Capturing the world with Photography, Painting and Drawing

Posts tagged “foveon x3

Sigma SD15

Sigma SD15 1
Sigma SD15 with 15-30mm f3.5 lens

Sigma’s SD15

If anyone has read my other camera reviews you will have noticed that I don’t review any of my Pro level slr cameras from Nikon or Canon , the reason I don’t do that here is simple.

Here is a good reason why, I was out walking our golden retriever, one Sunday about two weeks ago and passed two photographers with Canon SLR’s, Tripods, all top of the range equipment. On passing I overheard one talking to the other about the lens he had just purchased “It the best in the country , the only one so far”, I am mostly very good at passing on these types of comments and I didn’t know them . However on returning past them again about an hour later, they were still talking cameras, pointing in the same direction and taking pictures of very little if anything.

If this is what they enjoy doing then good luck to them, it did however remind me of just how some people can be, when it comes to camera equipment and the need to have the best. For what reason though, for image creation or talking to friends about.

So I don’t believe that the race to the top of the camera food chain has anything to do with good or great photography, photography is the skill of good and interesting image making, it goes back well over a hundred years and in all that time photographers have been making images that are both iconic and outstanding.

You don’t need the perception of owning the best and greatest equipment to create good images.

While being into image creation, you do need a camera that you both like to use and can trust. For me out in the field the choice of which camera I would take for any given function is selective. I don’t think I have a best camera body, they all do something differently good and bad, they can be used in different ways.

So down to this review

The Sigma SD15

Sigma SD15 2
Sigma Sd15 Slr.

Firstly I think this is one of the most interesting, challenging and creative cameras to be produced for a long time, it will never be seen as the king of the food chain nor will many photographers, with the need for the best to boost their self esteem, stop looking down on it and the even newer Sigma SD1.

Sigma cameras contain foveon, ccd imaging sensors

Foveon X3® direct image sensor

Foveon has combined the best of what both film and digital have to offer. This is accomplished by the innovative design of the three layer Foveon X3 direct image sensor. Similar to the layers of chemical emulsion used in color film, Foveon X3 image sensors have three layers of pixels. The layers of pixels are embedded in silicon to take advantage of the fact that red, green, and blue light penetrate silicon to different depths – forming the first and only image sensor that captures full color at every point in the captured image.

A Dramatically Different Design

The revolutionary design of Foveon X3 direct image sensors features three layers of pixels. The layers are embedded in silicon to take advantage of the fact that red, green, and blue light penetrate silicon to different depths — forming the world’s first direct image sensor.

From point-and-shoot digital cameras to high-end professional equipment, Foveon X3 technology offers multiple benefits to consumers and manufacturers alike. At the same time, it opens the door for other innovations, such as new kinds of cameras that record both video and still images without compromising the image quality of either.

Having read about this sensor technology and the camera for sometime, in May 2013, I exchanged an old Nikon D200 for a Sigma sd15 camera and a couple lenses, ( 15-30mm f3.5 and a 70-300mm f4-5.6).

I was no longer using the D200 so felt, why not take a chance and try the claims for the Foveon sensor and the SD15 out.

Sigma SD15 3
Sigma SD15

Something that is less important than you my think to the pro/semi-pro photographers alike is images size or pixel counts, a much more important aspect of a digital image is the amount of details captured at any defined pixel location and this is something that I have found the Sigma SD15 to be wonderful at.

There is little point in crushing huge amounts of pixels on to an image sensor if the detail capture is low or poor.

The simple facts with the Foveon x3 sensor is that all possible colours are captured at each pixel location, this fact alone increases the level of detail some three fold over a traditional sensor, that splits colour detection into groups of three pixels, each of which can only see one colour from (Red, Green or blue), the effect on an image using this method are the creation of unwanted artefacts in the final image. So the use of a filter over the sensor is needed to stop this effect. This filter blurs the detail level in the image by a factor of around a third at each pixel group locations.

In recent times traditional sensors have increased in pixel counts to a point where the effects of artefact creation are less than before, so some expensive camera models have removed the needed filter over the sensor. This is good and produces better image resolution, however you need a three times bigger image file size to produce the same level of true detail that you find from the Foveon sensor.

Large image sizes take up more disk space are slower to process and longer to upload or email.

My final question related to printed and end results, if you print an unprocessed file from the SD15 at the same size as one from say a Nikon D700, do you get the same detail in the final image, well I have found the answer to mostly be yes, in most cases, yes looking at large prints I can detect very little difference if any.

Don’t get me wrong, I still own and use other cameras , however I have been amazed at the results from this Camera and its Foveon sensor, the colour definition is also wonderful.

Sigma and Foveon claim that the SD15 has 14 million pixels, but this is in three layers and that the newer Sigma Sd1 has 48 million pixels again layered, this is a difficult and controversial claim as each image size is only the given amount divided by three.

