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M42->MAF Adapter With Focus Confirmation

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Sky_walker View Drop Down
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Post Options Post Options   Quote Sky_walker Quote  Post ReplyReply Direct Link To This Post Posted: 15 October 2012 at 13:24
Hm... yea, I guess I need one for 35mm f/2 (and possibly another for 2/55).

Anyone got any experience with chips available in UK that include focal length and aperture?
Sony A77, A200, Minolta α7, Flashes, Several lenses covering 8-300mm in total. Primes shooter (though not avoiding zooms).
 



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gouldina View Drop Down
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Post Options Post Options   Quote gouldina Quote  Post ReplyReply Direct Link To This Post Posted: 15 October 2012 at 14:00
Originally posted by Sky_walker Sky_walker wrote:

Hm... yea, I guess I need one for 35mm f/2 (and possibly another for 2/55).

Anyone got any experience with chips available in UK that include focal length and aperture?


Do they do them for specific apertures? If so, why?
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Sky_walker View Drop Down
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Post Options Post Options   Quote Sky_walker Quote  Post ReplyReply Direct Link To This Post Posted: 15 October 2012 at 15:50
They make them for focal length/aperture combinations - main reason being sorting data in Lightroom (which can use EXIF data) - thanks to this you should find it easier to differ this lens from the others.


Edited by Sky_walker - 16 October 2012 at 08:43
Sony A77, A200, Minolta α7, Flashes, Several lenses covering 8-300mm in total. Primes shooter (though not avoiding zooms).
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Bob J View Drop Down
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Post Options Post Options   Quote Bob J Quote  Post ReplyReply Direct Link To This Post Posted: 15 October 2012 at 16:01
Whatever you have as the aperture reported will appear in EXIF. If you have both minimum and maximum aperture set to the same value you can proof against knocking the aperture setting on the camera off maximum: other than that it doesn't make much difference, you can still set any aperture on the lens.

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Sky_walker View Drop Down
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Post Options Post Options   Quote Sky_walker Quote  Post ReplyReply Direct Link To This Post Posted: 16 October 2012 at 08:45
Yep, well put.
I think that having chip set for aperture below f/2.8 makes camera try to use double-cross AF points - otherwise they are inactive (might be helpful for focus confirmation).

Anyway - any ideas on my question from the first post on this page?
Sony A77, A200, Minolta α7, Flashes, Several lenses covering 8-300mm in total. Primes shooter (though not avoiding zooms).
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Post Options Post Options   Quote ifreedman Quote  Post ReplyReply Direct Link To This Post Posted: 07 February 2013 at 04:55
Originally posted by ifreedman ifreedman wrote:

Yeah!!! I FINALLY managed to reprogram my chip from BIG_IS (aka weakpotoman) to a new focal length using my A33. I'm not sure if this technique will work with other camera models as well.

The chip had started as 50mm 1.4 but strangely changed focal length to about 100mm for some unknown reason. After reading this forum I was completely stuck. I then emailed big_is, who sent me directions that were identical to the instructions Peekayoh posted several months ago (prob. because he wrote it for Big_Is). Unfortunately, following these directions didn't work. But the one thing I noticed was that, when I messed around with slight variations of these instructions, every so often the focal length did change. But I couldn't figure out why or how to control it. Here's what I finally discovered.

To change the focal length of a big_is chipped adapter on an a33 (note some language is taken from Big_Is's directions)

1. Set both the Program Mode (top dial) and the Focus Mode (front switch) to “Manual”.
2. Choose a shutter speed of 1/100.
3. Go into the Menu and activate “Auto Review” if not already in use.
4. Change to a display mode where you can see the focal length.
5. Turn the camera OFF and install the adapter.
6. Take out the storage card if you don't want to delete unwanted images later.
_____________________________
7. Turn on your camera (you now supposedly have a 10 second window to enter programming mode).
8. Push the DOF button.
9. Push the Lens Release Button, but don't remove the lens.
10. Push the shutter button and take a picture. This should have advanced the focal length of your chip by 1 "step." (Example, from 50mm to 60mm)
11. Turn off the camera.
12. Repeat steps 7 through 11 until you reach the focal length that you want.

