[aleonx3]

Try using the focus point selection option instead of center focus and recomposition. If you still have problem with softness, it could likely be BF/FF issue which you can correct with the debug menu on the K10D.

[Pål Jensen]

I disagree, I have both lenses, the 28-75 is brutally sharp at f/2.8 at or close to 75mm, I would say pretty close to the FA 50 1.4 closed to 2.8.

Also the 70-300 is pretty sharp for it's price range even wide open. Sharper than the Pentax 50-200.

No lens is brutally sharp with a low quality filter in front. Telephoto lenses in particular cannot often even focus if the filter is not designed as part of the optical system.

I don't believe these are focus issues as the unsharpnes seem to affect the whole frame equally.

Try stop down the lens 2-3 stops and remove the filters.....

[deludel]

WOW, I am blessed for the magnitude of responses here! Although there are conflicting opinions in some areas (soft images at wide open apertures), it’s all good stuff because I clearly need to do several experiments to eliminate different possibilities.
I’ve noticed this problem more and more recently, then of course it’s only recently that I started to get paid for my work .. so of course when I have a paying client, I get even more frustrated when I have lost shots!

This weekend, I will be going to Central Park for the day (I live in CT) and will do lots of experimenting while taking careful notes.

I agree this has less to do with wide open softness as it has to do with an AF calibration problem with these lenses. At 100%, you wouldn't see any detail in these shots - they're just all OOF. Does this happen with all your lenses, Lori? Has this just started happening? Anything different about your lenses?

It has not “just started”, but lately has seemed to have gotten worse. I only use these two lenses, but do have the kit lens and a 50mm/f1.8 manual focus .. I will try them ALL this weekend to see if I get different results. I also need to go through my recent series of images and look to see when it has/hasn’t happened (comparing EXIF data)

The last time I got results like that it was because I had turned the autofocus off.

Hmm, do you mean the lever on the front .. the AFS/AFC/M lever?

If you're using the K10D, don't rule out the need to send it in for focus calibration with the lenses you use as it has many instances of less than accurate AF focusing. Test focus by focusing manually and compare it with an AF shot, set up the camera on a tripod and aim at a known object beforehand.
Did you inadvertently switch the AF focus point?
Did you wait until the SR hand icon in the viewfinder is off before releasing the shutter fully?
Did you mistake the red AF point indicator with the green AF focus confirmation light in the viewfinder when shooting?
Too many variables so it is best you slowly weed out the possibilities.

Good points. I didn’t even notice that hand icon!! Lots of things to pay attention to this weekend .. I plan to jot down the image #s with the settings.

Shirt in the last looks likes simple camera shake. Others aren't reproduced large enough to tell if its out of focus or shake. I guess the question is, do you *ever* get sharp pictures, or did something go wrong in these?

I do get SOME sharp ones, relatively speaking. Never sharp enough, compared to many other’s images I study. Either I have the wrong settings, or I have a shaking syndrome I do not know of, or my camera is focusing on the wrong place … or … ??

Try using the focus point selection option instead of center focus and recomposition. If you still have problem with softness, it could likely be BF/FF issue which you can correct with the debug menu on the K10D.

Will try that, and more. FYI – I always have SR on (I forget about it, embarrassingly) … but will experiment with it on/off. Sounds like I have to lug the tripod to NYC this weekend! I’ll use my remote cable, and/or a 2-sec timer just to be sure. Thanks, everyone. I’ll post my findings!

[rfortson]

Those suggesting it's because the lens is wide open are on drugs, it's far, far too soft to be that.

I suspect dud focussing (no real sharp areas anywhere though TBH) or a dud lens.

Agreed. Plus the Tamron 28-75 is one of their better lenses normally. So, something is amiss here.

[PentaxPoke]

I feel for you Lori. Those appear to be senior portrait shots, and I am sure you want them to be perfect. Those are clearly, very unacceptably soft. It has nothing to do with the aperture used, as others have said. You should get much more sharpness out of those lenses even wide open. Look how sharp this portrait is, and it is f/3.5 which is wider than 2 of yours:


First, take those filters off. No one should need UV filters with modern digital cameras (unless you are a klutz and it is for protection ) UV filters are a holdover from film days where the blue layer of film was sensitive to UV as well as blue light. Unless you have very high quality (expensive) filters, all it will do is reduce the optical quality of the lens.

