DAs Versus Kit

Lemmy,
as an example... I have individual focus adjustments set for my DA*16-50 and my FA 50 (they are both quite different). My DA* 60-250 did not need an adjustment.
BTW these are settings in my camera, not the lenses.

Three lenses three different focus adjustments, that's my experience

Lemmy

The GX10 like the K10 does not allow individual lens adjustment, so any adjustment you make via a special debug menu will be a compromise and will affect all your lenses. This is one of the big advantages of the K20/GX20 over the earlier models.

In the case of my K10 I settled on an adjustment that seemed to work well with my FA 35, FA 31, DA 16 -45 and DA 18 - 55. The biggest problem this causes me is FF with my FA 50mm.

I was going to post some comparative images of the 4 lenses above at 35mm, but I think the point has already been well made. The FA [email protected] and FA [email protected] are sharp wide open. The DA 16 - 45 is not to far at F4.0 behind, at F 8 all are good.

Steve

So this focus adjustment is necessary with manual focussing as well?
I simply find it hard to believe that if I see a sharp image on screen (with all my lenses) and they all show a sharp image when tested against the ruler, that somewhere there is a focussing problem.
I must say that after a lifetime as a professional photographer and never experiencing any (sober) focussing problems with any cameras and with lenses ranging from fisheye through 400 f2.8, rangefinder and all, a digital cameras is produced that cannot translate a sharp image on screen into a sharp one on the screen.
Who would let a camera out with such poor quality control? What use is a sharp lens to the average amateur as I am now, if you cannot buy it and have it work from the box?
This is an appalling step backwards. Leica could produce a camera with reliable focussing, line up the rangefinder and go, 70 years ago.
If I post a series of pix from my lenses of the ruler, say, could someone help me evaluate them?

Leicas don't have a pentaprism Lemmy, they have a rangefinders.

In any DSLR or SLR with a pentaprism, what you see in the viewfinder whilst focusing, is the image reflected from the mirrors IN FRONT of the sensor. Therefore there can be a discrepancy between what you see in the viewfinder (or what the camera reads as correct auto-focus) and what is recorded by the sensor.

Exactly the same issue was present in film times, only that than it was much more rare to pixel peep at 100%, and the slightest focus issue would rarely become a problem.

THe article i posted explains everything about how quality control assures a measure of 'correctness' in both body and lens. Inside this measure (say +/- 1 ) everything is quality control acceptable.

But anyway, there hasn't been any step backwords, it is only modern technology that allows you to 'see more' than you used to before.

It would be better if you did a very thorough examination with a focus chart. BUT, and this is a big BUT, it is almost pointless for you to worry about this issue, because as Steve said, your camera cannot be adjusted to individual lenses, and it would need to be sent to Pentax (or Samsung) together with every lens you own, for them to calibrate all of them together, body with each lens. Probably the repair would not be successful, because under examination the lenses and body probably fit in the quality control measurement, so nothing will be changed.

Sorry about all this, I understand its a pain to understand these issues, and it would just be much better to keep your 'soft' 15mm and enjoy it to the fullest!

Isn't the simplest thing Lenny can do is buy a K20D and configure each lens?

In days of film keeping the wretched stuff flat in the camera was always a challenge. I can recall applying a microscope to Leica and Nikon negatives and being impressed by the detail you could see but I don't recall doing it to evaluate focus in the way we pixel peep these days. Bear in mind I was a nerd before the word was invented. Born out of my time!

Let's also recall that while the rangefinder was good in a Leica so was their engineering and boy didn't you pay for it. I can't recall what a new Leica IIIC would cost new in today's money but I bet it's a whole lot more than 500 quid. I think a Leica III with lens cost $300 new in 1947 and using an inflation calculator that's $8,000 today (YMMV).

And here's an interesting link about how a Leica could lose it's focus

link

For myself I'm still so happy that Nathan posted that link which explains how you can get an apparently superb lens for no clear reason. Now I know why I love my 35mm f2 - it sits on the sweet spot of my body. The temptation to get a K20 is becoming ever greater - argh!

Mike

Well, I thank everyone here for their help. I have worked for some of the greatest mags and newspapers in the world, was Paul McCartney's photog for two years and never had focus issues. What kind of living would I have made with out of focus pictures at this level?
I now find that I have a camera for which I can pay over £500 for a lens which I can never be sure of focussing accurately - or if I can focus this one accurately I cannot be sure of the others. If what I see on the screen does not correlate with what I find in my picture, I question the purpose of an slr.
I'll ignore the fatuous remark about Leicas having a pentaprism. I have my old M2 on my office desk - I see that it does not have one. It does focus accurately, though, with both the 35mm f2 and 90mm Summicrons.
I guess I'll change systems, I'd like a system where I could rely on the integrity of the maker, if there is one, of course. Even Leica is just a rebadged Panasonic now.

