Tag Archives: photography

DSLR astrophotography from La Palma

I was lucky enough to get one last observing run at the Mercator Telescope on La Palma, so I spent another eleven nights at the telescope last month, bringing up my totals to 139 nights there (and to 232 overall at international observatories). Since my contract at the Institute of Astronomy ended on the 30th of September, this number will not change anymore :(

Anyway, to make the most out of my last payed trip to the Canaries, I decided that it was time to bring my heavy duty photography equipment with me again, but instead of shooting more time lapse movies, I wanted to do some more serious astrophotography, so I also bought (and then brought along) a compact sized motorised equatorial mount (a Sky-Watcher Sky Adventurer). I mounted the tracking mount on my good old Manfrotto tripod, and used an extra Manfrotto ball head to support and enable easy pointing of my Canon EOS 6D. You can also see the Canon TC-80N3 timer I was using to automate the image acquisition sequence so I did not have to press the shutter release button every two minutes. (Small note: I enabled mirror lock-up and used the 2 second self-timer setting in the camera, so when the TC-80N3 timer gave the signal, the mirror locked up, and 2 seconds later the actual exposure started, eliminating any unwanted vibration from the movement of the mirror. This meant setting an exposure time of 122 seconds on the TC-80N3 timer when I wanted an actual exposure time of 120 seconds.)

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While I have done some very basic astrophotography before (and of course time lapse videos), I never had a tracking mount, so I was always limited in terms of exposure time by the Earth’s rotation. Also back then my DSLR was a Canon EOS 7D, that had worse noise levels than my current Canon EOS 6D, which meant that I could not really go above ISO 1600… But now with a better camera, a tracking mount, and a good amount of research before my trip, I was ready to step up my game.

My first few nights were lit by the bright Moon (I arrived just the day after Full Moon), so I spent the short amount of dark time before moonrise to experiment with the mount, my two lenses, and the camera settings. It took me four nights (of very little dark time) to figure everything out, but starting with my 5th night, my camera was outside from the beginning of the astronomical twilight until moonrise (which happened later and later as the days went by). I found out that I prefer taking more zoomed-in photos, so instead of using the Canon 16-35mm f/4 L IS USM lens, I went for the Canon 50mm f/1.4 USM lens. None of these lenses are really made for astrophotography, meaning that wide open they have a pretty bad coma towards the corners of the image on a full frame sensor, therefore I had to stop the lens down to f/4 to get a result that I was happy with. I used ISO 3200 (after reading a lot about ISO levels for astrophotography here), and an exposure time of 120 seconds (to expose the images to a good overall brightness). As a comparison, in 5 to 10 seconds the stars would already move away enough (thanks to Earth’s rotation) that they would appear as short lines instead of circles on the photo without a tracking mount, (see, e.g., my attempt from a few years ago here). After a good polar alignment (which was pretty uncomfortable with such a low mount, but I managed), I had zero issues with the tracking. Even after one hour, there was basically no shift in the stars’ positions, so I was very happy with the whole setup.

To make one picture, I took 30 to 50 120 second exposures of the same spot of the sky (accounting for a total exposure time between 3600 and 6000 seconds), and also ~30 dark and bias frames for proper calibration (no flats since I have no dirt on my sensor, the vignetting at f/4 is negligible, and taking properly illuminated flats with a DSLR is a mess anyway). Then I processed these in AstroPixelProcessor (really great and pretty much self-explanatory software, with a 30 day trial version!), and at the end I saved an average (or median) image to improve the signal to noise ratio of the images. Finally, I used Adobe Lightroom to do some final adjustments mostly on the curves and colour of the photographs. To show how much this process means for the results, here is a comparison of a selected region from a final processed image, and the same area from a single 120 second unprocessed RAW exposure out of the 30 that were used to create it.

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It is a quite impressive improvement. I liked doing this so much that I would definitely get more into astrophotography if I did not live under one of the most light polluted skies of the world here in Belgium… :D :( Anyway, below is a selection of the images I made on La Palma, and you can find more on my Flickr (at even higher resolution). Since even these 8 resized to ~50% weight in at ~40 MB, you will have to click after the first one for the rest.

1) The centre of the Milky Way, looking towards Scorpius, Sagittarius, and Ophiuchus, with Saturn in the very centre of the image, and many bright and dark nebulae visible around the field of view. A sum of 30 exposures of 120 seconds each.

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Panning photography: Eneco Tour 2015 – Stage 4 (ITT)

There are only two (not one day) UCI WorldTour-races (the highest level cycling events) between the Tour de France and the Vuelta a España, first the Tour de Pologne, then the Eneco Tour. The latter goes through Belgium and the Netherlands, so it is not too difficult to go and watch a stage. The last time I took pictures on a cycling race was back in 2010 during the first stages of the Tour de France, so I was happy to go along with Nadia to watch the individual time trial (ITT) of this year’s Eneco Tour just over the border in Hoogerheide, and try my luck in panning photography.

We parked in the neighbouring village towards the southern sections of the 13.9 km long course, so we had no problem with the crowds around the start and finish area in Hoogerheide, and after a short walk, we managed to find a nice section to watch the race. From a photographer’s point of view, we had to be standing on the right side of the cyclists, so the pictures show the chainrings and the derailleurs, and also preferably in the shade, since colours are nicer there when the Sun is high up in the sky. After finding a suitable spot, we just had to wait for the 152 cyclists to pass one-by-one, which took three hours.

