While true, I don't think this is helpful to understanding the lens characteristics, which is my objective here.

If I want vignetting for artistic effect, I'll put it in. Otherwise, I'd rather there was none. Obviously, no lens is ideal, so I need to establish whether what there is, is a problem in reality.

From the unpredictability I've now seen, I'm really only concerned about the apparent asymmetry, since this might suggest that the optics haven't been assembled quite right.

I trust it goes without saying that none of the wall shots I did were cropped at all - that would just be silly.

Indeed it does.

I've just done a load of white wall shots, and stopped down, there's none at all to speak of.

Wide open, it's very apparent, strangely much more so at the long end.

Here's one at f5.6 and 135mm:

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/K-5%20and%2018-135%20early%20impressions/IMGP0016-56-135.jpg[/IMG]

You can see it, but increasing the contrast has an enormous effect:

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/K-5%20and%2018-135%20early%20impressions/IMGP0016-56-135-ac.jpg[/IMG]

So in the field, there's likely to be wide variation of the amount of vignetting. Once you add the post-processing into the equation, it becomes somewhat unpredictable - more contrast and a different focal length could easily result in different vignetting from shot to shot.


If it was symmetrical, I'd just ignore it, but it doesn't look centred to me, either.

Should I be worried about this?

Ok, this was taken a couple of days ago. The light was horrible, flat grey sky, so no particular photographic merit in the next few shots.

Here's the whole frame:

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/K-5%20and%2018-135%20early%20impressions/IMGP0268-wf.jpg[/IMG]

I chose this subject because the hard lines against featureless sky would show up the CA that's been reported.

135 mm, this time - 1/250 at F7.1, ISO 400

100% crop, sharpened as before:

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/K-5%20and%2018-135%20early%20impressions/IMGP0268-cr1-hp.jpg[/IMG]

Lateral CA apparent as reported elsewhere, but I wouldn't say it's terrible.

Here's another 100% crop, of a better-exposed part of the image:

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/K-5%20and%2018-135%20early%20impressions/IMGP0268-cr2-hp.jpg[/IMG]

I had to work a little harder on the sharpness, so subjectively it's not as good as the 24mm shot earlier. Hard to say - none of these were taken on a tripod, so there could be a little shake. Even so, I'd still say it's acceptable - close to the centre, anyway.

The point of concern I alluded to is the apparent vignetting, which seems not to be symmetrical. It's possible, of course, that it was unevenness in the sky, but I've seen this pattern a few times now. I'll look for some other examples.

This thread is more about the lens than the photography, since one or two have asked about that, so I've put this here rather than in Your Photos.

This from yesterday - DNG, 24 mm, F10, 1/200s at ISO 200

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/K-5%20and%2018-135%20early%20impressions/IMGP0303-crsmsh.jpg[/IMG]

It's almost the whole frame, with just a little featureless sky and foreground cropped.

This is a 100% crop with no sharpening:

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/K-5%20and%2018-135%20early%20impressions/IMGP0303-cr-ns.jpg[/IMG]

And this is the same thing with a little sharpening (high pass filter on an overlay layer):

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/K-5%20and%2018-135%20early%20impressions/IMGP0303-cr-hps.jpg[/IMG]

And here's another 100% crop, similarly sharpened, from the tree line:

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/K-5%20and%2018-135%20early%20impressions/IMGP0303-cr2-hps.jpg[/IMG]


This example is an encouraging start, I think. It's not jaw-droppingly sharp, but even the 100% crop is quite acceptable with a little sharpening, and the CA that's been reported isn't at all offensive.

I'll add a few more examples shortly - I do have one concern, which I'll illustrate in the next one.

I can't comment on the W90, but I'm quite liking it on the K-5. One of the things that annoyed me the most on the K10D was how easy it was to overexpose sky, so I've been experimenting with D-Range on the K-5.

I'm liking it so far, although it doesn't work miracles.

This is certainly how it seems to me. Losing a little of the extremes would be a small price to pay for not ruining all those shots.

What I don't know is what happens if you take a picture with D-Range on, when you didn't need it. Does it boost the shadows and cut the brights anyway, or is it clever enough to only do it if it needs to?

Yes, me too.

The leaves, in particular.

Might saunter along the tow path in Teddington, see if I can spot any suspicious characters photographing herons.

Ah - 'members', obviously (doh!)

Also Community > Member portfolios.

Obvious when you know.

Cheers George

Ok, I'm being super thick here... how do I find a particular photographer's portfolio on EPZ?

Do many beginners have CS5?