I bought the D7000 about a year ago. I abused it in many ways, but not once I have ever tested its ISO performance. It wasn't what I am interested in anyway. I can't tell what is a tolerable noise level. I have no way to measure it, and I was taught to keep the ISO as low as possible.
Due to the weather condition in February, some matches have to be rescheduled. Several matches from the FA Premier League Cup ended up in conflict with other league, cup or whatever on Sunday, so they move their fixtures to Wednesday evening. Although the very first football game I have ever photographed was a night game, I have no confidence to shoot another one (can you believe it? I actually posted those photographs in exercise 8!). After some procrastinations, I contact my not-so-local team (never once have I though one day I might be rich enough to live in Camden Town) and see if they let me do test shot during their practice. They kindly let me to tag along, so I have some interesting test result :D
First question, what setting do I get away with?
Basically maxed out everything I have on hand. To get any reasonable actions, I was working at 1/640s, at ISO 6400, f/2.8. When the lens is at 200mm, the depth of field is about 4cm for a subject who is 4m away from me. It sounds horrible, but the fact is Bigma (my usual lens for football) at maximum focal length at f/8 has roughly the same depth of field for somebody 10m away from me. The 1/640s is slightly worrying, but I don't feel I can push the ISO any further. In fact, even at this setting, the built-in meter indicated that I underexposed the screen. Exposure is for a night football game is a bigger issue that I will discuss it later.
Next, how much noise am I looking at?
I don't have a systematic way to compare noise given that there is never two totally identical situations in sport. Hand-waving analysis compares image sharpness, so I pick somebody who has light colour hair, zoom in at 100% crop (big enough to print a 2 meter long poster) and check if their hair is sharp!
Image 1: This is taken at the practice at night with ISO 6400, at 145mm, 1/640s, f2.8 using the 70-200mm lens.
Image 2: This is taken last Sunday during the KIKK vs Brentford match. It was raining, and I took this at ISO 2000, 420mm, f/6.3 (also wide open), 1/800s with Bigma
Looking at just one example (see, this is so un-scientific), it is tempted to say that the noise level at ISO 6400 is acceptable (ie, I get the same crap in other game under bad weather anyway, what more can I ask for?). However, it just make me wonder if the performance is lens specifc, or weather, or something else? So I dig up some old shots.
Image 3: This is taken during Tottenham 3rd vs Barnet reserves. ISO 200, 320mm, f/7.1, 1/1000s, with Bigma
Guess what? I actually can't tell. Is there any reason why it is not totally convincing that the shot is cleaner at ISO 200?
To be honest, everything should be like the image below.
Image 4: Taken during KIKK vs Luton Town Reserves. ISO 200, 160m , 1/500s, f5.6, using the 70-200mm lens.
Pin sharp :)
Anyway, back to exposure. Let's start with these two images.
I don't usually like the burst mode because it is not a healthy tool in an education stand point. The best sport photographer should have the ability to predict what is going to happen next and position him/herself to capture just that moment but not anything more. Since I am not that good (yet?), so I did have the burst mode enabled to get ready to cheat :). The two images above are taken 0.2 second apart from each other, and notice the difference between the brightness on the two images. The electric power in UK is running at a 50Hz A/C, which means the power will go from peak to zero at 1/50/4 = 1/200 second. Since my shutter speed is at 1/640s, I can (by chance) get near the peak power, or near the lowest power of the flood light above! The question is, which one should I meter? It is not predictable (without a spectrometer) which power signal am I getting the moment I hit the shutter, and the light meter is probably telling me the average incoming flux instead of what I will get when I hit the shutter. So? It may worth using the brust mode in a night match and throw away half of the images that is less exposed. It is much easier to fix a slightly over-exposed image than an under-exposed one at post processing stage.
What else? Well, the lighting is not uniform through out the whole pitch. Some spots are definitely brighter. And depending on which direction the players are facing, they face may be under exposed (back-lighted). As a result, there are only few spots I can realistically stand and only certain direction I should be photographing, but not more. Having the flood light coming from the top also given a shadow around the eye area. The depth of the shadow depends on the actual shape of the skull of the individuals. However, most indigenous European (the politically incorrect term is white people), their bond structure will almost always guarantee a deep shadow around the eye (panda eyes if you ask me) in this situation.
If the weather is perfect, usually over 90% of the image I take are acceptable, with about 10% are decent. If the weather is bad, the acceptable figure drops to 70-80%. From this practice, if I takes out the stationary images, the hit rate goes down to something like 5%....
I need couple days to think about the match next week. At the moment, the best solution seems to be emailing Watford and tell them that I got hit by a bus...
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