I have 2 spare split-prism screens for the MX, as I always use a plain micro-prism version.

PM me, if you're interested?

R

Looks like there's a lot of confusion around the different kinds of CA and Purple Fringing - at least there is in my mind

However, I found the following paper which seems to explain things nicely:

http://www.vanwalree.com/optics/chromatic.html

Of course, the original point of my thread was not to debate the minutiae of CA, but rather to establish whether the excessive amounts of blue fringing produced by my 16-50 were normal or whether I have a duff one

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

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

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

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

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

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

In my experience, the FA is by far the best of the 28/2.8's.

My copy is impressively sharp wide open, only the K28/3.5 is as good.

If you can find a good one, I wouldn't hesitate

R

It was good to meet Will & Unlocker. Shame I missed everybody else who came down.

My main objective was to check out the new 300, which I fancied as a replacement for my venerable old M*300. However, I was most impressed by the 200 - what a great lens it seems to be!

Also tried the 55-300, which was pretty good at the long end - much better than the 50-200 is at 200.

Looks like myself and Will missed out on all the freebies though

To compound things, Chris twisted my arm to buy a "Pre-owned" 16-50 and I was in a lot of trouble when I got home, after promising not to buy anything

Here's a (full size) shot of the new 35mm which I took with the 16-50.

http://www.bulsara.com/K20D/IMGP0190.jpg

This was taken on a pre-production K10D (note the 0.00 firmware version ), but look how good the white balance looks in the mixed (& dark) shop lighting...

Anyway, thanks to Chris for laying all this on!

Cheers,
R