13. When you're done, turn off the camera and remove the battery to save the setting.

I should note that the focal length options for my chip weren't the same as Peekayoh posted. My chip went by different increments from 50mm to 1000mm (for example, it passed through 400mm), and then reset to 50mm. It did not go through any of the smaller focal lengths! I'm not sure why.

That's how it finally worked for me. Now that I finally reached 50mm, I'm not going to keep playing with it to make sure my method is correct because it took way too long to get this far. If you find a correction, please post it or let me know.

Ian



I noticed that the focal length of my adapter has "drifted" again (to 24mm now from 50mm). But now I have an A57, and this method does not work on my camera. Nor do Peekayoh's methods, nor the video methods. Etc. Very frustrating. I might need to buy a new adapter and reappropriate this adapter to my 28mm Tak. At least it would be fairly close then.

Any new suggestions would be most welcome, too. Thanks.
A77ii, A6000 + various alpha, homemade and adapted lenses
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Post Options Post Options   Quote Peekayoh Quote  Post ReplyReply Direct Link To This Post Posted: 07 February 2013 at 09:51
Ian, if I were you, I'd return the adapter and ask for a replacement. You must have a faulty chip on yours.
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ifreedman View Drop Down
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Post Options Post Options   Quote ifreedman Quote  Post ReplyReply Direct Link To This Post Posted: 07 February 2013 at 15:01
I've had the chip for 2 years, and overall I'm happy with it. And it's given me some wonderful pics, especially since my 50mm tak is probably my most used lens with when shooting kid pics in these dark winter months. If I need a replacement, I'll just order another one. Thanks for the suggestions, though.
A77ii, A6000 + various alpha, homemade and adapted lenses
Articles: Tilt-Shift Lenses
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Post Options Post Options   Quote Macca Quote  Post ReplyReply Direct Link To This Post Posted: 07 February 2013 at 16:54
Ian,Peekayoh is right about it being faulty. I have two Bigis adapters and never had a focal length change yet through extensive use. I even tried to change it on my A35 using your and Peekayoh methods to see if I could use on a longer tele length but couldn`t.
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Post Options Post Options   Quote laptoprob Quote  Post ReplyReply Direct Link To This Post Posted: 03 March 2013 at 15:19
What happens if you use a 50mm chip on a 135mm lens? Wrong EXIF obviously, but also 'wrong' image stabilisation? Focus confirmation doesn't change I guess?
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Post Options Post Options   Quote ifreedman Quote  Post ReplyReply Direct Link To This Post Posted: 03 March 2013 at 15:30
That sounds about right. I'm not sure how much wrong IS would affect things. It might make it a bit worse, or it might not do as good of a job. In theory a 135mm lens would need more IS than a 50mm lens, so it would undercorrect I think. But turn of IS and you'd be fine.
A77ii, A6000 + various alpha, homemade and adapted lenses
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Post Options Post Options   Quote primetime Quote  Post ReplyReply Direct Link To This Post Posted: 20 June 2013 at 23:31
I just got one of these and it's great.

Edited by primetime - 23 June 2013 at 11:10
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Post Options Post Options   Quote Trogdon Quote  Post ReplyReply Direct Link To This Post Posted: 13 August 2013 at 20:15
Is there any way to get a chipped adapter that's set to just 135mm f2.8? I want to use a lens of that length on my a77, and I know that if I got one for 50mm it wouldn't IS right.
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Post Options Post Options   Quote Peekayoh Quote  Post ReplyReply Direct Link To This Post Posted: 14 August 2013 at 12:25
Sure you can.
James Lao will do that for you as will Big_is (eBay seller).
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