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Forum: Pentax SLR Lens Discussion
05-19-2023, 12:26 AM
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Hi,
Now some time passed and I can say it worked.
If you examine it very closely with a microscope you will see some very small airbubble (0.1mm?) in the glue
between both lens. But I think it is okay and better than scap it without trying it. The picture with this lens are okay.
In case someone needs it, here are the two stl files for printing the plastic part I used for prober centering the lens:
http://www.criseis.ruhr.de/Pentax_K1/macroprint.zip
Olaf
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Forum: Pentax SLR Lens Discussion
08-01-2020, 10:47 AM
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Today I was out for some pictures with me good old Pentax-M 1:4 100mm Macro.
Before I took a picture I found that the lens had very low contrast. I looks like fog.
All picture I took with this lens are garbagge!
At home I examine the lens carefully, oben it, clean the front lens, because I thought there was fungus
on the lens. But this was not the reason! The front lens depends on two lens glued together.
And the canada balsam between the lesen become bad!
Attachment 504423
It is not so easy to take a picture from this to show you.
Attachment 504424
On the lens it is only visible with light in very special direction! It is easy for me to took a picture where you can not see it.
The last time I used this lens 6month ago it was okay. So it happen quickly when it happen. I don't think the lens becomes to hot. It did not stay in my car for example.
I check all my other lens and found another one. The old 200mm/4. With this lens it happens at the back side and it is
smaller, only at the border of the lens.
I search at ebay for the 100mm and found one with the same problem. So check the lens carefully!
I think I will now seperate the two lens, clean it and glue it again. Not an easy task of course!
Olaf
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Forum: Pentax SLR Lens Discussion
02-01-2021, 07:20 AM
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After 2-3month I found that my repaired lens showed a problem. There happens some bubbles between
the two glued lens. :fedup:
So I open it again. This time the lens stayed over night in acetone, but that did not work. Than I put
it for a hour in a thermos-bottle with cooking water. That works and I had two lens again.
I invented a part to put the two lenses in the correct position and printed it:
Attachment 524060
I ordered a special UV Glue from internet that I used now:
Attachment 524061
I cured it with an UV led for a few hours and waited another day before I install it back in the lens.
Now the lens looks like new. I hope this time it will work. :hmm:
Olaf
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Forum: Pentax SLR Lens Discussion
02-01-2020, 09:01 AM
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Hi everybody,
I was curious about the comunication protocol. At first I checked the internet but I did not found so much. And most things I found are wrong. So I switch on my oszi and did some research.
Attachment 485869
On this picture you can find a complete exchange of data. The K1 did this three times in a second.
On most pages about Pentax mount they talk about a special digital pin for communication. I think this is wrong. The new pin for KAF is power supply for the lens.
The camera uses the SPI protocol, but without /CS. I think CS is not necessary because there is only one ASIC(old lens) or one microcontroller (new lens) inside the lens.
After the ASIC is switched on the camera start communication to the lens. For this it uses the old KA contact. I think there are resistor in the ASIC or lens-PCB so a KAF lens
on older KA mount shows correct values for aperture. On KAF or newer the lens transmit and perhaps accept data on this lines.
On the picture you can see it is possible to detect the 19 databyte from the lens. There is no EEPROM in the lens. I think it is a least an ASIC because they values are changing when you focus the lens or change the focal length. Of course I started with an old Pentax F35-135 1:3.5-4.5 becaue it is KAF.
On the new KAF4 the must be also a way to send data to the lens. I thing this is done with the MISO line. But this is untested.
There is only on surprise now. The camera deliver 4V to the lens. I think it is an unusual voltage. You would expect only 5V or 3.3V for this. The reason is perhaps that it is 5V but curent limited inside the body in case someone exchange the lens when the body delivers power.
The next point is to decipher the meaning of the 19 databyte. Until now this is an exercise for the reader. :lol:
The picture shows two analog channel and four digital channel from my oszi.
Olaf
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Forum: Pentax SLR Lens Discussion
02-02-2020, 01:46 PM
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I can read the lens data with a microcontroller now.
Attachment 486017
I also found some issues!
