[ReneFisherPhoto]

Greetings Pentaxians... like most people I occasionally miss focus. I'm assuming most of the time it's due to movement/camera shake, but I just wanted to clear things up and/or get tips on preventing this from happening, as I, like most, love tack sharp images.
I have two examples, both shot within seconds of each other (same lighting, essentially the same settings) but one was in focus, and the other was not. Obviously I've had countless other similar cases but these were just two I picked out that were somewhat slow moving subjects shot with fast shutter speed.
Both were taken on my K3II camera, with my 300DA* lens, but the owl had a 1.4x TC as well.



(SOOC so try and overlook the slight under exposure)

You can note the settings at the top, but both had what I think were pretty fast shutter speeds, but both were taken handheld. I always use back button spot focus on the center focus point, T/av mode, with exposure bracketing (3 shots) and neither subjects were moving exceptionally fast. Any theory as to why one is sharp and the other is not?

Is it simply not a fast enough shutter speed for camera shake? Any tips on trying to prevent this from happening, or advice on how you are able to get tack sharp wildlife shots? Obviously I've gotten nice sharp pictures as well, it just seems kinda random sometimes what turns out to be sharp and what doesn't.

I should note that my lens unfortunately suffered a small scratch just a small distace from center of the lens. I didnt think it affected the lens in any way, but could this be why I'm sometimes missing focus? I am assuming this isnt something that can be easily repaired, but would moving my focusing point away from center help a bit?

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Last edited by ReneFisherPhoto; 02-24-2020 at 11:09 AM.

[hjortron]

No lens is totally free from mis-focusing and auto focus can get confused. My best strategy is taking multiple shots while focusing on different objects.

[biz-engineer]

Both were taken on my K3II camera, with my 300DA* lens, but the owl had a 1.4x TC as well.

I had the K3 TC1.4x and DA*300, optically sharp when in perfect focus but the autofocus wasn't consistent. I sold the DA*300, replaced it by the DFA150-450 which is very consistent on autofocus and a little less sharp then the DA*300 prime, when both lenses are at f/5.6. The DFA150-450 has some kind of step motor for focusing, this is how the focus positition can be memoried by the lens and refocus at the exact same place everytime, the DA*300 is an older design doesn't have such motor and control electronics. That said, the photos shown here are heavily cropped, so even if the focus was perfect the detail on the subject is still not great, being closer to subject would greatly improve the image even if the focus isn't perfect.

[pschlute]

Any theory as to why one is sharp and the other is not?

Your shutter speed is fast enough to prevent camera movement blur and to freeze the action, as long as you are not moving backwards/forwards between focus lock and capture. You use BBF but is that with AF-C or AF-S ? It is entirely possible that the single AF point is not centred on a sufficiently high contrast area to get perfect focus each time. I would experiment with 9 point AF and see if that helps.

Also the f4 of the lens, and slower when mixed with a TC is not optimal for the AF sensor especially if lighting conditions and subject contrast may be an issue.

How many shots do you see misfocussed like this ?

[telum]

depending on how close those subjects were the DOF can be extremely shallow with 420mm F1/5.6, but I assume they are quite heavily cropped?

[Apet-Sure]

Did you have the SR system on? Something I've wondered about, and perhaps others can comment on, is the advisability of having SR on when using sufficiently fast shutter speeds. I usually turn it off if the shutter speed is at least as fast as the reciprocal of focal length. If you don't need it on, it may do more harm than good to have it on. Such is the case when using a tripod.

Have you tried using the catch-in-focus method of triggering the shutter? The shutter will fire the instant the camera detects an in-focus condition. With the very shallow DOF of long telephoto lenses at moderate apertures this method can help when shooting hand-held. I'm not a drinker, but I can tend to weave back and forth a bit unless I'm leaning against something solid. Check out this DOF calculator A Flexible Depth of Field Calculator Set the crop factor (CF) to 1.5 for Pentax APS-C cameras like the K3II. This particular calculator doesn't do half-stop aperture settings like f/6.3, but you can use f/5.6 or f/8 and compare the results.

