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!

Lemmy, I am not upset by your pictures, I am upset by your mis-understanding of what i've been trying to explain to you.

FIrst of all, cameras like the K20 have INDIVIDUAL FOCUS ADJUSTMENT FOR EACH LENS. And therefore, yes, as you say, "it is reasonable to expect a photographer to do this"!!!

I did not say that "each lens will be focussed differently because they are constructed differently" I said that EVERY LENS IS DIFFERENT, AND MIGHT BE FOCUSSING DIFFERENTLY. (Please read the article I linked previously)

THe distance between the last element of a lens and the sensor is probably different in every lens you own. Just look at them!! My 100mm Macro's last element is a whole inch inside the body of the lens!

I really wished you understood the physical difference between lenses as REALITY - And then preoccupy yourself with assessing, if your lenses actually have an individual back-focus/front-focus issue, or not. (The answer is YES btw!)

passionately i would say.

I am italian, and I apologise for the "loudness" of my post.

[quote:3496ace15f="lemmy"]I am beginning to lose the will to live here!

I am satisfied that the focus is not out. Both the kit lens at 35mm and the DA at 35mm were on auto-focus for these shots. If one is out, would the other not be? The phase detection focus unit is in the body, after all, not in the lens. ""

OH MY GOD ARE YOU KIDDING ME?

And you are the one that's beginning to loose the will to live???

So you're saying that if 1 lens focuses correctly on your body (which you still haven't said what body it is) then ANY OTHER LENS MUST BE FOCUSSING CORRECTLY AS WELL???????

Seriously now, you do understand that every lens is different, has completely different design, number of elements, distance from one component to the other, and distance from the focussing screen and sensor. How can you even think that each lens will behave in the same way???

and NO i'm sorry, but as good as the kit lens might be, it is NOT better than ANY prime lens in the pentax range - IF - you have a correct focus of the lens on your body. THe pictures from the 15mm are horrible, and the lack of distorsion is nothing special at all, considering that many zooms are just as good.

It helped me not loosing hope on my 50 f1.4, and 31 f1.8, and 100mm macro that all need some minimal adjustment, and I can look forward to buying the K7 that (like the K20) should have lens focus adjustment....

Can't wait!!

I completely agree with Daniel.

What is astonishing to me is the fact that with your "Hasselblad, Nikon, Leics, professional days" - can consider these results acceptable.

Surely your experience should tell you that a £400 lens SHOULD be sharper than that, and if it isn't then PROBABLY there's a focus issue which you haven't been able to takle.

Maybe this article will explain why, we insist on the fact that your lenses seem to have FF or BF situations.
http://www.lensrentals.com/news/2008.12.22/this-lens-is-soft-and-other-myths


Regards,

I'm absolutely not sure about the fact that Snootchies needs another flash. AT ALL.

Flash is a very VERY complicated thing to work out, and in portraiture, one wouldn't want to start experimenting with flash until long after having mastered natural light.

therefore, here are my suggestions.

- Its great to experiment, and your wife is very kind in helping you out. I do this as well with my wife-to-be, and sometimes I ask her for 10 minutes of her time to pose for me. I will ask her in advance what type of shot i want to do, so that she (who's not a model) is prepared to assume a certain pose, or facial expression. examples might be - Sexy look, fashion look, innocent look, girl power, provocative, or anything else that comes to your mind. She also helps me out by wearing clothes that more or less represent the need of the shoot. (A black shirt is not always the best option for the type of portraiture you are doing.)

- Ok PUT DOWN THE FLASH! immediately!!!
THe flash on the camera is completely pointless, it will give only harsh lighting, very harsh shadows, and no flattering images at all.
- In your situation I would strongly suggest to use ONLY natural window light, and learn how to master that. So place your model next to a window, and (if you want to experiment) get a sheet of kitchen foil, and use it as a reflector on the shadowed side of the face.

- Camera settings.
Anything below 30mm (+/-) will deform to some extent, due to the wide angle. I think you should definitely use 35mm and above for any portrait work you do. Ideally you should use much longer focal lenghts, to allow for a more flattering perspective of the model's face (50-100mm).
ISO should be kept low. Although I don't know what camera you're using, to retain image quality so necessary for portrait work, you want to use ISO below 400.
Aperture can be wide open if the lens is sharp- or even if its a bit soft. DO consider that you might not have the whole face in focus though, and perhaps you might want to stop the lens down by 1-2 stops to provide enough depht of field to have the whole body in focus.

- IF these parameters give you a long exposure time, I would strongly suggest you get a tripod. Or, to make it cheaper, a beanbag, or anything you can rest your arms, or the camera on, whilst shooting.

- One more suggestions would be to place the model some distance away from the background, so that she doesn't look squished into it, flattening the image.


I think the starting point is great, and I've seen your work on flickr and some images are really gorgeous. Now you only need to go slowly, and not rush into lighting and complicated setups that will only distract you from the task of taking a good portrait.

Good luck, and hope this helps.

Oh Hey John! how's your DS doing ????

Usually by kit lens we intend the DA 18-55mm M I or II , so reading your first post, it was unclear as where you could find 70mm on an 18-55mm lens.

Cameras are bundled with lenses to help buyers. They don't "come with lenses" - they are DSLR's and therefore could easily come with a 300mm lens instead of the 18-55mm.

Although I appreciate your certainty in assessing the correct focus of your prime lenses, perhaps a thorough examination with focus chart and shots at various apertures would allow (us) to understand why a 15mm limited prime lens that costs much more than an 18-55 is so much less sharp than the zoom.

It is indeed very common for prime lenses to be slightly front focussing, or back focussing, and the results would become apparent in a test like the one you carried out.

Regards,

Hi there,

In order to try and give some advice, I have a couple of questions.

-What was the intention of the shoot, for you and for the model

-What lighting have you used

- What focal lenghts have you used -

- What aperture and time have you used.

If you can answer these questions, then probably we'll be able to help understanding what went right, and what didn't.

Looking forward to your response!

Nathan