Pentax's Well Intentioned SR and AF Flaws

Started Jul 9, 2014 | Discussions thread
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MightyMike Forum Pro • Posts: 37,179
Pentax's Well Intentioned SR and AF Flaws

So recently my K-3 had its first airshow and i was mighty disappointed in its performance, after going through the 1472 photos i took i had deleted 681 off the top before picking through and choosing the photos worthy of going in a gallery.

Now when shooting at an airshow with a fast jet you typically want a fast shutter speed, so i shot at 1/2000th to 1/8000th sec. but that isn't good enough, you also should pan with the plane. Panning with the plane is where the problem occurs, where on previous models and thousands of photos i could pan at high shutter speeds with SR on no problem I cannot for the life of me do it with the K-3. Someone at Pentax came up with what on the surface sounds like a brilliant idea, turn SR off during panning, this will help avoid blur errors int he direction of the pan but does not help stop blur errors perpendicular to the direction of the pan. To further cause problems now the SR is in a constant state in between spooling up and turning off as the panning may be irregular and therefore never actually working instead rather ruining the photos. So large quantities of my photos at very fast shutter speeds came out as double imaged and blurry as though i was shaking the camera excessively. This shouldn't happen even at 1050mm equiv. and 1/2000th sec where i have double the recommended shutter speed.

To prove this was the case I turned SR off completely and shot sports at 1/4000th sec and had not 1 double image error nor 1 blur error that wasn't an AF or photographers fault.

I say there needs to be a user option to turn the panning SR auto-off off, otherwise its a big fail

One more example from the airshow, when shooting a prop you want prop blur, therefore a slow shutter speed and panning, as soon as you pan the SR turns off and now that slow shutter speed is causing all sorts of shake blur, I used to get great shots this way with the SR still on but they've arbitrarily taken that out of the control of the user.

Now for the AF, That hold AF function is a great idea but also a double edged sword, at the airshow and the sports event i had it set to medium. I used to complain that the AF would jump in and out of focus at a whim and instantaneously. I thought the hold AF would help there and sure enough it does kind of. You see when in AF-C and bursting and using Expanded Area AF if you don't obtain a good AF lock before you start bursting the whole sequence can be out of focus, if the first shot was just slightly front focused the whole series will likely stay just slightly front focused and many times this is hard to see in the VF. We all know or all should know that the focus priority in AF-C option doesn't work and has never really worked so this hold AF feature though well intentioned and a good idea can also fail significantly for us by working perfectly.

The final problem is with the EA AF, in the sports event there were sequences where the focus didn't seem to move, the player i was trained on would go from in focus to out of focus through the burst sequence. the grass would stay in focus... my guess is despite the center area being so small the camera would lock onto the grass rather than the player and hold focus on the grass. perhaps a little sloppy on my part but also not what the camera should be doing and hard to notice in a fast paced environment.

I will try without the expanded area on the next sports event and maybe set the hold AF to low or off

Ricoh/Pentax give us back full control over SR and a proper more advanced AF algorithm that will track focus and not track slightly out of focus, also a focus system that tracks what moving rather than whats standing still.

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Mike from Canada
"I am not a great photographer! God is a great creator! All I do is capture His creation with the tools He has provided me."
'I like to think so far outside the box that it would require a telephoto lens just to see the box!' ~ 'My Quote :)'

Pentax K-3
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