[MnR]

Hi,

An Old trick back when P&S were the hot thing was to use a small cheap flashlight. if the light was anoying then you could cover the flashlight with a red or yellow filter (either homemade or store bought).

Rudy

[jensm]

You did not mention what type of photography you are aiming. For me , I would say other than the extreme fast sport or bird in flight images. Pentax prevail particulary in the bang for buck ratio.


Daniel

Kids in flight are just as hard...

/jens

[ChrisA]

Group people
Aim centre AF point at people bodies (centre of one)
Half press shutter release
recompose

This is how I do 99% of my focusing on the K10D, and it works fine.

If it's not working for you, one of the following is probably the case:

- your camera is faulty
- you're releasing the half-press while you reframe, so it refocuses when you take the picture
- you have AF-C set, in which case it will refocus continuously while you have the button half-pressed

The subject will be at a different perpendicular distance from the camera when you reframe, so if it's very close, the reframe can put the subject out of focus. But for most practical purposes this effect is not noticeable.

[bt*ist]

I love my K10D dearly, but that doesn't mean I don't at times pine for a slightly better autofocus. Centre-focussing is definitely the order of the day, and always on Continuous Autofocus. Nothing worse than the camera hesitating and you missing out on the shot (I'm talking candids and street photography and maybe star-spotting at movie premieres). Generally shoot with a wider lens and then crop afterwards to improve the composition. Higher f-stops to hedge your bets, use a higher ISO to support this.

So what I'm saying is - I know how to work around the K10D's weaknesses... but there's nothing wrong with dreaming of a better Autofocus!

[ChrisA]

As for the OP: I wonder if he's using a Pentax flash? The flashes have a built-in AF assist beam (the body does as well if you pop up the popup flash but that's white and bright instead of IR).

The AF-assist from the Pentax flashguns is red light, not IR.

[ChrisA]

Centre-focussing is definitely the order of the day, and always on Continuous Autofocus.

Erm, you do realise that this is only any good when the subject is in the centre of the frame, don't you? As I said a couple of posts back, AF-C means that the "half-press to focus, then reframe and take" technique doesn't work at all.

Particularly when the light is a bit on the low side, this technique becomes much more important - since picking a high-contrast spot to focus on often makes the difference between focus lock and not.

So using AF-C all the time is probably fooling you into thinking that Pentax AF is worse than it actually is.

Of course, as you say, AF-C is useful for moving, centred targets.

[RiceHigh]

Neither you nor any of the existing Pentax DSLR users could do anything to make our Pentax DSLRs focus better, only Pentax could, but very unfortunately they haven't done it yet.

Every time when my Pentax DSLR hunts in quite many "quite normal" conditions, it recalls my memory of my old but much better 1999 Pentax designed MZ-30's AF system which just costed me $180.

I do have very strong faith that Pentax do know how to cure this persistent and long-lasting sluggish and insensitive AF issue, but only if they are willing to do so!

For your case, the only solution is to get a new DSLR of another brand. The AF system of that new camera will do the required job for you. Thats exactly what I did early last year when I acquired a Canon 5D, but for a Pentax AFSLR user for more than two decades, I do hope some days later Pentax do roll out a "proper" body finally but the sad thing is that this wait has been endless since 2003 when I bought my first DSLR body from Pentax!

Ever since I got my K100D two years ago and found this forum, I've learned a lot. My Canikon friends all tried to talk me out of Pentax, but I got all defensive and touted things like cost, IQ, etc. I was happy as a clam. Then today, I walked into my local store and I played with the D700. Dang. Now I know what I'm missing.

The autofocusing.

Over the years, I've found myself bringing my camera primarily to lots of low-light, birthday party/restaurant/awards ceremony/wedding kinds of situations. I know this has been discussed before, but my K100D hunts all the time, still spot-focuses on the plant and not the person, and rarely gives you the razor sharp "nose-and-eyes" kind of focusing you'd like to see. I bought an FA35/2 (great lens!) and pump up the ISO, but it's not the noise -- I still miss most of my shots from poor focusing. I've resorted to manual focusing at times, but it's too slow for candid work.

How can I make my K100D focus faster and better in low light?

I've tried out the K20D + DA16-50 combo, and ths HSM is better, but the autofocusing still feels the same, with results to match. I was blown away today by the D700 + 24-70/VR system. Granted, price points are totally different. But what do you guys think? Instead of upgrading to the great IQ of the K20 once I start making a real salary (woohoo!) in 6 months, I'm now considering the D90 or D300. It's very sad.

For those of you who are sticking with Pentax, how have you made it focus better in low light? Or is it a matter of skill? Perhaps I need to practice more ...

[Marc Sabatella]

Here's a typical situation...

Group people
Aim centre AF point at people bodies (centre of one)
Half press shutter release
recompose
review photo... trees in background are sharp, people fuzzy!

Actually, that's to be *expected*. See the following link:

Why Focus-Recompose Sucks

The author goes too far - most lenses do in fact have a somewhat curved "plane" of focus, not flat as the author assumes. Flat focus planes are one of things that make true macro lenses different from ordinary lenses with a close-focusing feature.

Anyhow, bottom line: any time you change your camera angle, the "plane" of focus changes with you. If you only move a little, or you have a small aperture, it shouldn't matter. But it matters a lot with large apertures and/or if you put the subject all the way to the edge of the frame.

A simple way to test what is going on: first take the picture *without* recomposing. Is it in focus? If so, the camera has done it's job, end of story. If the subject is out of focus after recomposing, you are seeing exactly the effect describe in the above article. It's not the camera's fault - it's just a flaw in the technique itself. Assuming, of course, you are not in AF-C mode or haven't inadvertently triggered a second AF operation after the recompose.

