Chromatic aberration/ the fringe

Some of you will realise that i've not been on the forum for some time. The reason being that i left the Pentax fold after a 38 year relationship and am reasonably happy where i am though i'd like to return via the K1.
My last and the camels back breaker was the K3's sensor which suffered terribly from the purple menace. No it was not the lenses, which were the same i'd used on the K5 and images taken with my present camera confirm this. So does the K1 suffer from such an affliction?

Never experienced it. Well not true, but only the result of lenses, usually older ones not designed for digital. The newer lenses use achromatic optical designs and special extra-low dispersion elements to reduce it. The K-1 with the new DFA lenses is brilliant! You may get CA using some older glass.

Thanks for your reply John but I'd only ever encountered it once with the k5 using a m28mm f3.5 and never with the k200 also using a 16-45mm. The k3 displayed it using the 16-45 which I replaced with the 16-85 and it was worse. Reasearch also lead me to conclude that it was indeed the sensor and not the well worn theory that the optics are at fault.

The K1 has a CA reduction setting in the camera settings, which works with jpeg and raw files.

I will try and take a few pictures today with setting on and off, with the M 28mm 3.5 and post them here for you.

I have only just got the K1 and not used any of the M series lenses yet, but no sign of CA in any of the pictures I have taken with DFA and FA lenses.

I have occasionally got a little chromatic abherration where you would most expect it, high contrast against a bright white sky for example with the DFA 150-450 lens. However one click in Lightroom removes it with no noticeable loss of picture quality. As with noise reduction in Lightroom I have found that the RAW images from the K-1 respond much better than those from my K-50.

I measure CA as part of the EPZ lens reviews, and most lenses are very well corrected these days. Sometimes CA approaches zero at the centre.

CA is not a major problem as any residual fringing can be removed by the camera or by software, so I really wouldn't worry about it.

The in camera CA reduction can only be used with lenses the camera recognises, so can't be used with the M-series.

These three were taken with the K1 and M 28/3.5. At f3.5/5.6/8. Almost gone at f5.6.

These two taken with DFA 24-70 at f3.5. First one is with CA adjustment off, second with it on.

Surely if it was a sensor problem it would affect every image. I've not heard of that being a reason but would be interested to view what you researched suggesting it is. While not a problem, a sensor is quite different to a film emulsion.

The M 28 is one of the older lenses that can be subject to CA at the edges and being fully manual has no means of passing through its details to the camera body. The only way with that lens is to remove any CA in post processing. Most of the old pre digital lenses suffer from this to some extent but at normal magnification and viewing distances it doesn't usually present a problem. Back in the film days there weren't pixels to peep at 100% and the lenses were designed for film emulsions (sensors hadn't been invented!) The fact the old lenses work as well as they do on digital is a huge bonus and having a dedicated FF camera to use them on is the icing on the cake. Using them as intended at their original focal length on a full frame sensor means any aberrations are not so highly magnified; whereas using them on APS-C is the equivalent of using a digital zoom on a compact camera, lens faults are more obvious. One used to read that the K-1 would highlight lens faults more but that was not true (unless pixel peeping at high magnifications which is the same as with APS-C in any event.)

I'm surprised you had an issue with the 16-85mm I find that lens superb in all respects on several APS-C bodies, perhaps you had a bad one or hadn't calibrated its focus and it was out more than usual or more likely, you hadn't turned on chromatic aberration correction, or a combination of these. The 16-85, however, wouldn't be a first choice lens for full frame as its image circle doesn't cover the whole full frame sensor.

Many thanks to you all for taking the time to post some very informitive replies which have convinced me that the issue is very well controlled on the K1.

In hindsight i may have been rash in getting rid of the K3 and moving elsewhere especially as i had a plethoria of old K series lenses which i imagine will work a treat with the K1. However the raging red mist had taken over after reading this review

http://www.techradar.com/reviews/cameras-and-camcorders/cameras/digital-slrs-hyb...

Review correction - the 18-55WR kit lens is weatherproof. Have other reviews found a problem with CA? Looks like the reviewer was looking for reasons NOT to switch from Canikon. Cannot recall anything but high praise for the K-1 image quality, at least one saying it is possibly the best landscape dslr available today.

I've looked at her example of CA, and struggled to see it without zooming in to such an extreme that the picture quality had already degraded into a mess of 'jaggies'. I'd like to think I can be objective over the good and bad of 'my' brand of camera, but I really can't see the extreme CA she complained of.

I also read her review of the K3II, which despite being little more than a minor upgrade to the K3 (her view, not mine), appeared to be CA free. I'm afraid despite her antecedents I have doubts about her competence as a reviewer.

My K3 continues to delight. I'm very impressed at the range of corrections Pentax offers in camera for its lens range including correcting (minor) aberrations which are indeed down to severe pixel peeping! Funny old things online reviews at times and how years later we still have to put up with them unlike the old printed press.

I agree 100% with the contemporary comment after the article by Semi regarding that review. It seems the reviewer wasn't familiar with the camera enough to write a comprehensive review of it.
The point about burning out highlights seems very odd as if its something you'd want to happen. You wouldn't!
The fact some lenses show chromatic aberration shows how good the sensor is, out resolving the lenses. The 18-135 isn't a bad lens, but it isn't top of the range either, it's a consumer superzoom! The image I believe that was used as an example to show CA was the view through the tree. If so I can't actually detect any CA in it, even after clicking through to the full resolution image. That said, the same photo taken on ANother brand might well show CA, it isn't purely a Pentax issue, its down to compromises in lens designs.
I have to say in reality the review was quite ill informed and seemed intent on doing Pentax a disservice. Even so, the K-3 still got four stars, for what they're worth! It's sad the OP here was swayed by such a review that didn't suggest ways of overcoming the problem (if indeed it was a problem which it wasn't.)
Expect to notice flaws in lens designs using a K-1, but its not the camera's fault when they are evident. For Pentax branded lenses, the camera's correction database will do its best to mask any lens issues if you wish to use that option (the downside of that is It makes the process of writing a file to the memory card longer which could be dealt with in PP afterwards.)
It should be mentioned the K-3's dynamic range far exceeds much of the opposition at its price level and the K-1 betters that. It seems some of the other brand users are switching the way of Pentax now. Indeed the K-1 has proved so popular its price has increased, not gone down like most others do! Normally when buying a new camera model one expects to loose out being an early adopter pricewise. Not so with the K-1.

Here's one example of many where the issue is evident on the two trees at each side of the frame.