Go ahead, if you think you can find one. In the real world, all DSLR manufacturers have the same problem. The big three, Pentax, Nikon, and Canon (I don't count the toy manufacturers) allow for AF adjustment on their bodies.

I think you're a little harsh and are a victim of the new technology. I am sure that there were many cheaper and less well engineered cameras that didn't focus as well as Rolleis, Hassleblads and Leicas in their day but we didn't have the technology nor inclination to be quite so investigative.

I can recall (just) the tests AP used to do on cheaper cameras and lenses such as the Practica that showed quite soft results and no way to improve them. If the Practica say was £100 in 1970 then that's nearly £900 today. You're not comparing like with like and expecting Leica build for Practica prices. Didn't happen then, doesn't happen now. Or am I wrong?

Your own solution is to get a K20 body and calibrate each lens - or perhaps visit a dealer and do this to assess the real potential of your lenses.

That said I was very happy with the results from a 40 year old Rollei and 30 year old Leica in the 70's but I never enlarged above 10x12 which would be about 6 times enlargement for the Rollei and 10 times for the Leica? Given pixel peeping the magnification must be much more than those?

Mike

Peter, Olympus do also on their newer bodies

What a commotion.
Lemmy download a foucs test chart and simply try out how the focus is.
When looking at the photo of the ruler it looks like the focus is alright though to be honest.
It's just very strange that more expensive primes doesn't preform better then a "simple" £60 zoomlens, I hope you do agree on that and understand us being negative on your result.
I don't believe the DA15 is optical an excellent lens wide open at f/4 qua sharpness but it's almost distortion free so in that respect.

Could you redo the test but then at f/8, the results should even out.

I do feel cheated - I spend £1000 on lenses which I cannot just fit on a camera body and use to their capability without being a technical expert.
It's true that I'm not buying to the same standard as when they were tax allowable for me but having come back in to photography after a few years, I expected it to be less of a technical minefield rather than more, most technology having become consumerised.
I can understand autofocus being dodgy - it's not necessary anyway, just a convenience and I mostly don't use it. It's the fact that I'm going to get fuzzy pix even if I focus manually that bugs me. If the focus was always out by a certain amount I could learn to compensate but the fact that it's different for each lens is a real mess (to me).
If I had known I woudn't have bought the 'fuzzy' 15mm or chanced to luck with the other DAs, I'd have stuck with the 'sharper' kit lens since I can't have both with accurate focus. There was no information about that that I saw when I bought and now the only recourse if I want full peformance from all my lenses is to spend out yet more on a body that's regarded as 'better' merely it does what it's supposed to. How many people buying this stuff know that when they buy, I wonder?
That's marketing, I guess.

anvh, to answer your comment, I'm so p***** off with my gear that I don't even want to put the lens on the camera again. I can tell you that at f8 it's a different lens. But so is the kit....There aren't many lenses that are no good at f8.
I've paid out over £500 for a lens I can't focus and whose only advantage is a lack of distortion which I can correct on the kit lens in Photoshop anyway - if not quite as well.

Lemmy focus isn't probable your problem simple get to know your lens better. Limited are great lenses and also very small and that also comes with some cost of course so sharpness isn't the best wide open but stopped down. Then also the bokeh and other aspect of the lens comes into play, sharpness isn't everything. I believe you said something like this earlier.

The DA15mm is a great lens for landscape and architecture so what is more important for that type of photography, sharpness at f/4 or distortion free lens?
The DA15 is still good sharp in the middle wide open so still usable for the strange shots handheld in my opinion and if you use it between f/5.6 and f/8 the sharpness improves a lot.

The same thing with the DA35mm MACRO
The only lens you used like it was designed to do were the kit lenses and the DA70mm and those do prefrom well indeed.
So now campare the DA15mm and the DA18-55 when doing architecture, I'm sure the DA15 would be the best one.

Lemmy, I'm sorry you are frustrated with the lenses you have purchased but as a beginner to this wonderful hobby, I will gladly take your DA 35mm Macro off you and take my chances with it on my K200D. For a reasonable price of course!

Don

Thansk for your patience with me, gents. I'm going to research the value of my stuff and decide what to do.
I feel a loss of money coming on!