16-50 Purple Fringing
CA on the other hand can be quite tricky to remove from shots at 16mm.
Regards,
Dan
https://www.flickr.com/photos/honourabletyr/

I usually do something similar at the Raw stage in Silkypix by desaturating purples with the Fine Colour Controller. This isn't as fine-grained as the approach you've pointed out, but being Silkypix it's easy to save the corrections away in a "taste" and re-use them for photos with similar PF.
R
Other than to test the lens's limits on ca/pf I can't think of a single reason to bother turning on the camera.
Whenever an unplanned photo op presents, you are left with two options:
A) you got interesting light, and must find an interesting subject/composition.
or
B) you got a great subject and need to find a good angle to get the light.
Without either great subject material, or great light...why bother snapping a photo at all?
Fired many shots. Didn't kill anything.

I took some test shots with the 16-50 at SRS on saturday, and wasn't that impressed with the focal length extremes at wide apertures, edges of the frame didn't look too good, with CA being particularly bad a wide angles.
Don't think this really helps you, but at least it might indicate yours isn't a one off.

Laptop's about to run out of power so can't post an example.
Dan
K-3, a macro lens and a DA*300mm...



I'm sure I have seen some comments that suggest that the K10D sensor also contributes to this effect. In any case the DA* 16-50 is a lot better than my Sigma 18-50 F2.8 EX DC in this respect.
Here is a 100% crop from my 16-50 @ 16mm and the very reduced picture shows the full frame.


Glyn
Thanks Tyr.
It's pretty obvious in some of the shots I took.
I think you are seeing more lateral CA there than straight PF. In your test images different colours can be seen on each side of branches at a tangent to the centre of the lens, this is generally an indication of LCA, PF tends to be visible as a relatively uniform colour at every high contrast juncture at a similar subject distance. LCA is largely correctable in post processing.
Rob Studdert
HURSTVILLE AUSTRALIA
http://home.swiftdsl.com.au/~distudio/publications/
Pentax user since 1986, PDMLer since 1998
I took some test shots with the 16-50 at SRS on saturday, and wasn't that impressed with the focal length extremes at wide apertures, edges of the frame didn't look too good, with CA being particularly bad a wide angles.
Hi Dan,
The quality of your testing was obviously much better than mine

I was impressed by your duck pictures with the 300 - I guess the Pentax people let you walk around outside the shop with it?
R

I think you are seeing more lateral CA there than straight PF. In your test images different colours can be seen on each side of branches at a tangent to the centre of the lens, this is generally an indication of LCA, PF tends to be visible as a relatively uniform colour at every high contrast juncture at a similar subject distance. LCA is largely correctable in post processing.
Rob, I would agree that GlynM and Unlocker's samples look like CA, as you can see balancing yellow fringes on the opposite side to the blue, however I don't see that on my sample (the first one).
R
Hi Dan,
The quality of your testing was obviously much better than mine

I was impressed by your duck pictures with the 300 - I guess the Pentax people let you walk around outside the shop with it?
R
Only noticed once I was at home at the pics were on the PC, I don't think you can really judge that sort of thing on the camera monitor. And although there were various things I would have liked to have bought, I had already decided not to spend any money on the day, so there was no question of me getting carried away.
Although a deposit on the 300mm was sorely tempting.

Yes, I tried it outside the shop. I was with the other lady there, (Chris's wife? should really have ckecked

Should have seen how it was at minimum focus too.

Dan
K-3, a macro lens and a DA*300mm...



Vic.
K5, LightRoom 5
Sigma 8-16 Pentax DA 16-45 Pentax DA 55-300 Pentax 18-55WR Tamron 90 Di Macro Metz 44 AF-1
Reuben0
Member
Devon, UK
I know that this was one of the criticisms PhotoZone levelled at the Tokina version, but I was wondering what other people who have the lens think or have I bought a lemon?
Thanks,
R