techniques

LED astray

in

I paid a visit to the Frankfurt Dippemesse on the 5th of May to get some photos of the fireworks and the fair at night. Generally I got some decent long exposures using a tripod and settings with low ISO and 2 to 4 second shutter. There are a lot of bright lights so f stop can be f8 to f11 and even f16 for more starry effects in the bright spots.

glittery white lights

glittery white lights

One thing that I noticed when looking at the photos is that most of the lights on them did not produce constant blur lines in the photo. Most of the lines of light are composed of dots when you look at them closely. I have noticed this phenomenon more over the years and finally realised the cause after blaming my technique, camera and other superstitious reasons.

dots are visible at fast speeds

dots are visible at fast speeds

In the olden days, lights were almost all incandescent bulbs or halogen. Nowadays, everything is LED. LEDs are cheap, efficient, don't produce heat like halogens and last longer, so they are now find everywhere in torches, home and automobile lighting and even fun fairs. The downside to LED lights is that they pulse (for cheap ones) at a much slower rate than incandescent lights or florescent tubes. As far as I can tell from reading on the internets an old style light bulb pulses at twice the frequency of the power supply current, while a cheap LED pulses at half of the frequency. This is measured in Hertz. Let's pretend the power supply is 50 Hertz, a florescent light would pulse at 100 Hertz, an LED at 25. Apparently, all lights on AC flicker but the effect is made more prominent with LEDs as photon are not emitted when they are flickering on and off. While a regular light bulb is in an off state it still produces heat and some light. If the LEDs are dimmable, this is achieved not by lowering the amount of voltage as in the case of a light bulb, but by increasing the time the LED is off per flicker cycle.

Digital dots of the break dancer ride

Digital dots of the break dancer ride

Does any of this matter?

Health-wise, lights that flicker at a slower cycle can cause seizures in some people.  For long exposures, lights with slower flickers on fast moving objects are easy to spot as a series of dots rather than a single line as in the examples here. Photographers have long been aware of the effect of florescent lighting and shutter speed causing issues at certain rates. The LED issue is a newer version of this but I also found recently that if a room is predominantly lit by LED, my Sekonic flash meter doesn't function properly as it thinks a flash has been fired when it is actually the room lighting flickering. It was unable to get a reading at all while the LEDs were on. This even occurred when a regular light was the dominant light source. The only solution was to turn off the offending lights while reading for flash exposures. Seeing as LEDs are not going away any time soon, I guess we will just have to get used to seeing lines of Morse code instead of smooth clean light trails during long exposures in future.

Day 240

in
The Street

The Street

While looking for the right person to take a photo of this morning, I spoke to an inelligent guy (who I didn't photograph) who really got me thinking about what I am doing when I talk to somebody and ask them for a photograph. I haven't completely formulated my thoughts into words yet but can say there is something distinctly different between street photography and street portraits. They employ different skills and a different way of looking at the world. I perceive subjects in street photography as demonstrating humans in their natural world doing what they do without noticing the photographer which forms a barrier between them and the observer. Sometimes the cameraman holds a power that may be abused and results in a stolen moment in time. Galleries everywhere are filled with such moments but there is seldom any true connection between the subject and the viewer - we are just voyeurs looking down on somebody without them being able to reciprocate. On the rare occasion that the subject looks through the lens at the viewer and breaks that 4th wall, there is an expression that cannot be gained by having spoken to that person to receive their permission before having taken the shot and this tends to give the person in the photo a greater connection to the viewer.

However, being allowed to take somebody's portrait while on the street invites the photorgrapher and viewer to enter into that subject's personal space with their express permisson. The look the person has is completely different and the overall tone of the image feels softer to me. Even though there is the briefest of exchanges before the shot, there is a trust from the subject that the photographer respects them and their personal property will not be misused or abused. In constrast to this, knowing that a camera is pointed their way, the subject stops behaving normally and will try to pose and look as they feel is apporopriate and this might be at odds with what would make the best photograph for them. This can form quite a dilemma as a photographer needs to balance their own desires with the rights of the person in the image and what would be the best method for obtaining a photo that could satisfy all parties.