I was typically using a focal length of 105 mm (to isolate the cyclists from the background better, and to achieve a sense of speed without the need for too long exposure times), f/7.1 (not wide open at f/4, so a slight focusing error will not produce a totally out-of-focus image), an exposure time of 1/200 seconds, while the ISO was left at auto. Since I always use RAW, white balance and other settings were not taken care of on the spot, only during post-processing. I was shooting in burst mode, which is 4.5 frames/second on the Canon EOS 6D (compared to my more sport-photography oriented old 7D with 8 frames/seconds), using the central autofocus point only, and AI Servo tracking autofocus. The idea of panning photography is to follow the subject while shooting, this way even with relatively longer exposure times, you can keep the subject more-or-less sharp, while the background gets blurred from the motion of the tracked subject in the foreground. The difficulty is tracking the subject: 1) the tracking speed during the approach of the cyclist changes as the subject gets closer to you (think of standing at the side of a road and looking towards a car approaching towards you, while the car is still far, you don’t have to turn your head much, but while it passes in front of you, you will need to turn your head very quickly to follow through). 2) The cyclists were riding at 50 km/h, and I was standing only 5-10 metres away, so the tracking speed was really high when they passed. Even with an exposure time of 1/200 seconds, the cyclists have covered 7 cm during one exposure. For the image to be sharp, you need to track this movement with a half pixel accuracy. 3) The focus distance changes also very quickly as the cyclist approaches, which is very difficult to deal with for the autofocus system. I have taken more than 400 pictures during the stage, and almost 100 of these turned out to be technically all right (acceptably sharp). I would say that 65% of the bad pictures resulted from the tracking autofocus loosing the cyclist, while 35% from me not being able to track the movement precisely enough. Below you can find a small selection of the nicer images. It was a very nice experience, I am glad Nadia (and Clio) convinced me to go.

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Just as an example (or a technology demo), here is one shot with a longer exposure time of 1/60 of a second (so the cyclist travelled 23 cm during the exposure). It is borderline impossible to follow such fast and extensive movement with a much better precision, so I am quite happy with this image too, even though I only tried one series with this setting, because the success rate was clearly lower compared to 1/200 seconds… Actually, you can see that a few cogs towards the top of the front chainring are perfectly sharp, meaning that I followed the movement of that part precisely.

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Getting ready for the Tour de France

Tomorrow morning I am leaving to Rotterdam for the Prologue of the Tour de France. I will be there as an accredited photographer (so cool, isn’t it?!?) shooting for Bikemag, the market leader cycling magazine of Hungary. I will take the high-speed train (Thalys) from Brussels (leaving with a local train from Leuven on the very early morning – at least getting up at 6:30 is extremely early for me) – for the first time in my life – which will cross the Dutch border traveling with 300km/h on a quite recently (end of 2009) completed new track. After taking pictures on the Belgian Championship last Sunday, I am not (too much) worried about my equipment anymore – though I am far from being experienced in sports-photography -, but I am a bit afraid of the weather… At the moment (17:35 CEST), it is quite likely that there will be showers passing by on the afternoon as a moderate cold-front swipes through from the west, meaning that there is a chance of 33% that rain will fall on a given spot (where I stand with my camera). Though this is much better than constant rain (because you can take photographs at least in between the – hopefully – short rainy periods, and wet roads look great in pictures), but it still makes the life of the photographer much harder (extra clothes needed, and you have to search for places when you may take cover if needed). Also, stormy weather is very unfair during individual time-trials, because conditions (wet/dry road, wind, etc.) can change radically in 5 minutes, and completing the course on dry roads with no wind is incomparably easier than riding against the wind in heavy rain. So it might be a very interesting afternoon (but the Tour will definitely not be decided on the first day), but I keep praying for dry weather anyway.

As I am not a professional photojournalist, (I mean it is not my job, but a hobby – something I do for free, just for fun), I can not spend a huge amount of time on preparations (like reading through all the predictions and interviews, memorizing the face of all the riders – to be able to recognize them around e.g. the team buses, to always know whom I should take a picture of -, etc.), because I have already spent a lot of money on train tickets (100€ just for a return ticket to Rotterdam) and new equipment (I do not want to count that). But as we all know: “There are some things money can’t buy. For everything else, there’s MasterCard”. So experiencing the atmosphere of the Tour from the photographers’ side will be probably unforgettable. I will try to do my best (of course I have red a lot of things, plus I am following several cyclists on Twitter – and not only Lance Armstrong -, and I have a good guess about which cyclists should finish around the top 10).

This is the equipment I will use on the Tour de France (TdF) – all goes into a Lowepro Fastpack 250 backpack:

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Canon EOS 7D body
Canon EF-S 15-85mm f/3.5-5.6 IS USM lens with EW-78E hood and a B+W UV filter
Canon EF 70-200mm f/2.8 L IS USM lens* + ET-86 hood + Hoya UV filter
Canon Speedlite 430EX II flash
Canon LP-E6 battery packs (2x) and charger
SanDisk memory cards (8GB Extreme III, 4GB Ultra and a 1GB normal – very old one)
MacBook (with Adobe Photoshop CS4) + mouse, power adapter and Tucano second skin
and other small things (money, phone, USB-cable, B+W lens cleaner)
*thanks to Dr. Stefan Uttenthaler

What else am I supposed to say now? I am very excited, I have already packed almost everything, so I could leave in a half hour, if I had to. (Luckily, this is not the case, so I can still go for an ice-cream and watch the World Cup with my colleagues tonight.) In the following couple of days, I will try to give an insight into not only the most important and famous cycling race of the year, but I will also show you the photographer’s life on the Tour. Look back regularly, I will try to keep you updated! Vive le Tour!