LED astray

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

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

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

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 The LED issue is a newer version of this but I also found recently that if a room is predominantly lit by LED, my Sekonic flash meter doesn't function properly as it thinks a flash has been fired when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.

Congratulations

 something old, something new, something borrowed, something full frame

I might have to work on my rhyming skills. I did some photography at a wedding last week and while it was a long day, it was sunny and enjoyable every minute. Weddings are a special time and this wedding was certainly that involving a ceremony, party at a cafe and a trip on the local Frankfurt apple wine tram!

On my part, before the wedding I researched the locations, hunted for good photo places online and in person, did lots of research, found an able assistant and made tons of prep notes which all went out the window as time and circumstance didn't work in my favour at all...

Even so, it was a great event that I was proud to be a part of, and hopefully have recorded some decent memories of! If anybody needs any advice for wedding shoots - definitely have a back up camera even if you just borrow; take more batteries than you think you will need and make sure they are all fully charged; take time to relax amongst the chaos and have fun! 

DEAD HOT PIXELS!

This is not nearly as glamorous as it sounds. Products like TVs and LCD screens are covered in millions of pixels and as they are not all guaranteed to work by the manufacturer, sometimes you just have to live with a dead one or two on your massive TV screen. The same is true for camera sensors but somehow seeing bright spots in photos that I know should be completely black irks me a lot more.

Try it with your camera. Take the lens off and put the body cap on then take a photo on a manual setting at 100 ISO for a couple of seconds. The whole image should be black. If you have any pixels on your sensor that are misbehaving you will see a bright white or red/green/blue spot. I was originally looking for ways to fix dust on photos taken before using the "Dust Delete Data" tool on my Canon, but glad I stumbled on this youtube video for beating hot pixels - How To Fix A Hot or Dead Pixel (Canon 7D & 5D & others).

After following the tip in the vid and taking another photo the same way as before and checking on my camera's screen, all of the hot pixels appear to be gone! So try it out if you have been plagued by any stuck pixels on your camera too.

No regrets!

If there is one piece of advice I would recommend to everyone is never go anywhere without a decent camera. When the voice pops into your head that says 'I won't need it, I'm only going to the shops/pub/put for a moment,' ignore it, or better yet overrule it. The opportunities for photos is practically infinite and I only regret not taking the photos I wished I had.

If your main camera is too big to carry all the time, go smaller and get a compact for emergencies.  Last night I was out in the countryside trying to get a good sunset. I got a couple of OK shots but nothing great. Tonight I decided to go out for a meal without my camera and to my dismay the whole sky was filled with flaming whisps of red cloud on a perfect turquoise that faded into a light yellow below. Such moments are never repeated again exactly the same way, so I will suffer the extra baggage for the chance of the right photo in future!

Lost in the nth dimension part 3

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.

B+W XS-Pro Digital 010 UV-Haze-Filter MRC nano 77 mm

B+W

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 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.

Sigma 120-400 mm F4,5-5,6 DG OS HSM-Objektiv (77 mm Filtergewinde) für Canon Objektivbajonett

SIGMA

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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!