If on the other hand the subject is out of focus even without recomposing, then you may have a FF/BB problem worth investigating.

[RiceHigh]

Just believe it or not, the AF errors are far more significant than what the "shoot and recompose" will introduce.

For those who still don't believe, pick up a shallow DoF lens like the 85/1.4 and use MF, doing MF at the centre, and recompose (oh, didn't we do that with MF cameras too for decades??) and then see if "recomposition sucks"!

Well, nonetheless, you're right that the in-focus plane is not a perfectly flat *plane*.

Actually, that's to be *expected*. See the following link:

Why Focus-Recompose Sucks

The author goes too far - most lenses do in fact have a somewhat curved "plane" of focus, not flat as the author assumes. Flat focus planes are one of things that make true macro lenses different from ordinary lenses with a close-focusing feature.

Anyhow, bottom line: any time you change your camera angle, the "plane" of focus changes with you. If you only move a little, or you have a small aperture, it shouldn't matter. But it matters a lot with large apertures and/or if you put the subject all the way to the edge of the frame.

A simple way to test what is going on: first take the picture *without* recomposing. Is it in focus? If so, the camera has done it's job, end of story. If the subject is out of focus after recomposing, you are seeing exactly the effect describe in the above article. It's not the camera's fault - it's just a flaw in the technique itself. Assuming, of course, you are not in AF-C mode or haven't inadvertently triggered a second AF operation after the recompose.

If on the other hand the subject is out of focus even without recomposing, then you may have a FF/BB problem worth investigating.

[Marc Sabatella]

Just believe it or not, the AF errors are far more significant than what the "shoot and recompose" will introduce.

Which AF errors? I was responding to a post that seemed implying the initial focus was fine, and the problem was introduced by recomposing. If that's not the case - his focus problems were there even before the recompsoe - that should be easy enough to test, as I suggested. I'd wager that 99% of the cameras and lenses sold are fine, but of course, we here the complaints from the minority that are not.

For those who still don't believe, pick up a shallow DoF lens like the 85/1.4 and use MF, doing MF at the centre, and recompose (oh, didn't we do that with MF cameras too for decades??) and then see if "recomposition sucks"!

As I said, the author of that article went too far. But I'm surprised that someone who prides himself on measuring things is unable to see the pretty obvious change in focus even with a lens with a much deeper minimum DOF, such as the DA40/2.8.

[jamonation]

Just believe it or not, the AF errors are far more significant than what the "shoot and recompose" will introduce.

For those who still don't believe, pick up a shallow DoF lens like the 85/1.4 and use MF, doing MF at the centre, and recompose (oh, didn't we do that with MF cameras too for decades??) and then see if "recomposition sucks"!

Umm, why recompose when you can just manually focus correctly in the first place? Give me a grand and I'll go pick up an 85mm f1.4 any day though Dunno why I'd want to use AF with it, just my personal preference I guess.

I'd like to see 2 sample images from that 85mm f1.4 -- one with default AF, and one recomposed. That way we can compare the differences between the two. Then I'd like to see the same comparison at f2.8, f4 etc. Then I'd like to see it done with a Nikkor and Nikon 85mm f1.4 too.

[kenyee]

Which AF errors? I was responding to a post that seemed implying the initial focus was fine, and the problem was introduced by recomposing. If that's not the case - his focus problems were there even before the recompsoe

I think it's the issue of the focus points overlapping. As I mentioned above, I've seen pictures from this weekend's wedding where I swear I locked on the people and did focus recompose and the K10D locked on the background...

[Powermarc]

Well, i'm not too professionnal (more of a hobbyhist/prosumer kinda) but i've shot a wedding a couple of weeks ago and i found that a number of shots that i've took seemed to be a tad soft, focus was "ok" but a little off for my taste.

It turned out to be a horrible back focus problem, and i had to reajust the AF from the debug menu and after doing this with my 3 lenses, i got out there and get a couple fo shoots with my wife, and focus was now dead on. (shooting at F1.4 tells you that focus have to be perfect) However, i have to agree that sometimes AF hunts a lot (normal if you are using a 18-250 lens at max zoom with an aperture fo 6.3, but even with a 50mm F1.4 it's sometimes picky about focus). In order to eases that, i try to AF the scene, and see if MF would improve the focus. MF can be a lifesaver sometimes, in some cases if a flash, spot beam, flashlight or any kind of assistive lights are not welcomed or required, MF is the way to go.

But hey, i prefer to keep those 3K$ to buy a K20 and some good glass, and keep doing a small amount of MF 2% of the time, than buying a D700 without any money to spare for glass.

[Marilith]

Well, i'm not too professionnal (more of a hobbyhist/prosumer kinda) but i've shot a wedding a couple of weeks ago and i found that a number of shots that i've took seemed to be a tad soft, focus was "ok" but a little off for my taste.

It turned out to be a horrible back focus problem, and i had to reajust the AF from the debug menu and after doing this with my 3 lenses, i got out there and get a couple fo shoots with my wife, and focus was now dead on. (shooting at F1.4 tells you that focus have to be perfect) However, i have to agree that sometimes AF hunts a lot (normal if you are using a 18-250 lens at max zoom with an aperture fo 6.3, but even with a 50mm F1.4 it's sometimes picky about focus). In order to eases that, i try to AF the scene, and see if MF would improve the focus. MF can be a lifesaver sometimes, in some cases if a flash, spot beam, flashlight or any kind of assistive lights are not welcomed or required, MF is the way to go.

But hey, i prefer to keep those 3K$ to buy a K20 and some good glass, and keep doing a small amount of MF 2% of the time, than buying a D700 without any money to spare for glass.

Debug menu?
Which Model do you have?

[paulusta]

instead of focus-recompose,
why not using the SEL and choose which focusing area for AF?