K7 going into Pentax repair

sterretje · 04-13-2010, 10:51 AM

knoxploration already mentioned it; looking at your third picture (post #9), isn't there a front focus issue? Maybe time to post an non-processed example.

Having said that, there are a few threads here about Sigma lenses on Pentax bodies. It might be that the Sigma needs to be rechipped (not sure what it exactly means; adapted to K7?). Maybe you should contact them and hear what they say. Don't forget to ask if it will influence functionality with other bodies.

Somebody mentioned that he send his Sigma and Pentax body to Sigma and they came back perfectly calibrated.

MSsuper · 04-13-2010, 11:42 AM

Yeah, I was just thinking that. It looks like the focus point is just in front of the subject. The water just in front of the duck looks crisp.
I would swap the lens and see if it's a calibration issue with the Sigma lens only before recalibrating. Nothing else wrong here.

OrenMc · 04-13-2010, 07:05 PM

I appreciate the info guys but why am I not having any issue with the K10d. I tried focus adjustment on the K7 and that didn't really help.
I uderstand you can't say for sure without seeing unprocessed full file. But for the life of me I can't really get a good sharp picture with K7 and the K10 all I have to do is point and shoot and it sharp and crisp. I can easily shoot at a slow shutter speed aslo with k10 handheld but the k7 no way. If I don't have bright good light and fast shutter speed forget it. I know it not the lens.

knoxploration · 04-13-2010, 09:09 PM

Originally posted by OrenMc

I uderstand you can't say for sure without seeing unprocessed full file.

Why not post some, then...?

OrenMc · 04-14-2010, 03:11 AM

You can see full res at my flickr

knoxploration · 04-14-2010, 08:18 AM

Originally posted by OrenMc

You can see full res at my flickr

Unfortunately EXIF data has been stripped from the photo, so we don't know the shot conditions, which could tell us a lot.

It looks like the focus point is slightly nearer than the duck's head, though - the breast appears more in focus. It also seems from a quick glance like the entire image has slight motion blur - perhaps your shutter speed was too low, you took the shot before SR was ready (or with it disabled if you were shooting off-tripod / enabled and shooting on a tripod maybe). I'm guessing the shot was on a fairly long lens, as you probably weren't right up in the duck's face - SR is less effective at longer focal lengths, so if that's the case I'd again suspect the shutter speed.

But no way to know without the EXIF data, I'm just making wild guesses.

cardinal43 · 04-14-2010, 09:38 AM

Go to his flickr page and the duck picture looks to be the first 1 on the left. If you click on "more properties", the exif data will be listed.

knoxploration · 04-14-2010, 12:26 PM

Originally posted by cardinal43

Go to his flickr page and the duck picture looks to be the first 1 on the left. If you click on "more properties", the exif data will be listed.

Well caught. I downloaded the full-sized image from Flickr, so I guess either Flickr strips the EXIF data from the image, or my web browser did.

250mm (375mm equivalent) at 1/200 second with SR enabled - I'm going to guess that camera shake was the culprit for the blur. Either the SR just wasn't enough to counteract the camera shake at a longer focal length, or perhaps there's an SR issue.

OrenMc · 04-15-2010, 03:46 AM

Im thinking it is a SR issue. I have heard a few problems with the K7 and SR.
I can pull some crisp photos with the K10D at 300mm 1/30 sec.

Thanks again for all the help!

tokyoso · 04-15-2010, 03:59 AM

Originally posted by OrenMc

Not sure what that means. I have some okay photos there as I only post the keepers. I will post examples of poor shots sometimes. I don't have which shots are from K10, K20 or K7. The photos further back are from K10 and K20 but I do have a few newer one from those cameras also the I just recently processed.

ah, thats what I meant. your flickr page is full of sharper photos compared to the two you posted that you didn't like.

Marc Sabatella · 04-15-2010, 01:19 PM

Originally posted by OrenMc

Im thinking it is a SR issue. I have heard a few problems with the K7 and SR.
I can pull some crisp photos with the K10D at 300mm 1/30 sec.

Well, sure, it's never a matter of ironclads guarantees of success versus guarantees of failure - it's just a question of odds. Sure, *sometimes* SR will enable a sharp picture at 300mm and 1/30", but more often it won't. Your odds are *better* with 250mm at 1/200", but it's still no guarantee. So offhand, nothing about a few failures would seem to be indicative of any sort of problem at all. I think you need to do some controlled tests - same shot with same exposure settings, maybe 10-20 trials each with the K10D and K-7, and comparing results.

As it is though, the nature of the shots you are posting aren't very useful as tests. the subjects are moving, and assuming you are using AF, the scenes often have a confusing jumble of potential targets for the AF system. That introduces another random variable. A controlled tests means one in which the AF system has *nothing* else to focus on besides what you want.

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04-13-2010, 10:51 AM	#16
sterretje Veteran Member Join Date: Dec 2008 Location: Roodepoort, South Africa Photos: Gallery \| Albums Posts: 3,561	knoxploration already mentioned it; looking at your third picture (post #9), isn't there a front focus issue? Maybe time to post an non-processed example. Having said that, there are a few threads here about Sigma lenses on Pentax bodies. It might be that the Sigma needs to be rechipped (not sure what it exactly means; adapted to K7?). Maybe you should contact them and hear what they say. Don't forget to ask if it will influence functionality with other bodies. Somebody mentioned that he send his Sigma and Pentax body to Sigma and they came back perfectly calibrated.

