Last night (here in Australia – as it’s now Friday afternoon) I decided to do a bit of testing of my Nissin 866ii flash’s ability with respect to AF in the dark. I tested on my 7D, and was using my Canon 15-85mm lens, which has USM focus.
I tested the AF assist-beams (two red assist lights), both on a blank white wall and on a patterned curtain (dark background with some lighter flowers). For both of these I tested at different distances from camera to ‘subject’.
When up close (e.g. within 2 metres), using the AF point just above centre (or even 2 above centre) meant it focussed a bit quicker (as a bit higher than centre of the frame / composition is where the AF beams are, particularly noticeable up close, on the blank wall).
I had no lights in my darkened room. It was so dark my camera was metering at ISO 12,800 and f/4 – and it required an exposure of between 0.3 and 1.5 seconds. The wall being ‘lighter’ – hence shorter exposure time.
Each time I did the test, I manually moved my focus to the other extreme (e.g. for closer to the subject, I moved focus to infinity, when further away from the subject, I manually moved focus to macro). My 7D had no problems obtaining focus on either the curtain or the blank wall. I could confirm both were accurately focussed. One may ask, how so on a blank wall? Well, in the extreme corners I had wall features, e.g. wall hangings and bookshelf, which were in focus.
The focus speed in the dark was ‘adequate’ – i.e. noticeably slower than in bright light (on the same subjects) – but not terribly slow. The 866ii emits an initial 0.5 second duration AF assist beam, and then about half a second later, it emits a about 3 pulses of the beams (within about another 0.5 to 1 second). So within about 2 seconds (at times, within about 1 second) I was always guaranteed of an accurate focus.
Should you have moving subjects, such as you wrote, being in nightclub situations, you might find the 866ii AF assist beam inadequate. I am not a Nightclub photographer – though I have taken several ‘event’ photos in low light, e.g. some camps, concerts, wedding receptions, annual city-wide prayer breakfast (in a darkened big hall, so the powerpoint could be viewed). As I wrote above, I can not provide any comparison between this and other flashes, but hopefully it gives you an idea. I have used the 7D without flash in these situations, and on a few occasions with AF beam, which does help in certain situations (e.g. if subject is already backlit, the AF assist beams help achieve focus better and quicker).
Note: using the 7D’s menu, I can ‘force’ the Nissin 866ii not to fire the flash, but to actually still use the AF beams (which is a very handy feature to have).
Also, because I use the back AF-on button, I can focus once, and then either recompose (if not using a narrow depth of field), or use that same AF setting later (if subject and camera don’t move).
There you go! I enjoyed ‘practicing’ and putting my gear through its paces. 8)
Paul
I tested the AF assist-beams (two red assist lights), both on a blank white wall and on a patterned curtain (dark background with some lighter flowers). For both of these I tested at different distances from camera to ‘subject’.
When up close (e.g. within 2 metres), using the AF point just above centre (or even 2 above centre) meant it focussed a bit quicker (as a bit higher than centre of the frame / composition is where the AF beams are, particularly noticeable up close, on the blank wall).
I had no lights in my darkened room. It was so dark my camera was metering at ISO 12,800 and f/4 – and it required an exposure of between 0.3 and 1.5 seconds. The wall being ‘lighter’ – hence shorter exposure time.
Each time I did the test, I manually moved my focus to the other extreme (e.g. for closer to the subject, I moved focus to infinity, when further away from the subject, I manually moved focus to macro). My 7D had no problems obtaining focus on either the curtain or the blank wall. I could confirm both were accurately focussed. One may ask, how so on a blank wall? Well, in the extreme corners I had wall features, e.g. wall hangings and bookshelf, which were in focus.
The focus speed in the dark was ‘adequate’ – i.e. noticeably slower than in bright light (on the same subjects) – but not terribly slow. The 866ii emits an initial 0.5 second duration AF assist beam, and then about half a second later, it emits a about 3 pulses of the beams (within about another 0.5 to 1 second). So within about 2 seconds (at times, within about 1 second) I was always guaranteed of an accurate focus.
Should you have moving subjects, such as you wrote, being in nightclub situations, you might find the 866ii AF assist beam inadequate. I am not a Nightclub photographer – though I have taken several ‘event’ photos in low light, e.g. some camps, concerts, wedding receptions, annual city-wide prayer breakfast (in a darkened big hall, so the powerpoint could be viewed). As I wrote above, I can not provide any comparison between this and other flashes, but hopefully it gives you an idea. I have used the 7D without flash in these situations, and on a few occasions with AF beam, which does help in certain situations (e.g. if subject is already backlit, the AF assist beams help achieve focus better and quicker).
Note: using the 7D’s menu, I can ‘force’ the Nissin 866ii not to fire the flash, but to actually still use the AF beams (which is a very handy feature to have).
Also, because I use the back AF-on button, I can focus once, and then either recompose (if not using a narrow depth of field), or use that same AF setting later (if subject and camera don’t move).
There you go! I enjoyed ‘practicing’ and putting my gear through its paces. 8)
Paul
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