Here's my situation - I had an acquaintance at work who DJs afterhours who invited me out to shoot him while he's spinning. The fastest lens I have right now is the 14mm f/2.5 and it was barely cutting it wide open. Quite a bit of hunting for focus and I found myself having to push the ISO way up (something I would prefer to avoid if possible).
What do you mean by "barely cutting it wide open"? Was the problem the autofocus hunting or was it something to do with IQ and, if so, what? How high were you setting the ISO and how were you metering your scene?
It's easy to say that something is "low light" but there's a huge difference between low light as in a moonlight scene outdoors with little sky area in the frame and a club scene with lots of dark shadowed areas and poole of much brighter light. You'd get much better results using an averaging meter mode with the moonlit scene where things are much more uniformly dark and no real brightly lit areas, and with a spot meter mode in the club scene, metering your subjects if they are in the more brightly lit areas. Kevin Paris is "spot on" with his spot metering suggestion for that type of work because if you include the shadow areas in the metering the meter is going to want to bring the average value of the whole scene up to mid-grey whereas if you spot meter in the more brightly lit areas it's going to suggest an exposure that will render the area you meter as mid grey. If you meter white caucasian skin, then give the suggested exposure +1 stop EV compensation, really dark black skin gets - 0.5 to -1 stop EV compensation. The person's skin tones will be rendered correctly and surrounding shadows will look quite dark in comparison, as they do in the actual scene. You may well find that just metering that way is worth an extra stop or more in lens speed to you. Also, once you get your exposure set for your subject lock the exposure setting and don't change it as you take shots with different framing. The lighting on the subject isn't changing so the exposure for the subject isn't changing, no matter how the average exposure value of the scene overall changes as the proportions of well lit and shadow areas in the frame change.
Also, in terms of getting the equivalent of extra lens speed, don't ignore shooting in RAW rather than JPEG so you've got more data to work with and much more leeway in processing, and using your camera's image stabilisation as well. Each of those suggestions may well be worth a stop of lens speed to you if you're not using them.
Since it was a small venue, I was jammed in the booth with him and the 14mm focal length was barely wide enough - that's the main reason I am leaning towards the 12mm since it would give me a hair more width to work with for composing shots. Can't use a flash, and I am trying to take advantage of the club lights for lighting but I need something faster than the f/2.5 lens. The 17mm isn't the optimum width, but it's a tad faster which is an advantage (or at least I would think) and I might be able to make 17mm work if need be.
So, I'm after opinions on the 12mm f/2.0 vs 17mm f/1.8 for shooting in low-light at nightclubs and such.
Should I expect as much hunting for focus out of the 12mm or the 17mm under these conditions?
Both lenses are newer than the 14mm and auto focus should work better but auto focus works better when the focus target is well lit and has good contrast. Low contrast target areas in low light are harder for auto focus to home in on.
Is there going to be a significant difference between f/2.0 vs f/1.8 in this type of shooting environment?
That's around a third of a stop difference. It's pretty insignificant in the overall scheme of things, especially when the sorts of strategies mentioned above are often equivalent to a stop or more of lens speed in benefit. Even the difference between F/2.5 and F/1.8 is only around two thirds to three quarters of a stop. If you want a real gain in lens speed you'd be better thinking in terms of F/1.4 or faster.
If both lenses were equal in image quality, would you go with wider (12mm) or faster (f/1.8)?
If both were equal in image quality I'd go for the one whose field of view best suited what I was trying to do. There's not enough difference in speed to worry about when there's a much bigger difference in field of view in play. Even if there was a bigger difference in image quality than there is, and I have both lenses, I'd choose between them based on field of view. There's no point in buying the lens with better image quality if the field of view doesn't give you the sort of images you want to get.
I know the obvious answer is "Buy both!!!" :smile: but unfortunately the checkbook won't support that at the moment.
Thoughts?
I'm not certain that you need to buy either since there's probably things you can do with your current lens and improved technique which would deliver as big a speed benefit as either lens would over your 14mm. The other thing that I'd be considering is why I want the lens. If all you're going to do with it is take some shots of your friend working, and you're not doing that on a regular basis, then either lens is expensive for what you're going to get from the purchase. The fact is that if you're going to buy a lens and keep it, then you're going to be using it for other things, and probably more for those other things than for photographing your friend while he's working. In that case it makes more sense to buy the lens based on what you're going to be using it for most and considering what you do with it while shooting your friend at work as a "side benefit". If you're not going to use the lens for other things, then just consider renting a lens for doing your shots for your friend. If you rent then I'd go for the 12 since you find the 14 a little tight at the distances you're working at.
