Disappointing image quality: me, the lens, or the filter?

[Hub]

I was away down in Cornwall last week, out and about in bright sunshine and taking general walkabout snaps, and a lot of wide angle landscapes using the Canon 18-55IS kit lens on my 500D. I left a Polarising filter on most of the time. I got some I liked, but some of the results I'm quite disappointed in. For example in the 100% crops below (straight out of the camera in jpg mode, landscape settings) I find they are not very sharp, and when sharpened up in PS still don't give a really satisfactory image quality. Also, what is worse is the noticeable level of chromatic aberration displayed (though I know the bright weather probably didn't help). High detail landscapes seem to suffer worse, such as grass and vegetation.

So... am I fussing about nothing or should I be concerned? Have I reached the limits of the kit lens or have I got a duff one? They do get good reviews but I am not finding mine to be that great for image quality - certainly in comparison to the other lenses I have (50mm 1.8 and 55-250IS).

Alternatively, could it be the Polarising filter that is causing some of the problems? Or is it something I'm doing wrong?


F5.6 1/100


F9.0 1/160


F8.0 1/200

Pic which the first crop was taken from (resized for quick upload):

Edited by Hub on Friday 10th June 10:15

[14-7]

Hub said:

So... am I fussing about nothing?

In one word, yes.

The images will never be totally clear and in focus when at 100% crop. Not even on a 1Dmkiv that costs over £4k.

[RobDickinson]

14-7 said:

The images will never be totally clear and in focus when at 100% crop. Not even on a 1Dmkiv that costs over £4k.

Ofcourse it can be. Using a kit lens with a polariser isnt likely to result in a best case scenario tho.

Whats the polariser.
Whats the exif info from the shots.
How did you focus, single point, multi point, AI servo or single?

A polariser, especialy a cheaper one will hit image quality, and you wont be using a lens hood, and it will rob you of up to 2 stops of light making the camera open the aperture up (if in auto mode) or introducing more camera shake etc.

The kit lens isnt the best but it should be up to producing OK results, and as 24-7 says getting a 100% crop looking good is quite tricky

[Hub]

The Polarising filter is a fairly cheap Hama one. I use single point focusing, generally on P program or A Priority.

I know that 100% crops will never look good - but I only zoomed in because I was unahppy at what I was seeing on the screen anyway, lack of clarity evident even there. The red and blue fringing adds to my concerns as the pics don't look as good to my eyes as my old Panasonic ZX18 superzoom thing.

First pic F5.6 1/100
Second pic F9.0 1/160
Third Pic F8.0 1/200

Edited by Hub on Friday 10th June 10:16

[BigAlinEmbra]

I have not technical advice to add, but the last picture is the nicest one.

I hope you find this of some comfort.

[Webber3]

Hub said:

The red and blue fringing adds to my concerns as the pics don't look as good to my eyes as my old Panasonic ZX18 superzoom thing.

Try shooting in RAW and run the image through DPP, there's a function that removes chromatic aberration. It will also show you if it's just a soft jpeg you're seeing. I find that RAW images, with a few clicks in DPP, are way sharper than the jpegs that come out of the camera.

[DIW35]

And to rule out whether it's the filter causing the problem, try taking a few shots without it for comparison.

[RobDickinson]

Hub said:

The Polarising filter is a fairly cheap Hama one. I use single point focusing, generally on P program or A Priority.

I know that 100% crops will never look good - but I only zoomed in because I was unahppy at what I was seeing on the screen anyway, lack of clarity evident even there. The red and blue fringing adds to my concerns as the pics don't look as good to my eyes as my old Panasonic ZX18 superzoom thing.

First pic F5.6 1/100
Second pic F9.0 1/160
Third Pic F8.0 1/200

Well you've got enough shutter speed probably, f5.6 is probably too wide an aperture, f8 should be ok but the kit lens wont have great CA in strong contrast.

I'm betting though the filter is a big part of the problem. Do some quick tests, tripod, 2 second timed shots, in raw and use dpp. Add sharpening etc (or picture style).

[Murph7355]

To see whether it's the kit you're using, you need to take some better reference test shots. Tripod, same shot, the different lenses you have, with and without added bits of glass. And then compare them side by side. Try and find something that won't be susceptible to the vagaries of outdoor light etc too.

That said, kit lenses are often not the best. They're selected to make the kit attractive at a price point, especially on the consumer range of SLRs.

FWIW though, I also suspect you might be expecting quite a lot looking at the full image you posted. Aside from some noise in the sky etc which is probably down to the resizing, it's a nice enough shot. Expecting to crop it so you can see Uncle Bert and Aunty Hilda waving at you in that particular image would be pushing things with most kit IMO, and especially consumer end gear.