Originally posted by dlh I've noticed, Des, that you tend to use aperture settings in what I'd think of as the "low-middle" range of that lens. You seem to control the depth of field really well and don't go nuts over excessively shallow focus. You're also not afraid to use higher ISO numbers - I've got this prejudice, I suppose, from the days of celluloid, of never, ever, going about 800 for anything, generally using 400 for indoor shots and sticking to 100 - 200 wherever possible, to avoid the graininess from the larger silver nitrate crystals in the higher numbered film. What aspects, would you say, you optimize in your settings? In other words, what's the highest priority among things like exposure, sensitivity, and aperture? I have a theory that people tend to optimize for some specific characteristic and then build the remaining settings around whatever that preferred area of control may be.
It's an interesting question Dan. Thanks for asking. I think your theory is right, although for me (and I'm sure for most people) the priority will depend on the subject - e.g. for wildlife/sport, usually shutter speed; for landscape, aperture and ISO.
I probably came to digital photography without the same degree of aversion to higher ISO as you had. Some time in the 1980s I went from using 100 ASA slides and negs to 400 ASA and was prepared to trade some grain for greater versatility. When I got the K100D Super in 2007, I tended to let the ISO float (to a whopping 800!). With the K-30 (2013-16) I sometimes (too often in retrospect) went to 3200 or even 6400. With the K-3 (2015-) and K-S2 (late 2016-), I've reined it in - especially with the K-3, where I've generally capped it at 1600 or less (2000 with the K-S2). The DxO software does such an excellent job that mid-level ISO (800-2000) generally cleans up very well; if the light is good, even higher ISO (to allow faster shutter speeds or narrower aperture) can come out quite well. I think TAv is my favourite mode, which reflects my common use of floating-ISO, although I use Av, M, P, Tv or X as the occasion requires.
But to put the ISO in perspective, of the 170 images from DFA 100 that I've uploaded to Flickr, only 10 are higher than 1600; in fact only 36 of the 170 are over 800. Of those 10 that are over 1600, I think I should have kept the ISO lower in most of them.
For landscapes, of course, I keep the ISO as low as possible - I tend to use Av with fixed ISO. The landscape samples above are all 100 ISO, except the 4th one, where the dim early light required 1/20th, f4.5 and 1600 ISO.
As for aperture, you are right that I don't go wide open very often. At 100mm, the DOF at f2.8 can be too shallow to get, say, the whole of a flower or insect even at 1 metre. With the pademelon (wallaby) above I used f4 because I wanted the whole face in focus but nothing else - f2.8 would not have achieved this because I was quite close. With the brown cow I went for f4 to be sure to get the whole cow in reasonable focus, while getting some separation. With the bull it was f5.6 - perhaps I could have gone for f4, but I wanted to be sure to get all the hay in focus. Most of the flower samples and (one of the seaweed images) are at quite narrow apertures (e.g. f9) to achieve adequate DOF. So long as it leaves me a reasonable shutter speed (generally 1/100th or so at 100mm), I don't mind pushing the ISO to 400 or 800 or sometimes more to get the DOF I want. Most of the landscapes above are f9-f11. With macro and close focus I often use a narrow aperture to squeeze out every bit of DOF (e.g. f9 for the frog, f11 for the dew-drops, often f16 for 1:1 macro). I'm using flash more often now for these sorts of shots.
One of the beauties of the DFA 100 is that you don't need to stop down just to get the best resolution. It's centre-sharp from f2.8-f16 and edge-sharp from f5.6 (arguably even f4) to f16.
(Chart from Ephotozine)
So you can pretty much choose the aperture to get the effect you want and not worry about resolution.
For birds/wildlife in mediocre light I switch between the @Normhead strategy of low ISO/slow shutter (lots of throw-aways, but the good ones are really good), the avoid-blur-whenever-possible strategy of bumping shutter speed and ISO (when you might not get another chance) and the add-flash-and-try-to-balance-ambient strategy. But that's a discussion for another thread.