Contact 7: (The new KAF pin) This is only power for the lens. It is okay to provide 3.3V
Contact 6: This is /CS and not a data input to the lens! (look at my first picture and you can see it, it shows an activ low chipselect)
The clockrate is 32khz and I use SPI-Mode3.
Olaf
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Forum: Pentax SLR Lens Discussion
08-17-2020, 10:19 AM
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It is working! I clean the lens very carefull and install it.
The first testpicture, a part of my headphone amplifier:
Attachment 505871
Of course it will need some more test, but it did looks hopefull. :D
Olaf
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Forum: Pentax SLR Lens Discussion
08-17-2020, 08:05 AM
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I glued it together! I use Cytoseal XYL for this. Unfortunatly this is expensive. You need to know a doctor or biologist to lend his bottle for one drop. :cool:
Attachment 505863
I made a small paper strip put it around the lens to align it correct. A small amount of the glue touch the front and back part of the lens. :fedup:
But I think it is no problem to clean it.
Attachment 505864
After a few minutes I cut my paper strip and it open themself little bit. So it is easier to remove the paper later.
Now I will to wait until tomorow before I try to clean the lens. The lens looks realy good, no air bubble. I am full of hope! :asleep:
Olaf
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Forum: Pentax SLR Lens Discussion
08-16-2020, 07:59 AM
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It was possible to oben the front group without destroying it!
Attachment 505757
It heat the lens in my oven 10min for 100degree (Celsius!), 10min for 150, 10min for 200, 10min for 220, than it stayed there for 1h to cool down.
After this I put the lens in acetone and wait 1h. Now it was easy to open the lens.
Attachment 505758
Now it will stay there for some time to remove the old glue.
Of course the most interesting part is gluing it again. I will wrote about it in the next days...
Olaf
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Forum: Canon, Nikon, Sony, and Other Camera Brands
01-22-2020, 10:43 AM
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A bought a Panasonic GX-80/85 for the same reason.
It is small, it is cheap, it has image stabilisation better than on the K1.
Of course the sensor is small, I would not recomend to replace a K1 by M43, but it is a good camera for day you did not like to carry the heavy gear.
Olaf
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Forum: Pentax SLR Lens Discussion
11-03-2019, 01:54 AM
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Perhaps you have seen that I ask the question between 31 and 35 myself three weeks ago at this place. My choice was the 31mm and I am very lucky with it. I agree with the sentence above by 100% and there is something more. I have a huge 4k TV that I use for viewing my picture. I had to crop/cut my picture to 16/9 and in this case a few extra-mm are worse the money. When I view the picture on my 27" 16/10 computer monitor they are looking good, but at the huge TV (58") they are unbelievable. The 31mm on a huge TV brings you back to the place where you took the picture. It looks definitive different/better than 35mm.
The next point, the size and the build quality with the integrated lens hood make this lens a good choice for the K1 one for just walk around.
The only think I dislike on this lens (and the 35 limited macro) is the lens cap.
Olaf
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Forum: Pentax SLR Lens Discussion
10-28-2019, 10:16 AM
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Okay, now I am back to Germany, my brain is mostly adapted to German time and I checked my picture. .-)
I did 800picture and perhaps around 270 are good. I made more than 80% with the new 31mm I bought
at the beginning of the trip. The mechanical quality is as good as expected, the optical quality is better than I expected.
Sometimes I was to lazy to carry more than the 31mm with me and I had to crop only a small part of the picture and even than the pictures are good.
The small 31mm fit very well on the K1 and made it a light travel camera for everyday use. :-D
On a few picture I also found the pixie-dust experience. It is different than the DFA*50 but on the same level.
Olaf
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Forum: Pentax SLR Lens Discussion
10-13-2019, 08:12 AM
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This is a first picture with the 31mm, a nice lens!
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Forum: Flashes, Lighting, and Studio
10-01-2019, 10:51 PM
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I have no experience with the AF540, but you describe a well known problem with all kind of encoder in many electronic devices.
An encoder consists of two switches. This switches have now a loose connetion becaus of dirt.
You have to open the 540 and clean the inside of the encoder. There my be some kind of cleaning solvent, but I only know German product. After cleaning it is possible that you have to apply a special grease on the contact so the switch runs smooth and to protect the switch from oxigen. After this you can expect the encoder will work for ten years again.