04-13-2010, 11:42 AM	#17
MSsuper Junior Member Join Date: Oct 2009 Posts: 48	Yeah, I was just thinking that. It looks like the focus point is just in front of the subject. The water just in front of the duck looks crisp. I would swap the lens and see if it's a calibration issue with the Sigma lens only before recalibrating. Nothing else wrong here.

04-13-2010, 07:05 PM	#18
OrenMc Veteran Member Join Date: Apr 2008 Location: USA Photos: Gallery Posts: 1,901 Original Poster	I appreciate the info guys but why am I not having any issue with the K10d. I tried focus adjustment on the K7 and that didn't really help. I uderstand you can't say for sure without seeing unprocessed full file. But for the life of me I can't really get a good sharp picture with K7 and the K10 all I have to do is point and shoot and it sharp and crisp. I can easily shoot at a slow shutter speed aslo with k10 handheld but the k7 no way. If I don't have bright good light and fast shutter speed forget it. I know it not the lens.

04-13-2010, 09:09 PM	#19
knoxploration Veteran Member Join Date: May 2009 Location: Knoxville, Tennessee Posts: 846	Originally posted by OrenMc I uderstand you can't say for sure without seeing unprocessed full file. Why not post some, then...?

04-14-2010, 03:11 AM	#20
OrenMc Veteran Member Join Date: Apr 2008 Location: USA Photos: Gallery Posts: 1,901 Original Poster	You can see full res at my flickr

04-14-2010, 08:18 AM	#21
knoxploration Veteran Member Join Date: May 2009 Location: Knoxville, Tennessee Posts: 846	Originally posted by OrenMc You can see full res at my flickr Unfortunately EXIF data has been stripped from the photo, so we don't know the shot conditions, which could tell us a lot. It looks like the focus point is slightly nearer than the duck's head, though - the breast appears more in focus. It also seems from a quick glance like the entire image has slight motion blur - perhaps your shutter speed was too low, you took the shot before SR was ready (or with it disabled if you were shooting off-tripod / enabled and shooting on a tripod maybe). I'm guessing the shot was on a fairly long lens, as you probably weren't right up in the duck's face - SR is less effective at longer focal lengths, so if that's the case I'd again suspect the shutter speed. But no way to know without the EXIF data, I'm just making wild guesses.

04-14-2010, 09:38 AM	#22
cardinal43 Veteran Member Join Date: Oct 2007 Location: Virginia Photos: Gallery Posts: 2,412	Go to his flickr page and the duck picture looks to be the first 1 on the left. If you click on "more properties", the exif data will be listed.

04-14-2010, 12:26 PM	#23
knoxploration Veteran Member Join Date: May 2009 Location: Knoxville, Tennessee Posts: 846	Originally posted by cardinal43 Go to his flickr page and the duck picture looks to be the first 1 on the left. If you click on "more properties", the exif data will be listed. Well caught. I downloaded the full-sized image from Flickr, so I guess either Flickr strips the EXIF data from the image, or my web browser did. 250mm (375mm equivalent) at 1/200 second with SR enabled - I'm going to guess that camera shake was the culprit for the blur. Either the SR just wasn't enough to counteract the camera shake at a longer focal length, or perhaps there's an SR issue.

04-15-2010, 03:46 AM	#24
OrenMc Veteran Member Join Date: Apr 2008 Location: USA Photos: Gallery Posts: 1,901 Original Poster	Im thinking it is a SR issue. I have heard a few problems with the K7 and SR. I can pull some crisp photos with the K10D at 300mm 1/30 sec. Thanks again for all the help!

04-15-2010, 03:59 AM	#25
tokyoso Veteran Member Join Date: Jan 2010 Location: Tokyo Photos: Albums Posts: 723	Originally posted by OrenMc Not sure what that means. I have some okay photos there as I only post the keepers. I will post examples of poor shots sometimes. I don't have which shots are from K10, K20 or K7. The photos further back are from K10 and K20 but I do have a few newer one from those cameras also the I just recently processed. ah, thats what I meant. your flickr page is full of sharper photos compared to the two you posted that you didn't like.

04-15-2010, 01:19 PM	#26
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,685	Originally posted by OrenMc Im thinking it is a SR issue. I have heard a few problems with the K7 and SR. I can pull some crisp photos with the K10D at 300mm 1/30 sec. Well, sure, it's never a matter of ironclads guarantees of success versus guarantees of failure - it's just a question of odds. Sure, sometimes SR will enable a sharp picture at 300mm and 1/30", but more often it won't. Your odds are better with 250mm at 1/200", but it's still no guarantee. So offhand, nothing about a few failures would seem to be indicative of any sort of problem at all. I think you need to do some controlled tests - same shot with same exposure settings, maybe 10-20 trials each with the K10D and K-7, and comparing results. As it is though, the nature of the shots you are posting aren't very useful as tests. the subjects are moving, and assuming you are using AF, the scenes often have a confusing jumble of potential targets for the AF system. That introduces another random variable. A controlled tests means one in which the AF system has nothing else to focus on besides what you want.