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Old Apr 8, 2007, 4:29 AM   #11
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robar wrote:
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i see you do not know pentax lenses at all.
BURN! Hayward, you got served!
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Old Apr 8, 2007, 9:30 PM   #12
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Hi All, thanks for the replies,

As mentioned, it is a pentax m 300 f4 prime...

I really wouldve loved to upload a picture....but unfortunately my pc crashed, so I cant upload a pic

I will test the lens more and try to improve the results....

And Also the lens itself has a hood built in....

Will try to find a 70mm uv filter, but those are damn hard to find here
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Old Apr 9, 2007, 1:17 AM   #13
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And that is not a cure all either, and my DEEPLY hooded SIGMA 70-300mm would be very muddy/cloudy looking just off axis setting sun than my new (to me) Tamron hoodless 70-210mm early (pre SMC... if there was AF then... or post cheap subbrand Ta) FA lens.

Does a remarkable job of rejecting that just off axis) flair/clouding/muddiness. It can take a hoog but filter mount only. (About a 15-20 deg difference in that between current (non APO) Sigma and a pre SMC(or cheap post second brand) Takumar 70-210mm. Sill a very shap/bright good contrast lens for what it is... especially used for about $80

As to UV filter, direct into (or near) light source shots (like a sunset), even the best can cause real internal reflection (like ghost spot) issues.
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Old Apr 10, 2007, 3:14 AM   #14
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Hi Chesslanka,

PF is more common with long tele lenses, and for some reason the K10 seems to exhibit it more than the previous 6 MP Pentax bodies, in my experience. I believe that it's due to sensor "blooming" in high contrast areas, and all my lenses (some really good ones included) show it to varying degrees in the situations where I'm shooting a dark subject with a bright sky in the background, or a white subject in front of a dark background.

The M* 300 /4 is, IIRC, the same optically as the A* 300/4 and is a GREAT lens, but the optical design does not control CA and PF as well as later models. The design of the F* and FA* 300/4.5s added ED (Extra Low Dispersion glass) lens elements which control these better, but not completely. ED glass is also known as LD (Tamron) SD (Tokina), and APO (Sigma). Generally, shooting at smaller apertures as Crash mentioned will cut down or eliminate this, but sometimes you don't have enough light, so you just have to correct for it in PP.

Scott


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Old Apr 10, 2007, 3:18 AM   #15
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snostorm wrote:
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Hi Chesslanka,

PF is more common with long tele lenses, and for some reason the K10 seems to exhibit it more than the previous 6 MP Pentax bodies
Well again that is TOTALY a LENS ISSUE it has NOTHING to do with camera or body, except MAYBE in post recorded exageration... but in the image/lens to begin with
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Old Apr 10, 2007, 3:23 AM   #16
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Still haven't seen an example of what you are talking about.... MAY WE???


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Old Apr 10, 2007, 11:59 AM   #17
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Patience guys....I live a long way from home.......Next weekend for sure
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Old Apr 10, 2007, 2:10 PM   #18
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Hayward wrote:
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snostorm wrote:
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Hi Chesslanka,

PF is more common with long tele lenses, and for some reason the K10 seems to exhibit it more than the previous 6 MP Pentax bodies
Well again that is TOTALY a LENS ISSUE it has NOTHING to do with camera or body, except MAYBE in post recorded exageration... but in the image/lens to begin with
Unlike you, I've shot extensively with both the DS (over 40K shots) and the K10D (over 10K shots). I shoot birds predominantly, and that means a lot of shooting in situations where PF rears its ugly head.

Here are two shots with the Tamron SP 300/2.8 + Tamron 1.4x Adaptall II and the Pentax F 1.7x AFA. Totally unscientific -- just picked up the cameras and shot through my back door window handheld. The shots are about 20 seconds apart, and I didn't notice any change in the lighting, but the eyes are easily fooled.

first the DS



and with the K10D



I was quite surprised by the difference in PF exhibited by these shots -- it usually isn't this stark -- and I can't explain the difference in exposure -- both cameras were set to the same settings though the K10 shot exif shows ISO 400 -- it was set to 200 on the camera, like the DS.

All I know is that I immediately saw the difference inCA and PF when I first got the K10D, while playing around with my workhorse FA*300/4.5. I'd never thought that the body/sensor would make a significant difference, but it obviously does. The difference in exposure probably exaggerated the aberration, but I think that these results still tell the tale.

. . .and no, I'm not interested in trying another comparison, trying to get the exposures exactly the same. I know what I've seen in a quite a few shots with both cameras, and I know that there's a difference between bodies/sensors. You may believe it or not -- or come up with whatever explanation that you want. I just know what I know from experience, and tho I might not be the most stable person, I am a reasonably competent bird photographer, and will go with what I've experienced over what I've only read.

BTW, I remember this subject coming up in the DPR forum, and a number of people had come to the same conclusion, but the search there has been down for quite a while, so I didn't bother looking for the thread as corroboration (sp?).

Scott


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Old Apr 10, 2007, 2:33 PM   #19
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hey scott,
i'm very surprised by these shots also. it must be the way the camera's processor is reading the wave lengths. i think i'd write pentax and show them this example. this looks totally like a programming error that should be addressed in a firmware update.

roy
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Old Apr 11, 2007, 4:00 PM   #20
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Hi Roy,

This is a good suggestion, but I don't know if there's a firmware fix that's feasible, but I imagine it's worth a shot.

Personally, I'm not that bothered by PF and CA that much -- a high percentage of what I shoot is in very high contrast situations, and with TCs which only make the problem worse -- I've learned how to pretty easily and quickly correct it in PP when necessary, but it would be nice if I didn't have to deal with it at all.

Scott
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