Sometimes lazy people only use contact spray from outside. They are to lazy to do the job right. In this case the encoder will only work for a few month and fail again. And there is acid in the cleaning solvent. That acid will destroy everything after some time if you not clean it carefully.
Savety warning: Inside the 540 is a huge Capacitor that may contain more than 300V DC Voltage. That can kill if you touch it.
Before open the 540 trigger a flash with maximum power and open the battery compartment imeaditly. And when you open the 540 and find the capacitor short his contact with a screwdriver.
I hope it was understandable...
Olaf
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Forum: Pentax SLR Lens Discussion
07-03-2019, 09:51 AM
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Nah...I will visit mapcamera in Tokyo soon and will check if they have both of them in good-used-condition and compare them.
But I fear I will go with the 31, because it has the better look&feel, sigh.
Olaf
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Forum: Pentax SLR Lens Discussion
02-09-2019, 07:51 AM
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Forum: Digital Processing, Software, and Printing
10-28-2018, 06:42 AM
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I detect an interesting bug in Centos7 in combination with jpg from Pentax
I think the users user of the best camera brand in the world will use the best operating system in the world, so I like to share you my results. :)
A few weeks ago I decided to update my darktable at Centos7.3 at my desktop computer. When doing this the system (yum) did also update many libarys. One of the library is exiv2. This is a very often used library (perhaps in other operating system, too)
After this I found my gwenview crashed every time when I try to open a directory with pentax images in it. Yesterday I installed the newest Centos on my laptop and the same behavior!
In internet I found I am not the only one who run in this problem:
Bug #1305: Segmentation fault on certain image - Exiv2
Attachment 9755 Details for Bug 21158 ? Patch fixes exiv2 segfault on images from pentax cameras
This bug happens to everyone with the newest libexiv2.so.26.0.0
To solve the bug it is necessary to download the sourcecode of version 26 at this page:
Exiv2 - Image metadata library and tools
And install the patch in pentaxmn.cpp std::ostream& PentaxMakerNote::printShutterCount()
from the link above.
After compiling the library it is necessary to replace the old libexiv2.so.26.0.0 to the new version.
Now I can view the pentax pictures again. :-)
Olaf
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Forum: Pentax K-1 & K-1 II
10-13-2018, 11:19 PM
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I agree with that! A few days ago I tested a cheap (13Euro!) sqare ND filter on the FA*28-70. It was easy to find out with my eyes in the viewfinder that the picture becomes bader when I move/shift the filter in front of the lens.
The problem is, people think a filter on lens is no problem or it is a huge problem. But in real live it is sometimes a problem on some lens in some focus distance and it depends of the light, too. So the answer for me is: I never put any kind of filter in front of my lens when it is possible to do a picture without, but sometimes it is not possible...
Olaf
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Forum: Pentax K-1 & K-1 II
10-06-2018, 11:13 AM
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This picture was only a short test after I replaced my focusing screen with a Canon Ec. It it done with the old PK85/1.8
Olaf
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Forum: Pentax K-1 & K-1 II
10-03-2018, 11:57 AM
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I did this 2-3years ago with my K5IIs. (Sorry K1 not available at this time)
I used a DA35mm macro and printed an adapter for slides with my 3D-printer. On the camera I use the 360FGZ
and took the pictures in front of a white paper with PTTL.
Olaf
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Forum: Pentax K-1 & K-1 II
08-29-2018, 07:40 AM
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Forum: Pentax K-1 & K-1 II
03-26-2017, 06:10 AM
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I like to say that the SMC 1:2.5 135 is one of my favorite lens! Especially for using at concert. It is very sharp, very good color, small, high quality feeling. The same class like the 85/1.8 oder 200/2.8. Oh..and it is cheap. For this reason I did't know why I should think about a new 135. :p
Olaf
p.s: The old 135/3,5 is not so good!
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Forum: Pentax K-1 & K-1 II
09-03-2017, 05:53 AM
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Forum: Pentax K-1 & K-1 II
01-21-2017, 04:02 PM
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Both picture are done at a concert with K1 and FA* 28-70. Both are 1/25s. The first picture is 3200 F4.5, the second ISO1600 with F2.8.
Good to test the low light quality of the K1. :-)
Olaf
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