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05-02-2009, 06:23 PM   #1
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Who is causing this ghost effect: Takumar 28 or K10D?

Hello guys. I've been lurking this fantastic forum for about 2 years, but just now I have a big question for all the wizards we have here.
Wizards, because even after almost 10 thousand pictures I've made since I bought my beloved K10D 2 years ago, I can't achieve the same fantastics results i saw here so many times.

Please have a look in this picture I took yesterday with my K10 and a SMC-Tak 28/3.5, no pp, just crop. Could you tell me what can make this wierd ghost effect you see in the sign?

All my pictures look like this and I can't figure what's wrong. I'm using an original pentax adaptor, alluminium foil for right metering, it was a sunny day, lens perfectly clean, no filter attached, i just can't understand what's going on. Many thanks

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05-03-2009, 04:39 AM   #2
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Mybe I couldn't express myself good enough (sorry but english is not my first language ) or maybe that's not the right place to post, but you can see what I mean about my pictures in this extreme crop. Letters seems to be blurred. Is this a problem of no infinity focus? Or, is there any problem if the lens is not properly mounted? (I remember i folded the alluminium foil twice or three times before use it).
Thanks
Ron
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05-03-2009, 05:29 AM   #3
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If don't use the aluminum foil, are the pictures still blurred? I find that if I fold the foil it becomes to thick for infinity focus. I don't use the foil anymore these days unless I plan on not changing lenses.
05-03-2009, 07:44 AM   #4
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Pardon my ignorance, but why and where are you using aluminum foil?

Before your answer, I presume you are using the aluminum foil "sandwiched" between lens and body mount, as to short some of the contacts in order to have a "proper" light reading.

If this is the case, let me tell you a long story as short as possible.

I have an FA*200/2.8 IF (ed) lens, which from new, was not giving very good results, even when used back then with my PZ1P (film). About a year ago, I took the lens for a complete CLA at the local Pentax representative (along with all my other 12 lenses) and two days later, the technitian called me and asked me If I was getting "acceptable" images with the FA*200/2.8. I told him that I was not completely happy with it and thus that lens was rarely used.

He told me he discovered, when disassembling and then putting back together the lens, that the front elements group was misadjusted "very slightly" (he used a colimator for the adjustments). He asked me to go by so he could show me what kind of misadjustment he was taling about.

The thing is that this lens`s fron elements group does not "stop" at some flange into lens body. The front elements group goes into a very thin helicoid thread and it should be "adjusted" to the proper position. In my lens's case, the factory setting and the real perfect adjustment position, was off about 1/6" of the helicoid thread turn. In real terms, this is about 1/6 of a helicoid thread path of about 1/2 a milimiter, or about 0.0833 millimiters.

This very slight misadjustment, made a HUGE difference. Now my lens is tack sharp from wide open to closed down. The only thing that pisses me off is that I had that lens for almost 8 years before and never ever thought about it could be misadjusted from factory.

This is an example:





Now, back to your aluminum foil..... how thick is it?

05-03-2009, 10:25 AM   #5
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OMG!!! What a sharp this parrot is! I'm really impressed.
I never got a picture sharp like this and always find excuses for that. First I say that's because it's a "kit" lens, them because sigmas are soft, or because I'm using a manual lens and finally when everything is right I blame my own eyes for not take a sharp picture.
So, as being able to try different lenses, manuals and automatics, screw mounts or PK mounts, and get always a soft or out of focus finish, do you think that could be a problem with my camera? Is there any way to test it, homemade speaking?
05-03-2009, 11:21 AM   #6
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It's not really fair to compare your kit lens to the FA*200. of course it isn't as sharp. But don't underestimate the skill of the photographer, either.

Anyhow, in your original picture, I have no idea if the foil is affecting anything of not, but can you prove the sign should have been in focus? It's kind of hard to tell, but it looks like the point of sharpest focus is a little in front.

Mostly, though, the softness you are seeing seems likely to be the sort of thing many lenses exhibit when shot close to wide open in harsh lighting. Do you remember what aperture you were at? Also, if that was shot with a 28mm lens, it must have been a pretty significant crop. Hard to tell from just the one shot, but I'm not sure it looks out of the ordinary for a 100% crop from a lens shot wide open in a high contrast setting like this.
05-03-2009, 03:14 PM   #7
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Something definitely looks wrong IMO, though I don't know what. There is strong side lighting but you say 'all pictures'. At first I thought that a lens element could be misaligned, but if you are getting this kind of result with all of your lenses then I have to think that the camera is to blame, almost like the sensor is smudged. You say that all your pictures look like this, if that's really true then something's definitely wrong. This also happens with K mount and AF lenses?
05-03-2009, 04:07 PM   #8
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Paying closer attention to your picture, It comes to my mind that a few months ago, I started getting results much like yours. Some strange "glow" from contrasty objects and it happened ONLY when using my Tamron 2X TC, plus any lens in my arsenal. I used the TC only with my FA 50/1.4 or FA 135/2.8(IF).

