Sunday, March 25, 2007

Unfavourable Colour Response of Quite Some Recent Pentax Lenses

Since I owned my D-FA 100 Macro lens two years ago, I found that it often produced colours which look somehow strange to my eyes. Such unfavourable colour response is simply something which I don't like, maybe personally, but, it has never been seen by me before for any previous original Pentax lenses, especially for Pentax primes which have been renowned for decades for their rich but yet accurate and natural colour rendition.

Indeed, the unique favourable colour response of Pentax's optics *was* one of the top reasons for "why Pentax?". However, this unique Pentax character seems to have been got lost for quite some of their latest lenses since the Tokina-Pentax "Co-development" era and/or since the "Lens Made in Vietnam" age. Another top reason to go with Pentax have been their superb and unsurpassed flare control of their lenses, it still holds true for most of their current products, yet very fortunately.

To describe more about the "unfavourable colour response", the problem is that pictures happened to have WB (no matter for Auto or Manual) wrong more frequently but even though the WB is correct, pictures look cool plus usually the green and blue colours are looking odd. Skin tones are not looking good neither. Scenes and landscapes are looking unnatural. (So, what application would the lens is ideal for?) There is usually kinds of blueish and/or greyish tone on the images, which is hard to describe. For green colours for trees and leaves, an overlaid yellow tone could be seen.

Here are some examples (of mine):-

(All pictures were shot in RAW and with some amount of +ve digital compensations when converted to Jpegs to compensate for the underexposure and no other adjustment was made, except for the last one of which the WB was also adjusted as the AWB was seriously off with very strong orange cast for the recorded RAW.)

It should be further noted that the same observation of mine holds true for all the Pentax DSLRs I have used, when I compared the D-FA prime lens against other older FA primes or even zooms, for the same camera body used with the different lenses.

Actually, you can view quickly the brief EXIF info, which I have preserved in the above downsized pictures, I recommend to install this extension for Mozilla web browsers. To view the pictures in large size, just click on them.

To compare further, I have selected a set of similar macro photos with my "digital optimised" D-FA lens against an older FA Star lens, first see the following recent photo of mine which I took last month, for a little bee, with my K100D:-

Indeed, I took the picture under direct sunlight in RAW and the original RAW file did sufffer from very strong yellow/orange cast. Ditto for quite some flower shots which were taken at the same time. This is not an AWB problem as even I chose the standard "Daylight" setting in the Pentax Photo Lab (the original bundled RAW convertor), it still didn't help. So, I corrected it using the grey point tool. In fact, I have never experienced similar problem(s) with any of my FA primes for similar shooting environments, i.e., the colours are right mostly at the first place when shot under sunlight as recorded and no significant re-touching was required!

To compare and to see what is the true Pentax quality on colour rendition, anyone can look at the samples below, which were taken with a FA* 200 Macro, especially for the excellent rendered colours. The pictures were taken with a K100D too, which I must say is the best Pentax DSLRs up till now for the colour response (Sorry, not the K10D, IMHO):-

BTW, some people may ask: What's the big deal? ..even if you yourself don't like the colour reproduction of a *particular* lens . . .

But what I wish to point out is that the mentioned strange colour reproduction is NOT an isolated case for *recent* Pentax lenses in the *current* "digital" lineup. It is indeed a common "problem" in my opinion, especially for quite some of those more expensive ones! (but Why?) First see this (terrible) sample photo below, which is posted in the latest K10D review of Steve's Digicams, which was taken with a DA 70 Limited:-

Once again, I can see the unfavourable colour response which I have mentioned above and this one is actually very exaggerated for the undesirable effect. Well, and, that undesirable effect is exactly of the same "style" of what is being described and shown here (but the effect is even more dominant).

Well, again, to compare, we can have a look on another picture taken for the same scene in Steve's K100D review, this time with a DA 21 Limited:-

What I would say is that the colour reproduction of the DA 21 Limited is right on the K100D and it is what a *Pentax* lens should produce in my mind. Although the picture was taken in the "Bright Mode", I can guarantee that the huge difference you see is simply not because of this and I can surely tell that the Bright Mode can only make things worst if there is any colour cast or any unfavourable colour response! It is just because the Bright Mode exaggerates colour saturation and brightness and if there is a colour problem, it will be shown up more clearly. Although one may still argue that the weather and lighting conditions could be different, I would say the big difference in colour response can be seen clearly, already. Also, I think that an experience reviewer like Steve would not be stupid enough to shoot a sample photo in bad weather or poor lighting conditions, would he? I bet he does know how to take nice looking sample photos for his review afterall.

Recently, Ned Bunnell has posted a number of the DA* 50-135 sample photos at his blog:-

Unfortunately, I found the same problem in most of his photos and I don't like the colour response neither. As Ned's sample photos should be considered as more than semi-official, I must be "convinced" this time!

Ironically, I must mention about that the same problem has *never* been found with the $60 kit lens DA 18-55/3.5-5.6 which I have already got two copies of it together with my *ist DS and K100D. The colour reproduction is of the old Pentax style which is very nice, although this kit lens's colour rendition is somehow over-saturated and exaggerated, but it is still "correct"!

So, at least, the good thing is that there still exists *some* recent Pentax lenses in the latest Pentax digital lens lineup that are right inside and are having the true Pentax image quality in the colour rendition department, e.g., the DA 21 and the kit lens DA 18-55. But unfortunately many others in the lineup seem do not, and even more unfortunately, those are usually upper class ones! (which required "co-development"?)

I don't know if there are some other people who will like or even love the "new" colours, but I'm sure I am not and will not be the one and so do many other people, I bet! The most worrying thing here is that the "new" colour representation seems to be the future way to go with the latest and coming Pentax lenses! Oh, No! Please.. I cannot really accept this trend, but, it seems to be the reality!

P.S. When people will probably ask me again, "What's the fuss about?", then I shall probably ask back the main question, "Where has the true Pentax character gone?" :-( Well, of course, I refer to the unique and favouable optical character here, especially for the colour rendition department, but, those were the days..

Read also:-
Scary Tokina 16-50/2.8 Official Sample Photos

RiceHigh's Subjective Ratings on Pentax Lenses on Pentax DSLRs


Anonymous said...

Your monitor must be off.

RiceHigh said...

Can't you see the differences??

Anonymous said...

Nope, me neither.

chromatic said...

I actually see what you mean, and I do agree to some extent. Using my m42 lenses gave me better results at first, but then one of my co-workers pointed out something important: newer lenses for digital aren't, like older lenses, optimized for maximum contrast and warming, like the older were. Back in the day, contrasty was good, because you could always use a "flat" film if you wanted to, and most shots would go straight from negative to paper. What I did to get perfect results was to up the contrast and some times the saturation in camera for those street shots, and then more accurately measure WB, or just shoot raw.

And BTW I have the same problem with Canon, Oly and Nikon, even though Nikon is slightly more accurate when it comes to the matter.

tot said...

I have a k10d from about one year. Just using this camera(my first DSLR) I saw that something is wrong : focus in low light, colors, metering underexpose, the shadows are posterized etc.
you have right about all - including new lenses. nice blog !

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