16-50 Purple Fringing

Just been out using my newly acquired 16-50 and noticed it seems to have quite a lot of purple fringing at the wide end (even more than the 16-45!).

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

I have not noticed any major PF in any of the shots I've taken with my 16-50. I have not really shot in high contrast with lots of edges though. I'll have a look through my photos and see if there is anything there. Seeing as I don't know I'd generally take that as I've not seen any.

CA on the other hand can be quite tricky to remove from shots at 16mm.

Thanks Tyr.

It's pretty obvious in some of the shots I took.

Here's a 100% crop from the 16-50 at 16mm (wide open):




Here's the same view using the 16-45:




Not great, but nowhere near as bad as the 16-50

R

Hello all, this is my first posting here since finding the excellent forum and I hope it can be of help. I've only just become a Pentax user (K100D super) and also via the recommendations on here, a Tamron 70-300mm lens owner. This lens suffers the same PF problem at the long end. I recently found a link to an article on how to repair the dreaded PF (a regular occurence on my Fuji). The article revolves around altering the hue/saturation and light levels using Photoshop, PS Elements and Paint Shop Pro but the same outcome can be got with many other editing programmes. Link to the article here: http://www.great-landscape-photography.com/remove-purple-fringing.html

Thanks for the tip Gowerray

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

I'm looking at that shot, and am left wondering "why?".
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?

Not sure what you're getting at - it's a crop from a test picture

Hi Reuben,

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

I'm not sure if it will make you feel any better but mine does it too. However it only seems to happen in extreme conditions and for me ususaly does not detract from the purpose of picture.

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

Hope this helps:-









I'm sure if it's not up to spec, Chris would have no problems sorting out, bought mine there as well (new).

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.

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

Thanks GlynM and Unlocker for your samples

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

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 ), a very nice lady who didn't mind me taking it for a quick walk. Would have liked to have given it a longer try, but that would've been unfair on all the nothers who wanted to see it.

Should have seen how it was at minimum focus too.

Dan

Has anyone tried using an Ultraviolet filter to cut down PF/CA?

Vic.