My images lacked contrast and like yours, they showed an unusual glare around contrasty object, not neccesarily highlights.

After close inspection of my Tamron 2C TC, which showed no signs of fungi, fingerprints or dust (it looked mint clean), I decided to do the flashlight test. That is, to light a flashlight through the lens (in this case the TC), removed from camera body. To my surprise, the TC exhibited a "milky" glow inside the glass, which my other TC (Tamron 1.4X) did not exhibited.

A quick call to the camera repair shop and the guy told me that most likely, an element group which was factory cemented, probably developed this fogginess that could only be seen with a strong light through the glass. To make another long story short, my TC was toast.... I was only able to compare it to another TC (identical, new in box) which did not exhibited this glow. Now my TC, after "degutting it" has become a fulll AF auto aperture extension tube....

So, go get a strong flashlight, remove lens, open wide and say Ahhhhhh!

05-04-2009, 03:38 AM   #9
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I'm right now trying to corfirm my statement, looking my photo collection with different lens and I will try to post different examples. I'm sure that this extreme case happened before with other manual lenses - i have a few. Unfortunately I don't have many AF, just the kit lens and two other sigmas zooms. Maybe the original focus screen allied by a unfocused vision is my main problem . Maybe it's time to try another focus screen instead to blame my lens.
05-04-2009, 08:49 AM   #10
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looks like a dirty filter or lens element to me

do you clean your lenses?
05-04-2009, 10:25 AM   #11
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Yes. Most of the times, they are pretty clean. The takumar I used in this picture was very clean, front and rear. I don't use filters, not as a protection factor, only polarizer and nd filters.

QuoteOriginally posted by Gooshin Quote
looks like a dirty filter or lens element to me

do you clean your lenses?
05-05-2009, 08:11 AM   #12
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QuoteOriginally posted by Marc Sabatella Quote
It's not really fair to compare your kit lens to the FA*200. of course it isn't as sharp. But don't underestimate the skill of the photographer, either.

Anyhow, in your original picture, I have no idea if the foil is affecting anything of not, but can you prove the sign should have been in focus? It's kind of hard to tell, but it looks like the point of sharpest focus is a little in front.

Mostly, though, the softness you are seeing seems likely to be the sort of thing many lenses exhibit when shot close to wide open in harsh lighting. Do you remember what aperture you were at? Also, if that was shot with a 28mm lens, it must have been a pretty significant crop. Hard to tell from just the one shot, but I'm not sure it looks out of the ordinary for a 100% crop from a lens shot wide open in a high contrast setting like this.
What is up with the foil?

Please clue me in.
05-05-2009, 12:52 PM   #13
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Some people like to use metal foil to short the electrical contacts when using certain lenses on certain cameras in order to fool the exposure & metering system into behaving differently. Can workaround certain types of exposure problems that occur with certain manual lens / camera combinations. If you don't have problems, then you don't need this (potentially dangerous) workaround. If you do have problems, you might try Googling for "foil" along with information about the specific problem you are seeing, to see if there is a simialr workaround for your particular problem.
05-05-2009, 01:13 PM   #14
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QuoteOriginally posted by rburgoss Quote
Paying closer attention to your picture, It comes to my mind that a few months ago, I started getting results much like yours...

After close inspection of my Tamron 2C TC, which showed no signs of fungi, fingerprints or dust (it looked mint clean), I decided to do the flashlight test. That is, to light a flashlight through the lens (in this case the TC), removed from camera body. To my surprise, the TC exhibited a "milky" glow inside the glass, which my other TC (Tamron 1.4X) did not exhibited....

So, go get a strong flashlight, remove lens, open wide and say Ahhhhhh!
I think you may be on to something here. That SMC Tak should be pretty damn sharp even wide open, and this "glowing" that's going on is something I've never seen with the several copies of the lens that I've had [and miss btw].

Regards,
Mike
05-05-2009, 01:22 PM   #15
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Looking at the flag behind the sign, it appears that it was windy. Maybe the sign was moving in the wind which affected the focusing. Or it could even be to do with light shining on the gold paint causing the effect.
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