Posts Tagged ‘channel mixer’

Patterns and shapes – Muzeum Techniki

Monday, June 30th, 2008

muzeum-techniki - damien demolderThis ship’s propeller really caught my eye as I walked around in Warsaw, Poland, as its curved form is surrounded by a mass of squares and triangles.

Much of Warsaw’s non-modern architecture is based on right angles and straight edged shapes with few curves or circles. Although I suppose I hadn’t really made a mental note of that fact, when I came across this object, that has no straight edges at all, I was quite struck with it. In taking the picture I wanted to get over the contrast between the roundness of the propeller and the sharp edges of the notice board next to it, plus the visually powerful squares of the walls behind it. It was only when I looked through the camera that I noticed the blocks of the car park and the lines painted on the floor. These were something of a visual bonus.

At the time I had a wideangle lens on the camera and this is what I made the first pictures on. Viewing them on screen I realized that I wasn’t getting across the strength of the squares, as being close enough to fill the frame was creating too dramatic a perspective, which in turn distracted from what I really wanted to show. Instead I fitted a more standard lens (in this case a 28mm on the APS-C camera). This meant I had to move further away, which helped me to include more of the ground and those lines, plus it flattened the perspective. Moving away also meant I would have to worry less about the lens distorting the brickwork into curves rather than those strong straight lines.

Keeping the camera absolutely level was essential for the graphic and purposeful image I wanted to create, and keeping a wide aperture would allow the propeller and the notice board to stand out from the background, while still retaining enough focus in the brickwork that the shapes could easily be seen. I didn’t have a tripod with me at the time, but I wished that I had. Although the shutter speed was short enough to hand-hold the camera without fear of camera shake, mounting on a tripod makes getting everything right-up and level so much easier. In the end I took about six pictures before I was satisfied that I’d got what I needed.

Fortunately the day was overcast, so the reduced contrast of the softer light allowed me to show the three dimensional shape of the propeller without burnt highlights or overly dark shadows. The soft contrast also helped to display all the fine detail in the stonework, the notice board and the car park.
Originally shot in colour, I converted the picture to black and white via a channels conversion, using a combination of green and red channels. The green channel gave me fine detail, while the influence of the red channel boosted the contrast of the scene a little.

I didn’t have to do too much else to the image, other than some minor curves adjustments and then some unsharp mask to finish. The exposure was already quite dark, which I think adds to the atmosphere. The place the picture was taken is quite hash and serious, so making a jolly picture would not have been appropriate.

Pentax K10D with 50mm manual focus lens, 1/80sec @ f/2 and ISO 400

To see more of my pictures visit my galleries at www.damiendemolder.com

To see more of my pictures
visit my photo galleries site
at www.damiendemolder.com


muzeum-techniki - damien demolder

Real-life perspective – Squeeze box man

Tuesday, May 27th, 2008

realistic perspective street portraitsThe idea of street documentary is to show the viewer what it is like to be in the place you are shooting – and to experience the things you are experiencing. To do this I try to shoot with a perspective that delivers to the viewer a feeling of being in the place rather than simply observing it from afar.

The simplest way to begin this process is to use a lens that captures an angle similar to that which the human eyes can see. Although a 50mm lens is seen as ‘standard’ for the 135 film format and full frame sensors this is still slightly long for a realistic view. On these formats I try to use a focal length of between 30-40mm, which is the same as between 20-30mm for cameras with an APS-C type sensor, and between 15-20mm for FourThirds users.

When you use a lens like this for the type of portrait shown here you have to forget your inhibitions and move in close. This chap was more than happy for me to take his picture, but I still asked by showing the camera and expressing my intentions. This is done in a split second through facial expressions, but makes the difference between guarrenteed co-operation and comfort, and not quite knowing how the subject will react once you start shooting. Having permission also improves your chance of getting good eye contact.
The accordion player was sitting down so I crouched to get on the same level as his chest, and so I could make a major feature of the instrument. It looked almost as old as him, with just as many lines, contours and interesting features.

The day was very overcast, so I didn’t have any trouble with contrasty light and shadows blocking up his eyes or shading his face beneath his hat. It also meant that exposure was easy, and I could leave the camera’s evaluative/matrix system to do the work for me.

I shot in colour as usual, but knew this one would end up in black and white. The conversion was made using the green channel – a favourite with me for getting an aged classic look.

I cropped square as well to keep the composition tight, and because the format seems to suit the shot well.

The final image has good depth and possesses a three dimensional effect that I would not have achieved had I stood back and shot with a long lens. While long lenses allow you to keep a distance, they always show that you were a long way from the subject – which makes it difficult for the viewer to connect with the subject. Actually getting close yourself makes a massive difference, and can be the difference between getting an ordinary shot and one that has some impact.

Shot with Pentax K20D, with Sigma 10-20mm f/4-5.6.

To see more of my pictures visit my galleries at www.damiendemolder.com

To see more of my pictures
visit my photo galleries site
at www.damiendemolder.com

realistic perspective street portraits

B&W conversion – Green Channel

Tuesday, May 20th, 2008

Colour images converted to black and white using the green channel have quite a distinctive look that is great for creating the feel of all classic images. In the days before panochromatic emulsions black and white films had no sensitivity to red (they could even be developed with a red light on in the darkroom).

Film was mostly sensitive to green light, and pinky reds recorded as black, and greens as bright tones. In most normal scenes though pictures record with a moderate contrast that makes a nice change from the over blown black and white work that is widely popular among enthusiasts.

There are two principle ways of creating a conversion using just the green channel – you either isolate it by deleting the red and blue channels, or go into a channel mixer tool to effectively turn off all but the green. Either method delivers much the same result.

Green channel conversions are great for all sorts of subject types, but I especially use it for portraits and city scenes when I want pictures to appear older than they really are.

As digital cameras has twice the number of green pixels as either red or blue you will find that green channel conversions present the absolute best you will get from your camera. Resolution and image detail is optimised, and image noise will be at its lowest.

Filters V channels

If your camera has a black and white mode you may have wondered whether it is better to shoot using this mode and coloured filters over the lens, or whether to shoot in colour and convert using a colour channel mixer or selector in software. You may find that most people will tell you that essentially the two methods add up to the sdame thing, but that one involves putting a piece of glass or plastic over your expensive lens which might degrafe your image quality. Actually there is a difference, though it is quite a subtle one.

If we compare digital processes to the days of film shooting with filters is just like when we shot with black and white film and filters, but when we use channel mixer tools it is like changing the characteristics of the film. Digital sensors are panochromatic – that is, they are sensitive to red, green and blue light. When we use a single channel by itself we are effectively altering the sesnitivity of the sensor. Using only the green channel makes the sensor behave as orthochromatic film, and using only the blue makes the sensor xyxy. When you put a filter over the lens you are still using a panochromatic sensor but you promote one colour and hold back another. The effect is quite different, as is the principle. Using a filter over the lens with a panochromic sensor will always produce a more extreme result, that can only be matched in magnitude in software by extensive manipulation that degrades the image.

This picture was taken using the Olympus E-3.

To see more of my pictures visit my galleries at www.damiendemolder.com

To see more of my pictures
visit my photo galleries site
at www.damiendemolder.com