[BrianK]

I found myself going through some images from our local Canada Day celebrations in Lightroom and thought I would see what cropping this image would do. I am very happy with the image quality from this new body. The image itself is nothing special as I could not take it from any angle that would not have the cars in the background. The girl sang Oh Canada for the opening ceremonies on the beach.

The original image was taken with the K5 IIS and the Sigma 18-250 OS lens. Shot in Raw with no processing in Lightroom other than conversion to Jpg to output at 1024 resolution for the web. The more I use the Sigma 18-250, the better I like it.


The second image is a crop from the original. I printed the cropped version and it is very sharp.

Original Image




Cropped Image

[Franky2step]

Looks great Brian, thanks for sharing this.

[rawr]

Good shots.
The more pix I see from this lens, the more I like it.

[Frater]

Good telephoto performance, given it was done at 250mm and wide-open (F6.3).

Even though your cropped Image is not a 100% crop (i.e. not made for die-hard pixel-peepers), but ~30%?, it doesn't develop signs of blur (as far as this magnification level may reveal), just some chromatic aberrations towards the edges, but those could be removed so easily in your Lightroom's Adobe Camera Raw module.

For the telephoto range, I own the Pentax 55-300, and never have been utterly happy about its performance in the range between 150 to 300. Would be interesting, if my 55-300 was surpassed by the Sigma super-zoom... makes me curious.

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Last edited by Frater; 07-05-2013 at 12:48 AM.

[BrianK]

Here is the image cropped to 100% or as close to it as I can get with Lightroom. When I click on the image created by the crop tool it does not magnify or shrink anymore so it must be close. You can see some blurring starting to appear but not bad for the long end of the Sigma 18-250 lens. Several reviews mentioned that it was not sharp at 250, I think I have a good copy! The OS is nice as you get to see a stabilized image in the viewfinder.

Maybe owners of the K5 IIs should run through all of their older lenses and re-test them if they have been reluctant to use some of them because they did not appear sharp. I am very sure that I could not do this type of crop from any images I have taken with the K5.

I will have to try to compare the Sigma 18-250 with the Pentax 55-300. I usually take the 18-135 and the 55-300 on outings but from now on if I think I won't have time to change lenses the 18-250 will be on the camera. I used it on a recent trip to Hawaii and it worked well there. I had just purchased the K5 IIs a couple of days before leaving. It was nice to have a new body with the same familiar control layout, just a sharper image.

Same image 100% crop
Cropped in Raw in Lightroom 5 then exported without resizing to JPG.

[Frater]

Thanks for that. The ear jewellery is as detailed as can be.

The only small distinction from a top prime lens may be, that the red channel is blurring some of its light slightly upwards, so that the small black pattern on the lady's shirt get a slight cast towards brown on their bottom regions. But that's only pixel-peeping.

Overall, I'm impressed as well, and also I think, it's on par with my Pentax 55-300, possibly even better?

I picked an example with enough small contrasty details, and made a central crop at 100%, and another crop from the left edge.
230mm, F8, 1/350s; RAW, I even turned off the RAW converter's default sharpening (not sure if you did as well), and of course I applied no lens corrections.

[Franky2step]

Have you tried sharpening the image? You can use a RAW pre sharpener if you have Nik Sharpener Pro, then a separate sharpener matching your output(printing or web)

[Frater]

No, I didn't sharpen the above examples, because for lens performance comparisons, I thought it's fair to do without.

If a lens is not really tack sharp, like my 55-300 isn't in the tele range, then I often crank up the sharpening tool in Adobe Camera Raw converter to nearly its maximum (=130%), and end up with the below result. Probably good enough for the center, but the edge is still not perfect, probably because the blur is complicated there (directional, or otherwise asymmetrical). So far I thought one can't do much about complicated blurs (including those coming from decentering, or camera shake). Or, another favourite case: if the color channels have different blur characteristics (often on the short end of wide angle zooms, where I find blur characteristics most complicated).

[Ray Pulley]

I found myself going through some images from our local Canada Day celebrations in Lightroom and thought I would see what cropping this image would do. I am very happy with the image quality from this new body. The image itself is nothing special as I could not take it from any angle that would not have the cars in the background. The girl sang Oh Canada for the opening ceremonies on the beach.

The original image was taken with the K5 IIS and the Sigma 18-250 OS lens. Shot in Raw with no processing in Lightroom other than conversion to Jpg to output at 1024 resolution for the web. The more I use the Sigma 18-250, the better I like it.


The second image is a crop from the original. I printed the cropped version and it is very sharp.

I have no argument against the K5 IQ. I think it may well become one of the legendary (and greatly under-appreciated by the masses) cameras ever made.

As for the image of the singer, it looks to me like the camera may have locked focus just behind and maybe off to the side a bit, maybe on the black railings just behind her, making her just a bit softer than I would expect.

It is hard to say for sure, as there isn't much detail in those rails to evaluate, but my K5 (with the legendary big'ish focus points) has locked onto similar contrasting near backgrounds on me before.

Ray