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11-13-2013, 06:01 AM   #31
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QuoteOriginally posted by RKKS08 Quote
I wouldn't know, as you can't see what's happening once the lens is mounted.

But I would try to repeatedly use the DOF feature, and in between un-mount and re-mount the lens.
A difference of up to 10 steps should be visible in the viewfinder, too.

Also this error would not show with another lens (the kit lens).

I am frequently browsing this forum for reported issues on the technical side. During the last years, there have been tons of descriptions very similar to yours. I have not made a statistic, but I feel the number of cases when the problems were caused by the lens (or body/lens coupling) exceeded the in-camera causes by far.
I never use the viewfinder (except very shortly for setting up at 1.2 and macro when I set the focus for the first time on a tripod), it heats up the sensor and is really really disturbing. I find the whole LCD really disturbing except when I do video (even then I wish i didn't have to use it since it's completely useless without focus peaking). By the way, when I do video and change the aperture it has no effect even with a manual lens, the exposure stays the same. Either it automatically adjusts the ISO to match instantly... or the camera forced the lens wide open the whole time and the aperture ring has no effect during the video because the lever is held in the open position? No idea... But I think it affects the DOF. I really have to test now! Okay, I just ran out of battery and i don't have another one here, I have to recharge this. I just had enough time to see that: the aperture stays wide open despite turning the aperture ring when it's not recording. When you start recording and turn the aperture ring it closes and opens normally. I didn't have time to see the difference on video but from what I remember, the camera adapts to the new aperture by automatically changing the ISO, at least up to a point. It can't do impossible things like really low light video at f/16 but the first few stops it seems to adapt to? I really need to get the k-3 for manual control, it's hard to troubleshoot when the camera is built so that you don't even know half the things happening in it (like the ISO and other settings in video)

11-13-2013, 06:04 AM   #32
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QuoteOriginally posted by tripodquest Quote
I really need to get the k-3 for manual control, it's hard to troubleshoot when the camera is built so that you don't even know half the things happening in it (like the ISO and other settings in video)
The K-3 is absolutely no different from the K-5 or any Pentax (or other) DSLR in this respect.

This is seeming more and more like user error than anything else.
11-13-2013, 06:15 AM   #33
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QuoteOriginally posted by elliott Quote
I just want to see the images, I want to see the inconsistencies and have some information to back it up. It is starting to sound like you aren't having exposure inconsistencies with the camera, though it is hard to pick out relevant information in your posts without some images to back up your words.


If you did the test with the DOF preview lever, like I mentioned earlier, it should rule this out. I just asked for a yes or no to "does the viewfinder get darker and brighter as it should". You seemed happy with the results from this test, though I have no idea what the relevance of the meter was, so I just left it alone.

Also, if the camera is able to open the aperture, then you have a native K mount lens. The other lever you see recessed into the mount is for communicating aperture ring position to film cameras for the meter, it is not used on a DSLR. Pictures of this lens would help too, of course.
I have pictures of the lens on a different computer. I could take new ones but I just ran out of battery. I don't have a new battery handy. The meter is supposed to show if the camera thinks the settings will make the picture come out correctly exposed. If changing the aperture manually changes the meter readings then obviously by some miracle the camera is aware of the aperture I'm setting on the ring though the aperture reading in the camera still reads F--. I was happy with it because it means the camera has a clue in the right direction for some reason, if it shows correct exposure when indeed the settings are correct settings for correct exposure at that aperture in that lighting. Incidentally I did a different test than the one you asked for because I missed the part about seeing if the viewfinder gets darker or brighter and I only looked at the readings. I don't think it did though. I don't know why but if I remember correctly, it never gets darker or even changes it's DOF, the viewfinder pretty much always looks the same (someone in this forum actually mentioned that the viewfinder doesn't even change DOF, it's always f/4, i tried it and found it to be true, as strange as it sounds). I can't test it now with the camera on, but with the camera off the aperture is wide open regardless of the aperture ring, it opens up as soon as you mount it and stays open til you press the shutter. I don't know if this is normal on k-5 or not?

Last edited by tripodquest; 11-13-2013 at 06:36 AM. Reason: edited out my own attitude. i'm sorry, i haven't gotten enough sleep! (not a great excuse, but it's true)
11-13-2013, 06:17 AM   #34
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QuoteOriginally posted by elliott Quote
The K-3 is absolutely no different from the K-5 or any Pentax (or other) DSLR in this respect.

This is seeming more and more like user error than anything else.
I'm not sure there is room for user error. If I set the aperture, ISO and shutter speed manually, take a picture, change nothing and take another picture, the exposure must match. If it doesn't, it's an error with the lens or the camera, I don't see any other explanation. If you disagree, please explain where the user error might lie? please don't randomly accuse me of things but try to help me find a solution. in case you didn't know, the k-3 has full manual control (ISO, aperture, shutter speed, + all the controls k-5 has) unlike the k-5 and unlike the k-5ii, so it's not at all the same thing.


Last edited by tripodquest; 11-13-2013 at 06:38 AM. Reason: edited the tone.
11-13-2013, 06:18 AM   #35
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That 'Petri' lens must be wonky. Sounds like someone in the past hacked it up somehow. Throw it away.

