Why do we need more AF points?


Snappyhoffy

Link Posted 29/09/2019 - 20:04
I am generally confused about the need for more AF points as rumoured for the newly announcements K Flagship.

Before I a) sell my DA* lenses or b) start syphoning off funds into that hidden PayPal account (to purchase said ‘flagship’). I could do with understanding more about the benefits.

I would genuinely like to be informed on the likely benefits. Is it likely to speed up focus capability of the DA* range and / or improve reliability of focussing over use of Live View focusing?

So far i do like what I see of the ‘physical’ appearance of the new model but need to boost up the ‘justification’ over my existing (lovely) K3.
'Life looks simple through a viewfinder'.....then I went Digital!
Keith
K3, DA* 16-50, DA* 50-135, DA* 300, AF360

pschlute

Link Posted 29/09/2019 - 20:38
First thing I do with a new camera is to change the AF points setting to central 9.

i want to be in charge of focussing, not allow the camera to use a blunderbuss approach.

Us the new camera with modern lenses and it will be lightening fast to achieve focus and track it. You have some quality lenses in your kit list, but they wont be the fastest at AF
Peter



My Flickr page
Last Edited by pschlute on 29/09/2019 - 20:40

richandfleur

Link Posted 29/09/2019 - 21:41
My take on this is I'm usually in single centre point single focus.

As I understand it, people use the AF selection to achieve the same thing, but where the object of interest is not in the middle. I guess an example would be where you are tripod mounted, and the object you want to focus on is off to the side. There is a technical reason why focus and recompose might not be suitable, with a difference in how that point is focused out the side of the lens vs straight through the middle. I must say I've never done this, but I think that's the idea.

On other systems though, the more focus points is for tracking AF. This allows you to select/mark the object you want to track, and then the camera is equipped with more points to accurately keep the object in focus, even if it drifts outside of the centre of the frame. Unless Pentax gets better at tracking objects, I don't really see the need for more AF points?

When I have to shoot action with my Pentax K-3, I've gone through a lot of trials and found a setup that works for me. I'm not near my camera now, but from memory there are a few key settings which weren't on the lower tier models like the K-30 I had previously. I have AF-C enabled, and then the option to first select the object via the centre point selection, which the camera will then continuously track around the expanded 9 areas around it. This is quite different to straight auto 9 segment, as with that you don't get to nominate the object you are interested in first. Sometime 25 if I'm feeling brave and think the camera will be able to achieve this.

There is also a setting called AF hold, which determines how long the camera will wait before trying to refocus. This is useful for birds going behind twigs etc, but not so good for objects coming to wards you, as the camera will wait before trying to follow it again.

Pentax is really bad at suggesting when to use these various settings. They're all detailed in the manual, but buried on different menus, and there's no overarching guide that points you to the best combo. Difference between a technical manual and a user guide I guess. However, I found a massive improvement when I finally got the combinations right.

That added with the ability to control the auto calculations, such as favouring speed vs low ISO in AV mode, made a huge difference for me. That's the real benefit of the higher spec models personally, as often the hardware components (sensors etc) are the same or similar between model ranges. The added control options allow you to get things just right, and often that's the bit that's missing from basic reviews, where the reviewer hasn't had any time to really get to know the product in detail.

richandfleur

Link Posted 29/09/2019 - 21:45
Snappyhoffy wrote:


So far i do like what I see of the ‘physical’ appearance of the new model but need to boost up the ‘justification’ over my existing (lovely) K3.

Yep, agreed. The new model looks fine (not a fan of that weirdly placed/after thought type mode dial, but that's a minor personal taste thing).
Honestly there's not much to write about from the model displayed, other than it doesn't appear to have a fold out screen and has a joystick.

Like you, the real info I'm interested in is the capabilities. Tracking AF and Video are Pentax's weaknesses, so I'd like to see what happens in these areas, again to justify the upgrade. The inclusion of a joystick control does suggest some AF improvement, so I'd also like to know what that meant for me and my existing range of lenses.

Side note but that Pentax PLM 55-300mm zoom focusing appears lightning fast in videos I've seen.

Daronl

Link Posted 29/09/2019 - 21:59
richandfluer
Quote:
Side note but that Pentax PLM 55-300mm zoom focusing appears lightning fast in videos I've seen.

The PLM 55-300 is indeed the quickest Pentax I have ever owned but cameras buffering is the issue I would hope has been addressed with the new model; it is the biggest inhibitor of continuous shooting /tracking action whether it be BIF or sports, particularly motorsports.
Daronl

richandfleur

Link Posted 29/09/2019 - 23:10
Daronl wrote:
richandfluer
Quote:
Side note but that Pentax PLM 55-300mm zoom focusing appears lightning fast in videos I've seen.

The PLM 55-300 is indeed the quickest Pentax I have ever owned but cameras buffering is the issue I would hope has been addressed with the new model; it is the biggest inhibitor of continuous shooting /tracking action whether it be BIF or sports, particularly motorsports.

What camera body do you use?

The K-3 has a pretty massive buffer, and this clears fairly quickly when used with fast SD Cards?

Jonathan-Mac

Link Posted 30/09/2019 - 09:07
I've never had a problem with my K-3 clearing the buffer as long as I use it with a fast card.