Second, I agree with the simple test that ping suggested with 3 batteries. Here is a picture of one I did. (this was showing view through the viewfinder, but it is the only pic I have of the test)



The odd thing is that the pictures are not in focus anywhere. The battery test will quickly tell if it is FF or BF. I suppose it could be shake. Some people have a different handhold threshold than others. Your shutter speeds are reasonable though.

Another suggestion (not related to sharpness): On some of your pictures, try a touch of fill flash. It may help your subject "pop" from the background.

[pingflood]

Shake seems really unlikely if she's using SR coupled with decent shutter speeds though.

But yeah, something is really wrong. It looks to me as if some parts closer to the camera than the subject are a bit better focused, but really hard to tell. There's clearly nothing really *sharp* anywhere.

[tigrebleu]

It has not “just started”, but lately has seemed to have gotten worse.

Same thing happened to me with my DA 16-45mm F/4... It would focus nice, then, last summer, it started back focusing a bit and slowly got worse and worse.

I sent the K10D + DA16-45 combo to Pentax Canada for AF adjustment and it worked... but only for the 45mm setting! The lens' AF accuracy is still erratic at 16mm, with lots of BF/FF shots. I'm presently looking at the possibility to use a DA21 as a replacement. (Note that the problem can either come from the body, the lenses or the combination of both.)

That said, it's difficult to find the reason why your pics are soft when looking at your samples (rather small size, lack of detailed info), but I'd say the pics are not focused properly.

Recomposing could be an issue at wide-angle because of the pronounced field curvature (when objects in the corners get out of focus while those in the center are just in focus, yet all are at the same distance), but I doubt it's the case here: lenses used at telephoto focal lengths usually show little field curvature.

Filters couldn't affect the image this much IMO. Even a soft focus filter will add diffusion but will not make an image as soft as yours.

Same goes for softness wide open... Although the Tamron 70-300 is not a pro lens, it's still usable wide open at 150mm and less (at least according to many reviews) and the 28-75 is renowned for its pretty good sharpness wide open.

Otherwise, I can only think of condensation inside the lens or on the sensor (that can happen at the end of the day when the temperature goes down rapidly). There's a slight chance it might be that... but I doubt it.

Hope it helps.

---

Last edited by tigrebleu; 07-24-2009 at 05:32 PM.

[Marc Sabatella]

Shake seems really unlikely if she's using SR coupled with decent shutter speeds though.

I'd agree, but that's what the shirt in the third picture loks like to me - shake, not OOF. Would be easier to tell with larger crops. Would be nice to be there while the pictures are being taken too, to see if the camera seems to be even *trying* to focus (and yes, MF means settings the focus switch on the front to MF).

[raz]

maybe would be best if deludel post an out of the jpg sample at it's original resolution, with intact Exif.

Is too strange that both lenses produces the same out of focus images, maybe something is wrong with the sensor or af in the camera ?

[falconeye]

The young man on the photos could be an extraterrest alien. We all know that only unsharp photos can be made of them ...

[Pål Jensen]

The young man on the photos could be an extraterrest alien. We all know that only unsharp photos can be made of them ...

It is not fuzzy enough for that!....

[PeteyJ]

The young man on the photos could be an extraterrest alien. We all know that only unsharp photos can be made of them ...

I was thinking Big Foot, after a nice shave of course.

[krypticide]

To me it seems pretty clear that the first image posted is correctly focused, as you can see a transition from out of focus to best focus to out of focus again from foreground to background (start from his jeans). So I have a feeling that it is likely your UV filter, or somehow your lens is dirty or otherwise compromised.

I agree with opinions here, don't use a UV filter and use a lens hood as protection.

[HeavyD]

Have you tried a Pentax lens on your camera? I recently bought a new open boxed K10d and a Sigma 17-70mm f/2.8-4.5 lens with a Hoya Pro1 UV filter. I was having the same focus issue with the Sigma as you are. First I took off the UV filter which helped slightly. I then bought a Pentax 16-45mm lens to see if it was a lens or camera issue. The AF is spot on with the 16-45. Heres two quick snap shots. The camera was mounted on a tripod and both photos where taken with the same camera settings, focus point was the pocket knife. The Sigma is out of focus while the Pentax is perfect.



Sigma 17-70mm



Pentax 16-45mm

[rawr]

Wow, that's a big difference. In your example HeavyD it's not a focus related issue at all. The Sigma is just plain soft.