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06-18-2021, 07:56 PM   #1
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K3-3 AF questions

I've just unboxed and set up my K3-3.

Notwithstanding the similarities to previous Pentax DSLRs, it's going to be a steep learning curve!

My questions for the moment centre around focusing:

In the past I only ever used the centre focus point. Now with the improvements in AF I want to try let the camera do some of the thinking, however it's just not working for me...

Firstly, if say I have two objects in front of me: the camera randomly decides what to focus on and more often than not focuses on the wrong object. How to I optimise the AF set-up?

Secondly, if I want to say track my cat walking towards me - it seems I have to switch from AFS to AFC - by which time the moment has passed.

I know it's early in my experience with the new camera but I'm getting quite frustrated and the manual is not particularly helpful.
Suggestions?


Last edited by Spock; 06-18-2021 at 08:21 PM.
06-18-2021, 08:20 PM - 1 Like   #2
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QuoteOriginally posted by Spock Quote
I've just unboxed and set up my K3-3.

Notwithstanding the similarities to previous Pentax DSLRs, it's going to be a steep learning curve!

My questions for the moment centre around focusing:

In the past I only ever used the centre focus point. Now with the improvements in AF I want to try let the camera do some of the thinking, however it's just not working for me...

Firstly, if say I have two objects in front of me, the camera randomly decides what to focus on and more often than not focuses on the wrong objects. How to I optimise the AF set-up?

Set up several user modes to switch quickly from AF-S to AF-C practice a bunch it will come naturally soon and you will start appreciating this great camera!

Secondly, if I want to say track my cat walking towards me, it seems I have to switch from AFS to AFC by which time the moment has passed.

I know it's early in my experience with the new camera but I'm getting quite frustrated and the manual is not particularly helpful.
Suggestions?
You are dealing with a whole new animal from Pentax with the Mk III especially Continuous A/F and autofocus areas. The A/f is hard to screw up. Try each auto focus area to get familiar with each one Expanded Area S, M and Large. Start out learning the Expanded AF Area Large as this area works hand in hand with Continuous A/F and tracks really well. Don't be afraid to work in TAV mode and let the ISO float just dial in a reasonable Aperture setting and depending on the speed of your subject set your shutter speed higher than you normally would with say a K-3 Mk I or a KP. Today I shot a couple of series of a guy riding a road bike with my 55-300 PLM and of forty to fifty or so Continuous A/F images not a single one was out of focus. Also don't worry about the little squares not being on the target sometimes the camera usually always stays locked in.

As for multiple subjects in the frame place the center + on the subject you want to track and use one of the red colored expanded Area AF selections. Experiment with the three different area sizes.

Last edited by Larrymc; 06-18-2021 at 08:28 PM.
06-18-2021, 08:48 PM   #3
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So should I bother with AFS? The K3-3 doesn't appear to have an AFA option like my original K3.

Btw- those autofocus squares are as near as dammit invisible against anything other than a light background.

And what is the point of the red flash of light in the viewfinder? If it's focus confirmation then all it's doing is duplicating the role of the green hexagon.
06-18-2021, 11:52 PM - 1 Like   #4
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For quick switching between AFS and C use the SFn wheel. Set SFn for AF type as default and then if you need you can just change AF type and fields as you need in a moment.

Just spent some time to learn how each AF works like and configure available options as you like and need.

There is some learning curve about configuration of camera, but once you set it up completely it is very easy and intuitive to switch settings to what you need.

06-19-2021, 01:34 AM - 1 Like   #5
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User modes are also a huge help for switching between shooting scenarios quickly. You can have a dedicated user mode for action with AF-C and the AF mode of your choice by default, so when your cat walks towards you, you can quickly switch to it.
The sFn wheel is also very helpful.

The full auto AF mode is very good for me for birds in flight against a uniform background like the sky. It will pick up even the smallest and fastest birds.

When the subject is less clear, the auto 21 can be good, or the expand area options if I expect the subject to move a lot in the frame. You have to be more precise in your initial focus with those, but after that, it tracks pretty well.
You just have to be sure to have focused on your subject and not the background just behind for instance. If the subject is small that can be tricky and the Auto 21 might do a better job as it uses subject recognition.
06-19-2021, 02:00 AM - 2 Likes   #6
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Easy to change between AF-S and AF-C: Press the AF mode button and turn the front wheel....
06-19-2021, 03:02 AM   #7
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QuoteOriginally posted by Pål Jensen Quote
Easy to change between AF-S and AF-C: Press the AF mode button and turn the front wheel....
Thanks. This certainly seems the most efficient way.

Regarding AF settings, I can't see any benefit in using multi-AF points for AFS. For static subjects it seems easiest to use the centre point and recompose as needed. Otherwise, for moving subjects it would be quick and easy to use the above method to switch to AFC.

Or am I missing something? I've never really understood how to use focus points for action shots.

06-19-2021, 05:47 AM - 1 Like   #8
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QuoteOriginally posted by Spock Quote
Thanks. This certainly seems the most efficient way.