Also be more concise in your descriptions, and include pictures. Even if they are mobile phone pictures of the lens and your setup, it will help people understand what you are talking about.
11-13-2013, 06:20 AM   #36
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QuoteQuote:
I can't test it now with the camera on, but with the camera off the aperture is wide open regardless of the aperture ring, it opens up as soon as you mount it and stays open til you press the shutter. I don't know if this is normal on k-5 or not?
That's normal for every Pentax body since the introduction of the K-Mount.
QuoteOriginally posted by tripodquest Quote
I never use the viewfinder (except very shortly for setting up at 1.2 and macro when I set the focus for the first time on a tripod), it heats up the sensor and is really really disturbing
Sorry, but when say 'viewfinder', it's always related to the optical one!

I now must shut off electricity (and my desktop) to repair an issue in my rooms. I may follow the thread on a tablet, but writing elaborated postings on these devices is kind of cumbersome. I may have another look in early evening (we are in the same time zone?).
11-13-2013, 06:25 AM   #37
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QuoteOriginally posted by rawr Quote
That 'Petri' lens must be wonky. Sounds like someone in the past hacked it up somehow. Throw it away.

Also be more concise in your descriptions, and include pictures. Even if they are mobile phone pictures of the lens and your setup, it will help people understand what you are talking about.


...wow do I feel stupid now. all this time i have been referring to it as Petri! it's not Petri! it's porst color reflex 55mm f/1.2 I'm so sorry, I have some Petri lenses and they both start with a P... *shakes head* anyway! the good news: there are pictures of it online!!

front side: https://secure.flickr.com/photos/astroman-photo/5603346543/
backside: https://secure.flickr.com/photos/kansalainen/4160210059/
11-13-2013, 06:29 AM   #38
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QuoteOriginally posted by tripodquest Quote
...wow do I feel stupid now. all this time i have been referring to it as Petri! it's not Petri! it's porst color reflex 55mm f/1.2 I'm so sorry, I have some Petri lenses and they both start with a P... *shakes head* anyway! the good news: there are pictures of it online!!

front side: https://secure.flickr.com/photos/astroman-photo/5603346543/
backside: https://secure.flickr.com/photos/kansalainen/4160210059/
That is what I was thinking it was, interesting lens, I've wanted one for a while. I was just assuming it was a rebrand with the Petri name, it was sold under many names.

Now, I see something though, the paint on the mount (Pictures of things help!). This can cause issues with newer DSLRs because it does not short the contacts of the mount. It assumes an M42 lens or no lens when these contacts are not shorted (EXIF data helps!), so it doesn't release the aperture tab because it doesn't know the lens has one.

Sand the paint off the mount in the area where it meets the contacts of the camera and you'll likely have much better luck.

11-13-2013, 06:31 AM   #39
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QuoteOriginally posted by RKKS08 Quote
That's normal for every Pentax body since the introduction of the K-Mount.
Sorry, but when say 'viewfinder', it's always related to the optical one!

I now must shut off electricity (and my desktop) to repair an issue in my rooms. I may follow the thread on a tablet, but writing elaborated postings on these devices is kind of cumbersome. I may have another look in early evening (we are in the same time zone?).
i haven't gotten enough sleep recently so I'm feeling a little confused, please excuse any misunderstandings and errors from my part! I blame it on not enough sleep... I really appreciate all the help and I'm sorry if I wasted anyone's time with my mistakes (like calling a porst a petri...) but I tried to answer all questions, running out of battery in the middle of it didn't help! as i ran out of battery it will take another 4 hours til it's recharged so you have no hurry and i'm not in a hurry anyway, i have plenty of other lenses! the problem is this has happened with several lenses, I think even with the kit lens (but i'm not sure) so it's really an issue i want to figure out... i believe sometimes it might happen because of a faulty lens, but all my lenses are not faulty, especially since some of them have been professionally cleaned and checked by the seller who is in the camera business and the lenses I've bought from him come looking like brand new even if they're 40 years old, so I really doubt any lenses from him have any faults (and if they did, they would be included in his quality/condition assessment sheet that he includes with the lenses.)
11-13-2013, 06:35 AM   #40
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QuoteOriginally posted by elliott Quote
That is what I was thinking it was, interesting lens, I've wanted one for a while. I was just assuming it was a rebrand with the Petri name, it was sold under many names.

Now, I see something though, the paint on the mount (Pictures of things help!). This can cause issues with newer DSLRs because it does not short the contacts of the mount. It assumes an M42 lens or no lens when these contacts are not shorted (EXIF data helps!), so it doesn't release the aperture tab because it doesn't know the lens has one.

Sand the paint off the mount in the area where it meets the contacts of the camera and you'll likely have much better luck.
I'm sorry, I understand pictures help, I could have told you the mount was painted black but you didn't think to ask and i didn't think to say it. I will sand off the paint, thank you for the suggestion. for what it's worth, it's a really great lens! it's perfect for stepping down to whatever arbitrary (f/1.543265346346) apertures, and the f/1.2 is suprisingly sharp when you focus it correctly. It's a perfectly USABLE f/1.2 in my opinion More than usable, I'm glad I got this lens, I'm not disappointed. I actually didn't even think to blame the lens for this problem, that's how much I like it.
11-13-2013, 06:48 AM   #41
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QuoteOriginally posted by elliott Quote
It assumes an M42 lens or no lens when these contacts are not shorted (EXIF data helps!), so it doesn't release the aperture tab because it doesn't know the lens has one.
about this, I will try to understand the value of EXIF data better from now on, though i still think any problem you have with a manual lens... should be solved manually! I don't know if the EXIF data would have helped, the last i looked at the exif data of a lens with a painted mount like this one, it said something like ?k or m mount lens I think.
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