Nikon D3000 Blurry Pictures. Focus Issue?

Question

Here are two examples:

Both pictures are in NEF format here.

The pictures have not been modified in any way except except for being resized and converted to PNG.

Just for kicks (and to prove I'm not crazy) I sharpened the butterfly image via "unsharp mask." It's not a pretty result but I just wanted to demonstrate "sharp" vs. "blurred."

Kind of annoying because I've ruined many epic shots with this odd focus problem.

My original Film SLR was a Minolta Dynax 505si Super 35mm (or in the same family, I think) and it performed marvellously. I used it for about 4 or 5 years all throughout high school and then (as an avid film photographer) begrudgingly made the switch over to digital in college. But the Minolta definitely gave me experience in photography and people genuinely enjoyed my photographs.

Early on, I don't know if I was just enamoured with the idea of vibrant digital images from an SLR or if I just didn't notice enough, but I don't remember a whole lot of images that came out blurry in the beginning. Maybe 60% of them (a liberal estimate). I accidentally deleted about a year's worth of early pictures so I'm unable to tell now.

The preview in the viewfinder doesn't appear to be blurry at all; then again, there's a huge different between the 3" preview screen and my 20" computer monitor.

Here are things I've tried:

1. Using a tripod (although, as you can tell, the issue is not a motion blur issue).
2. Tried different aperture settings (for example, the landscape image is f/22).
3. Tried different ISO.
4. Manual focus.
5. Auto focus.
6. Manually "de-focusing" the object (focusing behind it and focusing in front of it). Although, with the picture of the butterfly, this doesn't seem to be the case: it has varying depth of field and even the supposedly "in-focus" butterfly is out of focus.
7. Changing the "sharpening" property via the camera: Menu > Set Picture Control > (picture control -- e.g. "Neutral") > Sharpening
8. Went into a physical repair shop and they did test images. They didn't seem to find a problem, patted me on the head, and told me to be a good photographer and use the autofocus.
9. Letting someone else take the picture.
10. Chromatic aberration correction (typically through Digikam)
11. Different Lenses. The two below are using my AF-S Nikkor 18-55mm 1.3.5-5.6 G lens. I have a AF-S Nikkor 55-200mm 1.4-5.6G ED telephoto and get the same result (sometimes result is worse -- can post an example if needed).
12. And, oh, yeah, I even sent it into Nikon...three times. They said they fixed the problem. But, you know how those things go...

Oddly enough I've looked up reviews for my camera and both lenses and couldn't find many (if any) reviews stating blurry pictures for every picture.

A few thoughts:

• Could whichever photo editing program I'm using be the cause of the blur? I used Linux so I've used Digikam (my favorite), F-Spot, and the Gimp.
• Maybe it's normal for digital pictures to be blurry compared to film? Digital doesn't use crystals like film, so the opposite should seem true. I wonder this because a lot of work has gone into sharpening tools like unsharpen mask.

Sorry for the long post and various photo examples. Thanks in advance!

Answer 1

I see no problem in either of these images. They both appear correct. Lenses are not 100% sharp to begin with and on cheaper lenses it is not atypical for the resolution of the camera to outpace the resolution of the lens, particularly on entry level and kit lenses like the two you are using.

This is even further compounded by using high aperture on a crop body camera. The smaller point you try to focus light on, the more of an issue diffraction becomes when shining the light through a small hole. The smaller the hole, the more impact diffraction has and this reduces what level of quality is possible to capture. Try shooting at or above f/8 or so and diffraction limiting shouldn't be a problem. You might be able to go a bit higher than that based on your resolution, but I didn't do the calculations to figure out exactly when it is a problem. (There are calculators online if you want to check exactly when it should theoretically start being an issue.)

The first one certainly has a shallow depth of field, but it appears as sharp as expected for your choice of aperture and lens. Your unsharp masked version seems over-sharpened. It over-exaggerates the edges and makes things "jump out" more, but is unnaturally so.

Answer 2

After messing around with the settings and my photo editing software I found ways to mitigate the situation:

• Try to avoid wide-angle. This causes the lenses to refract the light on the edges more than the middle, causing the majority of the picture to appear blurry. I try to go for around 50mm. More expensive lenses tend to not have this flaw.
• In addition to refraction, the picture is distorted. It may not be obvious, but the fish-eye effect is always present unless your zoom is 50mm. While the distortion will always be there, many photo editing suites (my favorite is Digikam) have a tool to un-distort the images. This actually helps a great deal.
• Lastly, it's no sin to use the "sharpen" feature for every image. It's best to use "simple sharp," or something similar. For most images I set the sharpness to around 70 - 75%, and I'm still able to get a natural image.

I've also been learning (and it's mentioned in the previous answers, too) that pictures on my phone turn out so much better because my phone's software takes care of the majority of processing before saving as PNG. When my camera shots RAW, it's up to the photographer to post-process the image.

So, essentially this poor quality is a combination of a cheap camera and the fact that the camera processes PNGs but not RAWs.