Have you checked this lens for back focus or front focus problems?

[telum]

Another DOF calculator with some nice illustrations: DOF simulator - Camera depth of field calculator with visual background blur and bokeh simulation.

[FozzFoster]

Wouldn't be awesome if the hybrid viewfinder is a real thing on the new APS-C flagship?
Imagine having focus peaking available in the viewfinder!

[normhead]

What I'm noting is that both images are back lit.

When your subject is back lit, in the way they are, you get softness because of ambient light. Light is being reflected from many sources at many angles. You can probably solve the issues in the shots you've posted, especially the dog with a bit of fill light. The serious birders where I live have very powerful flashes mounted to the tops of their lenses with telephoto attachments.

If you don't have good light on the subject there's nothing you can do. You don't have bright enough light to create contrast and contrast does more to create photographic Sharpness than anything else. When you are back lit, you need to over-expose not under-expose. You probably missed by 1.5-3 stops.

I'm not seeing a problem other than that.

From yesterday....


K-3 and DA 55-300 PLM at 150mm
ƒ5.6, ISO 200, 1/2000s

There were 6 shots in this sequence, I threw 5 away, they were reasonably identical. IN other sequences I was able to pick out the best image and toss those not as sharp. I always shoot 3-6 shot bursts, when shooting moving critters or critters that might move, but depending on circumstances as much a 23 shots filling the buffer.

Also notice where the shadow is. It's on an angle to the bird's leg. That kind of lighting offset also creates more contrast, by creating a small shadow outlining the feather detail. So also important is the angle the light is hitting the subject. Head on is usually not the best. The owl is tough of course. It is where it is.

I'm advising ignoring everything else said so far and concentrate on better light for a bit. Pentax's are very good with stationary objects shooting from a tripod. IN body SR requires a little more tolerance for missed images than SR in the lens, you really have to keep the camera stable just to achieve focus. The in lens SR makes focussing easier. But, I compensate by taking 3-6 image. One of them will be good.

If you have good crisp light and are still missing shots, we'll talk further.

P.S. Also make sure you are set to focus priority, not shutter priority. On that first shot of the owl, your shutter shouldn't have fired.

[lesmore49]

My key for animals, people, etc...is to try to focus on the eye. I've found for me, if I get the eye in focus, usually everything about the subject looks ok too. I picked this up a number of years ago from a buddy who is a wonderful wildlife photographer. I'm not at his level, but his hint has helped me.

[DaveSimo]

I had the K3 TC1.4x and DA*300, optically sharp when in perfect focus but the autofocus wasn't consistent. I sold the DA*300, replaced it by the DFA150-450 which is very consistent on autofocus and a little less sharp then the DA*300 prime, when both lenses are at f/5.6. The DFA150-450 has some kind of step motor for focusing, this is how the focus positition can be memoried by the lens and refocus at the exact same place everytime, the DA*300 is an older design doesn't have such motor and control electronics. That said, the photos shown here are heavily cropped, so even if the focus was perfect the detail on the subject is still not great, being closer to subject would greatly improve the image even if the focus isn't perfect.

I would just like to second the DFA 150-450. I'm just astounded by the autofocus and tracking on this monster. These shots were taken handheld and I'm a terrible photographer to say the least

[ReneFisherPhoto]

Thanks for all the feedback everyone! Forgot to mention that they were both 1:1 100% crops. Not as noticeable without pixel peeping but I do like to make print occasionally if its an amazing shot so it is slightly important. I havent gotten around to checking front/back focus, but I definitely should I just need to make myself a makeshift setup to do so still. I appreciate the reminder to do so though. lol

Ill answer a few individually.

@biz-engineer
I'd say that accurately describes what happens... If I am sitting in one spot and shooting a still-ish bird or something from afar, I find constantly refocusing gives mixed results (i can hear/see the focus change despite not really moving). unfortunately probably not in the market for a lens any time soon, especially since my dumb mistake of scratching my own lens kinda ruins its trade-in/sell value.