Regarding more AF points, I generally use central point, focus and re-compose. When on a tripod (usually taking family pics while on holiday) I do change the AF point to make sure it's on us, and here it could be handy to have more, but I can always switch it to live-view and place the focus wherever I want it, so not really essential.

I think it's just part of the "more more more" approach that manufacturers would have us believe is necessary to get better photos.
Pentax hybrid user - Digital K3 & K200D, film 645 and 35mm SLR and Pentax (&other) lenses adapted to Fuji X digital
Fan of DA limited and old manual lenses

alfpics

Link Posted 30/09/2019 - 09:26
I guess more AF points might (also) be better if they cover more area in the viewfinder rather than just being more densely packed. I have on occasion wished that the selected AF point were able to be nearer to the edge of the viewfinder.
Andy

Mike-P

Link Posted 30/09/2019 - 13:00
The K-1 buffer is abysmal, not quite so bad when using it in crop mode.

The main problem with the Pentax AF points is that they are too large and so when you focus on a subject and there is something behind it the camera has a hard time deciding which it should be focusing on and so starts to hunt. Smaller points (and therefore more of them) should help a lot.

From the preview of the new camera it seems there is no tilt screen which limits the usefulness of it being touch sensitive I would have thought. Hopefully the AF tracking will be able to keep up with the DPR cycle coming at it head on though.
No equipment list here but thanks for taking an interest. My Flickr

Nigelk

Link Posted 30/09/2019 - 14:27
It is probably widely know but, just in case. Below is a link on how to and reasons to adjust AF points and size. I have a much simpler version on my K-S2 but it does make a difference.


http://www.ricoh-imaging.co.jp/english/photo-life/technic/001/

Cheers
Nigel
Last Edited by Nigelk on 30/09/2019 - 14:28

Don

Link Posted 30/09/2019 - 14:57
My Sony a7iii and Sony hdr-nx80 both share the most advanced af systems I’ve ever used.
The wide area af with tones af points allow the cameras to track objects, pick out subjects and nail focus in situations where the k3 falls on its face.
As a long time pro, who preferred manual focus and back button spot af, I can telll you 100% my camcorder and mirrorless on full af can outperform the k3, and me.
Anywhere, any time and under any conditions.

Having admitted that...
The k3 is still every bit the great camera it always was...
An upgraded af system that brings up to. The same league as the class leaders wouldn’t hurt anything but your pride if you find yourself using full auto more than you’d have ever believed possible in the past.
Fired many shots. Didn't kill anything.

johnriley

Link Posted 30/09/2019 - 15:03
Quote:
when you focus on a subject and there is something behind it the camera has a hard time deciding which it should be focusing on

Ironically, this is where I have found my K-1 excels, using centre point focus only. A typical example would be a strand of tall grass in front of a background of distant trees. The K-1 nails it every time, whereas several mirrorless cameras have been flatly unable to focus at all. The same applies to, say, a small bird within a mass of branches. Not an easy subject, but the K-1 is fully capable where many others fail.
Best regards, John

Mike-P

Link Posted 30/09/2019 - 15:51
Quote:
Ironically, this is where I have found my K-1 excels, using centre point focus only. A typical example would be a strand of tall grass in front of a background of distant trees. The K-1 nails it every time, whereas several mirrorless cameras have been flatly unable to focus at all. The same applies to, say, a small bird within a mass of branches. Not an easy subject, but the K-1 is fully capable where many others fail.

I wouldn't expect anything less from you John yet for me my D500 does it so much better than the K-1. Then again maybe it's because the blade of grass and the litle bird in the tree aren't moving so the AF has very little to do.
No equipment list here but thanks for taking an interest. My Flickr

johnriley

Link Posted 30/09/2019 - 16:39
I'm not able to comment on that Mike as I've never tried the D500.

But I do think we're talking here about precision rather than ability to track. Two different styles, two different requirements.
Best regards, John

Daronl

Link Posted 01/10/2019 - 22:48
richandfleur wrote:
Daronl wrote:
richandfluer
Quote:
Side note but that Pentax PLM 55-300mm zoom focusing appears lightning fast in videos I've seen.

The PLM 55-300 is indeed the quickest Pentax I have ever owned but cameras buffering is the issue I would hope has been addressed with the new model; it is the biggest inhibitor of continuous shooting /tracking action whether it be BIF or sports, particularly motorsports.

The K3 II IS LESS PROBLEMATICAL THAN THE K3 ; yhe fact is that the buffer gets overloaded in continuous shooting; the K3II is “ok” in jpeg but K3 is a little less capable. like the K1 shooting raw in continuous mode is a no-no.

The Nikon D500 never stops in continuous shooting mode .

I only use pro cards and it makes only a marginal difference to the problem; it seems it is the lack of capability in the camera to write the image data quick enough ( I think?)

Ad I said the K3 II IS “ok” but a day on Skomer shooting Puffins in flight shows up this issue vividly. The camera can’t keep up and overloads in ten- 15 seconds even in jpeg mode.

What camera body do you use?

The K-3 has a pretty massive buffer, and this clears fairly quickly when used with fast SD Cards?


Daronl
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