As yet, I don't have a clear vision of what is the best way to approach my own photography to push myself in the right direction regards street photography. However, the more I talk to, and take portraits of people on the street, the more I see the beauty in them and the value in making a connection and learning from each by coming out of our comfort zone. I think we miss out so much by being engrossed in commuting, playing mobile games, reading books and so on that we ignore a vast wealth of potential from the amazing people who are within touching distance of us sat on a train or at the next cafe table and one of the things that stops us from talking to each other and strengthening our communities against prejudices is the fear of rejection which may ultimately be why it feels easier to be a street photographer than a portrait photographer.

Lost in the nth dimension part 3

in

Continuing on from the last post, what other factors can influence lens buying choice?

Weight/length

I own a few cameras and some are quite heavy. You only need to feel a trapped nerve a couple of times to wish you had lighter equipment. If you go hiking with your camera then a light lens or a zoom that allows you to reduce the size of your kit is essential. Likewise, the bigger or longer the length of lens you buy, the more likely you will need to buy a bigger camera bag too! Lighter lenses are also easier to hold without shaking as much. The heavier the lens, the sooner fatigue can kick in which will make photography a drag while also reducing the number of good shots you can achieve. It's a good idea to hold one in a shop for a while to see how it feels.

 Construction

Cheaper lenses are often made of plastic while more expensive ones are made of metal. Metal lenses are more durable but heavier. Feel the weight of them in a shop before you buy to see if they feel comfortable for you. Although you may never need to care about the internal construction of a lens, there are certain things to look out for. E.g. you can check if the rear of the lens is made of plastic or metal. If the parts that attach to your camera are plastic, they may wear faster over time. You can turn the focus and zoom ring and make sure it feels smooth and not too loose. If you give the lens a gentle shake, listen out for any loose parts. You can also check out internet forums to see if the lens you like has any common failures. I bought a cheap Canon EFS 55-250mm lens a few years back that turned out to have a design issue as repeated zooming caused the auto focus to fail due to a particular cable wearing out. If I had found this out before buying, I would have got a different lens.

Some lenses claim to have better dust or moisture resistance, but it is mostly marketing jargon, don't expect any lens to work as well once you have moisture in it and certainly don't try dunking one in the sea! Treat any lens well and it should last many years.

Filter size

My biggest pet peeve is that every single lens I own has a different front legs element size so I can't share filters between them. When you are first starting out or on a really tight budget you can consider finding a lens that is the same diameter as any lens you already own to save cash when it comes to sharing filters. Filters have an issue of their own in that unless you spend a lot of money, a bad UV filter can make your photos less sharp while also cutting the light that gets through. I only have a filter regularly installed on my 24-105 f4 lens as I use it the most. I use a B+W UV haze mrc nano filter which is the only filter I found so far that has a minimal effect on photos and create no colour cast unlike cheap filters.

 Front element

Does the front of the lens move forward or rotate when zooming or focusing? The best lenses are often internal focusing so the lens doesn't get bigger as you zoom or focus. This means you always know how far you lens is from your subject or any obstacles that could get in the way or damage your lens. This might not be so important for telephoto lenses when bird watching but it's essential when doing macro photography. Having a non-rotating front element means you can use filters (e.g. a polariser or graduated ND filter) you can't use easily if the lens rotates.

Full time manual

As a beginner you may rely on auto focus all the time, but as you progress, taking photos in the dark or macros of objects up close may mean you need manual focus more and more. Cheap lenses can't cope with the photographer touching the focus ring if the lens is set to autofocus. I'm sure it can even ruin the lens as it strips gears of burns out the focus motor. I always prefer lenses that allow for full time manual focus override because if the camera won't focus on the spot you want, you can just tweak the focus without flipping switches or even removing your eye from the camera.

 Accessories

Some third party manufacturers like Sigma include more with a lens than the big names; Canon or Nikon. For example, I bought a Sigma 120-400 lens which came with a lens hood, tripod mount and padded case. For those on a budget, buying a lens with these accessories can make for a much better deal as some lenses show very little difference in quality to the more expensive brands.


Firmware/compatibility

Nowadays, some lenses have USB ports to allow you to update their firmware and improve camera compatibility and autofocus accuracy.  Third party lens makers may have a more difficult time making sure their lenses work with the camera manufacturers' latest camera models. And don't expect any product will have support indefinitely, so check online to see if your camera and lens combination doesn't have any known problems before you buy!