Monday, December 29, 2008

Evening dew

Pentax K10D + Zeiss Planar 50/1.4

As I mentioned before, I believe that high ISO performance is THE major argument in favor of large sensor SLRs. The Pentax K10D performs very well up to ISO 400, but above that the visible noise starts to interfere with image sharpness and an unattractive blotchy grain shows up in the underexposed areas.

The photo above was taken late in the afternoon, hand held at ISO 400, in one of those stressful situations when a photographer has only a few moments to take his shots, before the dimming daylight disappears for good. The way the light refracted within the dew drops, making them standout from the leaves, was what attracted me. But I didn't try enough compositions and so the results were a bit disappointing. In addition, some of the images would benefit from a higher depth of field, but I used only f5.6 or f8 because of the low light.

Does this mean I'm desperate for a full frame Pentax? Not really. I'll just have to practice using my AF-540 flash as a complement for my close up photography...

Sunday, December 21, 2008

Chestnuts on the fire

Pentax K10D + Zeiss Planar 50/1.4

My father-in-law still roasts chestnuts on the fireplace, using an old metal kettle. Roasted chestnuts and fireplaces are two of the nicest things of Winter.

For some reason, I had never taken photos of wood burning in a fireplace before. I like how the exposures turned out. The brick wall in the back got just the right amount of light. I also like the way how the fire defines the contours of the kettle in this particular photo.

Friday, December 19, 2008

Crack on the wall

Pentax K10D + Zeiss Planar 50/1.4

Old stone and mortar walls are great subjects for photography. Cracks, holes, moss, chipped paint, a whole landscape of textures, reliefs and light gradations. These are a challenge to the photographer's creativity and a good exercise for developing composition skills.

Monday, December 15, 2008

The power of the S curve

Pentax K10D + Zeiss Planar 50/1.4

The photo above could be titled something like "After the storm." The sun light hitting the fog horn and the stone walls, under a still threatening lead-gray colored sky, just seems to be fitting for that title.

Actually, the previous photo was based on the one below, a low key shot taken on an overcast Winter morning. There was no storm before or after the shot...

The only post-processing consisted on adjusting the tone curve in Silkypix, giving it a slight S shape instead of the default straight line. This increased the lightness of the lighter areas and made the rest darker. By adding an appropriate number of control points on the curve, I was able to give it the appropriate shape and obtain the result I was looking for. It's interesting how the sky became much more dramatic after this transformation.

Unlike Lightroom, which allows only for changing pre-defined sections of the curve, Silkypix lets one add any number of control points, providing a high degree of control over the lightness adjustments.

In most applications, when the mouse cursor is placed over the photo, the corresponding point is shown on the tone curve. This way the user can identify exactly which are the parts of the curve that should be made lighter or darker. Sometimes, even subtle adjustments have a very visible effect.

I find using tone curves (sometimes just called "curves") an essential part of post-processing, much more intuitive and effective than simply adjusting contrast/brightness levels.

Take another example. The next photo was taken on the same day:

Pentax K10D + Zeiss Planar 50/1.4

This is the original image:

This time the purpose was to decrease contrast and lighten up the darker areas, so as to create a version with a softer light. The tone curve used was now a flipped S. Many may prefer the original, higher contrast, image. But I like the processed version, as it somehow reminds me of XVIII century naturalist paintings.

Of course, S shapes are not the only possibilities for tone curves. I might post later on the power of the "double S" curve...

Tuesday, December 9, 2008

Blue and white

Sometimes, one makes photos from almost nothing...

Pentax K10D + Zeiss Sonnar 135/2.8

Pentax K10D + Zeiss Sonnar 85/2.8

Friday, December 5, 2008

Stones and melons

Recently, when visiting some relatives, I saw a pile of stones and melons lying in the garden of their house. The stones were for decorating flowerbeds and the melons were for making jam. The fact that they were together was just a coincidence. The winter afternoon sunlight reflecting from the white wall of the house created a beautiful soft lighting on that unexpected set. I quickly grabbed the camera and took some photos.

The rest of the family must have thought "For God's sake, why doesn't he take photos of the kids instead?!"

I actually ended up taking some photos of the kids. But the truth is that the stones and the melons came out better...

Pentax K10D + Zeiss Sonnar 85/2.8

Tuesday, December 2, 2008

Hexagonal highlights

Pentax K10D + Zeiss Planar 50/1.4 + extension tubes

I like the photo above. I like the color and shape of the flower's petals. Some readers, however, may notice those hexagonal shaped points of light in the background and say: "Uh-oh! Bad bokeh!"

The term "bokeh" describes the quality of the out-of-focus areas in a photo, when a shallow depth of field is used. When a lens produces a good bokeh, the out-of-focus highlights have fuzzy edges and are smoothly blurred, forming a pleasant background without distracting artifacts. Some people use the expression "creamy bokeh" in opposition to "nervous bokeh" to describe the good and bad forms of bokeh.

The lens optical construction will determine its bokeh. In addition, the number of diaphragm blades in the lens will determine the shape of out-of-focus points of light. Lens with six blades will create hexagonal shaped highlights. Nowadays, many lens have nine or more blades or curved blades in order to generate more "pleasing" circular highlights. The higher number of blades does not imply a better bokeh, though. The distinguishing factor is not the shape of the points of light, but how their brightness is distributed. In a lens with poor bokeh, the edges are noticeably brighter than the center and the overall effect in the background of a photo can be quite unpleasant and distracting, as in the cropped sample shown left (taken from the web - lens unknown). For good bokeh, the edges have to be diffuse and the center is the brighter area. The Zeiss lens used in the first photo produces the so called "neutral" bokeh, since the brightness is uniform across the hexagons. If you're interested in reading more about this, Ken Rockwell has a nice article on bokeh here and Rick Denney describes the results of a very informative lens test here.

As you may have guessed, many Zeiss lenses have only six straight blades and many people will quickly point their reproaching fingers at those hexagons. Of course, the photo I've shown in the beginning is not really a severe example, since the highlights are quite faint.

My view on hexagonal highlights is: if you were distracted by them, then most probably the photo was not very interesting.

Just to finish up, here's a couple more photos of those blue flowers, taken with another lens. I'm sure some bokeh purists might find several optical aberrations here. I really like the photos though.

Pentax K10D + Zeiss Sonnar 85/2.8 + extension tubes