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Adapted lens
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PostPosted: Fri Oct 02, 2020 6:31 am    Post subject: Reply with quote
iangreenhalgh1 wrote:
The Minolta donor lens has a set of five contacts that interface with the camera. Connected to those contacts by a flat ribbon cable is a microchip. Another ribbon cable leads from the microchip to a set of five sliding contacts mounted on the zoom ring that forms an encoder that tells the chip what focal length is selected. I simply cut the ribbon cable from the chip to the encoder when I removed the mount. So is it surprising that the chip is spitting out different values now it has no encoder connected to it? I'm surprised it even works without any encoder input.

Keep trolling, I find it both amusing and pathetic, especially coming from people who never post any photographic work and instead prefer to act like know-it-alls.


If nothing is connected to the contacts, no focal lenght can be registered by the camera... The chip alone can't communicate different focals missing the zoom mechanic. Yours it really looks a mirror climbing show to me, and yes, I totally agree, amusing and pathetic are the right words, the second one even better.

But I am ready to apologise when you will be so kind to show some pics of your modified lens, and a better explanation for the exif puzzle. About photographic works never posted, if you was thinking about me by any chance, you are absolutely right, I will do that shortly, since I have several lenses that probably worth to be introduced.

But please don't call me troll, because I tried till the end of this post to believe to you, until I felt fooled around


PostPosted: Fri Oct 02, 2020 1:26 pm    Post subject: Reply with quote
My Pentax K10 registered completely random focal lengths on the exif when I used manual lenses.


PostPosted: Fri Oct 02, 2020 4:19 pm    Post subject: Reply with quote
Lloydy wrote:
My Pentax K10 registered completely random focal lengths on the exif when I used manual lenses.


Good to know, then with the same lens you could have different FL recorded on the exif? Thanks for the info, my Canons leave a blank field when they cannot recognize the lens.


PostPosted: Fri Oct 02, 2020 4:53 pm    Post subject: Reply with quote
I think the exif takes the length of the lens from the setting for the shake reduction - or something like that.


PostPosted: Fri Oct 02, 2020 5:05 pm    Post subject: Reply with quote
Lloydy wrote:
I think the exif takes the length of the lens from the setting for the shake reduction - or something like that.


Sure, this makes sense, same when I used to shoot with Olympus


PostPosted: Fri Oct 02, 2020 10:12 pm    Post subject: Reply with quote
Lloydy wrote:
My Pentax K10 registered completely random focal lengths on the exif when I used manual lenses.


On Sony A cameras, if there is no communication between the lens and the camera's CPU (for example, when using a non-chipped adapter), the focal length recorded in the EXIF data is 0.0 mm:
.


Tthere is no random variation in the recorded focal length. Note, however, that this situation is totally different from that under discussion, in which, according to the OP, a manual focus lens was adapted to the electronic mount of a Minolta AF zoom lens, so the communication between camera and adapter remained active.


PostPosted: Sat Oct 03, 2020 2:25 am    Post subject: Reply with quote
iangreenhalgh1 wrote:
The Minolta donor lens has a set of five contacts that interface with the camera. Connected to those contacts by a flat ribbon cable is a microchip. Another ribbon cable leads from the microchip to a set of five sliding contacts mounted on the zoom ring that forms an encoder that tells the chip what focal length is selected. I simply cut the ribbon cable from the chip to the encoder when I removed the mount. So is it surprising that the chip is spitting out different values now it has no encoder connected to it? I'm surprised it even works without any encoder input.

Keep trolling, I find it both amusing and pathetic, especially coming from people who never post any photographic work and instead prefer to act like know-it-alls.


Ian, this is brilliant adaptation! Please show us some photos? I'm especially interested in the set of five sliding contacts. Also, could those be communicating on the focal length wires instead of wires for aperture? That would explain the different focal lengths in exifs.


PostPosted: Sun Oct 04, 2020 3:06 pm    Post subject: Reply with quote
Quote:
The Minolta donor lens has a set of five contacts that interface with the camera. Connected to those contacts by a flat ribbon cable is a microchip. Another ribbon cable leads from the microchip to a set of five sliding contacts mounted on the zoom ring that forms an encoder that tells the chip what focal length is selected.



