[Vital-Blurs]

Thanks for the input, everyone. It probably is just a case of me needing some more time to come to grips with this longer lens. Getting a sharp image from my Sigma 17-50mm was so easy. Plus, I'm still getting familiar with my K5's auto-focusing coming from a 100D.

I'll try bringing it back from 300 a bit with some different apertures and go back to manual focus. I don't normally use auto, but after getting some soft images at 300mm manually, I thought I'd try relying on the camera's focus and thought that f11 would have deeper DoF.

Cheers.

[pschlute]

I'll try bringing it back from 300 a bit with some different apertures and go back to manual focus. I don't normally use auto, but after getting some soft images at 300mm manually, I thought I'd try relying on the camera's focus and thought that f11 would have deeper DoF.

If I may add a comment again......there are a number of issues in your sentence here all which have similarities but are distinct subjects.

1. Focal length.....It may well be that 300 is not the sharpest FL on that camera, but for any picture taken at 300mm , the subject should be the sharpest part.

2. When assessing focus it is best done at widest aperture as this enables you to see clearly whether you have achieved focus on your subject or not. Using a smaller aperture can disguise this through a wider DOF.

3. If you have concerns about the ability of your lens to focus whether that be using manual or autofocus, the first step is always to focus using LV, both manually (zoomed) and using AF. if the camera is capable of achieving good focus where you want it to, then you have eliminated the lens as the source of the problem.

I would like to ask one more question. In the first picture of the bird ornament. What exactly is the problem as you perceive it ? The texture of the bird and the rusty wire on the same plane, and the greenery growing out of the wood all look pretty sharp to me. What are you seeing that I am not ?

[suraswami]

Simple tool, probably might help.

amazon.com: DSLRKIT Lens Focus Calibration Tool Alignment Ruler Folding Card(Pack of 2): Camera & Photo?tag=pentaxforums-20&

[clickclick]

Getting a sharp image from my Sigma 17-50mm was so easy.

Completely different beast. The depth of field in the range of this lens is significantly greater, and the general perspective (field of view) is less likely to be scrutinized, since it is wider. And the shutter speed required to freeze your camera's motion is not nearly as high. As mentioned, in most all of the photos, there's a section that is quite sharp. And definitely experiment with different apertures to find the sharpest range. With most lenses, you'll find they sharpen as you stop them down, but at some point, diffraction sets in and you loose sharpness. That's often in the f11-f16 range.

[Adam]

If you want to gauge the sharpness of the lens itself, rather than the accuracy of the AF, then definitely use live view (with magnification) to verify that the focus is correct. If and when you're satisfied with that, then AF fine adjustments can be used to improve the accuracy of focus through the viewfinder (the degree of adjustment needed, if any, will vary with each camera-lens pairing).

Based on the test shots, by unscientific impression is that the lens is performing as expected. Remember that this is a consumer-grade lens, so the expectations should be slightly lower than what you're used to seeing from your F2.8 zoom. Plus, it's a telephoto, so imperfections may be inherently easier to spot.

[normhead]

Even in the bottom image, I can pick out spider webs from 25 feet that you probably didn't see when you took the image... nothing wrong with that. The depth of field for 300mm ƒ8 25 feet is only about 7 inches, so a lot is going to be out of focus.

That being said, it's not the sharpest lens at 300mm and according to Optical Limits it's sharpest at ƒ11.
Pentax SMC DA 55-300mm f/4-5.8 ED - Review / Test Report - Analysis



The PLM is better, but still at it's sharpest at ƒ8 (a stop better) but still not up into an excellent rating, although it gets pretty close to excellent.
https://www.ephotozine.com/article/pentax-hd-pentax-da-55-300mm-f-4-5-6-3-ed...e-review-30837

[mikesbike]

I agree with Sandy, Norm and pschlute. Since your lens has WR, it also has HD coatings, another plus over the original, which I used to have but damaged the front threads, so now I have the same as the one being discussed here. I think your lens is fine also, and it is a very well-performing compact tele lens at a great price.

It can hold aperture to f/4-4.5 all the way out to just before 200mm, which is a good showing and an advantage when dealing with lower light or for a live subject. Lenses in general are not quite their best at wide open aperture, but you can get very decent results and getting the shutter speed up can make more difference in sharpness under certain conditions than a slight loss in resolution. Also, when it comes to telephoto, usually the central area performance is more important than the edges of the frame.

Norm's link to ephotozine is very interesting. At the end of their report of the newer PLM model, they also provide a link to the previous model, the same one the OP has, as I do also. That one is showing a number of excellent ratings especially in the central area. No results given for 200mm, but it is easy to guess being right between that for 100mm and 300mm. Looks very good to me as well.

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Last edited by mikesbike; 09-15-2019 at 08:57 PM.

[RookieGuy]

They look sharp enough to me. The sharp parts.

I'll be paying attention to this thread. I'm teaching myself how to work with longer focal lengths myself. Tripods are you friends. Yeah, I don't hike with one either. But I do hike with a beanbag or bandana. I'm not above using a stump, rock, or child's head to rely less on my rock steady hands. I don't see effects of that in yours though.

[dan.a.nesheim]

Looking at the focus point, i think its perfect. Now whether you focused where you intended, that's something else.

[Vital-Blurs]

Yes, I'm coming to grips with a much longer lens than I'm used to, and I've had a bit of a chance to test it in the environment that it was intended. Small, fast moving radio controlled race cars.

I still have some work to do, but I'm happy enough with the sharpness.

[csa]

One other point for the OP, if he has never used a longer telephoto lens before. Holding it steady is a must, if hand holding. So practicing this will also help the sharpness.

[Vmax911]

Yes, I'm coming to grips with a much longer lens than I'm used to, and I've had a bit of a chance to test it in the environment that it was intended. Small, fast moving radio controlled race cars.

I still have some work to do, but I'm happy enough with the sharpness.

Great pic, and certainly sharp enough. That lens is definitely best under bright lighting.

I used to race those little buggers 25 years ago!

[DeadJohn]

Yes, I'm coming to grips with a much longer lens than I'm used to, and I've had a bit of a chance to test it in the environment that it was intended. Small, fast moving radio controlled race cars.

I still have some work to do, but I'm happy enough with the sharpness.

Glad that you're having better luck with the lens.

[mikesbike]

Yes, I'm coming to grips with a much longer lens than I'm used to, and I've had a bit of a chance to test it in the environment that it was intended. Small, fast moving radio controlled race cars.

I still have some work to do, but I'm happy enough with the sharpness.

Fine job here! It substantiates that this lens is very capable, and a fine value for the money, as well as for lightweight carrying.

I have the top-guns category for when I need what that offers- a DA* 50-135mm f/2.8 SDM, DA* 200mm f/2.8, and FA* 300mm f/4.5 plus a Tamron 1.4x TC, all wonderful lenses. But the above HD 55-300mm WR lens is still so good I have no problem taking it out instead when I need its compactness and/or its wide zoom range to instantly change my framing.

[Ex Finn.]

Yes, I'm coming to grips with a much longer lens than I'm used to, and I've had a bit of a chance to test it in the environment that it was intended. Small, fast moving radio controlled race cars.

I still have some work to do, but I'm happy enough with the sharpness.

Nice result, I should take my lens back from my daughter