little difference in size between the Sigma 150 and Nikon 105VR.



    For a macro, it  is suprisingly fast, I would say a little better than the Nikon 105VR and another world with respect to the  Nikon 200 micro AfD still retains the archaic mechanical-geared Af. Great performance (for a macro lens).

    Manual focusing. 
    The focusing ring is adequate in size and well damped, perfectly usable, the only (little) flaw, as in many other "fast focusing" macro lenses, is that it takes only few mm of rotation to go from 3m to infinity, thus it becomes difficult focusing manually outside the macro area.
    The possiblity of manual focus override without fiddling with switches is a great advantage over the Nikon 200m  micro AfD.

    Image stabilizer.
    It works well. It may "jump" a little when started, but then all is steady. At higher  reproduction ratios the usefulness of stabilization decreases as usual. 

    • ago 09 2015 09:43
    • da Silvio Renesto