[Cannikin]

In using this lens handheld, I have come across a minor annoying issue: accidentally pressing the AF buttons.

I have fairly small hands, and when gripping the zoom ring it places the heel of my hand directly on the bottom AF button. The sheer weight of the lens means it's very easy to press the button by accident. I've resorted to holding the tripod foot, which actually works pretty well as far as balance, but that makes it a bit awkward to zoom.

I wish there was a mode to deactivate the buttons entirely.

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Last edited by Cannikin; 07-17-2015 at 03:04 AM.

[Glorfindelrb]

There is one, don't update your firmware or use a K5II

[Zygonyx]

if you don't press "AF preset" at any time, or if you put the preset switch on "cancel", you have no consequence when pressing the 4 buttons.

[Mike.P®]

That's great to read ! Have you the DA* 300 ?

Indeed I do ... although I doubt I will have it much longer.

[jpzk]

Indeed I do ... although I doubt I will have it much longer.

Better think twice (at least) before selling your DA*300/4 ! ... just in case.

[Cannikin]

if you don't press "AF preset" at any time, or if you put the preset switch on "cancel", you have no consequence when pressing the 4 buttons.

In "AF Cancel" mode, pressing the buttons puts the camera into Manual Focus mode (it even says "MF" in the viewfinder), interrupting any ongoing AF operations and disabling AF from the buttons on the camera.

[Zygonyx]

Yep, the lever should'nt be left there, just go on "cancel" and back to the green "AF" position - just checked now at home .

[Cannikin]

Yep, the lever should'nt be left there, just go on "cancel" and back to the green "AF" position - just checked now at home .

I'm sorry, but I'm not seeing what you're getting at. Putting it on "AF Cancel", pressing a button and putting it back to "AF" while holding the button will immediately start to AF again. Put the lens cap on to force it to hunt and you will see.

Even if it worked like I think you're suggesting, that's not a solution either, as that would require the button to be constantly held down, which is not what happens. Rather the button gets pressed multiple times as a result of maneuvering the lens. And never setting an AF preset is ridiculous non-solution, sacrificing one of the most useful features, not to mention far too late.

It's a design oversight, plain and simple. I'll just keep holding the tripod foot, deal with the awkward zooming, and hope they implement a firmware with a menu option to disable the buttons from the camera.

[RockvilleBob]

I would be interested in how the HD PENTAX-D FA 150-450mm F4.5-5.6ED DC AW compares to the Sigma 150-500 zoom. Does anyone have both of these?

[Zygonyx]

@ Cannikin : i'll try to explain how it works for me with more details :

1- If you do not preset any AF position with your lens, i.e. keep (or place) the switch on the green "AF" position from the start, the result is : no action when touching one of the 4 "back to preset value" buttons ;

2- in case you did first select any "AF preset" in focussing + memorising the focus with the dedicated rugged button : when you switch to "AF cancel", the preset position is deleted from the memory. So if you now push the switch directly to the green AF position without touching anything else, you keep the lens like if it were any other DA zoom (let appart the AF range limiter and quick-shift lever)

So : what's the problem ? Making anything else would just complexify the use of this lens.

[Cannikin]

@ Cannikin : i'll try to explain how it works for me with more details :

1- If you do not preset any AF position with your lens, i.e. keep (or place) the switch on the green "AF" position from the start, the result is : no action when touching one of the 4 "back to preset value" buttons ;

2- in case you did first select any "AF preset" in focussing + memorising the focus with the dedicated rugged button : when you switch to "AF cancel", the preset position is deleted from the memory. So if you now push the switch directly to the green AF position without touching anything else, you keep the lens like if it were any other DA zoom (let appart the AF range limiter and quick-shift lever)

So : what's the problem ? Making anything else would just complexify the use of this lens.

Selecting "AF cancel" most definitely does not erase the AF preset. Have you set yours the first time (put it in AF Preset mode, hold the preset button for several seconds)? There is no way to erase the AF preset, only set it to something else, and yes I have reviewed the manual (not that that would be a solution either, as I have an important saved preset for a specific purpose).

The three AF modes always do the same things no matter what order you do them in. The green AF mode makes the buttons AF. AF Cancel makes the buttons set the camera temporarily to MF mode. The AF Preset mode always goes to the AF preset. There is absolutely no way to make the AF buttons do nothing once the AF preset is set the first time (besides setting it to MF obviously).

[Nakedgun]

Does Pentax beta-test anything before releasing it to the general public?

[rawr]

What does the lens manual say about the operation of the buttons?

[Cannikin]

I've come up with a DIY solution to the issue. I taped a piece of corrugated cardboard over the bottom button. It's stiff enough that it requires a lot more pressure to press the button. It should prevent most accidental presses. A bit crude, but it seems to work ok.

Still, it could be easily fixed entirely with just some firmware to allow disabling the AF buttons from the camera menus. What's a good way to get feedback to Pentax engineers?

What does the lens manual say about the operation of the buttons?

[zantaphia]

Who said that Medium format is bulky? ;-)

K-3, RC1.4, DFA150-450.

vs.

645D, FA400/5.6