Regarding AF settings, I can't see any benefit in using multi-AF points for AFS. For static subjects it seems easiest to use the centre point and recompose as needed. Otherwise, for moving subjects it would be quick and easy to use the above method to switch to AFC.

Or am I missing something? I've never really understood how to use focus points for action shots.
For AF.S, you seem to be missing the existence of the joystick. Center point is totally inferior to the one that lets you use the joystick to select a point and four surrounding it. With that, you pretty much don’t have to recompose, unless you need to focus on something you want at the extreme edge of the frame. (Pushing in on the joystick centers the selected focus point, which can speed up moving the focus point a long way or just be a good way to ensure you’re starting from a neutral position.)
06-19-2021, 06:06 AM - 1 Like   #9
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QuoteOriginally posted by Pål Jensen Quote
Easy to change between AF-S and AF-C: Press the AF mode button and turn the front wheel....
Precisely with the A/F mode button it's much easier than trying to remember what the cryptic SFn/(num) means. The A/F mode button is just as easy to access as the S.Fn button is.
06-19-2021, 06:12 AM   #10
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QuoteOriginally posted by Larrymc Quote
Precisely with the A/F mode button it's much easier than trying to remember what the cryptic SFn/(num) means. The A/F mode button is just as easy to access as the S.Fn button is.
Where are you looking that you’re trying to remember what SFn/(num) means? I vaguely noticed this somewhere when I first got the camera, but now it never enters my view as I use the smart function system. As you turn the rear e-dial with the S.Fn button depressed, you can see in the OVF which smart function is selected. Depending on what smart function you settle into, you usually can see the effect of turning the smart function dial in the OVF.
06-19-2021, 06:19 AM - 1 Like   #11
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QuoteOriginally posted by Spock Quote
Thanks. This certainly seems the most efficient way.

Regarding AF settings, I can't see any benefit in using multi-AF points for AFS. For static subjects it seems easiest to use the centre point and recompose as needed. Otherwise, for moving subjects it would be quick and easy to use the above method to switch to AFC.

Or am I missing something? I've never really understood how to use focus points for action shots.
With A/Fs there is no selectable A/F areas (red boxes) involved just the white Auto Area boxes and as @mtkeller has stated you can use the joystick in lieu of focus and recompose for static subjects. For potentially non stationary subjects use A/Fc with the red boxes.
06-19-2021, 06:49 AM - 1 Like   #12
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QuoteOriginally posted by mtkeller Quote
Where are you looking that you’re trying to remember what SFn/(num) means? I vaguely noticed this somewhere when I first got the camera, but now it never enters my view as I use the smart function system. As you turn the rear e-dial with the S.Fn button depressed, you can see in the OVF which smart function is selected. Depending on what smart function you settle into, you usually can see the effect of turning the smart function dial in the OVF.
SFn/(Num) shows up in the lower right of the viewfinder. The reason I use the A/F mode button is that it allows me to add another smart function that otherwise could not be used because the A/F area selections occupies that selection. I also have SR as a smart function along with Drive Mode.
06-19-2021, 07:01 AM   #13
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QuoteOriginally posted by Larrymc Quote
SFn/(Num) shows up in the lower right of the viewfinder. The reason I use the A/F mode button is that it allows me to add another smart function that otherwise could not be used because the A/F area selections occupies that selection. I also have SR as a smart function along with Drive Mode.
I guess the icons are much more prominent to me and don’t require me to think about the SFn/(num) part. I prefer to have AF as a smart function because I can put in combinations that adjust the active AF area and AF hold setting and can make those adjustments without taking my eye from the OVF. Changing the active AF area by holding the AF mode button and rotating the rear e-dial in my case requires me to look at the rear display to see what has been selected. I have no problem just using the SR button to cycle through the SR options so don’t need a need for it as a smart function. (To be clear, these are just my preferences and I’m sharing them so that those who are figuring out how to set up their smart functions have different perspectives to consider. Different configurations are right for different folks.) Drive mode is a great use of smart function…especially when you limit what is selectable in the smart function with different user modes. I have one with drive modes that focus on tripod-based shooting and another one with drive modes for action shooting.
06-19-2021, 10:56 AM - 2 Likes   #14
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QuoteOriginally posted by mtkeller Quote
Center point is totally inferior to the one that lets you use the joystick to select a point and four surrounding it.
Different purposes. The center has the higher sensitivity (f/2.8) AF points. Clarification: Higher sensitivity to detect OOF with fast aperture lenses.


Steve

Last edited by stevebrot; 06-19-2021 at 02:23 PM. Reason: Clarification
06-19-2021, 01:32 PM - 1 Like   #15
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QuoteOriginally posted by stevebrot Quote
Different purposes. The center has the higher sensitivity (f/2.8) AF points.
And so if the points you want to use that don’t require you to recompose are struggling to lock focus because of low light, you can tap the joystick to go back to the center points, use them to focus, and recompose. No need to actually use the center point AF mode.
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