@pschlute

I'd say I usually get more shots than I miss, but I'm a perfectionist and occasionally I the one I "missed" is the one where the animal is looking at me. lol But that's wildlife photography! Just looking for tips to see if I'm missing anything. I almost always use AF-S unless its a raptor or small bird im trying to catch in flight. I may try experimenting with 9 point AF, but with birds especially, that gets tricky when its a bird surrounded by branches and AF doesnt know what to settle on.

@Apet-Sure

I could try experimenting with SR off in extra high shutter speeds, thanks for the idea! Ive done a bit of Catch in focus stuff, but it's a bit tough if you're shooting birds or wildlife and there's foliage in the way... I've grown up in the digital age so unfortunately my manual focusing abilities/speed are not reasonable enough to feel comfortable with leaving it on all the time. Worth a try practicing to get better at it though!


@normhead

Thanks for the feedback, and beautiful Grey Jay! Im actually headed to Algonquin tomorrow, hoping to see some of those guys and Pine martens.
I'd say in ideal light situations I have less of a problem, its more of a backlit/heavy overcast issue, so that definitely makes sense. Unfortunately you cant always change the angle much due to obstacles and the animals don't always cooperate(the other picture was actually of an arctic fox in captivity, so I was limited as far as where I could stand), was just wondering if there is a secret to shooting in sub-optimal lighting, but I suppose that's reaching a bit of the gear's limitation without flash. I almost always shoot in either high speed continuous shots or 3-6 bracketed exposure images if lighting is changing often or I can't be bothered to check on my settings often. I appreciate the tips though, Ill have to double check and see if Im on focus priority, I know I fiddled with that setting a while back and cant recall if I changed it back.
Thanks!

[rogerstg]

Any tips on trying to prevent this from happening, or advice on how you are able to get tack sharp wildlife shots?

It could be something as basic as how you press the shutter; stabbing at it vs rolling your fingertip for example. Like some others, I usually take a burst of 4-6. Often, one will be substantially better than the others.

[normhead]

Im actually headed to Algonquin tomorrow, hoping to see some of those guys and Pine martens.

It's a terrible year for wildlife, the Park sealed the garbage cans at Mew lake, the Pine martins are gone. Theres still one a Costello Creek picnic area and Opeongo Road. I briefly caught sight of a Pine marine at the Cameron road parking lot, but it must be young one and it's very shy. It stayed way too far away for images. I haven't heard tell of them at the Visitors Centre or Spruce Bog either. I'd direct you somewhere if I could. The one at the Costello Picnic area has left tracks, but not in the last few days.

The Canada Jays were at Spruce Bog around the back end of the loop before you leave the forest and the logging museum parking lot. I met a guy who did both Track and Tower and Mizzy Lake, (he was a marathoner) and didn't see much of anything. There's small chance I'll do my loop tomorrow, Oeopga to the Costello Creek Picnic area (Canada Jays and Pine Martin,) Opeongo Road ( Beavers, Otter and Mink (no sign of anything this year so far.) Cameron Road Parking lot (Canada Jays, Blue Jays, lots of Pine Martin Tracks but haven't sen him yet) Spruce Bog (there have been many sightings of Ruffed Grouse, I've seen him twice near the start fo the trail, and all the suet birds , Jays Chickadees, a stop in the visitors centre and then the Logging Museum on the way home. But, I've been two times in the last week, so, I'm not sure I'll feel like going. Have a great time. IF I do go, I'll be trying to get the Red Crossbill at the Visitors Centre as my main focus, although, I'll do everything else as well.

[pschlute]

I'd say I usually get more shots than I miss, but I'm a perfectionist and occasionally I the one I "missed" is the one where the animal is looking at me

Thanks for the reply. It may be as simple as the fact that PDAF is not and never will be 100% accurate. The DA* 300 is old tech now and when combined with a TC for the reasons i mentioned in my post you may only ever get 80% accuracy.