This description is inaccurate, to say the least. There is no "flat ribbon cable" inside the Minolta AF 70-210mm F4 lens! What is there is a single FPC (Flexible Printed Circuit) that goes from the contacts on the lens mount to the focal length encoder, with the microcontroller in between, as this figure in the service manual clearly shows:



The focal length encoder consists of the four segmented golden tracks (fixed contacts) plus the corresponding sliding contacts mechanically connected to the zoom ring:


from:https://i.ytimg.com/vi/V9GDcfYIXu8/maxresdefault.jpg

This video shows the sliding contacts moving as the zoom ring is rotated:
https://www.youtube.com/watch?v=V9GDcfYIXu8&feature=youtu.be&t=114


The chip soldered on the FPC is a microcontroller, whose function is to send to the camera's CPU certain specific lens information: lens model, maximum and minimum aperture, focal length, etc. When the lens is a zoom, the microcontroller periodically transmits to the camera's CPU the focal length actually being used and the corresponding maximum and minimum apertures.

Some examples of the hex data transmitted by the Minolta AF 70-210mm F4 microcontroller:


The maximum and minimum apertures are encircled in green and the focal lengths in red. The hex codes are interpreted by the camera's CPU as following:
29 --> F4
58 --> F32

42 --> 75mm
49 --> 105mm
4F --> 135mm
53 --> 160mm
59 --> 210mm


(to be continued...)


PostPosted: Sun Oct 04, 2020 4:28 pm    Post subject: Reply with quote
Gerald, just fuck off, you're nothing but a troll, when have you ever posted any photos? All you do is troll people, try to intellectually bully people, you're sad and pathetic. Can you even take a photo worth posting online? Do you know the first thing about photography? Why are you even on this forum which is a PHOTOGRAPHY forum when you've never even shown us any proof you are a photographer or can take a picture.

You're utterly pathetic with your constant attempts to correct people. You might call it a 'flat printed circuit' I called it a 'flat ribbon cable'; so what, it's irrelevant, you're just searching for any straw to clutch at, very sad and utterly obnoxious, arrogant behaviour. I correctly described the structure of the lens electronics, but no, you still have to try to be intellectually superior, which just makes you look pathetic and pedantic to the point of absurdity.


PostPosted: Sun Oct 04, 2020 5:07 pm    Post subject: Reply with quote
Come on Ian, please please show some photos of the adapter. Smile

I must agree with those who've worked in Electronics such as Gerald and myself who know the correct term here is FPC -- ribbon cables are flat ribbon cables made using wires, are not printed circuit traces on plastic.

I greatly appreciate Gerald's informative detailed expansion of the topic, offering more information I don't agree is trolling.


PostPosted: Sun Oct 04, 2020 5:57 pm    Post subject: Reply with quote
It's not about the language I used to describe a damn set of flat electric connections, ribbon, printed circuit WHO GIVES A DAMN, words are words, it's about trolling obnoxious assholes trying to paint me as a liar.

Why don't you demand Gerald posts some photos to prove he even knows how to use a camera and actually has a valid reason for being on this forum?

Why did he even check the EXIF in the first place? Why did he chose to troll me? Maybe he's jealous that he can't take a decent photo so has to take his dismay out on others?

This has ceased to be about my lens, it is now about the actions and behaviours of a troll.


PostPosted: Sun Oct 04, 2020 6:40 pm    Post subject: -- Reply with quote
iangreenhalgh1 wrote:
Why don't you demand Gerald posts some photos to prove he even knows how to use a camera and actually has a valid reason for being on this forum?


You may not remember, but on several occasions I posted pictures of my own. See, for example, this thread I created to show how I used a fisheye lens for landscape photos:

http://forum.mflenses.com/landscape-photography-with-a-fisheye-t74240.html

You even contributed three posts to this thread!


PostPosted: Sun Oct 04, 2020 8:49 pm    Post subject: Reply with quote
Changed the title and locked it, after it got way to personal!!

Should serve as an example how not to discuss here...
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