However if you take into account that they are only saying this because the camera market has taken as a standard, mega-pixel counts, image detail and colour definition are a much harder subject to sell, to the general public. So what Sigma and Foveon are doing with this claim of high pixel count is to say our cameras produce the same detail yet better colour definition than other cameras with traditional sensors at the level of 14mp or 48mp.

Is this claim true, well side by side A3 or A2 prints appear to say yes. This along with the fact that I just love the colour and image brightness and the great exposure produced from these cameras.

Pixel Counting Definitions

Prior to the existence of the Foveon X3 direct image sensor, there has been a 1:1 relationship between the number of pixels (photodetectors) and the number of pixel locations for a traditional CCD and CMOS image sensor. Given this relationship, the generic term “pixel” has been commonly used to reference both the pixel (photodetector) and the pixel location. Foveon direct image sensors are a new type of image sensor that incorporates three pixels(photodetectors) at every pixel location on the image sensor. The definition of a pixel as indicated below is consistent with standard industry conventions as applied to CCD image sensors, CMOS image sensors, and the Foveon X3 direct image sensor.

Pixel
A pixel on the image sensor of a digital camera is a light absorbing element (photodetector) that converts light (photons) into electrons. A pixel is also referred to as a pixel sensor when there is a need to distinguish the pixel from its location.

Pixel Location
A pixel location is the X,Y coordinate on the two-dimensional grid of an image sensor at which the pixel is located.

Below I have included some images from my first six months of personal photography while using this camera, I have grouped them into colour and black and white images.

I have also found the camera to be wonderful in the production of black and white photographs, the fact that it is naturally capturing colours in the way it is helps to produce a black and white result as a finish image.

One area that is possibly the only down side I have found is the fact that at higher than 800 iso, the images are noisy in low light, which is why you would need higher ISO, my reaction to finding this out is to say well so, every camera has its weak points. I guess what you could ask is , do the good sides of this camera out do the bad, in my own opinion yes they do, every single bit of camera equipment on the market today has good sides and bad sides.

This is what photography is about, learning what your camera is good at and bad at and working with these details in order to get the best results possible.

Can this sigma help you do that, yes it can and some !

Colour Gallery

Dragon fly on the Barrow 1

Golden Trees of Autumn 2

Grubb Monument the Vee county Tipperarys

When Rhododendron Bloom at the Vee 3

Kilkenny slate quaries 8s

Kilree Round Tower Kilkenny 1

Lismore castle 5

Merge

Sigma SD15 Golden fall 1

Sigma SD15 Kilkenny sunset 1

Sundays on the river bank 1

Sundays on the river bank 3

Black and white Gallery

The forgotten at rest 1

The forgotten at rest 4

Trees on the river bank

Images from the banks of the river suir 1

Kilcooley Abbey 3

Kilcooley Abbey 4

Sigma sd15 trees


Yellow Tutsan flowers

Yellow Tutsan flowwers 1
(hypericum), known as tutsan.
Irish nature and wildlife photography : Nigel Borrington

Hypericum

is a genus of about 400 species of flowering plants in the family Hypericaceae

Some species are used as ornamental plants and have large, showy flowers. Numerous hybrids and cultivars have been developed for use in horticulture, such as H. × moserianum (H. calycinum × H. patulum), H. ‘Hidcote’ and H. ‘Rowallane’. All of the above cultivars have gained the Royal Horticultural Society’s Award of Garden Merit.

St. John’s-worts can occur as nuisance weeds in farmland and gardens. On pastures, some can be more than a nuisance, causing debilitating photosensitivity and sometimes abortion in livestock. The beetles Chrysolina quadrigemina, Chrysolina hyperici and the St. John’s-wort Root Borer (Agrilus hyperici) like to feed on Common St. John’s-wort (H. perforatum) and have been used for biocontrol where the plant has become an invasive weed.

Hypericum species are the only known food plants of the caterpillar of the Treble-bar, a species of moth. Other Lepidoptera species whose larvae sometimes feed on Hypericum include Common Emerald, The Engrailed (recorded on Imperforate St. John’s-wort, H. maculatum), Grey Pug and Setaceous Hebrew Character.
Hypericin
Medical properties
Hyperforin
Hypericum olympicum in Botanic garden Liberec

Yellow Tutsan flowwers 3

Common St. John’s-wort (H. perforatum) has long been used in herbalism. It was known to have medical properties in Classical Antiquity and was a standard component of theriacs, from the Mithridate of Aulus Cornelius Celsus’ De Medicina (ca. 30 CE) to the Venice treacle of d’Amsterdammer Apotheek in 1686. Folk usages included oily extract (“St. John’s oil”) and Hypericum snaps.

H. perforatum is the most potent species and it is today grown commercially for use in herbalism and medicine; other St. John’s-worts possess interesting properties and chemical compounds but are not well researched. As these secondary compounds appear to be related to deterring herbivores, they are present in varying and unpredictable quantities: still, a number of high-yield cultivars have been developed.

