Choosing the right metering mode
Digital SLRs and various compact digital cameras offer you a choice of different metering modes. I got to thinking about them as a result of a discussion with Alan (Cordina) and Ian (Wright). I tried experimenting with the modes at the airshow, and I thought it would be worth presenting the results here. Typical metering options are: -- average: the camera meters the exposure off the entire frame -- pattern or evaluative: the camera biases the exposure reading towards whichever focusing points in the frame are activated by the autofocus -- spot: the camera reads the exposure at a single point in the centre of the frame. Modes can vary from camera to camera: the Canon 350D, for example, uses centre-weighted average metering (combination of readings in the centre and across the frame) rather than true average metering, and partial rather than pure spot metering. But you get the idea. What difference do these modes make in aviation photography? Well, those of you who were at the runway 14 threshold on the day before the airshow know that conditions were pretty gloomy at times. Average metering seems unable to cope with such conditions. I took this photo using average metering, without any exposure compensation. (This and the other photos below are resized but otherwise exactly as they came out of the camera). Awful isn't it? So then I tried evaluative metering and it made a dramatic improvement. The photo below was taken only minutes after the previous one and in much the same conditions. Again I used no exposure compensation. For aviation photography, where the subject is likely to be always centred in the frame, pattern and spot metering would probably work equally well. In gloomy conditions where the subject is not well lit, either mode works better than average metering. So should you simply keep the camera on pattern or spot metering all the time? My answer would be: at your peril! The photo below was taken at the airshow proper. I had been shooting the Tucano's air display on the 350D equivalent of spot mode and forgot to switch back to average when it landed. The result: Badly overexposed, but the wonderful Canon sensor was able to retain enough detail in the highlights to enable me to rescue the photo. So my conclusion is: -- for airborne subjects under gloomy conditions, switch to your camera's equivalent of either pattern or spot metering -- the same applies to dark-coloured aircraft in bright conditions, like the Tucano and Hawk during their airshow displays -- but for subjects on the ground, especially under sunny conditions, average metering is better. X'tahsbu? Charles

Hi Charles, I agree on most that you have stated above, and this is understandable, as I have been using this method (as we had discussed) for quite some time now, and with this method, often I get good enough results, in light conditions that would otherwise be absolutely useless with average or evaluative metering. This is because when the weather is so gloomy and grey, the whitish sky, surprisingly enough "gives off" / reflect a false (too much) level of light (I think because of its whiteness) and this "confuses" the meter and makes it go for a higher shutter speed, so as to compensate, and as a result your photos will only be good for deleting (too dark). The only thing that you maybe failed to stress upon is that when it is gloomy, the aircraft, especially the dark painted (military) ones, are always sort of "in the shade" because there is no sun out, so here it is not enough to work with spot / center weighted metering, so as to meter on the aircraft, rather than average of whole frame of which a good portion is that "dangerous" / decieving whitish sky, but one would need + exposure compensation of a third or half and sometimes up to a full 1 stop (according to conditions) to compensate. Below are some examples of recent photos that I took, apart from with centre weighted, there is also, a 2/3 (two thirds) of 1 stop (and sometimes 1 full stop) exposure compensation, without which the photos would have been good only for deletion. (too dark). http://www.jetphotos.net/viewphoto.php?id=5825727 http://www.jetphotos.net/viewphoto.php?id=5825954 http://www.jetphotos.net/viewphoto.php?id=5826057 http://www.jetphotos.net/viewqueued_b.php?id=1157860 The below one is where I had used all that is mentioned above, but not enough exposure compensation. I was on only + 1/3 where I should have been on 1 full, or at least 2/3 stop. Infact it is still a bit dark. It could have been lighter and better with 2/3 or 1 full. http://www.jetphotos.net/viewphoto.php?id=5825622 Charles, thank you for the credits, but after all, it is you who then is behind and the catalyst for these interesting and ever informative write ups. we're lucky to have people like Mark (Gilson) and you around. Alan.

Hi Alan Haven't looked at this forum since I posted my previous, hence the late reply. Life got a bit busy over the weekend ... and I see from your own post that you're even more of a night-owl than I am! X'kont qed taghmel imqajjem fis-saghtejn nieqes ghaxra ta' filghodu??? I agree with you about the need for exposure compensation. I wanted to illustrate the difference metering mode makes on its own, but this is only the starting-point. I dare say that if you get the metering mode right you will usually be able to save the photo in Photoshop even if you don't add exposure compensation, whereas if you get the mode wrong the photo will usually be unsalvageable regardless, as you say (my Tucano shot was a lucky exception). Regards, Charles PS on Saturday I went to shoot a Tu-154 takeoff in the evening light. I wanted to try and catch it with gear up (sounds familiar?), so I went to the gate off the Zurrieq/Qrendi roundabout directly opposite park 8. There was this car parked by the gate which I thought was empty, but as I waited for the plane to start taxiing I saw a head pop up and down again, then I swear the car started bouncing on its suspension! And there I was with my camera in hand, u bicca ta' lenti daqshiex ... mur ikkonvincihom li kont hemm biex niehu ritratt ta' ajruplan! I got my photo, then I got the hell out of there!

Ha Ha !!! .... You were risking !! Perils of our hobby !! Although new ones I must say !! Had never heard before of any aviation photographer risking a close encounter with 2 lovers !! ha ha... Yes I saw your TU-154 pic, which, yes, reminded me of mine when from the same spot, it had completely retracted undercairrage. BTW I wake up at around 08.45am !! c.u.