Low-light AF: DA* 16-50 vs DA18-55

Optical qualities and AF quietness and speed aside, would you expect the ability of the K10D to get AF lock in poor light to be better with the 16-50, purely because of its wide-open aperture being F2.8 rather than that of the much slower 18-55?

Yes.

G

Ok, supplementary question.

How much better?

Is it going to be along the lines of "much, much better; will substantially improve hit rate in bad light", or more like "a bit better, still quite hit and miss"?

I realise this is a bit harder to answer meaningfully, but I'd appreciate any attempts.

The context for all this is my attempts last night to take pictures at a dance venue, where the light was low, people were moving about quite a bit, and there were bright flashing coloured lights about.

AF aside, I was quite impressed with the ability of the AF540 (Samsung version) to expose decently. I was using it off-camera, all auto, mostly bounced with pop-up. Given that quite a few of the couples were wearing predominantly black or white, they wasn't the easiest of subjects.

Very difficult to quantify, especially as the 16-50 has an internal focus motor.

However, I would say (off the top of my head, and without doing any comparative tests) that the K10D and 16-50 focus significantly more quickly than any other lens/camera combo I have used.

And it's pretty good, though not perfect, in low light (where flash is essential).

Its ability to focus quickly, and to find focus in low light, was one of the justifications for my buying the lens.

G

I think it's going to have to go on my wish list then.

Once I realised (talk about a flash of the bleedin' obvious :roll that for AF purposes, the camera 'sees' at the lens' widest aperture, the 16-50's potential utility in low light became a lot clearer.

It's not often that I'd want F2.8 for landscapes, but for seeing in the dark I definitely would.

I think that is the biggest advantage, the DA 16-45 F4 and the DA 18-55 F3.5~5.6 are both fine for landscapes as you'd normally stop down to F8-11. Where they really fall down is in low light where they are just impossible to use. I can only use my A28F2.8 and A50F1.7 indoors without a flash let alone in low light.

Manual focus without any light is very challenging though, It can be very difficult to tell if you have actually focused on the right thing.

That's the easy bit. I have a DB5 convertible and a castle in a loch on my wish-list. Paying for them is another matter.

I look forward to these dark landscapes with no DOF. Could start a new photographic genre.

G

I want that lens too...
but at a cool $1000.00 cdn, I'm afraid I'll have to make do with my canon g5 and pro one as they have both active and passive af and can focus in total darkness.....

Yes absolutely...