Two main compounds of interest have been studied in more detail: hyperforin and hypericin. However, the pharmacology of H. perforatum is not resolved, and at least its antidepressant properties are caused by a wide range of factors interacting. As psychiatric medication, it is usually taken as pills, or as tea. Standardised preparations are available, and research has mainly studied alcoholic extracts and isolated compounds. What research data exists supports a noticeable effect in many cases of light and medium depression, but no significant improvement of severe depression and OCD.

The red, oily extract of H. perforatum may help heal wounds. Both hypericin and hyperforin are reported to have antibiotic properties. Justifying this view with the then-current doctrine of signatures, herbalist William Coles (1626–1662) wrote in the 17th century that

“The little holes where of the leaves of Saint Johns wort are full, doe resemble all the pores of the skin and therefore it is profitable for all hurts and wounds that can happen thereunto.”

Hypericum perforatum may also be capable of reducing the physical signs of opiate withdrawal. Caution should be taken, as high-dosage H. perforatum interacts with a wide range of medications due to activation of the Pregnane X receptor detoxification pathway, and it also causes photosensitivity.

Hypericum extract, by inducing both the CYP3A4 and the P-glycoprotein (P-gp), can reduce the plasma concentrations of different antineoplastic agents such as imatinib, irinotecan and docetaxel, thus reducing the clinical efficacy of these drugs.

Yellow Tutsan flowwers 2


A car boot sale camera – sigma dp1

Sigma Dp1 front

I found this little camera at the kilkenny car boot sale a couple of weekends ago, it just looked up at me from one of the tables and had a price tag of €50 with the Voigtlander viewfinder.

Its the original 2009 sigma DP1 , (follow the link for details). The stall it was on was a charity stall collecting for Africa so I felt I just had to put my hand in my pockets and hand over the €50.

I had always wanted to try out one of these little cameras but when new they cost a good €800, the reviews never put it in great light but I always had a feeling that it was a little better then the reviewers reported them to be. The somewhat bad reviews have left the second hand prices low.

Sigma Dp1 back

Last week I put the camera in my bag along with some other of my kit and on the way home stopped off at a local tourist venue. The images below are three images from about fifty I took just as a test of this little camera. I have to say just like the reviews always said its a little old fashioned to use and the poor LCD screen ( in the sun ) makes you use the external viewfinder a lot but it still felt very good to use, a little like using a good film compact camera. The focus is good and the controls and functions are simple to find and quick to change if your use to any high end compact system.

Image quality

So what about the results, well the big reason I had to try this camera was for its sensor, ( A Foveon X3 sensor ) You can read all the details from the link, its the only sensor on the market that captures pure colour at each and everyone of its mega-pixels. All other sensors are monochrome only, with a filter that cuts out (Red, green and blue in turn) for each of a set of three mega-pixel locations in a row, repeated. Thus they do not record colour but only a signal that some colour has come through a filter to them.

The sigma sensor however records pure colour in full and at the intensity at which it reaches the pixel point. This system is as close to film as it comes.

The images below show the results and I have to say I am very impressed, quality wise they are sharp and the colour is wonderful but it was when I did a colour conversion to black and white my eyes were truly opened, if you have done any black and white conversion from raw digital files you will know the work you need to do to get some true film like monochrome contrast back into your images. Not here. The images even at default setting are just wonderful.

I have started each of the below image pairs with the black and white conversion from the original colour image.

Sigma Dp1 sample 1 black and white
Sigma Dp1, iso50

The contrast is just wonderful here, yet nothing is lost between the black of the trees and the sun on the grass…

Sigma Dp1 sample 1
Sigma Dp1, iso50

The green in the sun-lit grass, along with its detail is fully retained, yet the sky behind the trees has retained a light blue colour and not just overexposed into white.

Sigma Dp1 sample 2 black and white
Sigma Dp1, iso50

Again just look at the contrast in this black and white image, the dynamic range is just amazing, the shadows have just the right detail for a good image, yet the bright areas are not over exposed. This was a very sunny and thus contrast filled day.

Sigma Dp1 sample 2
Sigma Dp1, iso50

Just look how the colours really pop out of the image, this is as good as landscape slide film was without any photoshop colour post processing. All I did was set what I felt to be the correct exposure in the camera itself. Again and unlike slide film none of the image detail is lost due to the high contrast of this sunny afternoon.

Sigma Dp1 sample 3 black and white
Sigma Dp1, iso50

Sigma Dp1 sample 3
Sigma Dp1, iso50

Again none of the detail is lost in the above two images and a full range of tones and colours has been recorded.

Image print size

One issue is the actual image size out of the camera, this only being some 5 mega-pixels, but as with many peoples comments on mega-pixel size, more does not equal good quality big prints if the sensor is not recording enough detail, this sensors pixels are recording both sharp images (with as much details that the lens holds) and full direct colour detail. I feel very confident that these images could be printed at least A3 in size and beyond, all you need to print landscape books or books that record a holiday or family event for example.

All in all not a bad find for €50, one I don’t think I will be finding every weekend 🙂